UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 10-K

For the fiscal year ended December 31, 2022

OR

For the transition period from ___________ to ___________

Commission file number 001-38811

TCR2 Therapeutics Inc.

(Exact name of registrant as specified in its charter)

100 Binney Street, Suite 710

Cambridge, Massachusetts 02142

(Address of principal executive offices)

(617) 949-5200

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐ No ☒

Indicate by check if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐ No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ☐ No ☒

Aggregate market value of the voting and non-voting common stock held by non-affiliates of the registrant as of June 30, 2022: $89,641,770

As of March 5, 2023, there were 39,244,199 shares of the registrant’s Common Stock, $0.0001 par value per share, outstanding.

TCR2 Therapeutics Inc.

Table of Contents

Summary of the Material Risks Associated with Our Business

Our business is subject to numerous material and other risks and uncertainties that you should be aware of in evaluating our business. These risks are described more fully in “Item 1A—Risk Factors,” and include, but are not limited to, the following:

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K of TCR2 Therapeutics Inc. (the “Company,” “we,” “us” and “our”) contains or incorporates statements that constitute forward-looking statements within the meaning of the federal securities laws. Any statements that do not relate to historical or current facts or matters are forward looking statements. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “could,” “should,” “expects,” “intends,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “projects,” “potential,” “continue” or the negative of these terms or other comparable terminology. Forward-looking statements appear in a number of places in this Annual Report on Form 10-K and include, but are not limited to, statements about:

Although we believe that the expectations reflected in these forward-looking statements are reasonable, these statements relate to our strategy, future operations, future financial position, future revenue, projected costs, prospects, plans, objectives of management and expected market growth and involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by these forward-looking statements. You are urged to carefully review the disclosures we make concerning these risks and other factors that may affect our business and operating results under “Item 1A. Risk Factors” in this Annual Report on Form 10-K. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this document. The Company does not intend and undertakes no

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obligation, to update any forward-looking information to reflect events or circumstances after the date of this document or to reflect the occurrence of unanticipated events, unless required by law to do so.

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Part I

Except where the context otherwise requires or where otherwise indicated, the terms “TCR2,” “TCRR,” “we,” “us,” “our,” “our company,” “the company,” and “our business” refer to TCR2 Therapeutics Inc. and its consolidated subsidiaries.

Item 1. Business

Overview

We are a clinical-stage cell therapy company developing a pipeline of novel T cell therapies for cancer patients suffering from solid tumors by powering the T cell receptor (TCR) with our proprietary, first-in-class TCR Fusion Construct T cells (TRuC-T cells). Designed to overcome the limitations of current cell therapy modalities, our TRuC-T cells, an HLA-independent T cell therapy platform, recognize and kill cancer cells by harnessing the entire TCR signaling complex, which we believe is essential for T cell therapies to be effective in patients with solid tumors.

Our lead TRuC-T cell targeting mesothelin-expressing solid tumors is gavocabtagene autoleucel (gavo-cel, formerly TC-210). We have completed the Phase 1 portion of our Phase 1/2 clinical trial for gavo-cel to treat patients with ovarian cancer, non-small cell lung cancer (NSCLC), malignant pleural/peritoneal mesothelioma (MPM) or cholangiocarcinoma. We estimate the patient population for gavo-cel in the four indications which we are exploring in our clinical trial is up to 81,000 patients in the United States alone.

We designed the Phase 2 portion of our Phase 1/2 clinical trial to assess gavo-cel in patients with ovarian cancer, NSCLC, malignant pleural/peritoneal mesothelioma or cholangiocarcinoma. In January 2023, we announced that we had narrowed the focus of our development of gavo-cel to ovarian cancer in combination with Opdivo® (nivolumab) and redosing strategies which we believe may increase the duration of benefit in patients. We expect preliminary durability data from the ovarian cancer cohort in the second half of 2023.

Our next most advanced program is TC-510, our first enhanced TRuC-T cell targeting mesothelin-expressing solid tumors which incorporates a PD-1:CD28 chimeric switch receptor. In our preclinical studies of TC-510, we have observed functional improvements over gavo-cel including enhanced signaling, increased proliferation, reduced exhaustion and improved in vivo efficacy against tumors with high PD-L1 expression. Based on these preclinical studies, we believe we can improve on the efficacy of gavo-cel in specific hostile solid tumor microenvironment settings and potentially expand into new solid tumor indications. We are conducting the Phase 1 portion of the Phase 1/2 clinical trial with initial data expected in the second half of 2023.

Proposed Transaction with Adaptimmune

On March 5, 2023, we entered into a definitive agreement with Adaptimmune Therapeutics plc ("Adaptimmune"), pursuant to which, upon the terms and subject to the conditions thereof, the Company will become a wholly-owned indirect subsidiary of

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Adaptimmune (the “Merger Agreement” and such transaction, the “Merger”). The combined company will create a preeminent cell therapy company focused on treating solid tumors. The combination provides extensive advantages for clinical development and product delivery supported by complementary technology platforms. The lead clinical franchises for the combined company utilize engineered T-cell therapies targeting MAGE A4 and mesothelin. These targets are expressed on a broad range of solid tumors and are supported by compelling early- and late-stage clinical data. The combined company also has a preclinical pipeline of additional target opportunities with development initially focused on PRAME and CD70.

The Merger Agreement was approved by our board of directors (the “Board”), and the Board resolved to recommend approval of the Merger Agreement to our stockholders. The closing of the Merger is subject to approval of our stockholders and the satisfaction of customary closing conditions. In connection with the execution of the Merger Agreement, certain of our stockholders and certain shareholders of Adaptimmune entered into voting and support agreements with Adaptimmune, pursuant to which they have agreed, among other things, and subject to the terms and conditions of the agreements, to vote their

shares in favor of the Merger Agreement and the Merger, in accordance with the recommendation of the respective boards of directors of Adaptimmune and the Company.

Subject to the terms of the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each issued and outstanding share of our common stock (other than shares of our common stock held as treasury stock, or shares of our common stock owned by Adaptimmune or any direct or indirect wholly-owned subsidiaries of Adaptimmune), including shares of our common stock underlying our restricted stock units that vest upon a change of control, will be converted into the right to receive 1.5117 American Depositary Shares of Adaptimmune (“Parent ADS”) with each Parent ADS representing six ordinary shares of Adaptimmune. Following the closing of the Merger, Adaptimmune shareholders will own approximately 75% of the combined company and our stockholders will own approximately 25% of the combined company.

Subject to approval by our shareholders and the shareholders of Adaptimmune and satisfaction or waiver of other closing conditions, the transaction is expected to close in the second quarter of 2023.

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Our Pipeline

The versatility of our platform is highlighted by our lead program and multiple approaches in development. We have generated a pipeline with assets that focus on solid tumors. Our product candidates are listed in the figure below.

Our Approach Utilizes the Full T-Cell Receptor

The TCR is one of the body’s most complex receptors, composed of an antigen-recognizing heterodimer (TCRα and TCRβ chains) which binds to specific peptide-MHC ligands in association with a complex of signaling subunits, collectively called CD3: CD3γ, CD3δ and two subunits each of CD3ε and CD3ζ. The contribution and interplay of the TCR’s six different receptor subunits to its very broad and complex signaling activities in T cells is not fully understood but we believe all subunits play an important role in regulating and tuning activation signals downstream of the TCR. In total, the six different CD3 subunits contain ten immune receptor tyrosine-based activation motifs (ITAM) and the multiplicity of ITAMs within the TCR regulates the signaling potency and thereby the strength of T cell activation following TCR ligation. Besides ITAMs, other unique motifs in the intracellular domains of CD3γ, CD3δ, CD3ε and CD3ζ are crucial for homeostasis, negative feedback regulation, signaling and function of the TCR complex. In contrast to CAR-Ts, which operate as stand-alone receptors utilizing only one of the six TCR subunits (CD3ζ), TRuCs fully integrate into the TCR complex and therefore have the potential utilize the full signaling capacity of the TCR and take advantage of its intrinsic regulatory mechanisms.

Our Novel T-Cell Receptor Fusion Construct (TRuC) Platform

We are pioneering the development of a novel, transformative T cell engineering platform which, based on its design and our preclinical and clinical studies, we believe has the potential to address the shortcomings of CAR-T cells and TCR-T cells and is fundamentally different from these existing approaches. Research over more than two decades has shown that each of the TCR subunits makes distinct contributions to the activation and regulation of T cells and the sum of the TCR subunits is required to optimally activate and control the function of T cells. We believe that engaging the entire TCR signaling complex is required to fully realize the potential of T cells in their fight against cancer.

Our T cell engineering approach relies upon natural TCR elements to produce therapeutic T cells that function independently of HLA restriction. To that end, we fuse a cancer antigen recognition domain (i.e. antibody-based binder) directly to a subunit of the TCR and use a lentiviral vector to transfer the genetic information for the TRuC construct into a patient’s own T cells. This

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modified subunit then naturally integrates into the native TCR complex, creating an engineered T cell equipped with a new "homing device" to detect and engage a specific antigen on the surface of cancer cells. Upon antigen engagement, these T cells harness the entire TCR to produce a highly potent T cell response against cancer. We refer to T cells engineered with our TCR fusion constructs as TRuC-T cells. In preclinical studies of both solid tumors and hematological malignancies we have observed greater anti-tumor activity, longer persistence and less cytokine release compared to CAR-T cells we have engineered to target the same cancer antigen. Our findings suggest that the signal delivered through the full TCR by TRuCs results in efficient T cell activation while avoiding overactivation and overproduction of cytokines as occurs in CARs. We believe that these properties could translate into more durable responses with potentially fewer adverse events for patients with cancer.

The figure below describes the natural HLA-restricted TCR complex as compared to the HLA-independent TRuC TCR.

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Our platform enables the design of TRuC-T cells with a number of potential advantages, as described in the table below:

Our goal is to improve upon the efficacy and safety of T-cell therapies by enhancing trafficking of T cells into tumors, tumor antigen targeting, the ability to withstand the tumor microenvironment, long-lasting T-cell persistence and a controlled anti-tumor response. In our preclinical studies, TRuC-T cells have shown improvements in each of these key characteristics compared to CAR-T cells, including those we have engineered with the same binders. Importantly, in our gavo-cel Phase 1 dose escalation, we have demonstrated proof-of-concept and benefit for patients in all treated indications.

Design of the gavo-cel TRuC Construct

The construct used to generate gavo-cel is comprised of a humanized single-domain antibody that specifically binds to mesothelin on the cell surface. This binding domain is tethered to the human CD3ε subunit via a flexible linker to form the mesothelin-targeting TRuC construct, as shown below. We use a lentiviral vector to transfer the genetic information for the TRuC construct into a patient’s own T cells. Once in the T cell, the TRuC protein is expressed and integrated into the endogenous TCR followed by transport of the reprogrammed TCR to the cell surface. There, it redirects the TRuC-T cells to recognize mesothelin-positive tumor cells and activate them to eliminate mesothelin-positive tumors. We believe that gavo-cel’s unique way of engaging and powering T cells as well as its humanized binding domain could lead to improved clinical outcomes for patients. The following figure illustrates the design of gavo-cel.

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Gavo-cel Market Opportunity

We estimate the patient population for gavo-cel in the four indications which we are exploring in our clinical trial is up to 81,000 patients in the United States alone. Mesothelin is overexpressed on the cell surface in multiple cancers, including approximately 76% of malignant pleural mesothelioma (the most common type of mesothelioma), 58% of ovarian cancers and 31% of NSCLC, among others. The following figure illustrates the proportion of cancer patients with mesothelin expressed on the surface of their tumors and are therefore potential candidates for gavo-cel therapy.

Ovarian Cancer Background

Epithelial ovarian cancer comprises approximately 90% of all ovarian malignancies. Approximately 21,000 patients in the United States were estimated to be diagnosed with ovarian cancer in 2021 with an estimated 12,400 cases expressing mesothelin on the cell surface.

Taxane and platinum-based combinations have been the backbone of ovarian cancer treatment for the past 20 years, despite having very low efficacy rates (below 15%) in patients with advanced forms of the disease. The majority of patients progressing after platinum retreatment have the options of three approved PARP inhibitors, expanding treatment options. Relapsed, recurrent ovarian cancer remains incurable with an estimated 13,770 deaths from ovarian cancer in 2021 in the United States alone.

NSCLC Background

NSCLC remains the leading cause of cancer-related mortality worldwide, accounting for approximately 18% of all cancer deaths. There are an estimated 235,760 new cases in the United States annually with an estimated 62,600 (27%) expressing mesothelin on the cell surface.

Patients with metastatic NSCLC have a poor prognosis with a median survival of approximately 26-months and a five-year survival rate of approximately 16% to 32%. While recent advances with checkpoint inhibitors have demonstrated promising results, the majority of patients treated with these agents do not derive a long-term benefit. Notably, no standard of care is available for patients failing to respond or relapsing after checkpoint inhibitor therapy, a segment of the NSCLC market which is expected to grow in size as the use of immune checkpoint inhibitors increases in first- and second-line settings.

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Malignant Pleural/Peritoneal Mesothelioma Background

Malignant mesothelioma is a rare and aggressive malignancy arising from mesothelial cells lining the cavity surrounding the lungs (pleura), abdomen (peritoneum), heart (pericardium) or testes. Patients with either malignant pleural mesothelioma or malignant peritoneal mesothelioma are eligible for enrollment in our Phase 1/2 clinical trial of gavo-cel.

Malignant pleural mesothelioma is the most common form of mesothelioma, accounting for an estimated 84% of cases. Asbestos exposure causes approximately 80% of malignant pleural mesothelioma cases. There are an estimated 2,600 new cases per year of malignant mesothelioma in the United States of which an estimated 1,800 express mesothelin on the cell surface.

Effective treatment options for patients with malignant pleural mesothelioma are very limited. In October 2020, the FDA approved Opdivo (nivolumab) in combination with Yervoy (ipilimumab) for the first-line treatment of adults with malignant pleural mesothelioma that cannot be removed by surgery. This is the first drug regimen approved for mesothelioma in 16 years and the second FDA-approved systemic therapy for mesothelioma. In second line, the standard of care recommended is chemotherapy that includes a platinum salt and an anti-folate. Unfortunately, the ORR is 17% to 40% and the median overall survival of patients with malignant pleural mesothelioma is 12 to 19 months when systemic chemotherapy is used with or without anti-angiogenic agents or targeted therapy. Malignant mesothelioma causes approximately 2,500 deaths in the United States annually.

Malignant peritoneal mesothelioma is the second-most common form of mesothelioma, accounting for an estimated 10% of cases. While malignant peritoneal mesothelioma is less commonly studied than malignant pleural mesothelioma, similar systemic chemotherapy regimens of platinum and antifolate combinations are often used. The prognosis for patients with malignant peritoneal mesothelioma is poor as only 35% of patients survive more than two years after diagnosis.

In the first half of 2022, we announced that we received an FDA Orphan Drug Designation for gavo-cel’s treatment of mesothelioma.

Cholangiocarcinoma Background

Cholangiocarcinoma is a form of cancer that is composed of mutated epithelial cells that originate in the bile ducts. There are an estimated 8,000 new cholangiocarcinoma cases in the United States per year with about 50% expressing mesothelin on the cell surface. Most patients with cholangiocarcinoma have advanced-stage disease at presentation, for which the available standard-of-care chemotherapy (gemcitabine and cisplatin) renders a median overall survival of less than one year. In 2020, the FDA approved pemigatinib for the treatment of unresectable locally advanced or metastatic cholangiocarcinoma with a fibroblast growth factor receptor 2 (FGFR2) fusion or other rearrangement, however this treatment addresses only 10-16% of patients. Multiple products, including checkpoint inhibitors and others, are being tested in clinical trials, but cholangiocarcinoma remains an unmet medical need. Cholangiocarcinoma causes over 7,000 deaths per year in the United States alone.

In 2021, we received an FDA Orphan Drug Designation for gavo-cel’s treatment of cholangiocarcinoma.

Gavo-cel Phase 1/2 Trial in Mesothelin-Positive Tumors

We have initiated a Phase 1/2 clinical trial of gavo-cel in patients with mesothelin-positive ovarian cancer, NSCLC, malignant pleural/peritoneal mesothelioma and cholangiocarcinoma. In January 2023, we announced that we had narrowed the focus of our development of gavo-cel to ovarian cancer in combination with Opdivo® (nivolumab) and redosing strategies.

Our Phase 1/2 clinical trial consists of two parts:

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Clinical findings

On September 28, 2022, we announced positive topline data from the Phase 1 portion of the gavo-cel Phase 1/2 clinical trial that enrolled 32 patients with mesothelin-expressing solid tumors. As of the September 9, 2022 data cutoff, six PRs according to RECIST 1.1 criteria were recorded among 30 evaluable patients treated on study in dose escalation. Gavo-cel was administered up to dose level 5 (DL5) (5x108/m2 following lymphodepletion).

Two dose limiting toxicities (DLTs) were reported: at DL1, one Grade 3 pneumonitis that resolved with supportive measures, which permitted the continuation of dose escalation and at DL5, one Grade 5 bronchoalveolar hemorrhage along with the development of severe CRS in all 3 patients treated at this dose level. Following the DLT at DL5, one patient had received gavo-cel at 3x108/m2 after lymphodepletion using a split dosing approach to refine the identification of the RP2D and an additional patient was treated at DL3 (1x108/m2 following lymphodepletion). In both cases gavo-cel was well tolerated with only Grade 1 non-hematological toxicities being reported. Since then, five additional patients were treated at 3x108/m2 after lymphodepletion and subsequently, in late December 2021, the SRT declared DL3 as the RP2D.

The primary objectives of the Phase 1 portion of the study are to define the safety profile of gavo-cel in patients whose tumors overexpress mesothelin and to determine the RP2D. Secondary objectives include ORR and DCR (response or stable disease lasting at least 12 weeks). Exploratory objectives include the assessment of expansion, tumor infiltration and persistence of gavo-cel.

Summary of trial conduct, baseline characteristics and gavo-cel dose:

Key clinical findings from 32 patients treated with gavo-cel:

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TC-510: Our First TRuC-T Cell Enhanced with a PD-1:CD28 Chimeric Switch Receptor Targeting Mesothelin Positive Solid Tumors

We are also developing TC-510, a mesothelin-targeted TRuC-T cell that co-expresses a PD-1:CD28 chimeric switch receptor to provide a local costimulatory signal in the hostile tumor microenvironment. In our preclinical studies of TC-510, the co-expression of the PD-1:CD28 switch receptor enhanced TCR downstream signaling, increased proliferation, reduced exhaustion and improved in vivo efficacy against tumors with high PD-L1 expression. Based on these studies, we believe TC-510 can improve on the efficacy of gavo-cel in a PD-L1 rich hostile solid tumor microenvironment and potentially expand into new solid tumor indications. We are conducting the Phase 1 portion of the Phase 1/2 clinical trial with initial data expected in the second half of 2023.

Design of TC-510

TC-510 cells express two transgenes: the mesothelin-specific TRuC construct used in TC-210 and a chimeric PD-1:CD28 switch receptor. Both proteins are encoded by a single genetic construct. As described for TC-210, a humanized single-domain antibody that specifically binds to mesothelin is tethered to the human CD3ε subunit via a flexible linker to form the mesothelin-targeting TRuC construct, as shown below. The PD-1:CD28 switch receptor is constructed by fusing the cytoplasmic signaling domain of CD28 to the extracellular domain of PD-1. We use a lentiviral vector to transfer the genetic information for the transgenes into a patient’s own T cells. Once in the T cell, the TRuC protein is expressed and integrated into the endogenous TCR. There, it redirects the TRuC-T cells to recognize mesothelin-positive tumor cells and eliminate mesothelin-positive tumors. The PD-1:CD28 switch receptor is co-expressed on the cell surface to engage with PD-L1 expressed in tumor microenvironment thereby co-activating the TRuC-T cells. We believe that TC-510’s unique way of engaging and powering T cells by providing local co-stimulation of T cells reduces TRuC cell exhaustion and improves persistence resulting in enhanced clinical outcomes for patients. The following figure illustrates the design of TC-510.

Summary of our Preclinical Data on TC-510

Our preclinical data support our hypothesis that TC-510 could have potent anti-tumor activity and improve clinical efficacy for patients compared to gavo-cel allowing expansion into additional solid tumor indications beyond gavo-cel’s initial cancer targets. TC-510 showed functional improvements in preclinical models where we compared the T cell signaling, cytokine production and anti-tumor activity of TC-510 with gavo-cel and gavo-cel with a mutationally inactivated CD28 signaling domain of the switch to

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eliminate the costimulatory function of the switch receptor, which we engineered with the same mesothelin binder as TC-510. In our preclinical studies of TC-510, we observed the following results:

TC-510 Cleared Tumors with High PD-L1 Expression in MSTO Mouse Model More Efficiently

We compared the anti-tumor activity of TC-510 with that of gavo-cel and gavo-cel with a mutationally inactivated CD28 signaling domain of the switch to eliminate the costimulatory function of the switch receptor in a MSTO-M/PDL1 model expressing high mesothelin and PD-L1. In order to make the tumor model more challenging, tumors were allowed to grow to a large size prior to treatment. Under these conditions, mice were treated with similar numbers of either unmodified T cells, TC-510, gavo-cel, or gavo-cel engineered with a mutationally inactivated CD28 signaling domain of the PD-1:CD28 switch receptor, in each case bearing an identical mesothelin-binding domain. As shown below, treatment with gavo-cel and gavo-cel with the CD28 mutated switch failed to control tumor growth, whereas TC-510 achieved deep tumor regressions in all treated animals, further confirming the importance of the CD28 signaling to TC-510’s function.

Broadening our Core TRuC-T Cell Platform with a Series of Next-Generation Enhancements

We have developed a novel, transformative platform to address the limitations of existing T cell therapies. Our TRuC-T cell platform is designed to deliver the first HLA-independent TCR-T cell therapies to a broader population of patients with solid tumors. Our approach is to fuse a cancer antigen recognition domain directly to a subunit of the TCR, which becomes fully integrated into the natural complex. This has the effect of activating the entire TCR to produce a more powerful, yet controlled T cell response to cancer.

We are focused on continued innovation to broaden our platform through internal research and collaboration with leading academic laboratories and industry partners in the field of T-cell immunology, cell therapy, gene editing and process development.

We are developing enhancements that further combat the immunosuppressive solid tumor microenvironment, including mechanisms designed to block a key cancer defense known as the PD-1/PD-L1 pathway. Our lead enhanced TRuC is TC-510, our mesothelin targeting TRuC-T cell co-expressing a PD-1:CD28 switch receptor. This switch receptor acts as a cell-intrinsic mechanism to overcome PD-L1/PD-L2 mediated immunosuppression. In our preclinical studies, upon repeated antigen stimulation, co-expression of the switch receptor in mesothelin-targeting T cells enhanced TCR signaling, prevented PD-L1-mediated functional T-cell inhibition, significantly increased proliferation and augmented the production of growth and effector cytokines.

Our next most advanced enhanced TRuC is TC-520, our fratricide resistant CD70 targeting TRuC-T cell co-expressing an IL-15 enhancement. In our preclinical studies, we have shown that an IL-15 enhancement can further improve the preclinical efficacy of

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our CD70 targeting TRuC-T cells due to IL-15 effectively improving the expansion, persistence and durable efficacy. We are conducting IND-enabling activities for TC-520 to treat patients with hematological malignancies and solid tumors, specifically renal cell carcinoma and acute myeloid leukemia. Due to the high expression of CD70 across many cancer types, we estimate that up to 141,000 patients express CD70 in the United States alone.

TC-520: Our First TRuC-T Cell Targeting CD70-Expressing Tumors

We are also developing TC-520, a CD70-targeted TRuC-T cell that incorporates an IL-15 pathway enhancement. In our preclinical studies of TC-520, the T cells exhibited potent activity against CD70-expressing cells, while the IL-15 enhancement improved T cell phenotype, function, and persistence. We are conducting IND-enabling activities for TC-520 to treat CD70-expressing solid tumors and hematological malignancies.

Design of TC-520

TC-520 cells express a TRuC construct that includes a proprietary CD70 binder and a membrane-bound IL-15 enhancement. The CD70 binder is tethered to the human CD3ε subunit via a flexible linker to form the CD70-targeting TRuC construct. Both the CD70 and the IL-15 proteins are encoded by a single genetic construct. We use a lentiviral vector to transfer the genetic information for the transgenes into a patient’s own T cells. Once in the T cell, the TRuC protein is expressed and integrated into the endogenous TCR. There, it redirects the TRuC-T cells to recognize CD70-positive tumor cells and eliminate CD70-positive tumors. The IL-15 protein is co-expressed on the cell surface.

Because CD70 expression occurs on activated lymphocytes as well as being overexpressed on various hematological and solid tumors, fratricide (self-killing of CD70 expressing activated lymphocytes) has been recognized as a significant challenge for CD70-targeting T cell therapies. In our preclinical studies of TC-520, we observed no evidence of fratricide. In addition, in our preclinical studies, we observed that the IL-15 enhancement improved persistence and increased expansion of the TRuC-T cells, as well as improved TRuC-T cell phenotype by increasing the proportion of cells with a memory stem T cell phenotype. The following figure illustrates the design of TC-520.

Manufacture and Delivery of TRuC-T Cells to Patients

TRuC-T Cell Production and Delivery

The process of manufacturing cell and gene therapies, such as TRuC-T cells, is highly complex. The generation of our TRuC-T cells starts with the collection of white blood cells from patients, known as leukapheresis, at the treatment center. The blood cells are shipped to a central manufacturing facility where they are further processed. Following the enrichment of the sample T cells, they are activated, which causes them to divide. In the next step, a viral vector is used to shuttle the genetic information encoding the TRuC construct into the T cells. During the assembly process of the TCR, the TRuC construct is integrated into the natural TCR complex and transported to the cell surface. The now reprogrammed TRuC-T cells are further stimulated to replicate and produce enough quantities to administer a therapeutic dose to the patient from whom the cells were originally collected.

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We use a next-generation cell processing platform that performs cell sample loading, cell washing, density-based cell separation, magnetic separation, cell culture and final product formulation. This is a semi-automated and functionally closed system that we believe will enable us to scale our TRuC-T cell manufacturing and overcome the constraints associated with current processes.

TRuC-T Cell Manufacturing Strategy

We are devoting resources in process development and manufacturing to optimize the reliability of our product candidates and reduce manufacturing costs and vein-to-vein time. This investment will ensure that our manufacturing and delivery process will have utility across all the product candidates in our pipeline.

The generation of a genetically-modified autologous T cell therapy such as TRuC-T cells involves several integrated and complex steps, including the collection of T cells through leukapheresis, cryopreservation, manufacture of the transfer vector under cGMP conditions, ex vivo selection, activation, transduction and expansion of the TRuC-T cells, ultimately leading to infusion of TRuC-T cells into patients. The technical, logistical and regulatory challenges associated with the virus and cell manufacturing processes are significant. We plan to simplify the manufacturing process through the implementation of automated technologies and the development of scalable processes aimed at reducing the cost of goods.

We have already taken two critical steps geared toward simplifying our manufacturing process. First, our TRuC-T cells are manufactured via a semi-automated and functionally closed system (CliniMACS Prodigy), which provides a common platform that will be employed in the development of all of the product candidates in our pipeline. This manufacturing process is economical, reliable and scalable and can support rapid development of the product candidates throughout the clinical life cycle and regulatory approvals. This system has a small footprint, which enables us to manufacture multiple products in parallel units within the same minimally controlled space, thereby reducing operating costs. Second, both the input leukapheresis material that enters the manufacturing process as well as the final TRuC-T cells are cryopreserved products, which simplifies the logistics for delivery to the patient and reduces the risk of product delivery failure. The entire vein-to-vein manufacturing process has safe-guards in place designed to ensure product identity and integrity throughout the production life-cycle.

We have entered into manufacturing agreements for the supply of GMP-S plasmids for generation of the viral vectors, which are manufactured by third parties. The viral vectors are manufactured through established agreements with various CDMOs. We outsource our T cell manufacturing process and we may enter into additional agreements to increase capacity for future clinical trials and commercialization if licensed. Because our starting materials are frozen, we expect to be able to base future agreements on rolling forecasts of regularly scheduled manufacturing runs, which we expect will minimize any cost overruns due to loss of reservation fees.

As part of our manufacturing strategy, we plan to be capital efficient by leveraging third party manufacturers and only expand or internalize manufacturing capacity in anticipation of a potential regulatory approval for any of our TRuC-T cell product candidates.

Intellectual Property

Intellectual property is a fundamental component of our business and of vital importance in our field. We actively seek to protect the intellectual property and proprietary technology that we believe is important to our business, including seeking, maintaining, enforcing and defending patent rights for our product candidates and processes, whether developed internally or licensed from third parties. We may additionally rely on regulatory protection afforded through orphan drug designations, data exclusivity, market exclusivity and patent term extensions where available.

The TRuC-T cell platform was initially conceived and developed by our scientific founder, Dr. Patrick Baeuerle. The priority patent application disclosing the TRuC-T cell platform was filed in May 2015. Our further work encompassing a broad range of TRuC concepts has been described in subsequent patent applications.

Additional patent applications filed by us since 2015 include at least the following additional technological innovations and product-related claims:

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Our strategy is to pursue a variety of broad claims in the United States and foreign jurisdictions to provide multiple layers of patent protection, including:

Many of the patent applications that we own or in-license, including our trademark filings, are still in the early stages of prosecution and no claims have been issued yet, with the exception of ten issued U.S. patents and 19 issued foreign patents as of March 5, 2023. Examination of many of the patent applications that we own has not yet commenced, because they are either provisional applications or Patent Cooperation Treaty (PCT) applications that are not examined. We will need to decide whether and where to pursue protection for the inventions disclosed in these provisional and PCT applications before applicable statutory deadlines, our applications will only be examined in jurisdictions where we elect to pursue protection and we will only have the opportunity to attempt to obtain patents in such jurisdictions where we elect to pursue protection. We are seeking protection across a range of commercially important territories, including (but not limited to) countries in North America, Europe and Asia.

As of March 5, 2023, our patent portfolio includes ten issued U.S. patents, at least 23 pending U.S. provisional or nonprovisional patent applications, at least 12 pending Patent Cooperation Treaty (PCT) international applications, 19 issued foreign patents and at least 120 pending foreign patent applications, which patent applications we own or in-license. The claims of these patent applications are directed toward various aspects of our product candidates and research programs including compositions of matter, methods of use and processes. These owned and in-licensed patents and patent applications, if issued, are expected to expire on various dates from 2036 through 2043, in each case without taking into account any possible patent term adjustments or extensions.

As of March 5, 2023, our patent portfolio includes multiple patents and patent applications with claims directed to gavo-cel, including compositions of matter, manufacturing methods, manufacturing precursors or uses thereof, of which there are (i) five issued U.S. patents, at least seven pending U.S. provisional or U.S. nonprovisional patent applications, at least two pending PCT international applications, 14 issued foreign patents and at least 41 pending foreign patent applications which we own and (ii) one U.S. patent, at least one pending U.S. nonprovisional patent application, three issued foreign patents and at least 11 pending foreign patent applications for which we have a nonexclusive license from Harpoon Therapeutics, Inc. (Harpoon). These owned and in-licensed patents and patent applications, if issued, are expected to expire on various dates from 2036 through 2043, in each case without taking into account any possible patent term adjustment or extensions.

As of March 5, 2023, our patent portfolio includes multiple patents and patent applications with claims directed to TC-510, including compositions of matter, manufacturing methods, manufacturing precursors or uses thereof, of which there are (i) five issued U.S. patents, at least three pending U.S. provisional or U.S. nonprovisional patent applications, 14 issued foreign patents and at least 25 pending foreign patent applications which we own; (ii) one U.S. patent, at least one pending U.S. nonprovisional patent application, three issued foreign patents and at least 11 pending foreign patent applications for which we have a nonexclusive license from Harpoon Therapeutics, Inc. (Harpoon) and (iii) one U.S. patent, at least one pending U.S. nonprovisional patent application, five issued foreign patents and at least five pending foreign patent applications for which we have an exclusive license from Drs. Stefan Endres and Sebastian Kobold at the Klinikum der Universität München (the PD-1 Switch License). Pursuant to the PD-1 Switch License we have an exclusive, world-wide, royalty free, sublicensable license to research, develop, make, use, sell, commercialize or otherwise exploit products that include a construct with a PD-1 extracellular domain with intracellular CD28 co-stimulatory domain (the PD-1 Switch). We incorporated the PD-1 Switch into TC-510. As consideration for the PD-1 Switch License, we issued the Inventors equity and have agreed to certain technology access fees and patent and development milestone payments. These owned and in-licensed patents and patent applications, if issued, are expected to expire on various dates from 2036 through 2043, in each case without taking into account any possible patent term adjustment or extensions.

Our trademark portfolio currently contains issued trademarks for TCR2, TRuC and our logo in the United States.

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Collaborations and Licenses

Harpoon License

In June 2017, we entered into a license with Harpoon (the Harpoon License) that grants us a perpetual, irrevocable, world-wide, non-exclusive, royalty free, sublicensable license to research, develop, make, use, sell, commercialize or otherwise exploit products based on Harpoon’s MSLN polypeptide binding proteins (the MSLN Binder). We have incorporated the MSLN Binder into gavo-cel.

As consideration for the Harpoon License, we granted Harpoon a perpetual, irrevocable, world-wide, non-exclusive, royalty free, sublicensable license to research, develop, make, use, sell, commercialize or otherwise exploit products based on certain binding proteins which we had developed (the Out-Licensed Binder). We do not incorporate the Out-Licensed Binder into any of our product candidates.

Under the Harpoon License, we retain ownership of the Out-Licensed Binder and own any of our improvements to the MSLN Binder and any of our product candidates incorporating the MSLN Binder. Similarly, Harpoon retains ownership of the MSLN Binder and owns any of its improvements to the Out-Licensed Binder and any of its products incorporating the Out-Licensed Binder. Each party is responsible for the prosecution and maintenance of the patent rights owned by such party.

The Harpoon License is effective through the expiration of all patents underlying the MSLN Binder and Out-Licensed Binder and it may be terminated by either party upon a material breach that remains uncured for 60 days after receiving notice thereof, or in the event of the other party’s bankruptcy.

Competition

We believe our novel TRuC-T cell platform, its design flexibility, superior performance over CAR-T cell and TCR-T cell therapies, emerging enhancements and our knowledge of cellular immunotherapy should enable us to successfully develop novel and highly effective treatments for cancer. However, we may face intense and increasing competition from larger biotechnology and pharmaceutical companies with greater financial resources, who are also developing immuno-oncology therapies (including cellular therapies) and more traditional treatments for cancer. In addition, academic institutions, governmental agencies, public and private research institutions and early stage or smaller companies could also prove competitive.

The market opportunity in oncology has led to a number of collaborations including Janssen Biotech, Inc. (Janssen)/ Nanjing Legend Pharmaceutical & Chemical Co., Ltd (Legend), bluebird bio, Inc. (bluebird)/ Regeneron Pharmaceuticals Inc. (Regeneron) and bluebird/Gritstone Oncology, Inc.) and major acquisitions (Gilead Sciences, Inc. (Gilead)/Kite Pharma Inc. (Kite)/Tmunity, Bristol Myers Squibb Co (BMS)/Celgene Corporation (Celgene)/Juno Therapeutics, Inc. (Juno), Takeda Pharmaceutical Company Limited (Takeda)/GammaDelta Therapeutics Limited (GammaDelta)), Astra Zeneca/Neogene, among companies focused on cellular cancer therapies. If this trend continues, which we expect, we could see further consolidation of technical expertise and human capital. This potentially provides a partnership opportunity for us but could also make it more challenging for us to acquire complementary technology or products and recruit and retain qualified scientific and management personnel. In addition, this competition could impact our ability to recruit clinical trial sites and patients in a timely manner for our clinical trials. Larger companies with greater financial flexibility and global reach may be able to obtain regulatory approvals and gain widespread market acceptance before us, which could impact our commercial launch and could make our products obsolete or non-competitive.

We are developing one of our lead product candidates, gavo-cel, in combination with an immune checkpoint inhibitors. Others are evaluating these immune checkpoint inhibitor approaches in combination with CAR-T cells and TCR-T cells to enhance efficacy in the treatment of solid tumors. We therefore could experience significant direct competition from this type of combination immunotherapy. We may also face substantial competition in the future from other immunotherapies, if their use alone or in combination demonstrates a significant improvement in efficacy. Development of more effective small molecules, antibody-based approaches, cancer vaccines, oncolytic viruses and other products could lead to them preferentially being used as first- or second-line treatments, which would reduce the opportunity for our product candidates.

Despite the unique approach that we have developed to address the limitations of CAR-T cells and TCR-T cells, we expect to face increasing competition as new more effective treatments for cancer enter the market and further advancements in technologies are made. We expect market adoption of any treatments that we develop and commercialize to be dependent on, among other things, efficacy, safety, delivery, price and the availability of reimbursement from government and other third-party payors.

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We expect the commercial opportunity for our products that we take to regulatory licensing to be reduced or eliminated if competitors develop and commercialize products that are more effective, safer (have fewer or less severe side effects), are more convenient or are less expensive or better reimbursed than any products that we may commercialize. We compete with larger, better-funded companies, who may obtain regulatory approval for their products more rapidly than we may obtain licensing for ours. This could result in our competitors establishing a strong market position for either the product or a specific indication before we are able to enter the market.

Competition for Our Product Candidates Targeting Mesothelin-Expressing Solid Tumors

The overexpression of mesothelin by numerous solid tumors, combined with its low expression on mesothelial cells lining the pleura, peritoneum and pericardium, has led to a number of different mesothelin-targeting agents being tested in Phase 1/2 trials. These approaches include novel antibody therapeutics, such as unconjugated monoclonal antibodies, antibody-drug conjugates, bispecific antibodies as well as vaccines. Antibody-based approaches are being pursued by Amgen Inc., Bayer AG, Bristol-Myers Squibb Company, Eisai, F. Hoffmann-La Roche Ltd, Harpoon Therapeutics, Inc., Morphotek, Inc., Selecta Biosciences, Inc. and Novimmune SA among others. Antibody-based agents in development have been limited to date by immunogenicity, poor tumor penetration and dose-limiting toxicities associated with the therapy. Adaptimmune, Atara Biotherapeutics, Inc., CARISMA Therapeutics Inc., Gracell Biotechnology Inc., Kiromic Biopharma, Inc., Biotech Corp, Memorial Sloan Kettering Cancer Center, the National Institutes of Health Clinical Center Inc., Takeda Pharmaceutical Co. Ltd., Tmunity Therapeutics, Inc., University of Pennsylvania, National Cancer Institute and several Chinese academic institutions are developing anti-mesothelin cell therapies.

Government Regulation and Product Licensure

Government authorities in the United States, at the federal, state and local level and in other countries and jurisdictions, including the EU, extensively regulate, among other things, the research, development, testing, manufacture, pricing, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting and import and export of biopharmaceutical products. The processes for obtaining marketing approvals in the United States and in foreign countries and jurisdictions, along with compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources.

Licensure and Regulation of Biologics in the United States

In the United States, biological products such as our lead product candidates, are licensed for marketing by the FDA under the Public Health Service Act (PHSA) and regulated by the FDA under the Federal Food, Drug, and Cosmetic Act (FDCA), as well as by other federal, state and local statute and regulations. Both the FDCA and the PHSA and their corresponding regulations govern, among other things, the testing, manufacturing, safety, potency, labeling, packaging, storage, record keeping, distribution, reporting, advertising and other promotional practices involving biological products. The FDA must license a biological product before it may be marketed within the United States. Within the FDA, the Center for Biologics Evaluation and Research (CBER) regulates cell therapy products.

The failure of an applicant to comply with the applicable regulatory requirements at any time during the product development process, including non-clinical testing, clinical testing, the approval process or post-approval process, may result in delays to the conduct of a study, regulatory review and approval and/or administrative or judicial sanctions. These sanctions may include, but are not limited to, the FDA’s refusal to allow an applicant to proceed with clinical trials, refusal to approve pending applications, license suspension or revocation, withdrawal of an approval, warning letters, adverse publicity, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines and civil or criminal investigations and penalties brought by the FDA or Department of Justice (DOJ), or other government entities, including state agencies.

An applicant seeking licensing to market and distribute a new biologic in the United States generally must satisfactorily complete each of the following steps before the product candidate will be licensed by the FDA.

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Preclinical Studies and Investigational New Drug Application

Before an applicant begins testing a product candidate with potential therapeutic value in humans, the product candidate enters preclinical testing. Preclinical tests include laboratory evaluations of product chemistry, formulation and stability, as well as other studies to evaluate, among other things, the toxicity of the product candidate. The conduct of the preclinical tests and formulation of the compounds for testing must comply with federal regulations and requirements, including GLP regulations and standards. The results of the preclinical tests, together with manufacturing information and analytical data, are submitted to the FDA a part of an IND. Some long-term preclinical testing, such as animal tests of reproductive adverse events and carcinogenicity and long-term toxicity studies, may continue after the IND is submitted.

The IND and IRB Processes

An IND is an exemption from the FDCA that allows an unapproved product candidate to be shipped in interstate commerce for use in an investigational clinical trial and a request for FDA authorization to administer such investigational product to humans. Such authorization must be secured prior to interstate shipment and administration of any product candidate that is not the subject of an approved BLA. In support of a request for an IND, applicants must submit a protocol for each clinical trial and any subsequent protocol amendments must be submitted to the FDA as part of the IND. In addition, the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical trials, among other things, must be submitted to the FDA as part of an IND. The FDA requires a 30-day waiting period after the filing of each IND before clinical trials may begin. This waiting period is designed to allow the FDA to review the IND to determine whether human research subjects will be exposed to unreasonable health risks. At any time during this 30-day period, or thereafter, the FDA may raise concerns or questions about the conduct of the trials as outlined in the IND and impose a clinical hold or partial clinical hold. In this case, the IND sponsor and the FDA must resolve any outstanding concerns before clinical trials can begin.

Following commencement of a clinical trial under an IND, the FDA may also place a clinical hold or partial clinical hold on that trial. A clinical hold is an order issued by the FDA to the sponsor to delay a proposed clinical investigation or to suspend an ongoing investigation. A partial clinical hold is a delay or suspension of only part of the clinical work requested under the IND. For example, a specific protocol or part of a protocol is not allowed to proceed, while other protocols may do so. No more than 30 days after imposition of a clinical hold or partial clinical hold, the FDA will provide the sponsor a written explanation of the basis for the hold. Following issuance of a clinical hold or partial clinical hold, an investigation may only resume after the FDA has notified the sponsor that the investigation may proceed. The FDA will base that determination on information provided by the sponsor correcting the deficiencies previously cited or otherwise satisfying the FDA that the investigation can proceed.

A sponsor may choose, but is not required, to conduct a foreign clinical trial under an IND. When a foreign clinical trial is conducted under an IND, all FDA IND requirements must be met unless waived. When a foreign clinical trial is not conducted under an IND, the sponsor must ensure that the study complies with certain regulatory requirements of the FDA in order to use the study as support for an IND or application for marketing approval or licensing. In particular, such studies must be conducted in accordance with GCP, including review and approval by an independent ethics committee (IEC) and informed consent from subjects. The GCP requirements in the final rule encompass both ethical and data integrity standards for clinical studies and the FDA must be able to validate the data through an onsite inspection, if deemed necessary by the FDA. The FDA’s regulations are

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intended to help ensure the protection of human subjects enrolled in non-IND foreign clinical studies, as well as the quality and integrity of the resulting data. They further help ensure that non-IND foreign studies are conducted in a manner comparable to that required for IND studies.

In addition to the foregoing IND requirements, an IRB representing each institution participating in the clinical trial must review and approve the plan for any clinical trial before it commences at that institution and the IRB must conduct continuing review and reapprove the study at least annually. The IRB must review and approve, among other things, the study protocol and informed consent information to be provided to study subjects. An IRB must operate in compliance with FDA regulations. An IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the product candidate has been associated with unexpected serious harm to patients.

Additionally, some trials are overseen by an independent group of qualified experts organized by the trial sponsor, known as a data safety monitoring board or committee (DSMB). This group provides authorization as to whether or not a trial may move forward at designated check points based on access that only the group maintains to available data from the study. Suspension or termination of development during any phase of clinical trials can occur if it is determined that the participants or patients are being exposed to an unacceptable health risk. Other reasons for suspension or termination may be made by us based on evolving business objectives and/or competitive climate.

Information about clinical trials must be submitted within specific timeframes to the NIH for public dissemination on its ClinicalTrials.gov website.

Additional Regulation for Gene Therapy Clinical Trials

In addition to the regulations discussed above, there are a number of additional standards that apply to clinical trials involving the use of gene therapy. The FDA has issued various guidance documents regarding gene therapies, which outline additional factors that the FDA will consider at each of the above stages of development, which relate to, among other things: the proper preclinical assessment of gene therapies; the CMC information that should be included in an IND; the proper design of tests to measure product potency in support of an IND or BLA; and measures to observe delayed adverse effects in subjects who have been exposed to investigational gene therapies when the risk of such effects is high. Further, the FDA usually recommends that sponsors observe subjects for potential gene therapy-related delayed adverse events for a 15-year period, including a minimum of five years of annual examinations followed by ten years of annual queries, either in person or by questionnaire, although the FDA recently proposed updating its guidance on long-term follow-up after administration of human gene therapy products.

The NIH and the FDA have a publicly accessible database, the Genetic Modification Clinical Research Information System, which includes information on gene therapy trials and serves as an electronic tool to facilitate the reporting and analysis of adverse events on these trials.

Human Clinical Trials in Support of a BLA

Clinical trials involve the administration of the investigational product candidate to human subjects under the supervision of a qualified investigator in accordance with GCP requirements which include, among other things, the requirement that all research subjects provide their informed consent in writing before their participation in any clinical trial. Clinical trials are conducted under written clinical trial protocols detailing, among other things, the objectives of the study, inclusion and exclusion criteria, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated.

Human clinical trials are typically conducted in three sequential phases, but the phases may overlap or be combined. Additional studies may also be required after licensing.

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In some cases, the FDA may approve a BLA for a product candidate but require the sponsor to conduct additional clinical trials to further assess the product candidate’s safety and effectiveness after approval. Such post-approval trials are typically referred to as Phase 4 clinical trials. These studies are used to gain additional experience from the treatment of a larger number of patients in the intended treatment group and to further document a clinical benefit in the case of biologics licensed under accelerated approval regulations. Failure to exhibit due diligence with regard to conducting Phase 4 clinical trials could result in withdrawal of approval for products.

In March 2022, the FDA released a final guidance entitled “Expansion Cohorts: Use in First-In-Human Clinical Trials to Expedite Development of Oncology Drugs and Biologics,” which outlines how drug developers can utilize an adaptive trial design commonly referred to as a seamless trial design in early stages of oncology drug development (i.e., the first-in-human clinical trial) to compress the traditional three phases of trials into one continuous trial called an expansion cohort trial. Information to support the design of individual expansion cohorts are included in IND applications and assessed by FDA. Expansion cohort trials can potentially bring efficiency to drug development and reduce developmental costs and time.

Progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA. In addition, IND safety reports must be submitted to the FDA for any of the following: serious and unexpected suspected adverse reactions; findings from other studies or animal or in vitro testing that suggest a significant risk in humans exposed to the product; and any clinically important increase in the case of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. Phase 1, Phase 2 and Phase 3 clinical trials may not be completed successfully within any specified period, or at all. Furthermore, the FDA or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the research subjects are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the product has been associated with unexpected serious harm to patients. The FDA will typically inspect one or more clinical sites to assure compliance with GCP and the integrity of the clinical data submitted.

Clinical trials sometimes require submission of an application for an Investigational Device Exemption, or IDE, to the FDA. The IDE application, when requested, must be supported by appropriate data, such as animal and laboratory testing results, showing that it is safe to test the device in humans and that the investigational protocol is scientifically sound. The IDE application must be approved in advance by the FDA, unless the product is deemed a non-significant risk device and eligible for more abbreviated IDE requirements. Clinical trials for a significant risk device may begin once the IDE application is approved by the FDA as well as the appropriate institutional review boards, or IRBs, at the clinical trial sites and the informed consent of the patients participating in the clinical trial is obtained.

Review and Approval of a BLA

In order to obtain approval to market a biological product in the United States, a marketing application must be submitted to the FDA that provides sufficient data establishing the safety, purity and potency of the proposed biological product for its intended indication. The application includes all relevant data available from pertinent preclinical and clinical trials, including negative or ambiguous results as well as positive findings, together with detailed information relating to the product’s chemistry, manufacturing, controls and proposed labeling, among other things. Data can come from company-sponsored clinical trials intended to test the safety and effectiveness of a use of a product, or from a number of alternative sources, including studies initiated by investigators. To support marketing approval, the data submitted must be sufficient in quality and quantity to establish the safety, purity and potency of the biological product to the satisfaction of the FDA.

The BLA is a vehicle through which applicants formally propose that the FDA license a new product for marketing and sale in the United States for one or more indications. Every new biological product candidate must be the subject of an approved BLA before it may be commercialized in the United States. Under federal law, the submission of most BLAs is subject to a significant application user fee. The sponsor of an approved BLA is also subject to an annual program fee. Certain exceptions and waivers are available for some of these fees, such as an exception from the application fee for products with orphan designation and a waiver for certain small businesses.

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Following submission of a BLA, the FDA conducts a preliminary review of the application generally within 60 calendar days of its receipt and strives to inform the sponsor by the 74th day after the FDA’s receipt of the submission whether the application is sufficiently complete to permit substantive review. The FDA may request additional information rather than accept the application for filing. In this event, the application must be resubmitted with the additional information. The resubmitted application is also subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review. The FDA has agreed to specified performance goals in the review process of the BLAs. Under that agreement, 90% of original BLA submissions are meant to be reviewed within ten months of the 60-day filing date and 90% of original BLAs that have been designated for “priority review” are meant to be reviewed within six months of the 60-day filing date. The review process and the Prescription Drug User Fee Act (PDUFA) goal date may be extended by the FDA for three additional months to consider new information or clarification provided by the applicant to address an outstanding deficiency identified by the FDA following the original submission.

Before approving an application, the FDA typically will inspect the facility or facilities where the product is or will be manufactured. These pre-approval inspections may cover all facilities associated with a BLA submission, including component manufacturing, finished product manufacturing and control testing laboratories. The FDA will not approve an application unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving a BLA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP.

In addition, as a condition of approval, the FDA may require an applicant to develop a REMS. REMS use risk minimization strategies beyond the professional labeling to ensure that the benefits of the product outweigh the potential risks. To determine whether a REMS is needed, the FDA will consider the size of the population likely to use the product, seriousness of the disease, expected benefit of the product, expected duration of treatment, seriousness of known or potential adverse events and whether the product is a new molecular entity.

The FDA may refer an application for a novel product to an advisory committee or explain why such referral was not made. Typically, an advisory committee is a panel of independent experts, including clinicians and other scientific experts, that reviews, evaluates and provides a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.

Fast Track, Breakthrough Therapy, Priority Review and Regenerative Medical Advanced Therapy Designations

The FDA is authorized to designate certain products for expedited review if they are intended to address an unmet medical need in the treatment of a serious or life-threatening disease or condition. These programs are referred to as Fast Track designation, Breakthrough Therapy designation, Priority Review designation and Regenerative Medical Advanced Therapy designation.

Specifically, the FDA may designate a product for Fast Track review if it is intended, whether alone or in combination with one or more other products, for the treatment of a serious or life-threatening disease or condition and it demonstrates the potential to address unmet medical needs for such a disease or condition. For Fast Track products, sponsors may have greater interactions with the FDA and the FDA may initiate review of sections of a Fast Track product’s application before the application is complete. This rolling review may be available if the FDA determines, after preliminary evaluation of clinical data submitted by the sponsor, that a Fast Track product may be effective. The sponsor must also provide and the FDA must approve, a schedule for the submission of the remaining information and the sponsor must pay applicable user fees. However, the FDA’s time period goal for reviewing a Fast Track application does not begin until the last section of the application is submitted. In addition, the Fast Track designation may be withdrawn by the FDA if the FDA believes that the designation is no longer supported by data emerging in the clinical trial process.

Second, a product may be designated as a Breakthrough Therapy if it is intended, either alone or in combination with one or more other products, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The FDA may take certain actions with respect to Breakthrough Therapies, including holding meetings with the sponsor throughout the development process; providing timely advice to the product sponsor regarding development and approval; involving more senior staff in the review process; assigning a cross-disciplinary project lead for the review team; and taking other steps to design the clinical trials in an efficient manner.

Third, the FDA may designate a product for priority review if it is a product that treats a serious condition and, if licensed, would provide a significant improvement in safety or effectiveness. The FDA determines, on a case-by-case basis, whether the proposed product represents a significant improvement when compared with other available therapies. Significant improvement may be

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illustrated by evidence of increased effectiveness in the treatment of a condition, elimination or substantial reduction of a treatment-limiting product reaction, documented enhancement of patient compliance that may lead to improvement in serious outcomes and evidence of safety and effectiveness in a new subpopulation. A priority designation is intended to direct overall attention and resources to the evaluation of such applications and to shorten the FDA’s goal for taking action on a marketing application from ten months to six months.

A product may be designated as a regenerative medicine advanced therapy if it is a regenerative medicine therapy that is intended to treat, modify, reverse or cure a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the product has the potential to address unmet medical needs for such disease or condition. The benefits of a regenerative medicine advanced therapy designation include early interactions with FDA to expedite development and review, benefits available to breakthrough therapies, potential eligibility for priority review and accelerated approval based on surrogate or intermediate endpoints.

Accelerated Approval Pathway

The FDA may grant accelerated approval to a product for a serious or life-threatening condition that provides meaningful therapeutic advantage to patients over existing treatments based upon a determination that the product has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit. The FDA may also grant accelerated approval for such a condition when the product has an effect on an intermediate clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality (IMM) and that is reasonably likely to predict an effect on IMM or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. Products granted accelerated approval must meet the same statutory standards for safety and effectiveness as those granted traditional approval.

For the purposes of accelerated approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure that is thought to predict clinical benefit but is not itself a measure of clinical benefit. Surrogate endpoints can often be measured more easily or more rapidly than clinical endpoints. An intermediate clinical endpoint is a measurement of a therapeutic effect that is considered reasonably likely to predict the clinical benefit of a drug, such as an effect on IMM. The FDA has limited experience with accelerated approvals based on intermediate clinical endpoints but has indicated that such endpoints generally may support accelerated approval where the therapeutic effect measured by the endpoint is not itself a clinical benefit and basis for traditional approval, if there is a basis for concluding that the therapeutic effect is reasonably likely to predict the ultimate clinical benefit of a product.

The accelerated approval pathway is most often used in settings in which the course of a disease is long and an extended period of time is required to measure the intended clinical benefit of a product, even if the effect on the surrogate or intermediate clinical endpoint occurs rapidly. Thus, accelerated approval has been used extensively in the development and approval of products for treatment of a variety of cancers in which the goal of therapy is generally to improve survival or decrease morbidity and the duration of the typical disease course requires lengthy and sometimes large trials to demonstrate a clinical or survival benefit. Thus, the benefit of accelerated approval derives from the potential to receive approval based on surrogate endpoints sooner than possible for trials with clinical or survival endpoints, rather than deriving from any explicit shortening of the FDA approval timeline, as is the case with priority review.

The accelerated approval pathway is usually contingent on a sponsor’s agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the product’s clinical benefit. Under the Food and Drug Omnibus Reform Act of 2022 (FDORA), the FDA may require, as appropriate, that such trials be underway prior to approval or within a specific time period after the date of approval for a product granted accelerated approval. Under FDORA, the FDA has increased its authority for expedited procedures to withdraw approval of the product or indication approved under accelerated approval if, for example, the confirmatory trials fail to confirm a clinical benefit during post-marketing studies. All promotional materials for product candidates licensed under accelerated regulations are subject to prior review by the FDA.

The FDA’s Decision on a BLA

On the basis of the FDA’s evaluation of the application and accompanying information, including the results of the inspection of the manufacturing facilities, the FDA may issue an approval letter or a complete response letter. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A complete response letter generally outlines the deficiencies in the submission and may require substantial additional testing or information in order for the FDA to reconsider the application. If and when those deficiencies have been addressed to the FDA’s satisfaction in a resubmission of the BLA, the FDA will issue an approval letter. The FDA has committed to reviewing such resubmissions in two or six months depending on the type of information included. Even with submission of this additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for licensing.

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If the FDA licenses a new product, it may limit the licensed indications for use of the product. The agency may also require testing and surveillance programs to monitor the product after commercialization, or impose other conditions, including distribution restrictions or other risk management mechanisms, including REMS, to help ensure that the benefits of the product outweigh the potential risks. REMS can include medication guides, communication plans for health care professionals and elements to assure safe use (ETASU). ETASU can include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring and the use of patent registries. The FDA may prevent or limit further marketing of a product based on the results of post-market studies or surveillance programs. After licensing, many types of changes to the licensed product, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further testing requirements and FDA review and approval.

Post-Licensing Regulation

If regulatory licensing for marketing of a product or new indication for an existing product is obtained, the sponsor will be required to comply with all regular post-licensing regulatory requirements as well as any post-licensing requirements that the FDA may have imposed as part of the licensing process. The sponsor will be required to report, among other things, certain adverse reactions and manufacturing problems to the FDA, provide updated safety and potency or efficacy information and comply with requirements concerning advertising and promotional labeling requirements. Manufacturers and certain of their subcontractors, and those supplying products, ingredients, and components of them, are required to register their establishments with the FDA and certain state agencies and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with ongoing regulatory requirements, including cGMP regulations, which impose certain procedural and documentation requirements upon manufacturers. Changes to the manufacturing processes are strictly regulated and often require prior FDA approval before being implemented. Accordingly, the sponsor and its third-party manufacturers must continue to expend time, money and effort in the areas of production and quality control to maintain compliance with cGMP regulations and other regulatory requirements.

A product may also be subject to official lot release, meaning that the manufacturer is required to perform certain tests on each lot of the product before it is released for distribution. If the product is subject to official release, the manufacturer must submit samples of each lot, together with a release protocol showing a summary of the history of manufacture of the lot and the results of all of the manufacturer’s tests performed on the lot, to the FDA. The FDA may in addition perform certain confirmatory tests on lots of some products before releasing the lots for distribution. Finally, the FDA will conduct laboratory research related to the safety, purity, potency and effectiveness of pharmaceutical products.

Once a license is granted, the FDA may withdraw the license if compliance with regulatory requirements is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the licensed labeling to add new safety information; imposition of post-market studies or clinical trials to assess safety risks; or imposition of distribution or other restrictions under a REMS program. Other potential consequences include, among other things:

The FDA strictly regulates the marketing, labeling, advertising and promotion of prescription drug products placed on the market. This regulation includes, among other things, standards and regulations for direct-to-consumer advertising, communications regarding unapproved uses, industry-sponsored scientific and educational activities and promotional activities involving the Internet and social media. Promotional claims about a drug’s safety or effectiveness are prohibited before the drug is licensed. After licensing, a drug product generally may not be promoted for uses that are not licensed by the FDA, as reflected in the product’s prescribing information. In the United States, health care professionals are generally permitted to prescribe drugs for such uses not described in the drug’s labeling, known as off-label uses, because the FDA does not regulate the practice of medicine. However, FDA regulations impose rigorous restrictions on manufacturers’ communications, prohibiting the promotion of

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off-label uses. It may be permissible, under very specific, narrow conditions, for a manufacturer to engage in nonpromotional, non-misleading communication regarding off-label information, such as distributing scientific or medical journal information.

If a company is found to have promoted off-label uses, it may become subject to adverse public relations and administrative and judicial enforcement by the FDA, the Department of Justice, or the Office of the Inspector General of the Department of Health and Human Services (HHS), as well as state authorities. This could subject a company to a range of penalties that could have a significant commercial impact, including civil and criminal fines and agreements that materially restrict the manner in which a company promotes or distributes drug products. The federal government has levied large civil and criminal fines against companies for alleged improper promotion and has also requested that companies enter into consent decrees or permanent injunctions under which specified promotional conduct is changed or curtailed.

In addition, manufacturers and other parties involved in the drug supply chain for prescription drug and biological products must also comply with product tracking and tracing requirements and for notifying the FDA of counterfeit, diverted, stolen and intentionally adulterated products or products that are otherwise unfit for distribution in the United States.

Pediatric Studies and Exclusivity

Under the Pediatric Research Equity Act, a BLA or supplement thereto for a biological product with a new active ingredient, indication, dosage form, dosing regimen or route of administration must contain data that are adequate to assess the safety and effectiveness of the product for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. Sponsors must also submit pediatric study plans prior to the assessment data. Those plans must contain an outline of the proposed pediatric study or studies the applicant plans to conduct, including study objectives and design, any deferral or waiver requests and other information required by regulation. The applicant, the FDA and the FDA’s internal review committee must then review the information submitted, consult with each other and agree upon a final plan. The FDA or the applicant may request an amendment to the plan at any time.

For products intended to treat a serious or life-threatening disease or condition, the FDA must, upon the request of an applicant, meet to discuss preparation of the initial pediatric study plan or to discuss deferral or waiver of pediatric assessments. In addition, FDA will meet early in the development process to discuss pediatric study plans with sponsors and FDA must meet with sponsors by no later than the end-of-Phase 1 meeting for serious or life-threatening diseases and by no later than ninety (90) days after FDA’s receipt of the study plan.

The FDA may, on its own initiative or at the request of the applicant, grant deferrals for submission of some or all pediatric data until after licensing of the product for use in adults, or full or partial waivers from the pediatric data requirements. Additional requirements and procedures relating to deferral requests and requests for extension of deferrals are contained in FDASIA. Unless otherwise required by regulation, the pediatric data requirements do not apply to products with orphan designation.

The FDA Reauthorization Act of 2017 established new requirements to govern certain molecularly targeted cancer indications. Any company that submits a BLA three years after the date of enactment of that statute must submit pediatric assessments with the BLA if the biologic is intended for the treatment of an adult cancer and is directed at a molecular target that FDA determines to be substantially relevant to the growth or progression of a pediatric cancer. The investigation must be designed to yield clinically meaningful pediatric study data regarding the dosing, safety and preliminary potency to inform pediatric labeling for the product. Deferrals and waivers as described above are also available.

Pediatric exclusivity is another type of non-patent marketing exclusivity in the United States and, if granted, provides for the attachment of an additional six months of marketing protection to the term of any existing regulatory exclusivity, including the non-patent and orphan exclusivity. This six-month exclusivity may be granted if a BLA sponsor submits pediatric data that fairly respond to a written request from the FDA for such data. The data do not need to show the product to be effective in the pediatric population studied; rather, if the clinical trial is deemed to fairly respond to the FDA’s request, the additional protection is granted. If reports of requested pediatric studies are submitted to and accepted by the FDA within the statutory time limits, whatever statutory or regulatory periods of exclusivity or patent protection cover the product are extended by six months. This is not a patent term extension, but it effectively extends the regulatory period during which the FDA cannot license another application.

Orphan Drug Designations and Exclusivity

Under the Orphan Drug Act, the FDA may designate a biological product as an “orphan drug” if it is intended to treat a rare disease or condition, generally meaning that it affects fewer than 200,000 individuals in the United States, or more in cases in which there is no reasonable expectation that the cost of developing and making a product available in the United States for treatment of disease or condition will be recovered from sales of the product. A company must seek orphan drug designation

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before submitting a BLA for the candidate product. If the request is granted, the FDA will disclose the identity of the therapeutic agent and its potential use. Orphan drug designation does not shorten the PDUFA goal dates for the regulatory review and licensing process, although it does convey certain advantages such as tax benefits and exemption from the PDUFA application fee.

If a product with orphan designation receives the first FDA approval for the disease or condition for which it has such designation or for a select indication or use within the rare disease or condition for which it was designated, the product generally will receive orphan drug exclusivity. Orphan drug exclusivity means that the FDA may not license another sponsor’s marketing application for the same drug for the same condition for seven years, except in certain limited circumstances. Orphan exclusivity does not block the licensing of a different product for the same rare disease or condition, nor does it block the licensing of the same product for different conditions. If a biologic designated as an orphan drug ultimately receives marketing licensing for an indication broader than what was designated in its orphan drug application, it may not be entitled to exclusivity.

Orphan drug exclusivity will not bar licensing of another product under certain circumstances, including if a subsequent product with the same biologic for the same condition is shown to be clinically superior to the licensed product on the basis of greater potency, purity or safety, or providing a major contribution to patient care, or if the company with orphan drug exclusivity is not able to meet market demand. This is the case despite an earlier court opinion holding that the Orphan Drug Act unambiguously required the FDA to recognize orphan exclusivity regardless of a showing of clinical superiority.

Biosimilars and Exclusivity

The 2010 Patient Protection and Affordable Care Act, which was signed into law on March 23, 2010, included a subtitle called the Biologics Price Competition and Innovation Act of 2009 (BPCIA). The BPCIA established a regulatory scheme authorizing the FDA to license biosimilars and interchangeable biosimilars. The FDA has licensed several biosimilar products for use in the United States. The FDA has issued several guidance documents outlining an approach to review and licensing of biosimilars. Additional guidance is expected to be proposed and finalized by the FDA in the near term.

Under the BPCIA, a manufacturer may submit an application for licensure of a biological product that is “biosimilar to” or “interchangeable with” a previously licensed biological product or “reference product.” In order for the FDA to license a biosimilar product, it must find, among other things, that the product is “highly similar” to the reference product notwithstanding minor differences in clinically inactive components and that there are no clinically meaningful differences between the reference product and proposed biosimilar product in terms of safety, purity and potency. For the FDA to license a biosimilar product as interchangeable with a reference product, the agency must find that the biosimilar product can be expected to produce the same clinical results as the reference product and, for products administered multiple times, that the biologic and the reference biologic may be switched after one has been previously administered without increasing safety risks or risks of diminished potency relative to exclusive use of the reference biologic.

Under the BPCIA, an application for a biosimilar or interchangeable biological product may not be submitted to the FDA until four years following the date of licensing of the reference product. The FDA may not license a biosimilar or interchangeable biological product until 12 years from the date on which the reference product was licensed. Even if a product is considered to be a reference product eligible for exclusivity, another company could market a competing version of that product if the FDA licenses a full BLA for such product containing the sponsor’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of their product. The BPCIA also created certain exclusivity periods for biosimilars licensed as interchangeable products and the FDA may approve multiple “first” interchangeable products so long as they are all approved on the same first day of marketing. At this juncture, it is unclear whether products deemed “interchangeable” by the FDA will, in fact, be readily substituted by pharmacies, which are governed by state pharmacy law.

Patent Term Restoration and Extension

A patent claiming a new biological product may be eligible for a limited patent term extension under the Hatch-Waxman Act, which permits a patent restoration of up to five years for patent term lost during product development and FDA regulatory review. The restoration period granted on a patent covering a product is typically one-half the time between the effective date of an IND and the submission date of a marketing application (such as a BLA), plus the time between the submission date of a marketing application and the ultimate licensing date. Patent term restoration cannot be used to extend the remaining term of a patent past a total of 14 years from the product’s licensing date. Only one patent applicable to a licensed product is eligible for the extension and the application for the extension must be submitted prior to the expiration of the patent in question and within 60 days after approval of the relevant marketing application. A patent that covers multiple products for which licensing is sought can only be extended in connection with one of the licenses. The USPTO reviews and licenses the application for any patent term extension or restoration in consultation with the FDA.

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Healthcare Law and Regulation

Health care providers and third-party payors play a primary role in the recommendation and prescription of biological products that are granted marketing licensing. Arrangements with providers, consultants, third-party payors and customers are subject to broadly applicable fraud and abuse, anti-kickback, false claims laws, patient privacy laws and regulations and other health care laws and regulations that may constrain business and/or financial arrangements. Restrictions under applicable federal and state health care laws and regulations, include the following:

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Some state laws require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government in addition to requiring manufacturers to report information related to payments to physicians and other health care providers or marketing expenditures. In addition, certain state and local laws require the registration of pharmaceutical sales representatives. State and foreign laws also govern the privacy and security of health information in some circumstances, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

Pharmaceutical Insurance Coverage and Reimbursement

In the United States and markets in other countries, patients who are prescribed treatments for their conditions and providers performing the prescribed services generally rely on third-party payors to reimburse all or part of the associated health care costs. Significant uncertainty exists as to the coverage and reimbursement status of products. Thus, even if a product candidate is licensed, sales of the product will depend, in part, on the extent to which third-party payors, including government health programs in the United States such as Medicare and Medicaid, commercial health insurers and managed care organizations, provide coverage and establish adequate reimbursement levels for, the product. The process for determining whether a payor will provide coverage for a product may be separate from the process for setting the price or reimbursement rate that the payor will pay for the product once coverage is licensed. Third-party payors are increasingly challenging the prices charged, examining the medical necessity and reviewing the cost-effectiveness of medical products and services and imposing controls to manage costs. Third-party payors may limit coverage to specific products on a licensed list, also known as a formulary, which might not include all of the licensed products for a particular indication.

In order to secure coverage and reimbursement for any product that might be licensed for sale, a company may need to conduct expensive pharmacoeconomic studies in order to demonstrate the medical necessity and cost-effectiveness of the product, in addition to the costs required to obtain FDA or other comparable marketing licenses. Nonetheless, product candidates may not be considered medically necessary or cost effective. A decision by a third-party payor not to cover a product could reduce physician utilization once the product is licensed and have a material adverse effect on sales, results of operations and financial condition. Additionally, a payor’s decision to provide coverage for a product does not imply that an adequate reimbursement rate will be licensed. Further, one payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage and reimbursement for the product and the level of coverage and reimbursement can differ significantly from payor to payor.

The containment of health care costs also has become a priority of federal, state and foreign governments and the prices of products have been a focus in this effort. Governments have shown significant interest in implementing cost-containment programs, including price controls, restrictions on reimbursement and requirements for substitution of generic products. Adoption of price controls and cost-containment measures and adoption of more restrictive policies in jurisdictions with existing controls and measures, could further limit a company’s revenue generated from the sale of any licensed products. Coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which a company or its collaborators receive marketing licenses, less favorable coverage policies and reimbursement rates may be implemented in the future.

In addition, in some foreign countries, the proposed pricing for a drug must be approved before it may be lawfully marketed. The requirements governing drug pricing vary widely from country to country. For example, the European Union provides options for its Member States to restrict the range of medicinal products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. To obtain reimbursement or pricing approval, some of these countries may require the completion of clinical trials that compare the cost effectiveness of a particular product candidate to currently available therapies. A Member State may approve a specific price for the medicinal product or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the medicinal product on the market. There can be no assurance that any country that has price controls or reimbursement limitations for pharmaceutical products will allow favorable reimbursement and pricing arrangements for any of our product candidates. Historically, products launched in the European Union do not follow price structures of the United States and generally prices tend to be significantly lower.

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Health Care Reform

There have been a number of federal and state proposals during the last few years regarding the pricing of pharmaceutical and biopharmaceutical products, limiting coverage and reimbursement for drugs and biologics and other medical products, government control and other changes to the health care system in the United States. In 2010, the ACA was enacted, which includes measures that have significantly changed health care financing by both governmental and private insurers. The provisions of the ACA of importance to the pharmaceutical and biotechnology industry are, among others, the following:

Other legislative changes have been proposed and adopted since the ACA was enacted:

These laws may result in additional reductions in Medicare and other healthcare funding and otherwise affect the prices we may obtain for any of our product candidates for which we may obtain regulatory licensing or the frequency with which any such product candidate is prescribed or used.

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There have been several recent U.S. congressional inquiries and proposed state and federal legislation designed to, among other things, bring more transparency to drug pricing, review the relationship between pricing and manufacturer patient programs, reduce the costs of drugs under Medicare and reform government program reimbursement methodologies for drug products.

Additionally, there has been increasing legislative and enforcement interest in the United States with respect to drug pricing practices. President Biden has issued multiple executive orders that have sought to reduce prescription drug costs. Although a number of these and other proposed measures may require authorization through additional legislation to become effective, and the Biden administration may reverse or otherwise change these measures, both the Biden administration and Congress have indicated that they will continue to seek new legislative measures to control drug costs.

The Inflation Reduction Act of 2022, or IRA includes several provisions that may impact our business to varying degrees, including provisions that reduce the out-of-pocket cap for Medicare Part D beneficiaries to $2,000 starting in 2025; impose new manufacturer financial liability on certain drugs under Medicare Part D, allow the U.S. government to negotiate Medicare Part B and Part D price caps for certain high-cost drugs and biologics without generic or biosimilar competition, require companies to pay rebates to Medicare for certain drug prices that increase faster than inflation, and delay the rebate rule that would limit the fees that pharmacy benefit managers can charge. Further, under the IRA, orphan drugs are exempted from the Medicare drug price negotiation program, but only if they have one rare disease designation and for which the only approved indication is for that disease or condition. If a product receives multiple rare disease designations or has multiple approved indications, it may not qualify for the orphan drug exemption. The effects of the IRA on our business and the healthcare industry in general is not yet known.

These healthcare reforms, as well as other healthcare reform measures that may be adopted in the future, may result in additional reductions in Medicare and other healthcare funding, more rigorous coverage criteria, new payment methodologies and additional downward pressure on the price for any licensed product and/or the level of reimbursement physicians receive for administering any licensed product. Reductions in reimbursement levels may negatively impact the prices or the frequency with which products are prescribed or administered. Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors.

At the state level, individual states are increasingly aggressive in passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures and, in some cases, designed to encourage importation from other countries and bulk purchasing. In addition, regional health care authorities and individual hospitals are increasingly using bidding procedures to determine what pharmaceutical products and which suppliers will be included in their prescription drug and other health care programs. These measures could reduce the ultimate demand for our product candidates, once licensed, or put pressure on our product pricing.

Review and Approval of Medicinal Products in the EU

In order to market any product outside of the United States, a company must also comply with numerous and varying regulatory requirements of other countries and jurisdictions regarding quality, safety and efficacy and governing, among other things, clinical trials, marketing authorization, commercial sales and distribution of products. Whether or not it obtains FDA licensing for a product, an applicant will need to obtain the necessary approvals by the comparable non-U.S. regulatory authorities before it can commence clinical trials or marketing of the product in those countries or jurisdictions. Specifically, the process governing approval of medicinal products in the EU generally follows the same lines as in the United States although the approval of a medicinal product in the United States is no guarantee of approval of the same product in the European Union, either at all or within the same timescale as approval may be granted in the United States. It entails satisfactory completion of preclinical studies and adequate and well-controlled clinical trials to establish the safety and efficacy of the product for each proposed indication. It also requires the submission to the relevant competent authorities of a marketing authorization application (MAA) and granting of a marketing authorization by these authorities before the product can be marketed and sold in the EU.

Clinical Trial Approval

The Clinical Trials Directive 2001/20/EC, the Directive 2005/28/EC on GCP and the related national implementing provisions of the individual EU Member States govern the system for the approval of clinical trials in the EU. Under this system, an applicant must obtain prior approval from the competent national authority of the EU Member States in which the clinical trial is to be conducted. Furthermore, the applicant may only start a clinical trial at a specific study site after the competent ethics committee has issued a favorable opinion in relation to the clinical trial. The clinical trial application must be accompanied by, among other documents, an investigational medicinal product dossier (the Common Technical Document) with supporting information

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prescribed by Directive 2001/20/EC, Directive 2005/28/EC and, where relevant, the implementing national provisions of the individual EU Member States and applicable guidance documents.

In April 2014, the new Clinical Trials Regulation, (EU) No 536/2014 (Clinical Trials Regulation) was adopted. The Regulation was published on June 16, 2014 but is not expected to come into effect until late 2020 at the earliest. It is expected that the Clinical Trials Regulation will apply following confirmation of full functionality of the Clinical Trials Information System (CTIS), the centralized EU portal and database for clinical trials foreseen by the regulation, through an independent audit. The regulation becomes applicable six months after the European Commission publishes notice of this confirmation. The Clinical Trials Regulation will be directly applicable in all the EU Member States - meaning that no national implementing legislation will be required - and it will supersede and repeal the current Clinical Trials Directive 2001/20/EC and any national legislation that was put in place to implement the Directive. Conduct of all clinical trials performed in the EU will continue to be governed by the Clinical Trials Directive and national implementing legislation until the new Clinical Trials Regulation becomes applicable. The extent to which on-going clinical trials will be governed by the Clinical Trials Regulation will depend on when the Clinical Trials Regulation becomes applicable and on the duration of the individual clinical trial. Clinical trials applications made before the entry into force of the Clinical Trials Regulation will continue to be governed by the Clinical Trials Directive for up to three years after the Clinical Trials Regulation becomes applicable, as will clinical trials applications made within one year of the Clinical Trials Regulation becoming applicable where the clinical trial sponsor elects for the trial to be governed by the old regime until the end of the three year transition period. If a clinical trial continues for more than three years from the day on which the Clinical Trials Regulation becomes applicable the Clinical Trials Regulation will at that time begin to apply to the clinical trial.

The new Clinical Trials Regulation aims to simplify and streamline the approval of clinical trials in the EU. The main characteristics of the regulation include: a streamlined application procedure via a single entry point, the “EU Portal and Database”; a single set of documents to be prepared and submitted for the application as well as simplified reporting procedures for clinical trial sponsors; and a harmonized procedure for the assessment of applications for clinical trials, which is divided in two parts. Part I is assessed by the appointed reporting Member State, whose assessment report is submitted for review by the sponsor and all other competent authorities of all EU Member States in which an application for authorization of a clinical trial has been submitted (the so-called Member States concerned). Part II is assessed separately by each Member State concerned. Strict deadlines have been established for the assessment of clinical trial applications. The role of the relevant ethics committees in the assessment procedure will continue to be governed by the national law of the Member State concerned. However, overall related timelines will be defined by the Clinical Trials Regulation.

PRIME Designation in the EU

EMA now offers a scheme that is intended to reinforce early dialogue with and regulatory support from, EMA in order to stimulate innovation, optimize development and enable accelerated assessment of PRIority MEdicines (“PRIME”). It is intended to build upon the scientific advice scheme and accelerated assessment procedure offered by EMA. The scheme is voluntary and eligibility criteria must be met for a medicine to qualify for PRIME.

The PRIME scheme is open to medicines under development and for which the applicant intends to apply for an initial marketing authorization application through the centralized procedure. Eligible products must target conditions for which where is an unmet medical need (there is no satisfactory method of diagnosis, prevention or treatment in the European Union or, if there is, the new medicine will bring a major therapeutic advantage) and they must demonstrate the potential to address the unmet medical need by introducing new methods or therapy or improving existing ones. Applicants will typically be at the exploratory clinical trial phase of development and will have preliminary clinical evidence in patients to demonstrate the promising activity of the medicine and its potential to address to a significant extent an unmet medical need. In exceptional cases, applicants from the academic sector or SMEs (small and medium sized enterprises) may submit an eligibility request at an earlier stage of development if compelling non-clinical data in a relevant model provide early evidence of promising activity and first in man studies indicate adequate exposure for the desired pharmacotherapeutic effects and tolerability.

If a medicine is selected for the PRIME scheme, EMA:

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Medicines that are selected for the PRIME scheme are also expected to benefit from EMA’s accelerated assessment procedure at the time of application for marketing authorization. Where, during the course of development, a medicine no longer meets the eligibility criteria, support under the PRIME scheme may be withdrawn.

Marketing Authorization

To obtain a marketing authorization for a product under EU regulatory systems, an applicant must submit an MAA, either under a centralized procedure administered by the EMA or one of the procedures administered by competent authorities in EU Member States (decentralized procedure, national procedure, or mutual recognition procedure). A marketing authorization may be granted only to an applicant established in the EU. Regulation (EC) No 1901/2006 provides that prior to obtaining a marketing authorization in the EU, applicants must demonstrate compliance with all measures included in an EMA-approved Pediatric Investigation Plan (PIP) covering all subsets of the pediatric population, unless the EMA has granted a product-specific waiver, class waiver, or a deferral for one or more of the measures included in the PIP.

The centralized procedure provides for the grant of a single marketing authorization by the European Commission that is valid across the European Economic Area (which comprises the 27 Member States of the European Union, together with Norway, Iceland and Liechtenstein). Pursuant to Regulation (EC) No. 726/2004, the centralized procedure is compulsory for specific products, including for medicines produced by certain biotechnological processes, products designated as orphan medicinal products, ATMPs and products with a new active substance indicated for the treatment of certain diseases, including products for the treatment of cancer. For those products for which the use of the centralized procedure is not mandatory, applicants may elect to use the centralized procedure where either the product contains a new active substance indicated for the treatment of other diseases or where the applicant can show that the product constitutes a significant therapeutic, scientific or technical innovation for which a centralized process is in the interest of patients at a European Union level. We anticipate that the centralized procedure will be mandatory for the product candidates we are developing.

Under the centralized procedure, the Committee for Medicinal Products for Human use (or the “CHMP”), which is the EMA’s committee that is responsible for human medicines, is responsible for conducting the assessment of whether a medicine meets the required quality, safety and efficacy requirements and whether the product has a positive benefit/risk profile. The CHMP is also responsible for several post-authorization and maintenance activities, such as the assessment of modifications or extensions to an existing marketing authorization. Under the centralized procedure in the EU, the maximum timeframe for the evaluation of an MAA is 210 days from the receipt of a valid MAA, excluding clock stops when additional information or written or oral explanation is to be provided by the applicant in response to questions of the CHMP. Clock stops may extend the timeframe of evaluation of an MAA considerably beyond 210 days.

Accelerated evaluation may be granted by the CHMP in exceptional cases, when a medicinal product is of major interest from the point of view of public health and, in particular, from the viewpoint of therapeutic innovation. If the CHMP accepts such a request, the timeframe of 210 days for assessment will be reduced to 150 days (excluding clock stops), but it is possible that the CHMP may revert to the standard time limit for the centralized procedure if it determines that it is no longer appropriate to conduct an accelerated assessment. At the end of this period, the CHMP provides a scientific opinion on whether or not a marketing authorization should be granted in relation to a medicinal product. Within 15 calendar days of receipt of a final opinion from the CHMP, the European Commission must prepare a draft decision concerning an application for marketing authorization. This draft decision must take the opinion and any relevant provisions of EU law into account. Before arriving at a final decision on an application for centralized authorization of a medicinal product, the European Commission must consult the Standing Committee on Medicinal Products for Human Use. The Standing Committee is composed of representatives of the EU Member States and chaired by a non-voting European Commission representative. The European Parliament also has a related “droit de regard”. The European Parliament’s role is to ensure that the European Commission has not exceeded its powers in deciding to grant or refuse to grant a marketing authorization.

The European Commission may grant a so-called “marketing authorization under exceptional circumstances”. Such authorization is intended for products for which the applicant can demonstrate that it is unable to provide comprehensive data on the efficacy and safety under normal conditions of use, because the indications for which the product in question is intended are encountered so rarely that the applicant cannot reasonably be expected to provide comprehensive evidence, or in the present state of scientific knowledge comprehensive information cannot be provided, or it would be contrary to generally accepted principles of medical ethics to collect such information. Consequently, marketing authorization under exceptional circumstances may be granted subject to certain specific obligations, which may include the following:

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A marketing authorization under exceptional circumstances is subject to annual review to reassess the risk-benefit balance in an annual reassessment procedure. Continuation of the authorization is linked to the annual reassessment and a negative assessment could potentially result in the marketing authorization being suspended or revoked. The renewal of a marketing authorization of a medicinal product under exceptional circumstances, however, follows the same rules as a “normal” marketing authorization. Thus, a marketing authorization under exceptional circumstances is granted for an initial five years, after which the authorization will become valid indefinitely, unless the EMA decides that safety grounds merit one additional five-year renewal.

The European Commission may also grant a so-called “conditional marketing authorization” prior to obtaining the comprehensive clinical data required for an application for a full marketing authorization. Such conditional marketing authorizations may be granted for product candidates (including medicines designated as orphan medicinal products), if (i) the risk-benefit balance of the product candidate is positive, (ii) it is likely that the applicant will be in a position to provide the required comprehensive clinical trial data, (iii) the product fulfills an unmet medical need and (iv) the benefit to public health of the immediate availability on the market of the medicinal product concerned outweighs the risk inherent in the fact that additional data are still required. A conditional marketing authorization may contain specific obligations to be fulfilled by the marketing authorization holder, including obligations with respect to the completion of ongoing or new studies and with respect to the collection of pharmacovigilance data. Conditional marketing authorizations are valid for one year and may be renewed annually, if the benefit-risk balance remains positive and after an assessment of the need for additional or modified conditions and/or specific obligations. The timelines for the centralized procedure described above also apply with respect to the review by the CHMP of applications for a conditional marketing authorization.

The EU medicines rules expressly permit the EU Member States to adopt national legislation prohibiting or restricting the sale, supply or use of any medicinal product containing, consisting of or derived from a specific type of human or animal cell, such as embryonic stem cells. While the product candidates we have in development do not make use of embryonic stem cells, it is possible that the national laws in certain EU Member States may prohibit or restrict us from commercializing our product candidates, even if they have been granted an EU marketing authorization.

Unlike the centralized authorization procedure, the decentralized marketing authorization procedure requires a separate application to and leads to separate approval by, the competent authorities of each EU Member State in which the product is to be marketed. This application is identical to the application that would be submitted to the EMA for authorization through the centralized procedure. The reference EU Member State prepares a draft assessment and drafts of the related materials within 70 days after receipt of a valid application. The resulting assessment report is submitted to the concerned EU Member States who, then seek to reach a consensus in relation to the assessment report and related materials within a further 50 days (although there may be clock stops within this period if more information is requested and such clock stops would extend this time period). If approved at this stage, the application proceeds to the grant procedure at concerned Member States level. If consensus is not reached by the relevant Member States during the initial 120-day period, the application enters a further assessment period. If at the end of that further assessment period a concerned EU Member State cannot approve the assessment report and related materials due to concerns relating to a potential serious risk to public health, disputed elements may be referred to the European Commission, whose decision is binding on all EU Member States.

The mutual recognition procedure similarly is based on the acceptance by the competent authorities of the EU Member States of the marketing authorization of a medicinal product by the competent authorities of other EU Member States. The holder of a national marketing authorization may submit an application to the competent authority of an EU Member State requesting that this authority recognize the marketing authorization delivered by the competent authority of another EU Member State.

Regulatory Data Protection in the EU

In the EU, innovative medicinal products approved on the basis of a complete independent data package qualify for eight years of data exclusivity upon marketing authorization and an additional two years of market exclusivity pursuant to Directive 2001/83/EC. Regulation (EC) No 726/2004 repeats the entitlement for medicinal products authorized in accordance with the centralized authorization procedure. Data exclusivity prevents applicants for authorization of generics of these innovative products from

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referencing the innovator’s data to assess a generic (abridged) application for a period of eight years. During the additional two-year period of market exclusivity, a generic marketing authorization application can be submitted and authorized and the innovator’s data may be referenced, but no generic medicinal product can be placed on the EU market until the expiration of the market exclusivity. The overall ten-year period will be extended to a maximum of 11 years if, during the first eight years of those ten years, the marketing authorization holder obtains an authorization for one or more new therapeutic indications which, during the scientific evaluation prior to their authorization, are held to bring a significant clinical benefit in comparison with existing therapies. Even if a compound is considered to be a new chemical entity so that the innovator gains the prescribed period of data exclusivity, another company may market another version of the product if such company obtained marketing authorization based on an MAA with a complete independent data package of pharmaceutical tests, non-clinical tests and clinical trials.

Periods of Authorization and Renewals

A marketing authorization has an initial validity for five years in principle. The marketing authorization may be renewed after five years on the basis of a re-evaluation of the risk-benefit balance by the EMA or by the competent authority of the EU Member State. To this end, the marketing authorization holder must provide the EMA or the competent authority with a consolidated version of the file in respect of quality, safety and efficacy, including all variations introduced since the marketing authorization was granted, at least nine months before the marketing authorization ceases to be valid.

The European Commission or the competent authorities of the EU Member States may decide, on justified grounds relating to pharmacovigilance, to proceed with one further five-year period of marketing authorization. Once subsequently definitively renewed, the marketing authorization shall be valid for an unlimited period. Any authorization which is not followed by the actual placing of the medicinal product on the EU market (in case of centralized procedure) or on the market of the authorizing EU Member State within three years after authorization ceases to be valid (the so-called sunset clause).

Orphan Drug Designation and Exclusivity

Regulation (EC) No. 141/2000, as implemented by Regulation (EC) No. 847/2000 provides that a drug can be designated as an orphan drug by the European Commission if its sponsor can establish: that the product is intended for the diagnosis, prevention or treatment of (1) a life-threatening or chronically debilitating condition affecting not more than five in ten thousand persons in the EU when the application is made, or (2) a life-threatening, seriously debilitating or serious and chronic condition in the EU and that without incentives it is unlikely that the marketing of the drug in the EU would generate sufficient return to justify the necessary investment. For either of these conditions, the applicant must also demonstrate that there exists no satisfactory method of diagnosis, prevention or treatment of the condition in question that has been authorized in the EU or, if such method exists, the drug will be of significant benefit to those affected by that condition.

Once authorized, orphan medicinal products are entitled to 10 years of market exclusivity in all EU Member States and in addition a range of other benefits during the development and regulatory review process including scientific assistance for study protocols, authorization through the centralized marketing authorization procedure covering all member countries and a reduction or elimination of registration and marketing authorization fees. During this market exclusivity period, neither the EMA nor the European Commission or the Member States can accept an application or grant a marketing authorization for the same therapeutic indication in respect of a “similar medicinal product”. A “similar medicinal product” is defined as a medicinal product containing a similar active substance or substances as contained in an authorized orphan medicinal product and which is intended for the same therapeutic indication. However, marketing authorization may be granted to a similar medicinal product with the same orphan indication during the 10-year period with the consent of the marketing authorization holder for the original orphan medicinal product or if the manufacturer of the original orphan medicinal product is unable to supply sufficient quantities. Marketing authorization may also be granted to a similar medicinal product with the same orphan indication if this product is safer, more effective or otherwise clinically superior to the original orphan medicinal product. The period of market exclusivity may, in addition, be reduced to six years if, at the end of the fifth year, it is established that the product no longer meets the criteria for orphan drug designation because, for example, the product is sufficiently profitable not to justify market exclusivity.

Regulatory Requirements after a Marketing Authorization has been Obtained

In case an authorization for a medicinal product in the EU is obtained, the holder of the marketing authorization is required to comply with a range of requirements applicable to the manufacturing, marketing, promotion and sale of medicinal products. These include:

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Pricing Decisions for Approved Products

In the EU, pricing and reimbursement schemes vary widely from country to country. Some countries provide that products may be marketed only after a reimbursement price has been agreed. Some countries may require the completion of additional studies that compare the cost-effectiveness of a particular product candidate to currently available therapies or so-called health technology assessments, in order to obtain reimbursement or pricing approval. For example, the EU provides options for its Member States to restrict the range of products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. Member States may approve a specific price for a product or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the product on the market. Other Member States allow companies to fix their own prices for products, but monitor and control prescription volumes and issue guidance to physicians to limit prescriptions. Recently, many countries in the EU have increased the amount of discounts required on pharmaceuticals and these efforts could continue as countries attempt to manage health care expenditures, especially in light of the severe fiscal and debt crises experienced by many countries in the EU. The downward pressure on health care costs in general, particularly prescription products, has become intense. As a result, increasingly high barriers are being erected to the entry of new products. Political, economic and regulatory developments may further complicate pricing negotiations and pricing negotiations may continue after reimbursement has been obtained. Reference pricing used by various Member States and parallel trade, or arbitrage, between low-priced and high-priced Member States, can further reduce prices. There can be no assurance that any country that has price controls or reimbursement limitations for pharmaceutical products will allow favorable reimbursement and pricing arrangements for any products, if approved in those countries.

Human Capital

As of March 5, 2023, we had 66 full-time employees, of which 15 of our employees have Ph.D. or M.D. degrees and 54 of our employees are engaged in research and development activities. Our headcount decreased by 52% in 2022.

Retention, Training and Development

The development, attraction and retention of our employees is a critical success factor for TCR2 and is reflected in our corporate goals. We cultivate a culture of learning and offer formal and informal training and development opportunities for employees at all levels. These programs include Insights Discovery® training, delivered with a custom curriculum designed to match our five core competencies: Team Work, Emotional Intelligence, Technical Expertise, Leadership, and Results Orientation. We take special care to ensure our managers are well-trained. Programming for managers includes an intensive Manager Bootcamp, a monthly thematic meet-up, and our 3-month Manager Essentials Course. We offer a quarterly Aspiring Managers workshop, actively promote from within and continue to fill our team with strong and experienced management talent.

We measure engagement through routine employee surveys and keep the lines of communication open through weekly all-Company meetings, regular office hours with the TCR2 People Team, and manager one-on-ones.

Compensation and Benefits

An important part of attracting and retaining key talent is competitive pay and benefits. To ensure our compensation and benefits programs are competitive, we engage nationally recognized outside compensation and benefits consulting firms to independently evaluate the effectiveness of our programs and to provide benchmarking against our peers within the industry. Our pay for performance philosophy seeks to motivate and reward employees while accomplishing the Company’s short and long-term strategic goals. As part of a robust performance management process, employees are evaluated both on what they accomplished

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and how they demonstrated our core competencies. Annual salary increases and incentive bonuses are based on merit and include individual and corporate performance factors.

To encourage our employees to think like owners and share in the Company’s success, all employees are granted stock options, certain employees are granted restricted stock units and all employees can elect to participate in our employee stock purchase plan. All full-time employees are eligible for health insurance, paid and unpaid leaves including paid parental leave, retirement plan with an employer contribution match, life and disability/accident coverage, parking or commuter assistance, dependent care accounts, a lifestyle allowance which may be used to repay outstanding student loans and/or on expenses related to wellness, work-life, or personal development, tuition assistance, an employee assistance program providing mental health, wellness support, legal and financial health resources. We celebrate successes through our STAR Recognition Program as well as kudos posted to our internal newsfeed, employee events, and at employee meet-ups multiple times per month.

Our Corporate Information

We were incorporated under the laws of the State of Delaware on May 29, 2015 under the name TCR2, Inc. In November 2016, we changed our name to TCR2 Therapeutics Inc. Our principal executive offices are located at 100 Binney Street, Suite 710, Cambridge, MA 02142 and our telephone number is (617) 949-5200. Our website address is www.tcr2.com. Our website and the information contained on, or that can be accessed through, the website will not be deemed to be incorporated by reference in and are not considered part of, this Annual Report on Form 10-K.

We are an "emerging growth company" as defined in the Jumpstart Our Business Startups Act of 2012. We will remain an emerging growth company until the earlier of: (i) the last day of the fiscal year (a) following the fifth anniversary of the completion of the IPO, (b) in which we have total annual gross revenue of at least $1.07 billion, or (c) in which we are deemed to be a large accelerated filer, which means the market value of our common stock that is held by non-affiliates exceeds $700.0 million as of the prior June 30th and (ii) the date on which we have issued more than $1.0 billion in non-convertible debt during the prior three-year period.

Available Information

Our Internet address is www.tcr2.com. Our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, including exhibits, proxy and information statements and amendments to those reports filed or furnished pursuant to Sections 13(a), 14 and 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, are available through the "Investors" portion of our website free of charge as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. Information on our website is not part of this Annual Report on Form 10-K or any of our other securities filings unless specifically incorporated herein by reference. In addition, our filings with the SEC may be accessed through the SEC’s Interactive Data Electronic Applications system at www.sec.gov. All statements made in any of our securities filings, including all forward-looking statements or information, are made as of the date of the document in which the statement is included and we do not assume or undertake any obligation to update any of those statements or documents unless we are required to do so by law.

Our code of conduct, corporate governance guidelines and the charters of our Audit Committee, Compensation Committee and Nominating and Corporate Governance Committee are available through our website at www.tcr2.com.

Item 1A. Risk Factors

Careful consideration should be given to the following risk factors, in addition to the other information set forth in this Annual Report on Form 10-K and in other documents that we file with the Securities and Exchange Commission, or SEC, in evaluating the Company and our business. Investing in our common stock involves a high degree of risk. If any of the following risks and uncertainties actually occurs, our business, prospects, financial condition and results of operations could be materially and adversely affected. The risks described below are not intended to be exhaustive and are not the only risks facing the Company. Additional risks and uncertainties not presently known to us or that we currently deem immaterial also may impact our business, prospects, financial condition and results of operations.

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Risks Related to the Development of Our Product Candidates

Risks Related to Clinical Development

Our approach to the discovery and development of product candidates based on our TRuC-T cell platform represents a novel approach to cancer treatment, which creates significant challenges for us.

Our future success depends on the successful development of our product candidates, which target solid tumors and hematologic malignancies using the complete T cell receptor (TCR) complex without the need for human leukocyte antigen (HLA) matching. Advancing our product candidates based on our innovative TRuC-T cell platform creates significant challenges for us, including:

In developing our product candidates, we have not exhaustively explored different options in the design of the TRuC construct and in the method for manufacturing TRuC-T cells. We may find our existing TRuC-T cells and manufacturing process may be substantially improved with future design or process changes, necessitating development of new or additional TRuC constructs and further clinical testing and delaying commercial launch of our first products. For example:

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We are early in our development efforts. Gavo-cel, our most advanced product candidate, is in the Phase 2 portion of the Phase 1/2 clinical trial, TC-510 is in the Phase 1 portion of the Phase 1/2 clinical trial and our other product candidates are still in preclinical development. If we are unable to advance our product candidates through clinical development, obtain regulatory approval and ultimately commercialize our product candidates, or experience significant delays in doing so, our business will be materially harmed. In January 2023, we announced that we have narrowed the focus of the ongoing Phase 2 clinical trial of gavo-cel to evaluate gavo-cel in ovarian cancer in combination with checkpoint inhibitors and redosing strategies, and prioritizing our second generation enhanced TC-510 and TC-520 programs.

We are early in our development efforts. Gavo-cel, our most advanced product candidate, is in the Phase 2 portion of the Phase 1/2 clinical trial, TC-510 is in the Phase 1 portion of the Phase 1/2 clinical trial and our other product candidates are still in preclinical development. Our ability to generate product revenues, which we do not expect will occur for many years, if ever, will depend heavily on the successful development and eventual commercialization of one or more of our product candidates. The success of our product candidates will depend on several factors, including the following:

If we do not achieve one or more of these factors in a timely manner or at all, we could experience significant delays or be unable to successfully commercialize our product candidates, which would materially harm our business.

We have limited experience as a company in conducting clinical trials.

We have limited experience as a company in conducting clinical trials. Our Phase 1/2 clinical trial for gavo-cel began in 2019 and our Phase 1/2 clinical trial for TC-510 began in 2022. Because of this limited experience and other factors, we cannot be certain that our planned and ongoing preclinical studies will be completed on time, or that our planned and ongoing clinical trials will begin, enroll sufficient patients, produce data on expected timelines or be completed on expected timelines, if at all. Large-scale clinical trials require significant additional financial and management resources and reliance on third-party clinical investigators, CROs and consultants. Relying on third-party clinical investigators, CROs and consultants may force us to encounter delays that are outside of our control.

Clinical development involves a lengthy and expensive process with an uncertain outcome and results of earlier studies and trials may not be predictive of future clinical trial results. If our preclinical studies and clinical trials are not sufficient to support regulatory approval of any of our product candidates, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development of such product candidate.

We cannot be certain that our preclinical studies and clinical trial results will be sufficient to support regulatory approval of our product candidates. Clinical testing is expensive and can take many years to complete and its outcome is inherently uncertain. Human clinical trials are expensive and difficult to design and implement, in part because they are subject to rigorous regulatory requirements. Failure or delay can occur at any time during the clinical trial process.

We may experience delays in obtaining the FDA’s authorization to initiate clinical trials under future INDs, completing ongoing clinical studies of our product candidates due to a variety of factors, including the impact of COVID-19 at our clinical sites and

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initiating our planned preclinical studies and clinical trials. Additionally, we cannot be certain that preclinical studies or clinical trials for our product candidates will begin on time, not require redesign, enroll an adequate number of subjects on time, or be completed on schedule, if at all. Clinical trials can be delayed or terminated for a variety of reasons, including delays or failures related to:

For example, in February 2019, we received a request from the FDA’s Center for Devices and Radiological Health (CDRH) for the submission of an investigational device exemption (IDE) application regarding our use of a commercially available in vitro diagnostic assay for screening mesothelin expression in tumors. The CDRH subsequently determined that we did not need to submit an IDE application, but such a requirement, or other unexpected FDA requests, could lead to future delays of our clinical trials. We may experience numerous adverse or unforeseen events during, or as a result of, preclinical studies and clinical trials that could delay or prevent our ability to receive marketing approval or commercialize our product candidates, including:

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If we are required to conduct additional clinical trials or other testing of our product candidates beyond those that we currently contemplate, if we are unable to successfully complete clinical trials of our product candidates or other testing, if the results of these trials or tests are not positive or are only moderately positive or if there are safety concerns, our business and results of operations may be adversely affected and we may incur significant additional costs. In addition, costs to treat patients with relapsed or refractory cancer and to treat potential side effects that may result from our product candidates can be significant. Accordingly, our clinical trial costs are likely to be significantly higher than those for more conventional therapeutic technologies or drug product candidates.

We could also encounter delays if a clinical trial is suspended or terminated by us, by the IRBs of the institutions in which such clinical trials are being conducted, by the Data Safety Monitoring Board (DSMB) for such clinical trial or by the FDA or other regulatory authorities. Such authorities may suspend or terminate a clinical trial due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical trial protocols, inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from the product candidates, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial.

If we experience delays in the completion, or termination, of any preclinical study or clinical trial of our product candidates, the commercial prospects of our product candidates may be harmed and our ability to generate revenues from any of these product candidates will be delayed or not realized at all. In addition, any delays in completing our preclinical studies or clinical trials may increase our costs, slow down our product candidate development and approval process and jeopardize our ability to commence product sales and generate revenues. Any of these occurrences may significantly harm our business, financial condition and prospects. In addition, many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of our product candidates. If one or more of our product candidates generally prove to be ineffective, unsafe or commercially unviable, our entire pipeline and TRuC-T cell platform would have little, if any, value, which would have a material and adverse effect on our business, financial condition, results of operations and prospects.

Our business is highly dependent on our clinical trials for our lead product candidates, gavo-cel and TC-510 and we must complete IND-enabling studies and clinical testing before we can seek regulatory approval and begin commercialization of any of our product candidates. We cannot be certain that we will be able to complete ongoing clinical trials, initiate future planned clinical trials, or advance our product candidates into additional trials, or to successfully develop, or obtain regulatory approval for, or successfully commercialize, any of our product candidates.

Our business depends heavily on our ability to complete clinical development and non-clinical studies of our lead product candidates, gavo-cel and TC-510 and our other product candidates and to obtain regulatory approval of and successfully commercialize these and any future product candidates. There is no guarantee that any of our product candidates will proceed in preclinical or clinical development or achieve regulatory approval. The process for obtaining marketing approval for any product candidate is very long and risky and there will be significant challenges for us to address in order to obtain marketing approval as planned or, if at all.

There is no guarantee that the results obtained in current preclinical studies, the Phase 2 portion of our Phase 1/2 clinical trial of gavo-cel, the Phase 1 and/or Phase 2 portions of our Phase 1/2 clinical trial of TC-510, or our other planned clinical trials will be sufficient to obtain regulatory approval or marketing authorization for such product candidates. The FDA may ultimately decide that the design, number and type of clinical trials, number of patients studied or results of our clinical trial for gavo-cel and/or TC-510, even if positive, are not sufficient for regulatory approval in their respective target indications. Changes in the manufacturing process as we scale-up and optimize our process for manufacturing our product candidates could also delay development or require us to conduct additional clinical trials or non-clinical studies or could lead to different results than achieved with the earlier processes. We may not be able to initiate or complete our clinical trials or announce results from our clinical trials on the timelines we expect. We may experience slower than expected enrollment and randomization of patients in our clinical trials. These types of delays can lead to delays in completion of a trial and announcement of results. There is also the potential for slower than expected clinical site initiation, delays or problems in analyzing data and the potential need for additional analysis or data or the need to enroll additional patients in any of our clinical trials. We may also encounter delays arising from unexpected adverse events in a trial or other unexpected hurdles or issues in the conduct of any trial. We may not be able to collect sufficient data in our clinical trials to obtain regulatory approval or marketing authorization or to continue with clinical development of one or more of our product candidates. For example, we may not be able to obtain sufficient patient samples because the patients we enroll in our clinical trials are unable or unwilling to complete follow-up visits and/or proceed with sample collection such as biopsy procedures. Consequently, we may not be able to produce translational or other data on expected timelines, or at all. Negative results in the development of our lead product candidates may also impact our ability to obtain regulatory approval for our other product candidates, either at all or within anticipated timeframes because, although other product candidates may target different

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indications, the underlying technology platform, manufacturing process and development process is the same for all of our product candidates. Accordingly, a failure in any one program may affect the ability to obtain regulatory approval to continue or conduct clinical programs for other product candidates.

In addition, because we have limited financial and personnel resources and are placing significant focus on the development of our lead product candidates, we may forgo or delay pursuit of opportunities with other future product candidates that later prove to have greater commercial potential, or may need to divert resources to other programs. For example, in October 2021, in alignment with our pipeline prioritization on solid tumors, we deprioritized the development of TC-110, a product candidate in a Phase 1 clinical trial. Further, we may forgo, delay, alter, or reduce focus and/or expenditure on development of certain lead product candidates in favor of, or to allow prioritization of, development of other product candidates. For example, in January 2023, we announced that we have narrowed the focus of the ongoing Phase 2 clinical trial of gavo-cel to evaluate gavo-cel in ovarian cancer in combination with checkpoint inhibitors and redosing strategies, and prioritizing our second generation enhanced TC-510 and TC-520 programs. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities or limit the opportunities we are able to pursue. Our spending on current and future research and development programs and other future product candidates for specific indications may not yield any commercially viable future product candidates. If we do not accurately evaluate the commercial potential or target market for a particular future product candidate, we may relinquish valuable rights to those future product candidates through collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such future product candidates.

Our preclinical studies and clinical trials may fail to demonstrate adequately the safety and efficacy of any of our product candidates, which would prevent or delay development, regulatory approval and commercialization.

Before obtaining regulatory approvals for the commercial sale of our product candidates, including gavo-cel and TC-510, we must demonstrate through lengthy, complex and expensive preclinical studies and clinical trials that our product candidates are both safe and effective for use in each target indication. We may not be able to demonstrate the efficacy and safety of gavo-cel, TC-510, or any of our other product candidates or any future product candidate at each stage of clinical development or we may encounter issues with any non-clinical studies required for regulatory submissions. Success in preclinical studies or in earlier stage clinical trials may not be repeated or observed in ongoing or future clinical trials involving TRuCs or other product candidates. The results of clinical trials or non-clinical studies of our product candidates at any stage may not support further development or may not be sufficient to obtain regulatory approval.

Based on the topline data readout presented on September 28, 2022 from patients in dose escalation in the Phase 1 portion of our Phase 1/2 clinical trial as of the September 9, 2022 data cutoff, gavo-cel was generally well tolerated with a manageable adverse event profile up until dose level (DL) 5, with no patients experiencing on-target, off-tumor toxicities. Two dose limiting toxicities (DLTs) were observed: one case of Grade 3 pneumonitis at DL1 that resolved with anti-cytokine therapy and one case of Grade 5 bronchoalveolar hemorrhage at DL5. Furthermore, all three patients treated at DL5 experienced Grade ≥3 CRS which resulted in 5x108 cells/m2 following lymphodepletion being declared the maximum tolerated dose (MTD) by the safety review team (SRT). After declaring the MTD, the study proceeded to a dose de-escalation portion, first at DL3.5 (3x108 cells/m2 following lymphodepletion) using a split-dosing approach and subsequently at DL3 (1x108cells/m2 following lymphodepletion) which was declared the RP2D. No new DLTs were observed during the dose de-escalation. While our data in the Phase 1/2 clinical trial has been positive with a manageable adverse event profile, these results may not be repeated or observed in future cohorts of patients treated in the currently ongoing clinical trial or in future clinical trials and may not be predictive of the results of later-stage clinical trials.

The drug-development process, including preclinical and clinical testing is expensive, can take many years to complete and may include post-marketing studies and surveillance, which will require the expenditure of substantial resources. The outcome of the drug development process is inherently uncertain. Of the large number of drugs in development in the U.S., only a small percentage will successfully complete the FDA regulatory approval process and will be commercialized. Failure can occur at any time during the preclinical study and clinical trial processes and, because our product candidates are in an early stage of development, there is a high risk of failure and we may never succeed in developing marketable products. Clinical trials of our product candidates are, and the manufacturing and marketing of our product candidates will be, subject to extensive and rigorous review and regulation by numerous government authorities in the U.S. and in other countries where we intend to test and, if approved, market any product candidate. Accordingly, even if we have the requisite financial resources, when needed, to continue to fund our development efforts, we cannot assure you that any of our product candidates will be successfully developed or commercialized either in the U.S. or in any country outside the U.S. Even if we gain approval of any of our other product candidates, we may never be able to successfully commercialize the product or to meet our expectations with respect to revenues or profits.

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The results of preclinical studies and early clinical trials of our product candidates may not be predictive of the results of later-stage clinical trials. There is typically an extremely high rate of attrition from the failure of product candidates proceeding through preclinical studies and clinical trials. Product candidates in later stages of clinical trials may fail to show the desired safety and efficacy profile despite having progressed through preclinical studies and initial clinical trials. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of potency or efficacy, insufficient durability of potency or efficacy or unacceptable safety issues, notwithstanding promising results in earlier trials. Most product candidates that commence preclinical studies and clinical trials are never approved as products.

Any preclinical studies or clinical trials that we may conduct may not demonstrate the safety and efficacy necessary to obtain regulatory approval to market our product candidates. If the results of our ongoing or future preclinical studies and clinical trials are inconclusive with respect to the safety and efficacy of our product candidates, if we do not meet the clinical endpoints with statistical and clinically meaningful significance, or if there are safety concerns associated with our product candidates, we may be prevented or delayed in obtaining marketing approval for such product candidates. There can be significant variability in safety and efficacy results between different preclinical studies and clinical trials of the same product candidate due to numerous factors, including changes in trial procedures set forth in protocols, differences in the size and type of the patient populations, changes in and adherence to the clinical trial protocols and the rate of dropout among clinical trial participants. Additionally, our preclinical studies comparing our product candidates to chimeric antigen receptor T (CAR-T) cells utilized CAR-T cells that we engineered, rather than the CAR-T cell therapies that are currently approved by the FDA. Although we believe, based on the results we observed in these preclinical studies, that our product candidates have the potential to improve upon the safety and efficacy of currently approved CAR-T cell therapies, these results may not be predictive of the outcome of our future preclinical studies and clinical trials, including any potential preclinical studies and clinical trials that may compare our product candidates to FDA-approved CAR-T cells.

Since the number of patients that we plan to dose in each of our Phase 1/2 clinical trials for gavo-cel is small, the results from these clinical trials, once completed, may be less reliable than results achieved in a larger clinical trial, which may hinder our efforts to obtain regulatory approval.

The number of patients we plan to treat in our clinical trial for gavo-cel is small and the results from this clinical trial, once completed, may be less reliable that results achieved in larger clinical trials. For example, in the Phase 1 portion of our Phase 1/2 clinical trial of gavo-cel, we evaluated the safety profile of gavo-cel and established the RP2D. In Phase 2, we intend to treat approximately 20 patients with ovarian cancer. The preliminary results of clinical trials with smaller sample sizes, such as our Phase 1/2 clinical trials of gavo-cel, can be disproportionately influenced by various biases associated with the conduct of small clinical trials, such as the potential failure of the smaller sample size to accurately depict the features of the broader patient population, which limits the ability to generalize the results across a broader community, thus making the clinical trial results less reliable than clinical trials with a larger number of patients. As a result, there may be less certainty that such product candidates would achieve a statistically significant effect in any future clinical trials. If we conduct any future clinical trials of gavo-cel, we may not achieve a statistically significant result or the same level of statistical significance, if any, that we might have anticipated based on the results observed in our initial Phase 1/2 clinical trials.

We may not be able to file INDs or IND amendments to commence additional clinical trials on the timelines we expect, and even if we are able to, the FDA may not permit us to proceed.

We may not be able to file INDs on the timelines we expect. For example, we may experience manufacturing delays or other delays with IND-enabling studies. Moreover, we cannot be sure that submission of an IND will result in the FDA allowing further clinical trials to begin, or that, once begun, issues will not arise that suspend or terminate clinical trials. Additionally, even if such regulatory authorities agree with the design and implementation of the clinical trials set forth in an IND, we cannot guarantee that such regulatory authorities will not change their requirements in the future. These considerations also apply to new clinical trials we may submit as amendments to existing INDs.

If we encounter difficulties enrolling patients in our clinical trials, our clinical development activities could be delayed or otherwise adversely affected.

We may experience difficulties in patient enrollment in our clinical trials for a variety of reasons, including impacts that have resulted or may result from the ongoing COVID-19 pandemic. The timely completion of clinical trials in accordance with their protocols depends on, among other things, our ability to enroll a sufficient number of patients who remain in the clinical trial until its conclusion. The enrollment of patients depends on many factors, including:

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Our clinical trials will compete with other clinical trials for product candidates that are in the same therapeutic areas as our product candidates and this competition will reduce the number and types of patients available to us because some patients who might have opted to enroll in our clinical trials may instead opt to enroll in a clinical trial being conducted by one of our competitors. In addition, patients may be unwilling to participate in our studies because of negative publicity from adverse events in the biotechnology industry or for other reasons. Since the number of qualified clinical investigators is limited, we expect to conduct some of our clinical trials at the same clinical trial sites that some of our competitors use, which will reduce the number of patients who are available for our clinical trials at such clinical trial sites. Moreover, because our product candidates represent a departure from more commonly used methods for cancer treatment, potential patients and their doctors may be inclined to use conventional therapies, such as chemotherapy and hematopoietic stem cell transplantation, rather than enroll patients in any future clinical trial. Additionally, because some of our clinical trials are in patients with relapsed/refractory cancer, the patients are typically in the late stages of their disease and may experience disease progression independent from our product candidates, making them unevaluable for purposes of the clinical trial and requiring additional patient enrollment.

Delays in completing patient enrollment may result in increased costs or may affect the timing or outcome of our ongoing and planned clinical trials, which could prevent completion or commencement of these clinical trials and adversely affect our ability to advance the development of our product candidates.

Our product candidates may cause undesirable side effects or have other properties that could halt their clinical development, prevent their regulatory approval, require expansion of the trial size, limit their commercial potential, or result in significant negative consequences.

Undesirable side effects caused by our product candidates could cause us or regulatory authorities, including IRBs, to interrupt, delay, or halt clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other comparable foreign regulatory authorities. Further, clinical trials by their nature utilize a sample of the potential patient population. With a limited number of subjects and limited duration of exposure, rare and severe side effects of our product candidates may only be uncovered with a significantly larger number of patients exposed to the drug. Because of our planned dose escalation design for our clinical trials, undesirable side effects could also result in an expansion in the size of our clinical trials, increasing the expected costs and timeline of our clinical trials. Additionally, results of our clinical trials could reveal a high and unacceptable severity and prevalence of side effects or unexpected characteristics, which may stem from our product candidates specifically or may be due to an illness from which the clinical trial subject is suffering. In the Phase 1 dose escalation portion of our Phase 1/2 clinical trial, as of the September 9, 2022 data cutoff, gavo-cel was generally well tolerated with a manageable adverse event profile up until DL5, with no patients experiencing on-target, off-tumor toxicities. Two DLTs were observed: one case of Grade 3 pneumonitis at DL1 that resolved with anti-cytokine therapy and one case of Grade 5 bronchoalveolar hemorrhage at DL5. Furthermore, all three patients treated at DL5 experienced Grade ≥3 CRS which resulted in 5x108cells/m2 following lymphodepletion being declared the MTD by the SRT. After declaring the MTD, the study proceeded to a dose de-escalation portion, first at DL3.5 (3x108 cells/m2 following lymphodepletion) using a split-dosing approach and subsequently at DL3 (1x108cells/m2 following lymphodepletion) which was declared the RP2D. No new DLTs were observed during the dose de-escalation. While our data in the Phase 1/2 clinical trial has been positive with a manageable safety profile, these results may not be repeated or observed in future cohorts of patients treated in the currently ongoing clinical trial or in future clinical trials and may not be predictive of the results of later-stage clinical trials.

Autoimmunity may occur after TRuC-T cell treatment. TRuC-T cells are generated from a patient’s own T cells isolated from their peripheral blood. There is a theoretical risk that this process will expand a patient’s own T cell that has autoreactivity, or that may recognize healthy cells and upon re-infusion may trigger an autoimmune reaction resulting in damage to normal tissues and potentially even death. Autoimmune reaction triggered by an interaction between a patient’s naturally occurring antibodies and engineered T cells is a theoretical safety risk of product candidates we develop using our TRuC-T cell platform. If a patient’s

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self-generated antibodies were directed to a target expressed on the surface of cells in normal tissue (autoantibodies), engineered T cells would be directed to attack these same tissues, potentially resulting in off-tumor effects. These autoantibodies may be present whether or not the patient has an active autoimmune disease. In our clinical testing, we plan to take steps to minimize the likelihood that this occurs, for example by excluding patients with a history of severe autoimmune disease from our trials. There is no guarantee, however, that we will not observe autoimmune reactions in the future and no guarantee that if we do, that we will be able to implement interventions to address the risk.

Immunogenicity, which is the reaction between a patient’s immune system and a foreign protein outside of the autoimmune context, is an additional theoretical safety risk of product candidates we develop using our TRuC-T cell platform. Patients’ immune systems may recognize the TRuC construct on the TRuC-T cell as a foreign protein and fight against it, potentially rendering it ineffective, or even provoking an allergic/anaphylactoid response or other adverse side effects. The immunogenic potential of novel therapeutics like TRuC-T cells is difficult to predict. There is no guarantee that we will not observe immunogenic reactions in the future and no guarantee that if we do, that we will be able to implement interventions to address the risk.

If unacceptable toxicities arise in the development of our product candidates, we could suspend or terminate our clinical trials or the FDA or comparable foreign regulatory authorities, or local regulatory authorities such as IRBs, could order us to cease clinical trials. Competent national health authorities, such as the FDA, could also deny approval of our product candidates for any or all targeted indications. Treatment-related side effects could also affect patient recruitment or the ability of enrolled patients to complete the clinical trial or result in potential product liability claims. In addition, these side effects may not be appropriately recognized or managed by the treating medical staff, as toxicities resulting from T cell therapy are not normally encountered in the general patient population and by medical personnel. We expect to have to train medical personnel using our product candidates to understand the side effect profile of our product candidates for both our planned clinical trials and upon any commercialization of any product candidates, if licensed. Inadequate training in recognizing or managing the potential side effects of our product candidates could result in patient deaths. Any of these occurrences may significantly harm our business, financial condition and prospects.

Our product candidates may target healthy cells expressing target antigens leading to potentially fatal adverse effects.

Our product candidates target specific antigens that are also expressed on healthy cells. For example, each of gavo-cel and TC-510 targets mesothelin, an antigen commonly found on mesotheliomas, ovarian cancers and NSCLC, as well in healthy cells that line the pleura, pericardium and peritoneum. Our product candidates may target healthy cells, leading to serious and potentially fatal adverse effects. In the Phase 1 portion of our Phase 1/2 clinical trial of gavo-cel we used, and in the Phase 1 portion of our Phase 1/2 clinical trial of TC-510 we are using, a dose escalation model to closely monitor the effect of gavo-cel and TC-510 on vital organs and other potential side effects. Even though we intend to closely monitor the side effects of our product candidates in both preclinical studies and clinical trials, we cannot guarantee that products will not target and kill healthy cells.

Our product candidates may have serious and potentially fatal cross-reactivity to other peptides or protein sequences within the body.

Our product candidates may recognize and bind to a peptide unrelated to the target antigen to which it is designed to bind. If this peptide is expressed within normal tissues, our product candidates may target and kill the normal tissue in a patient, leading to serious and potentially fatal adverse effects. Detection of any cross-reactivity may halt or delay any ongoing clinical trials for any TRuC-T cell based product candidate and prevent or delay regulatory approval. Unknown cross-reactivity of the TRuC-T cell binding domain to related proteins could also occur. We have also developed a preclinical screening process to identify cross-reactivity of the TRuC-T cell binders. Any cross-reactivity that impacts patient safety could materially impact our ability to advance our product candidates into clinical trials or to proceed to marketing approval and commercialization.

Our product candidates rely on the use of protein binding domains, or binders, to target specific cancers, which we may develop or which may be developed by third parties. We are limited in our ability to apply our product candidates to a wider range of potential target cancers by our ability to develop, partner for or acquire these binders on commercially reasonable terms.

TRuC-T cell therapies require the use of antigen-specific protein binding domains, or binders, which guide the TRuC-T cells and bind to the antigens on the surface of a tumor to target specific types of cancers. Our ability to develop and commercialize our product candidates will depend on our ability to develop these binders or partner for such binders on commercially reasonable terms for use in clinical trials as well as the availability of such binders for use in commercialized products, if licensed. For example, we have a non-exclusive license for the mesothelin binder incorporated into the TRuC construct for gavo-cel and for TC-510 from Harpoon Therapeutics, Inc. (Harpoon). However, we cannot be certain that our Harpoon license or potential future collaborations will provide us with a steady supply of binders that we can utilize in combination with the TRuC construct to develop

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future product candidates. If we are unable to enter into such collaborations on commercially reasonable terms or fail to realize the benefits of any such collaboration, we may be limited to using antibody fragments that we are able to independently develop which may limit the ability of our product candidates to target and kill cancer cells.

The failure to enter into a successful collaboration or to develop our own binders may delay our development timelines, increase our costs and jeopardize our ability to develop future product candidates as a commercially viable drug, which could result in delays in product development and harm our business.

Co-administering our TRuC-T cell product candidates with other approved therapies or enhancing our TRuC-T cells with new constructs may increase the risk of severe adverse events, including cytokine release syndrome and other toxicities, which could interrupt, delay, or halt our clinical trials.

We believe that co-administration and/or enhancing our TRuC-T cell product candidates may lead to better efficacy, durability and patient outcomes. However, enhancements and co-administration may increase the occurrence of severe adverse side effects, such as cytokine release syndrome (CRS). Undesirable side effects caused by our product candidates could cause us or regulatory authorities, including IRBs, to interrupt, delay, or halt clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other comparable foreign regulatory authorities.

We are evaluating gavo-cel in combination with the checkpoint inhibitor Opdivo® (nivolumab), an anti-PD-1 checkpoint inhibitor, and Yervoy® (ipilimumab), an anti-CTLA-4 checkpoint inhibitor, in the planned Phase 2 portion of our Phase 1/2 clinical trial. Nivolumab and ipilimumab are FDA approved therapies, but each has its own risks and side effects. Providing these therapies in combination with gavo-cel may increase gavo-cel’s efficacy, but it may also increase undesirable side effects from gavo-cel, nivolumab or ipilimumab.

Our first enhanced TRuC-T cell is TC-510, which is a TRuC-T cell targeting mesothelin-expressing solid tumors which incorporates a PD-1:CD28 chimeric switch receptor (PD-1 Switch). The PD-1 Switch is designed to translate the inhibition of a cancer cell’s PD-1 signal into a costimulatory CD28 signal, causing cell activity to increase rather than be suppressed by the hostile tumor microenvironment. Based on our preclinical studies, we believe that TC-510’s unique way of engaging and powering T cells could lead to improved T cell function and persistence and result in better clinical outcomes for patients. However, increased T cell function may also lead to greater risk of severe adverse side effects. We have observed adverse side effects with gavo-cel in the Phase 1 portion of our Phase 1/2 clinical trial, including several patients that developed grade 3 or higher CRS, one patient with Grade 3 pneumonitis that resolved with anti-cytokine therapy, and one patient with Grade 5 bronchoalveolar hemorrhage. It is possible that TC-510, which is similar to gavo-cel plus the PD-1 Switch, will have a greater risk of triggering CRS and other undesirable side effects.

We may not be successful in our efforts to identify or discover additional product candidates.

The success of our business depends primarily upon our ability to identify, develop and commercialize products based on our TRuC-T cell platform. Our research programs may fail to identify other potential product candidates for clinical development for a number of reasons. We may be unsuccessful in identifying potential product candidates or our potential product candidates may be shown to have harmful side effects or may have other characteristics that may make the products unmarketable or unlikely to receive marketing approval. Research programs to identify new product candidates require substantial technical, financial and human resources. We may focus our efforts and resources on potential programs or product candidates that ultimately prove to be unsuccessful. If any of these events occur, we may be forced to abandon our research, development or commercialization efforts for a program or programs, which would have a material adverse effect on our business and could potentially cause us to cease operations.

Risks Related to Manufacturing

Manufacturing and administering our product candidates are complex and we may encounter difficulties in production, particularly with respect to process development or scaling up of our manufacturing capabilities. If we encounter such difficulties, our ability to provide supply of our TRuC-T cells for clinical trials or for commercial purposes could be delayed or stopped.

The process of manufacturing and administering our product candidates is complex and highly regulated. The manufacture of our product candidates involves complex processes, including the manufacture of a lentiviral delivery vector containing the genetic information for our TRuC construct and manufacturing T cells containing the TRuC construct for the final product candidates. More

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specifically, the manufacture of our product candidates includes harvesting white blood cells from the patient, isolating certain T cells from the white blood cells, combining patient T cells with our lentiviral delivery vector through a process known as transduction, expanding the transduced T cells to obtain the desired dose and ultimately infusing the modified T cells back into the patient’s body. As a result of the complexities entailed in this process, our manufacturing and supply costs are likely to be higher than those at more traditional manufacturing processes and the manufacturing process is less reliable and more difficult to reproduce. Additionally, the number of facilities that are capable of harvesting patients’ cells for the manufacture of our product candidates and other autologous cell therapy products and product candidates is limited. As the number of autologous cell therapy products and product candidates increases, the limited number of facilities capable of harvesting patients’ cells could result in delays in the manufacture and administration of our product candidates and/or require us to prioritize among our clinical programs, potentially resulting in clinical trial delays.

We rely on third parties for the manufacture of our lentiviral vectors and our product candidates. These third-party manufacturers may incorporate their own proprietary processes into our lentiviral vector and product candidate manufacturing processes. We have limited control and oversight of a third party’s proprietary process and a third party may elect to modify its process without our consent or knowledge. These modifications could negatively impact our manufacturing, including product loss or failure that requires additional manufacturing runs or a change in manufacturer, both of which could significantly increase the cost of and significantly delay the manufacture of our product candidates. In addition, these third parties may have limited manufacturing capacity and we have less control over production methods, staffing and product quality when produced with third party manufacturers. In both cases, this can cause delays in planned manufacturing runs, require remanufacture due to failed runs and limit our ability to manufacture lentiviral vector and our product candidates as needed, resulting in delays for IND filings, clinical trials and non-clinical studies.

Our manufacturing process is and will be susceptible to product loss or failure due to logistical issues, including manufacturing issues associated with the differences in patients’ white blood cells, interruptions in the manufacturing process, contamination, equipment or reagent failure, power failures, supplier error and variability in patient characteristics. For example, in July 2018, a power failure that occurred during a manufacturing run to produce virus for our Phase 1/2 clinical trial of gavo-cel caused us to abandon that run and resulted in a month-long delay in the process of manufacturing the requisite virus to support our IND filing for gavo-cel and consequently a delay in the IND filing itself. Even minor deviations from normal manufacturing processes could result in reduced production yields, product defects and other supply disruptions. If for any reason we lose a patient’s white blood cells, or such material gets contaminated or processing steps fail at any point, the manufacturing process of the TRuC-T cells for that patient will need to be restarted and the resulting delay may adversely affect that patient’s outcome. If microbial, viral or other contaminations are discovered in our product candidates or in the manufacturing facilities in which our product candidates are made or administered, such manufacturing facilities may need to be closed for an extended period of time to investigate and remedy the contamination.

As our product candidates progress through preclinical studies and clinical trials towards potential licensure and commercialization, it is expected that various aspects of the manufacturing and administration process will be altered in an effort to optimize processes and results. We have already identified some improvements to our manufacturing and administration processes, but these changes may not achieve the intended objectives and could cause our product candidates to perform differently and affect the results of planned clinical trials or other future clinical trials. In addition, such changes may require amendments to be made to regulatory applications which may further delay the timeframes under which modified manufacturing processes can be used for any of our product candidates.

Developing a commercially viable process is a difficult and uncertain task and there are risks associated with scaling to the level required for advanced clinical trials or commercialization, including, among others, increased costs, potential problems with process scale-out, process reproducibility, stability issues, lot consistency and timely availability of reagents or raw materials. In addition, changes to our manufacturing process may also require further review and approval by the FDA, leading to delays in our clinical trials. Competitors have had difficulty reliably producing T-cell therapies in the commercial setting. If we experience similar challenges manufacturing product candidates to approved specifications, this may limit our product candidates’ utilization and our ability to receive payment for these product candidates once approved. We may ultimately be unable to reduce the expenses associated with our product candidates to levels that will allow us to achieve a profitable return on investment.

We do not have our own clinical-scale manufacturing facility and are currently reliant on a limited number of manufacturers for our lentiviral vector and TRuC-T cell product candidates. We will pursue additional manufacturing capacity to meet the patient demand for our product candidates as needed, however third-party manufacturing providers may not be able to provide adequate resources or consistent capacity to meet our clinical trial or commercial needs.

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We rely on third parties to manufacture our product candidates for our clinical trials.

We rely on third parties for the manufacture of our lentiviral vectors and our product candidates. We do not currently have a facility that can be used as our clinical scale manufacturing facility for our product candidates or lentiviral vector and we expect to rely on outside vendors to meet these manufacturing needs. The capacity of third party manufacturers may not be enough to support our clinical trials. In addition, since we do not train or control the workforce of the third party manufacturers that we utilize, we have less control over the production methods and procedures and the product quality. We have not yet caused any product candidates to be manufactured or processed on a commercial scale and may not be able to do so for any of our product candidates. We plan to make changes as we work to optimize the manufacturing process. For example, we may switch or be required to switch from research-grade materials to commercial-grade materials in order to get regulatory approval of our product candidates. We cannot be sure that even minor changes in the process will result in therapies that are safe and effective and licensed for commercial sale.

The facilities used by our contract manufacturers to manufacture our product candidates must be approved by the FDA, as part of our BLA, or other foreign regulatory authorities following inspections by the FDA or other foreign regulatory authorities. We do not control the manufacturing process of, and are completely dependent on, our contract manufacturing partners for compliance with cGMPs and any other regulatory requirements of the FDA or other regulatory authorities for the manufacture of our product candidates. We have no control over the ability of our contract manufacturers to maintain adequate quality control, quality assurance and qualified personnel. If the FDA or a comparable foreign regulatory authority finds deficiencies with or does not approve these facilities for the manufacture of our product candidates or if it finds deficiencies or withdraws any approval in the future, we may need to find alternative manufacturing facilities, which would significantly impact our ability to develop, obtain regulatory approval for or market our product candidates. In addition, these third parties may have limited manufacturing capacity and we have less control over production methods, staffing and product quality when produced with third-party manufacturers. In both cases, this can cause delays in planned manufacturing runs, require remanufacture due to failed runs and limit our ability to manufacture lentiviral vector and our product candidates as needed, resulting in delays for IND filings, clinical trials and non-clinical studies.

We may in the future establish our own manufacturing facility and infrastructure in addition to or in lieu of relying on third parties for the manufacture of our product candidates, which would be costly, time-consuming and which may not be successful.

As part of our manufacturing strategy and to mitigate our reliance on third-party vendors for the manufacture of TRuC-T cells, we may determine in the future that we will internalize some or all of our manufacturing capacity by utilizing our own company-operated manufacturing facility. The establishment of our own commercial manufacturing facility would be a costly and time-consuming process that would require significant additional capital to fund, and it may be unsuccessful. We have no experience as a company in the set up and building or management of a manufacturing facility or manufacturing suite and may never be successful in developing our own manufacturing suite, manufacturing facility or manufacturing capability. We would need to hire additional personnel to manage our operations and facilities and develop the necessary infrastructure to continue the research and development, and eventual commercialization, if approved, of our product candidates. If we fail to recruit the required personnel and generally manage our growth effectively or fail to select the correct location or otherwise determine that building or establishing our own manufacturing facility is no longer in line with our manufacturing strategy, the development and production of our product candidates could be curtailed or delayed or we could incur costs associated with closing down a manufacturing facility or with stopping development of our own manufacturing facility. For example, during the fourth quarter of 2022, we determined that we would cease the build-out of our own commercial manufacturing facility in Rockville, Maryland.

Even if we are successful in establishing a manufacturing suite or manufacturing facility in the future, our manufacturing capabilities could be affected by cost-overruns, unexpected delays, equipment failures, labor shortages, natural disasters, power failures and numerous other factors that could prevent us from realizing the intended benefits of our manufacturing strategy and have a material adverse effect on our business.

In addition, the FDA, the European Medicines Agency (EMA) and other foreign regulatory authorities may require us to submit samples of any lot of any licensed product together with the protocols showing the results of applicable tests at any time. Under some circumstances, the FDA, the EMA or other foreign regulatory authorities may require that we not distribute a lot until the relevant agency authorizes its release. Slight deviations in the manufacturing process, including those affecting quality attributes and stability, may result in unacceptable changes in the product that could result in lot failures or product recalls. Lot failures or product recalls could cause us to delay product launches or clinical trials, which could be costly to us and otherwise harm our business, financial condition, results of operations and prospects. Problems in our manufacturing process could restrict our ability to meet market demand for our products. The establishment of our own commercial manufacturing facility in the United States would result in our operations being subject to review and oversight by the FDA and the FDA could object to our use of our

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manufacturing facility. We must first receive approval from the FDA prior to licensure to manufacture our product candidates, which we may never obtain. Even if licensed, we would be subject to ongoing periodic unannounced inspection by the FDA and corresponding state agencies to ensure strict compliance with cGMPs and other government regulations. Our license to manufacture product candidates will be subject to continued regulatory review.

We also may encounter problems hiring and retaining the experienced scientific, quality-control and manufacturing personnel needed to operate our manufacturing processes, which could result in delays in production or difficulties in maintaining compliance with applicable regulatory requirements.

Any problems in our manufacturing process or facilities could make us a less attractive collaborator for potential partners, including larger pharmaceutical companies and academic research institutions, which could limit our access to additional attractive development programs.

We may have difficulty validating our manufacturing process as we manufacture TRuC-T cells from an increasingly diverse patient population for our clinical trials.

During our development of the manufacturing process, our TRuC-T cells have demonstrated consistency from lot to lot and from donor to donor. However, our sample size is small and the starting material is from healthy donors. Once we have experience with working with white blood cells taken from our patient population, we may encounter unforeseen difficulties due to starting with material from donors who are not healthy, including challenges inherent in harvesting white blood cells from unhealthy patients.

Although we believe our current manufacturing process is scalable for commercialization, we may encounter challenges in validating our process due to the heterogeneity of the product starting material. However, we anticipate that during the early phases of our clinical trials we will be able to adapt our process to account for these differences resulting in a more robust process. We cannot guarantee that any other issues relating to the heterogeneity of the starting material will not impact our ability to commercially manufacturing our product candidates.

The viral vectors used to manufacture our TRuC-T cells may incorrectly modify the genetic material of a patient’s T cells, potentially triggering the development of a new cancer or other adverse events.

Our TRuC-T cells are manufactured by using a viral vector to insert genetic information encoding the TRuC construct into the patient’s T cells. The TRuC construct is then integrated into the natural TCR complex and transported to the surface of the patient’s T cells. Because the viral vector modifies the genetic information of the T cell, there is a theoretical risk that modification will occur in the wrong place in the T cell’s genetic code, leading to vector-related insertional oncogenesis and causing the T cell to become cancerous. If the cancerous T cell is then administered to the patient with the TRuC-T cells, the cancerous T cell could trigger the development of a new cancer in the patient. We use lentiviral vectors to insert genetic information into T cells, which we believe have a lower risk of insertional oncogenesis as opposed to other types of viral vectors. However, the risk of insertional oncogenesis remains a concern for gene therapy and we cannot assure that it will not occur in any of our ongoing or planned preclinical studies or clinical trials. There is also the potential risk of delayed adverse events following exposure to gene therapy products due to persistent biological activity of the genetic material or other components of vectors used to carry the genetic material. The FDA has stated that lentiviral vectors possess characteristics that may pose high risks of delayed adverse events. If any such adverse events occur, further advancement of our preclinical studies or clinical trials could be halted or delayed, which would have a material adverse effect on our business and operations.

Risks Related to Commercialization

The market opportunities for our product candidates may be relatively small as it will be limited to those patients who are ineligible for or have failed prior treatments and our estimates of the prevalence of our target patient populations may be inaccurate.

Cancer therapies are sometimes characterized as first line, second line, or third line and the FDA often approves new therapies initially only for a particular line of use. When cancer is detected early enough, first line therapy is sometimes adequate to cure the cancer or prolong life without a cure. Whenever first line therapy, usually chemotherapy, antibody drugs, tumor-targeted small molecules, hormone therapy, radiation therapy, surgery, or a combination of these, proves unsuccessful, second line therapy may be administered. Second line therapies often consist of more chemotherapy, radiation, antibody drugs, tumor-targeted small molecules, or a combination of these. Third line therapies can include hematopoietic stem cell transplantation in certain cancers, chemotherapy, antibody drugs and small molecule tumor-targeted therapies, more invasive forms of surgery and new technologies. We expect to initially seek approval of our product candidates in most instances at least as a second or third line therapy, for use in patients with relapsed or refractory metastatic cancer. Subsequently, for those product candidates that we

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believe prove to be sufficiently safe and beneficial, if any, we would expect to seek approval as a second line therapy and potentially as a first line therapy, but there is no guarantee that our product candidates, even if licensed as a second or third or subsequent line of therapy, would be licensed for an earlier line of therapy and, prior to any such approvals, we may have to conduct additional clinical trials. Consequently, the potentially addressable patient population for our product candidates may be extremely limited or may not be amenable to treatment with our product candidates.

Our projections of both the number of people who have the cancers we are targeting, as well as the subset of people with these cancers in a position to receive a particular line of therapy and who have the potential to benefit from treatment with our product candidates, are based on our beliefs and estimates. These estimates have been derived from a variety of sources, including scientific literature, surveys of clinics, patient foundations or market research and may prove to be incorrect. Further, new therapies may change the estimated incidence or prevalence of the cancers that we are targeting. Consequently, even if our product candidates are approved for a second or third line of therapy, the number of patients that may be eligible for treatment with our product candidates may turn out to be much lower than expected.

We face significant competition and our operating results will suffer if we fail to compete effectively.

The biopharmaceutical industry is characterized by intense competition and rapid innovation. Our competitors may be able to develop other products or drugs that are able to achieve similar or better results. Our potential competitors include larger biotechnology and pharmaceutical companies with greater resources than us, academic institutions, governmental agencies, public and private research institutions and early stage or smaller companies. Many of our competitors have substantially greater financial, technical and other resources, such as larger research and development staff, experienced marketing and manufacturing organizations and well-established sales forces. In addition, many of these competitors are active in seeking patent protection and licensing arrangements in anticipation of collecting royalties for use of technology that they have developed. Mergers and acquisitions in the biotechnology and pharmaceutical industries may result in even more resources being concentrated in our competitors. Competition may increase further as a result of advances in the commercial applicability of technologies and greater availability of capital for investment in these industries. Our competitors, either alone or with collaborative partners, may succeed in developing, acquiring or licensing on an exclusive basis drug or biologic products that are more effective, safer, more easily commercialized or less costly than our product candidates or may develop proprietary technologies or secure patent protection that we may need for the development of our technologies and products. We believe the key competitive factors that will affect the development and commercial success of our product candidates are safety, potency, purity, tolerability, reliability, convenience of use, price and reimbursement.

The market opportunity in oncology has led to a number of collaborations including Janssen Biotech, Inc. (Janssen)/ Nanjing Legend Pharmaceutical & Chemical Co., Ltd (Legend), bluebird bio, Inc. (bluebird)/ Regeneron Pharmaceuticals Inc. (Regeneron) and bluebird/Gritstone Oncology, Inc.) and major acquisitions (Gilead Sciences, Inc. (Gilead)/Kite Pharma Inc. (Kite), Bristol Myers Squibb Co (BMS)/Celgene Corporation (Celgene)/Juno Therapeutics, Inc. (Juno), Takeda Pharmaceutical Company Limited (Takeda)/GammaDelta Therapeutics Limited (GammaDelta)), Astra Zeneca/Neogene Therapeutics Inc. (Neogene), Kite/Tmunity Therapeutics (Tmunity)) among companies focused on cellular cancer therapies. If this trend continues, which we expect, we could see further consolidation of technical expertise and human capital. This potentially provides a partnership opportunity for us but could also make it more challenging for us to acquire complementary technology or products and recruit and retain qualified scientific and management personnel. In addition, this competition could impact our ability to recruit clinical trial sites and patients in a timely manner for our clinical trials. Larger companies with greater financial flexibility and global reach may be able to obtain regulatory approvals and gain widespread market acceptance before us, which could impact our commercial launch and could make our products obsolete or non-competitive. Even if we obtain regulatory approval of our product candidates, the availability and price of our competitors’ products could limit the demand and the price we are able to charge for our product candidates. We may not be able to implement our business plan if the acceptance of our product candidates is inhibited by price competition or the reluctance of physicians to switch from existing methods of treatment to our product candidates, or if physicians switch to other new drug or biologic products or choose to reserve our product candidates for use in limited circumstances. For additional information regarding our competition, see “Business—Competition.”

Even if we obtain regulatory approval of our product candidates, the products may not gain market acceptance among physicians, patients, hospitals, cancer treatment centers and others in the medical community.

The use of engineered T cells as a potential cancer treatment is a recent development and may not become broadly accepted by physicians, patients, hospitals, cancer treatment centers and others in the medical community. Various factors will influence whether our product candidates are accepted in the market, including:

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In addition, although we are not utilizing embryonic stem cells or replication competent vectors, adverse publicity due to the ethical and social controversies surrounding the therapeutic use of such technologies and reported side effects from any clinical trials using these technologies or the failure of such clinical trials to demonstrate that these therapies are safe and effective may limit market acceptance of our product candidates. If our product candidates are licensed but fail to achieve market acceptance among physicians, patients, hospitals, cancer treatment centers or others in the medical community, we will not be able to generate significant revenue.

In addition, although our product candidates differ in certain ways from other engineered TCR-T cell and CAR-T cell approaches, serious adverse events or deaths in other clinical trials involving engineered TCR, CAR-T or other T cell products or with our use of licensed engineered TCR-T cell or CAR-T cell products, even if not ultimately attributable to our product or product candidates, could result in increased government regulation, unfavorable public perception and publicity, potential regulatory delays in the testing or licensing of our product candidates, stricter labeling requirements for those product candidates that are licensed and a decrease in demand for any such product candidates.

Even if our products achieve market acceptance, we may not be able to maintain that market acceptance over time if new products or technologies are introduced that are more favorably received than our products, are more cost effective or render our products obsolete.

Risks Related to Our Proposed Merger with Adaptimmune

Failure to complete, or delays in completing, the Merger with Adaptimmune announced on March 5, 2023 could materially and adversely affect our results of operations, business, financial results and/or stock price.

On March 5, 2023, we entered into an agreement with Adaptimmune pursuant to which, if all of the conditions to closing are satisfied or waived, we will become a wholly-owned indirect subsidiary of Adaptimmune. Consummation of the Merger is subject to certain closing conditions, a number of which are not within our control. Any failure to satisfy these required conditions to closing may prevent, delay or otherwise materially adversely affect the completion of the transaction. We cannot predict with certainty whether or when any of the required closing conditions will be satisfied or if another uncertainty may arise and cannot assure you that we will be able to successfully consummate the proposed Merger as currently contemplated under the Merger Agreement or at all.

Our efforts to complete the Merger could cause substantial disruptions in, and create uncertainty surrounding, our current

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and any planned future business plans, which may materially adversely affect our results of operation and our business. Uncertainty as to whether the Merger will be completed may affect our ability to recruit prospective employees or to retain and motivate existing employees. Employee retention may be particularly challenging while the transaction is pending because employees may experience uncertainty about their roles following the transaction. Uncertainty as to our future could adversely affect our business and our relationship with customers, collaborators, suppliers, vendors, regulators and other business partners. For example, vendors and other counterparties may defer decisions about working with us or seek to change existing business relationships with us. Changes to, or termination of, existing business relationships could adversely affect our results of operations and financial condition, as well as the market price of our common stock. The adverse effects of the pendency of the

transaction could be exacerbated by any delays in completion of the transaction or termination of the Merger Agreement.

Risks related to the failure of the proposed Merger to be consummated include, but are not limited to, the following:

The occurrence of any of these events individually or in combination could materially and adversely affect our results of operations, business, and our stock price.

We cannot be certain if or when the Merger will be completed.

The consummation of the Merger is subject to the satisfaction or waiver of various conditions, including the approval of the Merger by our stockholders. We cannot guarantee that the closing conditions set forth in the Merger Agreement will be satisfied. If we are unable to satisfy the closing conditions or if other mutual closing conditions are not satisfied, Adaptimmune will not be obligated to complete the Merger. Under certain circumstances, we would be required to pay Adaptimmune a termination fee equal to $2.4 million.

If the Merger is not completed, our board of directors, in discharging its fiduciary obligations to our stockholders, will evaluate our options which include pursuing other strategic alternatives or financing options that may be available, continuing our operations as they are currently being conducted, or continuing our operations with a further narrowing of focus or other strategic adjustments, which options and alternatives may not be as favorable to our stockholders as the Merger. Any future sale or merger, financing or other transaction may be subject to further stockholder approval. We may also be unable to find, evaluate or complete other strategic alternatives, which may materially and adversely affect our business.

Our efforts to complete the Merger could cause substantial disruptions in, and create uncertainty surrounding, our current and any planned future business plans, which may materially adversely affect our results of operation and our business. Uncertainty as to whether the Merger will be completed may affect our ability to recruit prospective employees or to retain and motivate existing employees. Employee retention may be particularly challenging while the transaction is pending because employees may experience uncertainty about their roles following the transaction. A substantial amount of our management’s and employees’ attention is being directed toward the completion of the transaction and thus is being diverted from our day-to-day operations. Uncertainty as to our future could adversely affect our business and our relationship with collaborators, suppliers, vendors, regulators and other collaboration partners. For example, suppliers and other counterparties may defer decisions concerning

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working with us, or seek to change existing business relationships with us. Changes to, or termination of, existing business relationships could adversely affect our results of operations and financial condition, as well as the market price of our common stock. The adverse effects of the pendency of the transaction could be exacerbated by any delays in completion of the transaction or termination of the Merger Agreement.

Until the Merger is completed, the Merger Agreement restricts Adaptimmune and us from taking specified actions without the consent of the other party, and, in regards to us, requires us to operate in the ordinary course of business consistent with past practice in all material respects. These restrictions may prevent Adaptimmune and us from making appropriate changes to our respective businesses or pursuing attractive business opportunities that may arise prior to the completion of the Merger.

Because the Merger Agreement provides for a fixed exchange ratio for the number of shares of Adaptimmune American Depositary Shares (“Adaptimmune ADSs”) that will be issued for each issued and outstanding share of our common stock, the consideration received at the time of the Merger may be lower than the public trading value of shares of our common stock when we entered into the Merger Agreement.

The Merger Agreement provides for a fixed exchange ratio for the number of shares of Adaptimmune ADSs that will be issued for each issued and outstanding share of our common stock in the Merger (other than shares of our common stock held by us as treasury stock, or shares of our common stock owned by Adaptimmune, Merger Sub or any direct or indirect wholly-owned subsidiaries of Adaptimmune), including shares of our common stock underlying our restricted stock units that immediatly vest upon a change of control of the Company. If the public trading value of shares of Adaptimmune ADSs declines over the period of time required to satisfy the Merger’s closing conditions, the consideration received at the time of the Merger may be lower than the public trading value of shares of our common stock when we entered into the Merger Agreement.

The Merger Agreement contains provisions that limit our ability to pursue alternatives to the Merger, could discourage a potential competing acquiror of us from making an alternative transaction proposal and, in specified circumstances, could require us to pay a termination fee to Adaptimmune.

The Merger Agreement provides that we shall not, and requires us to refrain from permitting our representatives to, among other things, solicit, participate in negotiations with respect to or approve or recommend any third party proposal for an alternative transaction, subject to exceptions set forth in the Merger Agreement relating to the receipt of certain unsolicited proposals. If the Merger Agreement is terminated, in certain circumstances, we may be required to pay Adaptimmune a termination fee equal to $2.4 million.

These provisions could discourage a potential third-party acquiror or merger partner that might have an interest in acquiring all or a significant portion of us or pursuing an alternative transaction from considering or proposing such a transaction, even if it were prepared to pay consideration with a higher per share cash or market value than the consideration in the Merger, or might result in a potential third-party acquiror or merger partner proposing to pay a lower price to our stockholders than it might otherwise have proposed to pay because of the added expense of the termination fee that may become payable in certain circumstances.

If the Merger Agreement is terminated and we determine to seek another business combination, we may not be able to negotiate a transaction with another party on terms comparable to, or better than, the terms of the Merger Agreement.

Lawsuits may be filed against us and the members of our board of directors arising out of the Merger, which may delay or prevent the Merger.

Putative stockholder complaints, including stockholder class action complaints, and other complaints may be filed against us, our board of directors, Adaptimmune, Adaptimmune’s board of directors and others in connection with the transactions contemplated by the Merger Agreement. The outcome of litigation is inherently uncertain, and we may not be successful in defending against any such future claims. Lawsuits that may be filed against us, our board of directors, Adaptimmune, or Adaptimmune’s board of directors could delay or prevent the Merger, divert the attention of our management and employees from our day-to-day business and otherwise adversely affect us financially.

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Risks Related to Our Reliance On Third Parties

Third Party Risks Related to Our Product Development

We rely on third parties to conduct our clinical trials. If these third parties do not properly and successfully carry out their contractual duties or meet expected deadlines, we may not be able to obtain regulatory approval of or commercialize our product candidates.

We utilize and depend upon independent investigators and collaborators, such as medical institutions, CROs, CMOs and strategic partners to conduct our preclinical studies and clinical trials under agreements with us, and we plan to continue to do so. We expect to have to negotiate budgets and contracts with CROs, trial sites and CMOs which may result in delays to our development timelines and increased costs. We will rely heavily on these third parties over the course of our clinical trials and we control only certain aspects of their activities. As a result, we have less direct control over the conduct, timing and completion of these clinical trials and the management of data developed through clinical trials than would be the case if we were relying entirely upon our own staff. Nevertheless, we are responsible for ensuring that each of our studies is conducted in accordance with applicable protocol, legal and regulatory requirements and scientific standards and our reliance on third parties does not relieve us of our regulatory responsibilities. We and these third parties are required to comply with good clinical practices (GCPs), which are regulations and guidelines enforced by the FDA and comparable foreign regulatory authorities for product candidates in clinical development. Regulatory authorities enforce these GCPs through periodic inspections of trial sponsors, principal investigators and trial sites. If we or any of these third parties fail to comply with applicable GCP regulations, the clinical data generated in our clinical trials may be deemed unreliable and the FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you that, upon inspection, such regulatory authorities will determine that any of our clinical trials comply with the GCP regulations. In addition, our clinical trials must be conducted with biologic product produced under cGMP regulations, including current good tissue practice (cGTP) regulations and will require a large number of test patients. Our failure or any failure by these third parties to comply with these regulations or to recruit a sufficient number of patients may require us to repeat clinical trials, which would delay the regulatory approval process. Moreover, our business may be implicated if any of these third parties violates federal or state fraud and abuse or false claims laws and regulations or healthcare privacy and security laws.

Any third parties conducting our clinical trials are not and will not be our employees and, except for remedies available to us under our agreements with such third parties, we cannot control whether or not they devote sufficient time and resources to our ongoing, clinical and non-clinical product candidates. These third parties may also have relationships with other commercial entities, including our competitors, for whom they may also be conducting clinical trials or other drug development activities, which could affect their performance on our behalf. If these third parties do not successfully carry out their contractual duties or obligations or meet expected deadlines, if they need to be replaced or if the quality or accuracy of the clinical data they obtain is compromised due to the failure to adhere to our clinical protocols or regulatory requirements or for other reasons, our clinical trials may be extended, delayed or terminated and we may not be able to complete development of, obtain regulatory approval of or successfully commercialize our product candidates. As a result, our financial results and the commercial prospects for our product candidates would be harmed, our costs could increase and our ability to generate revenue could be delayed.

Switching or adding third parties to conduct our clinical trials involves substantial cost and requires extensive management time and focus. In addition, changes in manufacturers often involve changes in manufacturing procedures and processes, which could require that we conduct bridging studies between our prior clinical supply used in our clinical trials and that of any new manufacturer. We may be unsuccessful in demonstrating the comparability of clinical supplies which could require the conduct of additional clinical trials. Additionally, there is a natural transition period when a new third party commences work. As a result, delays occur, which can materially impact our ability to meet our desired clinical development timelines.

If or until we develop our own manufacturing facility, we expect to rely on the use of manufacturing suites in third-party cGMP facilities or third parties to manufacture our product candidates. Our business could be harmed if we are unable to use third-party manufacturing suites or if the third-party manufacturers fail to provide us with sufficient quantities of our product candidates or fail to do so at acceptable quality levels or prices.

We do not currently own any facility that may be used as our clinical-scale manufacturing and processing facility and must currently rely on outside vendors to manufacture and process our product candidates, which is and will need to be done on a patient-by-patient basis. Our reliance on a limited number of third-party manufacturers exposes us to the following risks:

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Each of these risks could delay or prevent the completion of our clinical trials or the approval of any of our product candidates by the FDA, result in higher costs or adversely impact commercialization of our product candidates. In addition, we will rely on third parties to perform certain specification tests on our product candidates prior to delivery to patients. If these tests are not appropriately done and test data are not reliable, patients could be put at risk of serious harm and the FDA could place significant restrictions on our company until deficiencies are remedied.

The manufacture of biological drug products is complex and requires significant expertise and capital investment, including the development of advanced manufacturing techniques and process controls. Manufacturers of biologic products often encounter difficulties in production, particularly in scaling up or out, validating the production process and assuring high reliability of the manufacturing process (including the absence of contamination). These problems include logistics and shipping, difficulties with production costs and yields, quality control, including stability of the product, product testing, operator error and availability of qualified personnel, as well as compliance with strictly enforced federal, state and foreign regulations. Furthermore, if contaminants are discovered in our supply of our product candidates or in the manufacturing facilities, such manufacturing facilities may need to be closed for an extended period of time to investigate and remedy the contamination. We cannot assure you that any stability failures or other issues relating to the manufacture of our product candidates will not occur in the future.

We may fail to manage the logistics of collecting and shipping patient material to the manufacturing site and shipping the product candidate back to the patient. Logistical and shipment delays and problems caused by us, our vendors or other factors not in our control, such as weather, could prevent or delay the delivery of product candidates to patients. Additionally, we have to maintain a complex chain of identity and chain of custody with respect to patient material as it moves to the manufacturing facility, through

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the manufacturing process and back to the patient. Failure to maintain chain of identity and chain of custody could result in patient death, loss of product or regulatory action.

Our manufacturing process needs to comply with FDA regulations relating to the quality and reliability of such processes. Any failure to comply with relevant regulations could result in delays in or termination of our clinical programs and suspension or withdrawal of any regulatory approvals.

In order to commercially produce our products at a third party’s facility, we will need to comply with the FDA’s cGMP regulations and guidelines, including cGTPs. We may encounter difficulties in achieving quality control and quality assurance and may experience shortages in qualified personnel. We are subject to inspections by the FDA and comparable foreign regulatory authorities to confirm compliance with applicable regulatory requirements. Any failure to follow cGMP, cGTP or other regulatory requirements or delay, interruption or other issues that arise in the manufacture, fill-finish, packaging, or storage of our TRuC-T cells as a result of a failure of the facilities or operations of third parties to comply with regulatory requirements or pass any regulatory authority inspection could significantly impair our ability to develop and commercialize our TRuC-T cell programs, including leading to significant delays in the availability of our TRuC-T cells for our clinical trials or the termination of or suspension of a clinical trial, or the delay or prevention of a filing or approval of marketing applications for our TRuC-T cell product candidates. Significant non-compliance could also result in the imposition of sanctions, including warning or untitled letters, fines, injunctions, civil penalties, failure of regulatory authorities to grant marketing approvals for our TRuC-T cell product candidates, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of products, operating restrictions and criminal prosecutions, any of which could damage our reputation and our business.

If our third-party manufacturers use hazardous and biological materials in a manner that causes injury or violates applicable law, we may be liable for damages.

Our research and development activities involve the controlled use of potentially hazardous substances, including chemical and biological materials, by our third-party manufacturers. Our manufacturers are subject to federal, state and local laws and regulations in the United States governing the use, manufacture, storage, handling and disposal of medical and hazardous materials. Although we believe that our manufacturers’ procedures for using, handling, storing and disposing of these materials comply with legally prescribed standards, we cannot completely eliminate the risk of contamination or injury resulting from medical or hazardous materials. As a result of any such contamination or injury, we may incur liability or local, city, state or federal authorities may curtail the use of these materials and interrupt our business operations. In the event of an accident, we could be held liable for damages or penalized with fines and the liability could exceed our resources. We do not have any insurance for liabilities arising from medical or hazardous materials. Compliance with applicable environmental laws and regulations is expensive and current or future environmental regulations may impair our research, development and production efforts, which could harm our business, prospects, financial condition or results of operations.

Risks Related to Third Party Agreements

We have and may in the future form or seek collaborations or strategic alliances or enter into additional licensing arrangements in the future and we may not realize the benefits of such collaborations, alliances or licensing arrangements.

We have and may in the future form or seek strategic alliances, create joint ventures or collaborations, or enter into additional licensing arrangements with third parties that we believe will complement or augment our development and commercialization efforts with respect to our product candidates and any future product candidates that we may develop. Any of these relationships may require us to incur non-recurring and other charges, increase our near and long-term expenditures, issue securities that dilute our existing stockholders or disrupt our management and business.

In addition, we face significant competition in seeking appropriate strategic partners and the negotiation process is time-consuming and complex. Moreover, we may not be successful in our efforts to establish a strategic partnership or other alternative arrangements for our product candidates because they may be deemed to be at too early of a stage of development for collaborative effort and third parties may not view our product candidates as having the requisite potential to demonstrate safety and efficacy and obtain marketing approval.

Further, collaborations involving our product candidates are subject to numerous risks, which may include the following:

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As a result, if we enter into additional collaboration agreements and strategic partnerships or license our product candidates, we may not be able to realize the benefit of such transactions if we are unable to successfully integrate them with our existing operations and company culture, which could delay our timelines or otherwise adversely affect our business. We also cannot be certain that, following a strategic transaction or license, we will achieve the revenue or specific net income that justifies such transaction. Any delays in entering into new collaborations or strategic partnership agreements related to our product candidates could delay the development and commercialization of our product candidates in certain geographies for certain indications, which would harm our business prospects, financial condition and results of operations.

Our product candidates rely on the availability of specialty raw materials, which may not be available to us on acceptable terms or at all.

Our product candidates require many specialty raw materials, some of which are manufactured by small companies with limited resources and experience to support a commercial product. In addition, those suppliers normally support blood-based hospital businesses and generally do not have the capacity to support commercial products manufactured under cGMP by biopharmaceutical firms. The suppliers may be ill-equipped to support our needs, especially in non-routine circumstances like an FDA inspection or medical crisis, such as widespread contamination. We also do not have contracts with many of these suppliers and may not be able to contract with them on acceptable terms or at all. Accordingly, we may experience delays in receiving key raw materials to support clinical or commercial manufacturing.

In addition, some of our raw materials are currently available from a single supplier, or a small number of suppliers. For example, the type of cell culture media and cryopreservation buffer that we currently use in our manufacturing process for the TRuC-T cells for gavo-cel are each only available from a single supplier. In addition, the cell processing equipment and tubing that we use in our current manufacturing process is only available from a single supplier. We also use certain biologic materials, including certain activating antibodies, that are available from multiple suppliers, but each version may perform differently, requiring us to characterize them and potentially modify some of our protocols if we change suppliers. We cannot be sure that these suppliers will remain in business, or that they will not be purchased by one of our competitors or another company that is not interested in continuing to produce these materials for our intended purpose. If we have to change suppliers, the materials may only be available from another supplier on terms that are less favorable to us than the terms under which we currently obtain the materials. Accordingly, if we no longer have access to these suppliers, we may experience delays in our clinical or commercial manufacturing which could harm our business or results of operations.

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Risks Related to Our Financial Condition and Capital Requirements

Risks Related to Operating History

Our limited operating history may make it difficult for you to evaluate the success of our business to date and to assess our future viability.

We are a clinical-stage cell therapy company with a limited operating history. We commenced operations in May 2015, and our operations to date have been limited to organizing and staffing our company, business planning, raising capital, conducting discovery and research activities, filing patent applications, identifying potential product candidates, undertaking preclinical studies, establishing arrangements with third parties for the manufacture of initial quantities of our product candidates and component materials and initiating and conducting our first clinical trials. We have advanced three product candidates to Phase 1/2 clinical trials, with two product candidates currently in Phase 1/2 clinical trials, and our other product candidates are still in preclinical development. We have not yet demonstrated our ability to successfully complete any clinical trials, obtain marketing approvals, manufacture a commercial-scale product or arrange for a third party to do so on our behalf, or conduct sales, marketing and distribution activities necessary for successful product commercialization. Consequently, any predictions you make about our future success or viability may not be as accurate as they could be if we had a longer operating history.

In addition, as a young business, we may encounter unforeseen expenses, difficulties, complications, delays and other known and unknown factors. We will need to transition at some point from a company with a research and development focus to a company capable of supporting commercial activities. We may not be successful in such a transition.

We expect our financial condition and operating results to continue to fluctuate significantly from quarter to quarter and year to year due to a variety of factors, many of which are beyond our control. Accordingly, you should not rely upon the results of any quarterly or annual periods as indications of future operating performance.

We have incurred significant losses since inception, and we expect to incur losses over the next several years and may not be able to achieve or sustain revenues or profitability in the future.

Investment in biopharmaceutical product development is a highly speculative undertaking and entails substantial upfront capital expenditures and significant risk that any potential product candidate will fail to demonstrate adequate effect or an acceptable safety profile, gain regulatory approval and become commercially viable. We are still in the early stages of development of our product candidates. We have no products licensed for commercial sale and have not generated any revenue from product sales to date, and we continue to incur significant research and development and other expenses related to our ongoing operations. We have financed our operations primarily through private placements of our preferred stock, our initial public offering and subsequent public offerings.

We have incurred significant net losses in each period since our inception in May 2015. For the year-to-date period ended December 31, 2022, we incurred a net loss of $151.8 million. As of December 31 2022, we had an accumulated deficit of $501.3 million. We expect to continue to incur significant losses for the foreseeable future, and we expect these losses to increase substantially if and as we:

Because of the numerous risks and uncertainties associated with pharmaceutical product development, we are unable to accurately predict the timing or amount of increased expenses we will incur or when, if ever, we will be able to achieve profitability.

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Even if we succeed in commercializing one or more of our product candidates, we will continue to incur substantial research and development and other expenditures to develop, seek regulatory approval for and market additional product candidates. We may encounter unforeseen expenses, difficulties, complications, delays and other unknown factors that may adversely affect our business. The size of our future net losses will depend, in part, on the rate of future growth of our expenses and our ability to generate revenue. Our prior losses and expected future losses have had and will continue to have an adverse effect on our stockholders’ equity and working capital.

We have not generated any revenue from our product candidates and may never be profitable.

Our ability to become profitable depends upon our ability to generate revenue. To date, we have not generated any revenue from any of our product candidates. We do not expect to generate significant revenue unless or until we successfully complete clinical development and obtain regulatory approval of, and then successfully commercialize, at least one of our product candidates. Other than gavo-cel and TC-510, all of our product candidates are in the preclinical stages of development and will require additional preclinical studies, clinical development, regulatory review and approval, substantial investment, access to sufficient commercial manufacturing capacity and significant marketing efforts before we can generate any revenue from product sales. Gavo-cel, our most advanced mono TRuC-T cell product candidate targeting mesothelin-positive solid tumors, is in the Phase 2 portion of a Phase 1/2 clinical trial and will require additional regulatory review and approval, substantial investment, access to sufficient commercial manufacturing capacity and significant marketing efforts before we can generate any revenue from product sales. TC-510 is in the Phase 1 portion of a Phase 1/2 clinical trial and will require additional clinical study, regulatory review and approval, substantial investment, access to sufficient commercial manufacturing capacity and significant marketing efforts before we can generate any revenue from product sales. We are conducting IND-enabling activities for our preclinical product candidate TC-520. Many of our other TRuC-T cell product candidates are in early preclinical stages. We face significant translational risk as our product candidates advance to the clinical stage. Our ability to generate revenue depends on a number of factors, including, but not limited to:

Many of the factors listed above are beyond our control and could cause us to experience significant delays or prevent us from obtaining regulatory approvals or commercialize our product candidates. Even if we are able to commercialize our product candidates, we may not achieve profitability soon after generating product sales, if ever. If we are unable to generate sufficient

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revenue through the sale of our product candidates or any future product candidates, we may be unable to continue operations without continued funding.

Risks Related to Raising Additional Capital

If we fail to obtain additional financing, we may be unable to continue our research and product development programs.

Our operations have consumed substantial amounts of cash since inception. We expect to continue to spend substantial amounts (including net proceeds from public offerings of our common stock) to continue the clinical development of our product candidates, including our Phase 2 portion of the Phase 1/2 clinical trial of gavo-cel, our Phase 1/2 clinical trial of TC-510 and ongoing and planned IND-enabling studies for our other product candidates. If licensed, we will require significant additional amounts in order to launch and commercialize our product candidates.

In February 2019, we completed our initial public offering (IPO) raising gross proceeds of approximately $86.3 million, inclusive of the exercise of the underwriters' overallotment option. On July 31, 2020, we completed a stock offering raising gross proceeds of approximately $142.6 million. On January 22, 2021, we completed a stock offering raising gross proceeds of $140.0 million. As of December 31, 2022, we had cash, cash equivalents and short-term investments of approximately $149.2 million. Our existing cash, cash equivalents and short-term investments may not be sufficient to fund all of our efforts that we plan to undertake.

We believe that our existing cash, cash equivalents and investments, including our net proceeds from the IPO and secondary offerings, will be sufficient to fund our operations into early 2025. However, we have based this estimate on assumptions that may prove to be wrong. Additionally, changing circumstances may cause us to consume capital significantly faster than we currently anticipate, and we may need to spend more money than currently expected because of circumstances beyond our control. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. We cannot be certain that additional funding will be available on acceptable terms, or at all. Recent volatility in capital markets and lower market prices for our securities may affect our ability to access new capital through sales of shares of our common stock or issuance of indebtedness, which may harm our liquidity or limit our ability to pursue our clinical development plans. In addition, recent increases in interest rates may increase our borrowing costs, and may also affect our ability to obtain working capital through borrowings such as bank credit lines and public or private sales of debt securities, which may result in lower liquidity, reduced working capital and other adverse impacts on our business. If we are unable to raise additional capital in sufficient amounts or on terms acceptable to us, we may have to significantly delay, scale back or discontinue our research and development initiatives. We could be required to seek collaborators for our product candidates at an earlier stage than otherwise would be desirable or on terms that are less favorable than might otherwise be available or relinquish or license on unfavorable terms our rights to our product candidates in markets where we otherwise would seek to pursue development or commercialization ourselves.

Any of the above events could significantly harm our business, prospects, financial condition and results of operations and cause the price of our common stock to decline.

Raising additional capital may cause dilution to our existing stockholders, restrict our operations or require us to relinquish rights to our technologies or product candidates.

We may seek additional capital through a combination of public and private equity offerings, debt financings, strategic partnerships and alliances and licensing arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms may include liquidation or other preferences that adversely affect your rights as a stockholder. The incurrence of indebtedness would result in increased fixed payment obligations and could involve certain restrictive covenants, such as limitations on our ability to incur additional debt, limitations on our ability to acquire or license intellectual property rights and other operating restrictions that could adversely impact our ability to conduct our business. If we raise additional funds through strategic partnerships and alliances and licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies or product candidates, or grant licenses on terms unfavorable to us.

We have in the past relied in part on sales of our common stock through our at-the-market (ATM) offering program. Increased volatility and decreases in market prices of equity securities generally and of our common stock in particular may have an adverse impact on our willingness and/or ability to continue to sell our common shares through our ATM offering. Decreases in these sales could affect the cost or availability of equity capital, which could in turn have an adverse effect on our business, clinical development and research plans and the market price of our common stock.

In March 2020, we commenced an at-the-market, or ATM, program to raise capital. Under our ATM Program, we have entered into a sales agreement to sell common shares, up to a maximum aggregate market value of $100.0 million, through one or more at-the-market offerings. Given the decrease in the market prices of our common stock and volatility in the capital markets, we may

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not be willing or able to continue to raise equity capital through our ATM Program. We may, therefore, need to turn to other sources of funding that may have terms that are not favorable to us, or reduce our business operations given capital constraints.

Alternative financing arrangements, if we pursue any, could involve issuances of one or more types of securities, including common stock, preferred stock, convertible debt, warrants to acquire common stock or other securities. These securities could be issued at or below the then prevailing market price for our common stock. In addition, if we issue debt securities, the holders of the debt would have a claim to our assets that would be superior to the rights of stockholders until the principal, accrued and unpaid interest and any premium or make-whole has been paid. In addition, if we borrow funds and/or issue debt securities through a subsidiary, the lenders and/or holders of those debt securities would have a right to payment that would be effectively senior to the company’s equity ownership in the subsidiary, which would adversely affect the rights of holders of both the company’s equity securities and its debt and debt securities.

Interest on any newly-issued debt securities and/or newly-incurred borrowings would increase our operating costs and increase our net loss. If the issuance of new securities results in diminished rights to holders of our common stock, the market price of our common stock could be materially and adversely affected. Should the financing we require to sustain our working capital needs be unavailable or prohibitively expensive when we require it, the consequences could/would result in a material adverse effect on our business, operating results, financial condition and prospects.

Risks Related To Developments in the Financial Services Industry

Adverse developments affecting the financial services industry, such as actual events or concerns involving liquidity, defaults or non-performance by financial institutions or transactional counterparties, could adversely affect the Company’s current and projected business operations and its financial condition and results of operations.

Actual events involving limited liquidity, defaults, non-performance or other adverse developments that affect financial institutions, transactional counterparties or other companies in the financial services industry or the financial services industry generally, or concerns or rumors about any events of these kinds or other similar risks, have in the past and may in the future lead to market-wide liquidity problems. For example, on March 10, 2023, Silicon Valley Bank (“SVB”) was closed by the California Department of Financial Protection and Innovation, which appointed the Federal Deposit Insurance Corporation (“FDIC”) as receiver. Similarly, on March 12, 2023, Signature Bank was swept into receivership. Although a statement by the Department of the Treasury, the Federal Reserve and the FDIC stated all depositors of SVB would have access to all of their money after only one business day of closure, including funds held in uninsured deposit accounts, borrowers under credit agreements, letters of credit and certain other financial instruments with SVB, Signature Bank or any other financial institution that is placed into receivership by the FDIC may be unable to access undrawn amounts thereunder. As of the date of this Annual Report, we have less than $0.1 million of unrestricted cash, cash equivalents and investments and we have approximately $1.2 million of restricted cash as certificates of deposits for facility leases held at SVB, and we may not be able to access these funds due to the receivership of SVB. We are not a borrower or party to any such instruments with Signature Bank or any other financial institution currently in receivership, however, if any of our lenders or other counterparties to any such instruments were to be placed into receivership, we may be unable to access such funds. In addition, counterparties to SVB credit agreements and arrangements, and third parties such as beneficiaries of letters of credit (among others), may experience direct impacts from the closure of SVB and uncertainty remains over liquidity concerns in the broader financial services industry. Similar impacts have occurred in the past, such as during the 2008-2010 financial crisis.

Inflation and rapid increases in interest rates have led to a decline in the trading value of previously issued government securities with interest rates below current market interest rates. Although the U.S. Department of Treasury, FDIC and Federal Reserve Board have announced a program to provide up to $25 billion of loans to financial institutions secured by certain of such government securities held by financial institutions to mitigate the risk of potential losses on the sale of such instruments, widespread demands for customer withdrawals or other liquidity needs of financial institutions for immediately liquidity may exceed the capacity of such program. There is no guarantee that the U.S. Department of Treasury, FDIC and Federal Reserve Board will provide access to uninsured funds in the future in the event of the closure of other banks or financial institutions, or that they would do so in a timely fashion.

Although we assess our banking relationships as we believe necessary or appropriate, our access to funding sources and other credit arrangements in amounts adequate to finance or capitalize our current and projected future business operations could be significantly impaired by certain factors that affect us, the financial institutions with which we have credit agreements or arrangements directly, or the financial services industry or economy in general. These factors could include, among others, events such as liquidity constraints or failures, the ability to perform obligations under various types of financial, credit or liquidity agreements or arrangements, disruptions or instability in the financial services industry or financial markets, or concerns or negative expectations about the prospects for companies in the financial services industry. These factors could involve financial

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institutions or financial services industry companies with which we have financial or business relationships, but could also include factors involving financial markets or the financial services industry generally.

The results of events or concerns that involve one or more of these factors could include a variety of material and adverse impacts on our current and projected business operations and our financial condition and results of operations. These could include, but may not be limited to, the following:

In addition, investor concerns regarding the U.S. or international financial systems could result in less favorable commercial financing terms, including higher interest rates or costs and tighter financial and operating covenants, or systemic limitations on access to credit and liquidity sources, thereby making it more difficult for us to acquire financing on acceptable terms or at all. Any decline in available funding or access to our cash and liquidity resources could, among other risks, adversely impact our ability to meet our operating expenses, financial obligations or fulfill our other obligations, result in breaches of our financial and/or contractual obligations or result in violations of federal or state wage and hour laws. Any of these impacts, or any other impacts resulting from the factors described above or other related or similar factors not described above, could have material adverse impacts on our liquidity and our current and/or projected business operations and financial condition and results of operations.

In addition, any further deterioration in the macroeconomic economy or financial services industry could lead to losses or defaults by our customers or suppliers, which in turn, could have a material adverse effect on our current and/or projected business operations and results of operations and financial condition. For example, a customer may fail to make payments when due, default under their agreements with us, become insolvent or declare bankruptcy, or a supplier may determine that it will no longer deal with us as a customer. In addition, a customer or supplier could be adversely affected by any of the liquidity or other risks that are described above as factors that could result in material adverse impacts on the Company, including but not limited to delayed access or loss of access to uninsured deposits or loss of the ability to draw on existing credit facilities involving a troubled or failed financial institution. Any customer or supplier bankruptcy or insolvency, or the failure of any customer to make payments when due, or any breach or default by a customer or supplier, or the loss of any significant supplier relationships, could result in material losses to the Company and may material adverse impacts on our business.

Risks Related to the Current Novel Coronavirus (COVID-19) Pandemic on the Company

The current COVID-19 pandemic has caused, and could continue to cause, severe disruptions in the U.S., regional and global economies and could seriously harm our development efforts, increase our costs and expenses and have a material adverse effect on our business, financial condition and results of operations.

Public health pandemics or outbreaks could adversely impact our business. In December 2019, a novel strain of coronavirus (COVID-19) emerged in Wuhan, Hubei Province, China and has since spread to several other countries, including the United States and European countries, with infections and deaths reported globally. To date, the ongoing COVID-19 pandemic has caused widespread disruptions to the U.S. and global economy and has contributed to significant volatility and negative pressure in financial markets.

The extent to which the ongoing COVID-19 pandemic impacts our business, financial condition and results of operations will depend on future developments, which are highly uncertain and cannot be predicted with confidence, including the scope, severity and duration of the pandemic, the actions