TScan Therapeutics Inc

1. Nature of Business and Basis of Presentation

Nature of Business

TScan Therapeutics, Inc. (the Company) is a biotechnology company that was incorporated in Delaware on April 17, 2018, and has a principal place of business in Waltham, Massachusetts. The Company is a biopharmaceutical company focused on developing a pipeline of T cell receptor (TCR)-engineered T cell (TCR-T) therapies for the treatment of patients with cancer.

Risks, Uncertainties and Going Concern

The Company is subject to risks common to companies in the biotechnology industry, including, but not limited to, successful development of technology, obtaining additional funding, protection of proprietary technology, compliance with government regulations, risks of failure of preclinical studies, clinical studies and clinical trials, the need to obtain marketing approval for its product candidates and the ability to successfully market its therapies any products that receive approval, fluctuations in operating results, economic pressure impacting therapeutic pricing, dependence on key personnel, risks associated with changes in technologies, development by competitors of technological innovations and the ability to scale manufacturing to large scale production. Product candidates currently under development will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from therapy sales.

The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company has primarily funded its operations with proceeds from sales of capital stock, including the IPO completed in July 2021, issuance of convertible debt in September 2022, issuance of term loan in December 2024 and with payments received under its license and collaboration agreements. Since its inception, the Company has incurred recurring losses, including net losses of $127.5 million and $89.2 million for the years ended December 31, 2024 and 2023, respectively. As of December 31, 2024, the Company had an accumulated deficit of $375.1 million. The Company expects to continue to generate operating losses in the foreseeable future. The Company expects that its cash and cash equivalents and marketable securities as of December 31, 2024 will be sufficient to fund the Company’s operations for at least the next twelve months from the date of the issuance of the financial statements.

The Company will need to obtain substantial additional funding through equity offerings, debt financings, collaborations, strategic alliances and/or licensing arrangements in order to fund its research and development and ongoing operating expenses. The Company may not be able to obtain financing on acceptable terms, when needed or at all, and the Company may not be able to enter into collaborations, strategic alliances or licensing arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. Any collaborations, strategic alliances or licensing arrangements may require the Company to relinquish rights to certain of its technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable to the Company. If the Company is unable to obtain funding, the Company could be forced to delay, limit, reduce or eliminate some or all of its research and development programs, pipeline expansion or future commercialization efforts or grant rights to develop and market product candidates, which could adversely affect its business prospects. Although management will continue to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations when needed or at all.

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements reflect the operations of the Company and the Company’s wholly owned subsidiary, TScan Securities Corporation. The accompanying consolidated financial statements have been prepared in conformity with US GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative US GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB.

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany accounts and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of the consolidated financial statements in accordance with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting period. The Company bases its estimates on historical experience, known trends and other market-specific or relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. Actual results may differ from those estimates or assumptions.

Cash and Cash Equivalents

Cash includes cash in readily available checking and money market accounts. Cash equivalents include all highly liquid investments maturing within 90 days from the date of purchase. The cash equivalents consisted of money market funds and government securities.

Restricted Cash

In connection with the Company’s facility lease agreements, the Company is required to provide letters of credit totaling of$5.0 million for the benefit of the landlords to serve as security deposits. As of December 31, 2024 and 2023, the cash securing the letter of credit was classified as restricted cash (non-current) on the consolidated balance sheets.

Marketable Securities

The Company classifies all of its marketable securities as available-for-sale based upon its intent with regard to such investments. Unrealized gains on available-for-sale debt securities are reported as a component of accumulated other comprehensive loss in stockholders’ equity. The amortized cost of debt securities in this category is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization is included in interest and other income, net. Realized gains and losses and declines in value judged to be other than temporary on available-for-sale securities, are included in interest and investment income.

The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest and other income, net. To determine whether an other-than-temporary impairment exists, the Company considers whether it has the ability and intent to hold the investment until a market price recovery, and whether evidence indicating the recoverability of the cost of the investment outweighs evidence to the contrary.

Concentrations of Credit Risk

Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company’s cash deposits on hand at any one financial institution often exceed federally insured limits. The Company places its cash in financial institutions that management believes to be of high credit quality. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.

Property and Equipment

Property and equipment are stated at cost and depreciated using the straight-line method over the estimated useful lives of the respective assets as follows:

Major additions and betterments are capitalized; expenditures for repairs and maintenance, which do not improve or extend the life of the respective assets, are charged to operating expense as incurred. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation and amortization are removed from the accounts and any resulting gain or loss is included in loss from operations.

Impairment of Long-Lived Assets

Long-lived assets to be held and used, including property and equipment, are tested for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be fully recoverable. Evaluation of the recoverability of the asset or asset group is based on an estimate of undiscounted future cash flows resulting from the use of the asset or asset group and its eventual disposition. In the event that such cash flows are not expected to be sufficient to recover the carrying amount of the asset or asset group, an impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value. The Company did not record any impairment losses on long-lived assets during the periods presented.

Fair Value Measurements

Certain assets and liabilities are carried at fair value under US GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the user of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

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Level 1—Unadjusted quoted prices in active markets that are accessible to the reporting entity at the measurement date for identical assets and liabilities.

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Level 2—Inputs other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly for substantially the full term of the asset or liability. Level 2 inputs include the following:

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quoted prices for similar assets and liabilities in active markets

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quoted prices for identical or similar assets or liabilities in markets that are not active

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observable inputs other than quoted prices that are used in the valuation of the asset or liabilities (e.g., interest rate and yield curve quotes at commonly quoted intervals)

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inputs that are derived principally from or corroborated by observable market data by correlation or other means

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Level 3—Unobservable inputs for the assets or liability (i.e., supported by little or no market activity). Level 3 inputs include management’s own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk).

Leases

The Company records leases under ASU No. 2016-02 Leases (Topic 842) whereby the Company determines if an arrangement is or contains a lease at inception. For leases with a term of 12 months or less, the Company has elected to not recognize a right-of-use asset or lease liability. The Company’s operating leases are recognized on the consolidated balance sheets as other noncurrent assets, other current liabilities, and other noncurrent liabilities. The Company does not have any finance leases.

Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. As the rate implicit on the Company’s leases are not readily determinable, the Company uses an estimate of its incremental borrowing rate for secured borrowings with terms similar to the lease term based on the information available at the lease commencement date in determining the present value of lease payments. Operating lease right-of-use assets also include the effect of any lease payments made, including lease payments made in advance of lease commencement and excludes lease incentives. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense is recognized on a straight-line basis over the lease term.

Research and Development Costs

Research and development costs are expensed as incurred. Research and development costs that are paid in advance of performance (if any) are capitalized as a prepaid expense and amortized over the service period as the services are provided.

Accrued Research and Manufacturing Contract Costs

The Company has entered into various research and development and manufacturing contracts. These agreements are generally cancelable, and related payments are recorded as the corresponding expenses are incurred. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the research studies or clinical trials and manufacturing activities, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs.

Patent Costs

All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses.

Revenue Recognition

The Company accounts for revenue under ASU No. 2014-19, Revenue from Contracts with Customers (ASC 606). ASC 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, certain collaboration arrangements and financial instruments. ASC 606 provides a five-step framework whereby revenue is recognized when control of promised goods or services is transferred to a customer at an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following five steps:

(i)

identify the contract(s) with a customer;

(ii)

identify the performance obligations in the contract;

(iii)

determine the transaction price;

(iv)

allocate the transaction price to the performance obligations in the contract; and

(v)

recognize revenue when (or as) the performance obligations are satisfied.

The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration that it is entitled to in exchange for the goods or services the Company transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses whether the goods or services promised within each contract are distinct and, therefore, represent a separate performance obligation. Goods and services that are determined not to be distinct are combined with other promised goods and services until a distinct combined performance obligation is identified.

The Company then allocates the transaction price (that is, the amount of consideration the Company expects to be entitled to from a customer in exchange for the promised goods or services) to each performance obligation and recognizes the associated revenue when (or as) each performance obligation is satisfied. The allocation is based upon standalone selling price. The standalone selling price is the price at which an entity would sell a promised good or service separately to a customer. Because the Company have not sold the same goods or services in our contracts separately to any customers on a standalone basis, the Company estimated the standalone selling price of each performance obligation by taking into consideration internal estimates of research and development personnel needed to perform the research and development services, estimates of expected cash outflows to third parties for services and supplies and typical gross profit margins.

The Company enters into collaboration and licensing arrangements that are within the scope of ASC 606, under which the Company may exclusively license to third parties’ rights to develop, manufacture and commercialize its product candidates as well as options to acquire additional rights. The terms of these arrangements typically include payment to the Company of one or more of the following: nonrefundable, upfront license fees; development, regulatory and sales milestone payments; and royalties on net sales of licensed products.

Revenue is typically recognized using a cost-to-cost input model as the measure of progress. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which the Company is expected to complete the Company’s performance obligations under an arrangement. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The measure of progress, and thereby periods over which revenue should be recognized, are subject to estimates by management and may change over the course of the research and development and licensing agreement. Such a change could have a material impact on the amount of revenue the Company records in future periods.

Amounts received prior to revenue recognition are recorded as deferred revenue in the balance sheets. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as the current portion of deferred revenue in the balance sheets. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion in the balance sheets.

Customer Options

If an arrangement is determined to contain customer options that allow the customer to acquire additional goods or services, the goods and services underlying the customer options that are not determined to be material rights are not considered to be performance obligations at the outset of the arrangement, as they are contingent upon option exercise. The Company evaluates the customer options for material rights, or options to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement. To date, none of our arrangements have included any material rights. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. The observable price of a good or service sold separately provides the best evidence of standalone selling price. However, when standalone selling prices are not readily available, the Company is required to estimate the standalone selling price of each performance obligation. Key assumptions to determine the standalone selling price. Amounts allocated to a material right are not recognized as revenue until the option is exercised or terminates.

Milestone Payments

For each arrangement that includes milestone payments upon the achievement of performance-based milestones, such as development and regulatory milestones, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant reversal of revenue would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. Upfront and ongoing development milestones per the Company’s collaboration and license agreement are not subject to refund if the development activities are not successful. The Company reevaluates the probability of achievement of such milestones and any related constraint at each reporting period, and any adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. To date, the Company has not recognized any milestone revenues.

Royalties

For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license to the Company’s intellectual property is deemed to be the predominant item to which the royalties relate as it is the primary driver of value, the Company recognizes revenue when the related sales occur in accordance with the sales-based royalty exception. To date, the Company has not recognized any royalty revenue resulting from the Company’s collaboration and licensing agreements.

Income Taxes

Deferred tax assets and liabilities are recognized for the expected future tax consequences of events that have been included in the consolidated financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based on the difference between the consolidated financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. A valuation allowance is provided to reduce the deferred tax asset to an amount, which, more likely than not, will be realized.

The Company recognizes the tax benefit from any uncertain tax positions only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such a position are measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. Interest and penalties associated with uncertain tax positions are recorded as a component of income tax expense. As of December 31, 2024 and 2023, the Company hasnot identified any uncertain tax positions for which reserves would be required.

Segment Information

Operating segments are defined as components of an entity for which discrete information is available for evaluation by the chief operating decision maker, who is the CEO, in deciding how to allocate resources and in assessing performance. The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. All of the Company’s assets are held in the U.S.

Stock-Based Compensation

The Company accounts for stock option awards at fair value, which is measured using the Black-Scholes option-pricing model. The measurement date is generally the date of grant.

The Company recognizes stock-based compensation expense over the requisite service period, which is generally the vesting period of the respective award. For awards that include performance-based vesting conditions, stock-based compensation expense is recognized using the accelerated attribution method when the performance condition is deemed to be probable. The Company accounts for forfeitures as they occur. The Company determines the fair value of restricted stock awards in reference to the fair value of its common stock less any applicable purchase price

The Company classifies stock-based compensation expense in its consolidated statements of operations in the same manner in which the award recipient’s salary and related costs are classified or in which the award recipient’s service payments are classified.

Comprehensive Loss

Comprehensive loss includes net loss as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income was unrealized gains on marketable securities.

Net Loss Per Share

Basic net loss per share is calculated by dividing net loss by the weighted average common shares outstanding during the period.

Diluted net loss per share is calculated by adjusting weighted average common shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock and if-converted methods. For purposes of the diluted net income (loss) per share calculation, convertible debt and stock options are considered to be common stock equivalents. All common stock equivalents have been excluded from the calculation of diluted net loss per share as their effect would be anti-dilutive for all periods presented. Therefore, basic and diluted net loss per share were the same for all periods presented.

Recently Adopted Accounting Pronouncements

In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2023-07, “Segment Reporting - Improvements to Reportable Segment Disclosures.” The ASU requires disclosure of incremental segment information on an annual and interim basis and also requires companies with asingle reportable segment to provide all disclosures required by this ASU and all existing segment disclosures in Accounting Standard Codification (“ASC”) 280, “Segment Reporting.” The Company adopted this standard for this fiscal year ended December 31, 2024. The adoption of ASU 2023-07 did not have a material impact on the Company’s consolidated financial statements and related disclosures.

Recently Issued Accounting Pronouncements Not Yet Effective

In December 2023, the FASB issued ASU No. 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” This ASU updates income tax disclosure requirements primarily by requiring specific categories and greater disaggregation within the rate reconciliation and disaggregation of income taxes paid by jurisdiction. This ASU is effective for annual periods beginning after December 15, 2024, and is applicable to the Company’s fiscal year beginning January 1, 2025, with early application permitted. The Company is currently evaluating the impact of adopting this ASU on its consolidated financial statements and disclosures.

In November 2024, the FASB issued Accounting Standards Update (ASU) 2024-04, Debt-Debt with Conversions and Other Options. ASU 2024-04 is intended to clarify requirements for determining whether certain settlements of convertible debt instruments, including convertible debt instruments with cash conversion features or convertible debt instruments that are not currently convertible, should be accounted for as an induced conversion. This ASU is effective for all entities for annual reporting periods beginning after

December 15, 2025, and interim reporting periods within those annual reporting periods, with early adoption permitted. The Company is currently evaluating the potential impact of this guidance on its disclosures.

In November 2024, the FASB issued Accounting Standards Update (ASU) 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures. ASU 2024-03 is intended to improve disclosures about a public business entity’s expense and provide more detailed information to investors about the types of expenses in commonly presented expense captions. The amendments in this ASU are effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the potential impact of this guidance on its disclosures.

3. Property and Equipment

Property and equipment consist of the following (in thousands):

Depreciation and amortization expense for the years ended December 31, 2024 and 2023 was $4.1 million and $5.4 million, respectively.

4. Fair Value Measurements

The following tables set forth by level, within the fair value hierarchy, the assets carried at fair value (in thousands):

Money market funds and government securities are valued by the Company based on quoted market prices, which represent a Level 1 measurement within the fair value hierarchy. There wereno transfers among Level 1, Level 2, or Level 3 categories in the periods presented.

Assets and Liabilities Not Carried at Fair Value

The Company's convertible long-term debt was carried at amortized cost. The fair value of the convertible long-term debt was estimated to be $38.4 million at December 31, 2023. Fair value was determined using a convertible bond model using a binomial lattice approach. We classified the fair value disclosures for the long-term debt within level 3 of the fair value hierarchy because the fair value is derived using significant unobservable inputs, which include discount rates and volatility. The Company's convertible long-term debt was extinguished on December 20, 2024.

The carrying value of accounts payable and accrued expenses that are reported on the consolidated balance sheets approximate fair value due to the short-term nature of these liabilities. Based on the borrowing rates currently available to the Company for bank loans with similar maturities, the fair value of long-term debt is approximately equal to its carrying amount as of December 31, 2024.

5. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):

6. Stockholders' Equity

ATM Program

On May 16, 2023, the Company entered into a sales agreement (the Sales Agreement) with Wedbush Securities, Inc. (Wedbush), as sales agent, pursuant to which the Company could offer, issue and sell up to an aggregate amount of $75.0 million of shares of the Company's voting common stock, par value $0.0001 per share (Voting Common Stock), from time to time in “at-the-market” (ATM) offerings during the term of the Sales Agreement under a registration statement on Form S-3 (File No. 333-268260) filed with the SEC, which was declared effective on May 16, 2023. No Voting Common Stock has been sold under this Sales Agreement to date.

Equity Offerings

On June 1, 2023, the Company completed an underwritten public offering resulting in the issuance and sale of (a)23,287,134 shares of Voting Common Stock, at a price of $2.00 per share, and (b) pre-funded warrants (Pre-Funded Warrants) to purchase up to 47,010,526 shares of the Voting Common Stock, at a price of $1.9999 per warrant with an exercise price of $0.0001 per share. The Company received aggregate net proceeds of $134.7 million after deducting underwriting discounts, commissions and other offering expenses, with $42.4 million allocated to the Voting Common Stock and $92.3 million allocated to Pre-Funded Warrants.

On April 24, 2024, the Company completed an underwritten public offering resulting in the issuance and sale of (a)4,958,068 shares of Voting Common Stock, including the partial exercise of the underwriters’ option to purchase 2,485,487 additional shares of Voting Common Stock, at the closing market price on April 16, 2024, of $7.13 per share, and (b) Pre-Funded Warrants to purchase up to 18,577,419 shares of the Voting Common Stock, at a price of $7.1299 per warrant with an exercise price of $0.0001 per share. The Company received aggregate net proceeds of approximately $161.4 million after deducting underwriting discounts, commissions and other offering expenses, with $33.1 million allocated to the Voting Common Stock and $128.3 million allocated to Pre-Funded Warrants.

On December 27, 2024, the Company completed a registered direct offering with an existing investor for the issuance of pre-funded warrants to purchase up to 7,500,000 shares of the Company's Voting Common Stock, with an exercise price of $0.0001 per warrant. The pre-funded warrants were issued at a purchase price of $4.00 per warrant, resulting in gross proceeds of approximately $30.0 million, before deducting offering expenses of $0.2 million.

The Pre-Funded Warrants are immediately exercisable subject to certain ownership limitations, have an exercise price of $0.0001 pershare, may be exercised at any time and do not expire. The Pre-Funded Warrants were determined to be equity classified because they are freestanding financial instruments that are legally detachable and separately exercisable from the equity instruments, are immediately exercisable, do not embody an obligation for the Company to repurchase its shares, permit the holders to receive a fixed number of common shares upon exercise, are indexed to the Company’s common stock and meet the equity classification criteria. In addition, the Pre-Funded Warrants do not provide any guarantee of value or return. As such, proceeds received from the issuance from the Pre-Funded Warrants were recorded as a component of stockholders’ equity within additional paid-in capital. As of December 31, 2024, no Pre-Funded Warrants have been exercised.

7. Stock-Based Compensation

2021 Equity Incentive Plan

The 2021 Equity Incentive Plan (the 2021 Plan) was approved by the Company’s Board on April 22, 2021 and became effective immediately, althoughno awards were permitted to be granted under the 2021 Plan until July 15, 2021. The 2021 Plan replaced the 2018 Plan, however, awards outstanding under the 2018 Plan continue to be governed by their existing terms. In addition, shares of common stock subject to awards granted under the 2018 Plan that cease to be subject to such awards by forfeiture or otherwise after the termination of the 2018 Plan will be available for issuance under the 2021 Plan.

There were 3,278,048 shares of common stock initially reserved for issuance under the 2021 Plan and as of December 31, 2024, there were 5,781,492 shares of common stock available for issuance. The number of shares reserved for issuance under the 2021 Plan will be increased automatically on the first business day of each fiscal year, commencing in 2022 and ending in 2031. The aggregate number of common shares that may be issued under the 2021 Plan shall automatically increase by a number equal to the least of (a)4% of the number of the total outstanding common shares on the last day of the preceding fiscal year, or (b) a number of shares common stock determined by the Company’s Board.

2021 Employee Stock Purchase Plan

The 2021 Employee Stock Purchase Plan (the "2021 ESPP") was approved by the Company’s Board on April 22, 2021 and became effective immediately, althoughno awards were permitted to be granted under the 2021 Plan until July 15, 2021. A total of 254,390 shares of common stock were initially reserved for issuance under the 2021 ESPP. As of December 31, 2024 and 2023, there were 228,533 and 146,380 shares issued under the 2021 ESPP, respectively. As of December 31, 2024, there were 985,486 shares of common stock available for issuance under the 2021 ESPP. The number of shares reserved for issuance will automatically be increased on the first business day of each fiscal year, commencing on January 1, 2022 and ending on January 1, 2041. The aggregate number of shares of common stock that may be issued under the 2021 ESPP shall automatically increase by a number equal to the least of (i) one percent (1%) of the total number of shares of common stock actually issued and outstanding on the last day of the preceding fiscal year, or (ii) a number of shares of common stock determined by the Company’s Board.

Stock Compensation

Stock-based compensation expense related to stock options and the stock purchase plan for theyears ended December 31, 2024 and 2023 was classified in the consolidated statement of operations as follows (in thousands):

Stock Options

The Company typically grants stock options at exercise prices deemed by the Board to be equal to the fair value of the common stock at the time of grant, based upon the quoted price of the Company’s common stock.

The fair value of stock option grants is estimated using the Black-Scholes option-pricing model. The Company lacks sufficient company-specific historical and implied volatility information. Therefore, it estimates its expected stock volatility based on the historical volatility of a publicly traded set of peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. For options with service-based vesting conditions, the expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends and doesnot expect to pay any cash dividends in the foreseeable future.

The weighted-average for each of the assumptions the Company used to determine the grant-date fair value of options granted were as follows:

The following table summarizes the stock option activity:

Other information related to the option activity for theyears ended December 31, 2024 and 2023:

As of December 31, 2024, the unrecognized compensation cost related to outstanding options was $24.0 million, which is expected to be recognized over a weighted-average period of 2.66 years.

8. Income Taxes

During the years ended December 31, 2024 and 2023, the Company did not record an income tax provision due to the losses incurred and a full valuation allowance provided on the net deferred tax assets.

A reconciliation of the federal statutory income tax rate to the effective tax rate is as follows:

Deferred tax assets and liabilities reflect the net tax effects of net operating loss carryovers and temporary differences between the carrying amount of assets and liabilities for financial reporting and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and liabilities were as follows (in thousands):

In determining the need for a valuation allowance, the Company has given consideration to its cumulative book income and loss positions. The Company has assessed the available means of recovering deferred tax assets, including the ability to carryback net operating losses, the existence of reversing taxable temporary differences, the availability of tax planning strategies and forecasted future taxable income. As of December 31, 2024, the Company maintains a full valuation allowance against its net deferred tax assets. The valuation allowance increased by $39.3 million and $30.4 million during the years ended December 31, 2024 and 2023, respectively.

As of December 31, 2024, the Company had U.S. federal net operating loss carryforwards of approximately $113.6 million. The U.S. federal net operating losses have an indefinite life carryforward. As of December 31, 2024, the Company had Massachusetts net operating loss carryforwards of approximately $118.3 million that expire at various dates through 2043. As of December 31, 2024, the Company had U.S. R&D federal credit carryforwards of approximately $17.9 million that expire at various dates through 2043. As of December 31, 2024, the Company had U.S. state R&D tax credit carryforwards of approximately $9.5 million that expire at various dates through 2038.

Under Sections 382 and 383 of the U.S. Internal Revenue Code, if a corporation undergoes an ownership change, the corporation's ability to use its pre-change net operating loss carryforwards and other pre-change attributes, such as net operating losses and research tax credits, to offset its post-change income and taxes may be limited. In general, an ownership change generally occurs if there is a cumulative change in ownership by 5% stockholders that exceeds 50 percentage points over a rolling three-year period. Similar rules may apply under U.S. state tax laws. The Company has experienced an ownership change in the past and may experience ownership changes in the future as a result of future transactions in its share capital, some of which may be outside the control of the Company. As a result, if the Company earns net taxable income, its ability to use its pre-change net operating loss carryforwards, or other pre-change tax attributes, to offset U.S. federal and state taxable income and taxes is subject to significant limitations.

The Company accounted for uncertain tax positions using a more likely than not threshold for recognizing and resolving uncertain tax positions. The evaluation of uncertain tax positions is based on factors that include, but are not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, new audit activity and changes in facts or circumstances related to a tax position. The Company evaluates uncertain tax positions on an annual basis and adjusts the level of the liability to reflect any subsequent changes in the relevant facts surrounding the uncertain positions. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes. For the years ended December 31, 2024 and 2023, there wereno accrued interest or penalties in the consolidated statements of operations.

The Company is subject to taxation for federal and Massachusetts purposes. As of December 31, 2024, the Company is subject to examination by these taxing authorities for all years since inception.

9. Collaboration and License Agreements

Amgen

On May 8, 2023, the Company entered into a Collaboration Agreement with Amgen Inc. (the Amgen Agreement) to identify antigens recognized by T cells in patients with Crohn’s disease in accordance with a research plan. Under the terms of the Amgen Agreement, Amgen will retain all global development and commercialization rights. The proceeds from the Amgen Agreements included an upfront payment of $30.0 million, which was collected in July 2023. In addition, the Company is eligible to earn success-based milestone payments of over $500 million, based upon the achievement of certain clinical development and commercial milestones, as well as tiered single-digit royalty payments on net sales of products developed from the collaboration, subject to reductions set forth in the Amgen Agreement.

The Company concluded that Amgen meets the definition of a customer, as the Company is delivering research and development activities and a license of intellectual property. The Company identified performance obligations for research and development activities, the license, data reporting and participation in joint steering and research committees, which were determined to be a single combined performance obligation due to the services and licenses being highly interrelated.

For a certain time period during the term of the Amgen Agreement, Amgen has an option to add targets to the collaboration for payments specified in the agreement. Pursuant to the Amgen Agreement, the option for Amgen to select additional targets and to license, develop, and commercialize targets is not a performance obligation at the outset as these are customer options that do not represent material rights.

The Company looked to the promises in the arrangement to determine the method of recognition that best depicted the transfer of the services and the satisfaction of the combined performance obligations. The Company concluded that the performance of the research services over the expected research term was the predominant promise within the performance obligation. The Company will recognize the revenue associated with the performance obligation using an input method. The method of measuring progress towards delivery of the services incorporates actual internal and external costs incurred, relative to total internal and external costs expected to be incurred to satisfy the performance obligation. Changes in estimates of total internal and external costs expected to be incurred are recognized in the period of change as a cumulative catch-up adjustment. As costs are incurred, the Company will recognized revenue over time. At this time, it is estimated that the research term will be approximately 3 years.

The Company determined the $30.0 million upfront payment to be the entirety of the consideration to be included in the transaction price. The option to add additional targets was not included in the transaction price as this option was assessed to be improbable at this time. The potential milestone and royalty payments that the Company is eligible to receive were also excluded from the transaction price, as all milestone and royalty amounts were fully constrained based on the assessed probability of achievement. The Company will continue to assess the probability of the option to add additional targets and the probability of milestone achievement throughout the research term and will adjust the consideration in the contract accordingly.

For the year ended December 31, 2024 and 2023 the Company recognized $2.8 million and $14.2 million, respectively, of revenue associated with the Amgen Agreement. As of December 31, 2024, the Company recorded $12.9 million of deferred revenue, of which $1.2 million is classified as long-term.

Novartis

In March 2020, the Company entered into a Collaboration and License Agreement (the Novartis Agreement) with Novartis Institutes For BioMedical Research, Inc. (Novartis) to collaborate on their research efforts to discover and develop novel TCR-T therapies. At the inception date of the Novartis Agreement, Novartis or its affiliates held an ownership interest of more than 10% in the Company, and at December 31, 2024 and 2023, Novartis held less than 10% of the common shares outstanding. Under the Novartis Agreement, the Company was to identify and characterize TCRs in accordance with a research plan, and transfer data arising from the research plan. The Novartis Agreement provided for payments of an upfront fee of $20.0 million, research funding totaling $10.0 million, and potential milestone payments contingent on clinical, regulatory and sales success.

The Company concluded that the performance of the research services was the predominant performance obligation and was recognizing the revenue associated with the performance obligation using the input method, according to the actual costs incurred as a percentage of total expected costs to complete the research services.

The Company determined that the $20.0 million upfront payment, together with the $10.0 million of estimated research costs to be reimbursed by Novartis to be the entirety of the consideration to be included in the transaction price as of the outset of the arrangement. The potential milestone payments that the Company is eligible to receive were excluded from the transaction price, as all milestone amounts were fully constrained based on the assessed probability of achievement.

During the year ended December 31, 2023 the Company recognized $5.8 million of revenue associated with the Novartis Agreement, of which $1.9 million related to cost reimbursements under the Novartis Agreement that offset costs incurred within research and development expenses in the statements of operations. The research term ended in March 2023.

10. Commitments and Contingencies

Leases

The Company leasestwo facilities at 880 Winter Street and 830 Winter Street in Waltham, Massachusetts. Each lease has specified terms and includes renewal options. Given uncertainty as to the Company's intentions with respect to these leases, the renewal options were not deemed reasonably certain.

On November 8, 2023, the Company entered into a lease amendment extending the expiration date of the 830 Winter Street Lease from September 30, 2024 to October 31, 2029 and provides for one option to renew the 830 Winter Street Lease for afive-year period commencing on November 1, 2029, resulting in an increase in the lease liability of $6.2 million.

On October 28, 2024, the Company entered into a second lease amendment expanding the rentable space of 830 Winter Street. The amendment provides for an additional 25,628 square feet of space with a commencement date of December 1, 2024 and an expiration date of October 31, 2029 with one option to review for afive-year period. This amendment resulted in an increase in the lease liability of $6.1 million.

Summary of lease cost

The following table summarizes the presentation in the Company's consolidated balance sheets of its operating leases (in thousands):

The following table summarizes the effect of lease costs in the Company's consolidated statement of operations (in thousands):

During the years ended December 31, 2024 and 2023, the Company made cash payments for operating leases of$9.8 million and$9.4 million, respectively.

As of December 31, 2024, future payments of operating lease liabilities are as follows (in thousands):

As of December 31, 2024, the weighted average remaining lease term was 7.3 years and the weighted average incremental borrowing rate used to determine the operating lease liability was 10.0%. As of December 31, 2023, the weighted average remaining lease term was 8.6 years and the weighted average incremental borrowing rate used to determine the operating lease liability was 10.3%.

Brigham and Women’s License Agreement

The Company obtained the worldwide exclusive license to its foundational technology from The Brigham and Women’s Hospital, Inc. (or BWH). The license, as amended, grants worldwide exclusive use to the patent underlying the TargetScan technology in exchange for fees including development milestones and various royalties on product sales should they occur in the future.

Royalty Agreement

In June 2018, the Company amended and restated an existing royalty agreement with one of its founders. Under the amended and restated royalty agreement, the Company agreed to pay the founder an aggregate royalty of 1% of net sales of any product sold by the Company or by any of its direct or indirect licensees for use in the treatment of any disease or disorder covered by a pending patent application or issued patent held or controlled by the Company as of the last date that the founder was providing services to the Company as a director or consultant under a written agreement in perpetuity. Royalties are payable with respect to each applicable product for a defined period of time set forth in the royalty agreement. The founder assigned his rights and obligations under the royalty agreement to one of his affiliated entities in January 2021.

11. Loan and Security Agreements

K2 HealthVentures LLC

On September 9, 2022 (the Closing Date), the Company entered into a Loan and Security Agreement (the Loan Agreement) with K2 HealthVentures LLC (K2HV), pursuant to which convertible term loans in an aggregate principal amount of up to $60.0 million is available to the Company in three tranches, subject to certain terms and conditions. The Company drew the first tranche of $30.0 million from K2HV on the Closing Date. The Company had the option to draw the second tranche of $10.0 million upon the achievement of certain financial and clinical milestones and an uncommitted third tranche of $20.0 million could be funded by joint agreement of the Company and K2HV. On the Closing Date, the Company paid a facility fee of $0.4 million to K2HV and is subject to an additional 1% of the principal amount of any amount drawn on third tranche.

The term loan was expected to mature on September 1, 2026 (the Maturity Date), and was subject to interest only payments for 24 months, which could be extended to 36 months upon achievement of certain financial and clinical milestones, following which the term loans would amortize in equal monthly installments until maturity. The Company had the ability to repay the loan at any time either in cash or in shares, subject to applicable premiums as specified in the Loan Agreement. The term loans accrued interest at a per annum rate equal to the greater of (i)8.75% and (ii) the sum of (A) the prime rate (as last quoted in The Wall Street Journal) and (B)4.75%, subject to a cap of 9.90%.

On September 26, 2024, K2HV confirmed to the Company that the amortization commencement date would be October 1, 2025, thereby extending the interest-only period under the Loan Agreement for 12 months. This extension met the definition of an accounting debt modification in accordance with ASC 470-50 and was accounted for prospectively as a yield adjustment, with no resulting gain or loss recognized.

The lenders could elect at any time following the closing prior to the payment in full of the term loans to convert any portion of the principal amount of the term loans then outstanding into shares of the Company's common stock. The first tranche of the loan was convertible at the option of K2HV at a conversion price of $4.785 per share and future tranches could be convertible as specified in the agreement, provided that, such price shall be subject to the applicable conversion price floor and other adjustments in accordance with the Loan Agreement. The embedded conversion option met the derivative accounting scope exception since the embedded conversion option was indexed to the Company’s own common stock and qualifies for classification within stockholders’ equity.

The Company had the option to prepay all, but not less than all, of the outstanding principal balance of the term loans under the Loan Agreement subject to a prepayment fee ranging from 4% to 1% depending upon when the prepayment occurs. The Company was obligated to pay a final fee equal to 6.00% of the aggregate amount of the term loans funded (the Exit Fee), to occur upon the earliest of (i) the maturity date, (ii) the acceleration of the term loans, and (iii) the prepayment of the term loans. If, upon equity conversion, K2HV received gross proceeds in an amount equal to at least 1.5 multiplied by the principal amount converted from the sale or other disposition of such Conversion Shares (as defined in the Loan Agreement), then as to such principal amount, the Exit Fee would be reduced to zero.

On November 20, 2024, K2HV elected to convert $15.0 million of the outstanding principal balance into 3,134,796 shares of the Company's voting common stock at a price of $4.785, in accordance with the agreement.

On December 20, 2024 the Company repaid the remaining obligation of the debt agreement, which included $15.0 million in remaining principal, a $1.8 million Exit Fee, and a $0.3 million prepayment fee. The Company recognized a loss from extinguishment of $1.1 million.

The Company recorded $3.6 million and $3.8 million in interest expense for the years ended December 31, 2024 and 2023, respectively. The effective interest rate on the Loan Agreement, including the amortization of the debt discount and issuance costs, and accretion of the Exit Fee, was 12.61% upon extinguishment.

Silicon Valley Bank

On December 20, 2024 (the effective date), the Company entered into a Loan and Security Agreement (SVB Loan Agreement) with Silicon Valley Bank, a division of First-Citizens Bank & Trust Company (SVB). Under the SVB Loan Agreement, SVB will extend up to $52.5 million in a term loan facility, consisting of a first tranche of $32.5 million fully funded on the Effective Date and a second tranche of $20.0 million to be available to the Company at the Lender’s sole discretion on or prior to June 30, 2026.

The term loans will mature on September 1, 2029, and will be subject to monthly interest only payments until September 30, 2027, provided the Company achieves certain financial and clinical milestones, following which the term loans will amortize in equal monthly installments until maturity. If the Company does not achieve such financial and clinical milestones by June 30, 2026, the maturity date will be September 1, 2028, and the interest only period will end on September 30, 2026, following which the term loans will amortize in equal monthly installments until maturity.

The term loans will accrue interest at a per annum rate equal to the greater of (i)7.00% and (ii) the prime rate (as last quoted in The Wall Street Journal), minus 0.75%; provided that such interest rate shall not exceed 9.75% per annum. The Company will be liable for a final payment that is due on the earliest to occur of (a) the maturity date, (b) the repayment of the term loans in full, and (c) the date upon which the term loans are accelerated by the Lender, in an amount equal to the aggregate original principal amount of the term loans extended by the Lender to the Company, multiplied by 5.0% (Exit Fee). In addition, the Company will be liable for a prepayment fee equal to (x)3.0% of the principal amount of term loans prepaid during the first year of the term, (y)2.0% of the principal amount of term loans prepaid during the second year of the term, and (z)1.0% of the principal amount of term loans prepaid thereafter. The term loans will automatically accelerate upon the occurrence of a bankruptcy or insolvency event involving the Company or its subsidiaries.

The SVB Loan Agreement contains customary representations and warranties, events of default and affirmative and negative covenants, including covenants that limit or restrict the Company’s and its subsidiaries’ ability to, among other things, dispose of assets, make changes to its business, management, ownership or business locations, merge or consolidate, incur additional indebtedness, grant liens on its assets, pay dividends or other distributions, repurchase equity, make investments, and enter into certain transactions with affiliates, in each case subject to certain thresholds and exceptions. The New Loan Agreement does not require the Company to comply with a financial maintenance covenant. As collateral for its obligations under the New Loan Agreement, the Company granted the Lender a first-priority security interest on substantially all of the Company’s assets (other than intellectual property), subject to certain exceptions. The Company’s obligations under the SVB Loan Agreement will be guaranteed by each of the Company’s future direct or indirect subsidiaries, subject to certain exceptions.

The Company recorded $0.1 million in interest expense for the year ended December 31, 2024. The effective interest rate on the SVB Loan Agreement, including the amortization of the debt discount and issuance costs, and accretion of the Exit Fee, was 8.46% at December 31, 2024.

Future principal payments as of December 31, 2024 are as follows (in thousands):

12. Retirement Plan

The Company initiated a defined contribution plan under Section 401(k) of the IRC (the Plan) covering all qualified employees effective January 1, 2019. Employee contributions are voluntary and are determined on an individual basis subject to the maximum allowable under federal tax regulations. The Company made contributions to the Plan of $1.0 million and $0.7 million for the years ended December 31, 2024 and 2023, respectively.

13. Segment Reporting

Operating segments are defined as components of the entity for which separate financial information is made available and that is regularly evaluated by thechief operating decision maker (CODM) in making decisions regarding resource allocation and assessing performance. The Company's CODM is its chief executive officer and the Company manages its operations as asingle segment for the purposes of assessing performance and making operating decisions. The Company is focused on the development of T cell receptor (TCR)-engineered T cell (TCR-T) therapies for the treatment of patients with cancer.

The CODM assesses the Company's performance by reviewing GAAP net loss and significant expenses by function along with the annual budget. The chief operating decision maker considers budget-to-actual variances on a quarterly basis when making decisions about the allocation of operating and capital resources.

The following table provides information about the Company's single operating segment which includes significant expenses by function along with significant non-cash expense items.

14. Net Loss Per Share

Net Loss Per Share

Basic and diluted net loss per share was calculated as follows (in thousands, except share and per share data):

The 73,087,945 shares of the Company's common stock issuable upon exercise of the Pre-Funded Warrants described in Note 6 are included as outstanding common stock in the calculation of basic and diluted net loss per share.

The Company has two classes of common stock, each with identical participation rights to earnings and liquidation preferences, and therefore the calculation of net loss per share as described above is identical to the calculation under the two-class method. The Company excluded the following potential common shares from the computation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: