Scholar Rock Holding Corp

1. Nature of the Business and Basis of Presentation

Organization

Scholar Rock Holding Corporation (the “Company”) is a late-stage biopharmaceutical company focused on the discovery, development, and delivery of innovative medicines for the treatment of serious diseases in which signaling by protein growth factors plays a fundamental role. As a global leader in transforming growth factor beta (“TGFβ”) superfamily biology, the Company’s novel understanding of the molecular mechanisms of growth factor activation enabled the development of a proprietary platform for the discovery and development of monoclonal antibodies that locally and selectively target the precursor, or latent, forms of growth factors. By targeting the signaling proteins at the cellular level and acting in the disease microenvironment, the Company believes that it may avoid the historical dose-limiting safety challenges associated with inhibiting growth factors for therapeutic effect.

The Company’s first product candidate, apitegromab, is a highly selective, fully human, monoclonal antibody, with a unique mechanism of action that results in inhibition of the activation of the growth factor, myostatin, in skeletal muscle. Apitegromab is being developed as a potential first muscle-targeted therapy for the treatment of spinal muscular atrophy (“SMA”). The Company completed SAPPHIRE, a pivotal Phase 3 clinical trial to evaluate the efficacy and safety of apitegromab in patients with nonambulatory Type 2 and Type 3 SMA and announced positive top-line results in October 2024. The study achieved its primary endpoint. The Company submitted a U.S. Biologics License Application to the FDA in January 2025 and is planning to submit a European Union marketing authorization application to the European Medicines Agency (“EMA”) in the first quarter of 2025. If apitegromab is approved, the Company expects to initiate a commercial product launch in the fourth quarter of 2025 in the United States, with a commercial launch of apitegromab in Europe to follow. Additionally, in 2024, the Company announced data from the Phase 2 TOPAZ trial extension period which showed patient outcomes at 48 months of treatment with apitegromab. The FDA granted Fast Track designation, Rare Pediatric Disease designation and Orphan Drug designation to apitegromab for the treatment of SMA in May 2021, August 2020 and March 2018, respectively. The EMA granted Priority Medicines (“PRIME”) designation in March 2021 and the EC granted orphan medicinal product designation in December 2018 to apitegromab for the treatment of SMA.

In October 2023, the Company announced an expansion of its therapeutic focus into cardiometabolic disorders by advancing its anti-myostatin program with SRK-439, a novel, fully human anti-myostatin monoclonal antibody, for evaluation in cardiometabolic disorders, including obesity. The Company is developing SRK-439 towards a potential investigational new drug application (“IND”) submission in the third quarter of 2025. To inform the development of SRK-439, in May 2024 the Company initiated the Phase 2 EMBRAZE proof-of-concept trial, designed to assess the safety and efficacy of apitegromab to preserve muscle mass in individuals living with obesity and on background therapy of a GLP-1 receptor agonist (“GLP-1 RA”). In September 2024, the Company announced that it had completed enrollment in the Phase 2 EMRAZE proof-of-concept trial. Top-line results from this trial are expected in the second quarter of 2025.

The Company’s second product candidate, SRK-181, a highly selective inhibitor of the activation of latent TGFβ, is being developed for the treatment of cancers that are resistant to checkpoint inhibitor therapies, such as anti-PD-1 or anti-PD-L1 antibody therapies (referred to together as anti-PD-(L)1 antibody therapies). SRK-181 is being evaluated in the Company’s Phase 1 DRAGON proof-of-concept clinical trial in patients with locally advanced or metastatic solid tumors that exhibit resistance to anti-PD-(L)1 antibody therapies. The Company completed enrollment of the Phase 1 DRAGON trial in December 2023 and continues to treat patients who remain on study. This two-part clinical trial consists of a dose escalation portion (Part A) and a dose expansion portion evaluating SRK-181 in combination with an approved anti-PD-(L)1 antibody therapy (Part B). Part B commenced in 2021 and includes the following active cohorts: urothelial carcinoma, cutaneous melanoma, non-small cell lung cancer, clear cell renal cell carcinoma, and head and neck squamous cell carcinoma. Safety, efficacy and biomarker data were presented in June 2024 at the American Society of Clinical Oncology annual meeting and in November 2024 at the Society for Immunotherapy of Cancer 39th Annual Meeting.

Additionally, the Company continues to create a pipeline of product candidates to deliver novel therapies to underserved patients suffering from a wide range of serious diseases, including neuromuscular disorders, cardiometabolic disorders, cancer, fibrosis, and iron-restricted anemia. The Company was originally formed in May 2012. Its principal offices are in Cambridge, Massachusetts.

Since its inception, the Company’s operations have focused on research and development of monoclonal antibodies that selectively inhibit activation of growth factors for therapeutic effect, as well as establishing the Company’s intellectual property portfolio and performing research and development activities. The Company has primarily financed its operations through various equity financings, including in October 2024 (Note 9), as well as research and development collaboration agreements and the Company’s debt facility (Note 13).

Revenue generation activities have been limited to two collaborations, both containing research services and the issuance of a license. No revenues have been recorded from the sale of any commercial product.

The Company is subject to a number of risks similar to other life science companies, including, but not limited to, successful discovery and development of its drug candidates, raising additional capital, development by its competitors of new technological innovations, protection of proprietary technology and regulatory approval and market acceptance of the Company’s product candidates. The Company anticipates that it will continue to incur significant operating losses for the next several years as it continues to develop its product candidates. The Company believes that its existing cash, cash equivalents, and marketable securities at December 31, 2024 will be sufficient to allow the Company to fund its current operations through at least a period of one year after the date these financial statements are issued.

Basis of Presentation

The consolidated financial statements include the accounts of Scholar Rock Holding Corporation and its wholly owned subsidiaries. All intercompany balances have been eliminated in consolidation.

These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).

2. Summary of Significant Accounting Policies

Use of Estimates

The preparation of financial statements in accordance with GAAP requires management to make estimates and judgments that may affect the reported amounts of assets and liabilities and related disclosures of contingent assets and liabilities at the date of the financial statements and the related reporting of revenues and expenses during the reporting period. Management bases its estimates on historical experience and on various assumptions that are believed to be reasonable under the circumstances. Actual results could differ from those estimates.

Concentration of Credit Risk and Off-Balance Sheet Risk

The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts or other foreign-hedging arrangements. The Company follows an investment policy approved by the Board of Directors. Its primary objectives are the preservation of capital and maintenance of liquidity. The Company invests only in fixed income instruments denominated and payable in U.S. dollars including obligations of the U.S. government and its agencies and money market funds registered according to SEC Rule 2a-7 of the Investment Company Act of 1940. All securities must have a readily ascertainable market value, must be readily marketable and be U.S. dollar denominated.

Cash, Cash Equivalents and Restricted Cash

The Company considers highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. Cash equivalents are stated at cost, which approximates market value. At December 31, 2024 and 2023, cash equivalents include money market funds that invest primarily in U.S. government-backed securities and treasuries.

At December 31, 2024 and 2023, restricted cash consists of letters of credit related to its leased facility. The following table reconciles cash, cash equivalents and restricted cash per the balance sheet to the statement of cash flows (in thousands):

Marketable Securities

The Company classifies its marketable securities as available-for-sale. Marketable securities with a remaining maturity date greater than one year are classified as non-current if the Company does not intend to utilize the marketable securities to fund current operations. Marketable securities are maintained by an investment manager and consist of U.S. treasury obligations and government agency securities. Marketable securities are carried at fair value with the unrealized gains and losses included in accumulated other comprehensive income (loss) as a component of stockholders’ equity until realized. Any premium or discount arising at purchase is amortized and/or accreted to interest income and/or expense over the life of the underlying marketable security.

Although available to be sold to meet operating needs or otherwise, securities are generally held through maturity. The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense) within the statement of operations and comprehensive loss.

The Company reviews its portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit loss or other factors. If the decline in fair value is due to credit loss factors, a loss is recognized in net income. To date, the Company has not experienced any credit losses and does not believe it is exposed to any significant credit risk on these investments.

Property and Equipment

Property and equipment are recorded at cost. Expenditures for major renewals or betterments that extend the useful lives of property and equipment are capitalized; expenditures for maintenance and repairs are charged to expense as incurred. Depreciation is calculated on a straight-line basis over the estimated useful lives of the related asset. Property and equipment are depreciated as follows:

Impairment of Long-Lived Assets

Long-lived assets consist of property and equipment and right-of-use assets. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the

assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. The Company didnot record any impairment losses on long-lived assets during the years ended December 31, 2024 or 2023.

Leases

The Company accounts for leases using ASC Topic 842, Leases (“ASC 842”). At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Leases with a term greater than one year are recognized on the balance sheet as right-of-use assets, lease liabilities and, if applicable, long-term lease liabilities. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected remaining lease term. Certain adjustments to the right-of-use asset may be required for items such as incentives received. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its estimated incremental borrowing rates, which are the rates incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment.

In accordance with the guidance in ASC 842, components of a lease should be split into three categories: lease components (e.g., land, building, etc.), non-lease components (e.g., common area maintenance, consumables, etc.), and non-components (e.g., property taxes, insurance, etc.). Then the fixed and in-substance fixed contract consideration (including any related to non-components) must be allocated based on the respective relative fair values to the lease components and non-lease components. For operating leases, lease expense relating to fixed payments is recognized on a straight-line basis over the term and lease expense relating to variable payments is expensed as incurred.

Fair Value Measurements

ASC Topic 820, Fair Value Measurement ("ASC 820"), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes between the following:

Level 1 — Quoted market prices in active markets for identical assets or liabilities.

Level 2 — Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves.

Level 3 — Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use.

To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Segment Information

Operating segments are defined as components of an entity about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business inone operating segment (Note 16).

Revenue Recognition

The Company accounts for revenue using the provisions of ASC Topic 606, Revenue from Contracts with Customers (“ASC 606”). Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized for arrangements determined to be within the scope of ASC 606, the Company performs the following five steps: (i) identification of the contract(s) with the customer, (ii) identification of the promised goods or services in the contract and determination of whether the promised goods or services are performance obligations, (iii) measurement of the transaction price, (iv) allocation of the transaction price to the performance obligations, and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

The Company accounts for a contract with a customer that is within the scope of ASC 606 when all of the following criteria are met: (i) the arrangement has been approved by the parties and the parties are committed to perform their respective obligations, (ii) each party’s rights regarding the goods or services to be transferred can be identified, (iii) the payment terms for the goods or services to be transferred can be identified, (iv) the arrangement has commercial substance and (v) collection of substantially all of the consideration to which the Company will be entitled in exchange for the goods or services that will be transferred to the customer is probable.

The Company first evaluates license and/or collaboration arrangements to determine whether the arrangement (or part of the arrangement) represents a collaborative arrangement pursuant to ASC Topic 808,Collaborative Arrangements, based on the risks and rewards and activities of the parties pursuant to the contractual arrangement. The Company accounts for collaborative arrangements (or elements within the contract that are deemed part of a collaborative arrangement), which represent a collaborative relationship and not a customer relationship, outside of the scope of ASC 606. The Company’s two collaborations represented revenue arrangements.

For the arrangements or arrangement components that are subject to revenue accounting guidance, in determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must use significant judgment to determine: a) the number of performance obligations based on the determination under step (ii) above and whether those performance obligations are distinct from other performance obligations in the contract; b) the transaction price under step (iii) above; and c) the standalone selling price for each performance obligation identified in the contract for the allocation of transaction price in step (iv) above. The Company uses judgment to determine whether milestones or other variable consideration, except for royalties, should be included in the transaction price as described further below. The transaction price is allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. In determining the stand-alone selling price of a license to the Company’s proprietary technology or a material right provided by a customer option, the Company considers market conditions as well as entity-specific factors, including those factors contemplated in negotiating the agreements as well as internally developed estimates that

include assumptions related to the market opportunity, estimated development costs, probability of success and the time needed to commercialize a product candidate pursuant to the license. In validating its estimated stand-alone selling prices, the Company evaluates whether changes in the key assumptions used to determine its estimated stand-alone selling prices will have a significant effect on the allocation of arrangement consideration between performance obligations.

The Company estimates the transaction price based on the amount of consideration the Company expects to be received for transferring the promised goods or services in the contract. The consideration may include both fixed consideration and variable consideration. At the inception of each arrangement that includes variable consideration, the Company evaluates the amount of the potential payments and the likelihood that the payments will be received. The Company utilizes either the most likely amount method or expected value method to estimate the transaction price based on which method better predicts the amount of consideration expected to be received. If it is probable that a significant revenue reversal would not occur, the variable consideration is included in the transaction price.

Performance obligations are promised goods or services in a contract to transfer a distinct good or service to the customer. Promised goods or services are considered distinct when: (i) the customer can benefit from the good or service on its own or together with other readily available resources and (ii) the promised good or service is separately identifiable from other promises in the contract. In assessing whether promised goods or services are distinct, the Company considers factors such as the stage of development of the underlying intellectual property, the capabilities of the customer to develop the intellectual property on their own and whether the required expertise is readily available.

The Company allocates the transaction price based on the estimated standalone selling price. The Company must develop assumptions that require judgment to determine the standalone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the standalone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction and the estimated costs. Estimating costs for research and development programs is subjective as the Company estimates the costs anticipated to successfully complete the research performance obligations. As the research is novel, efforts to be successful may be significantly different than the estimated costs at the beginning of the contract. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated to each performance obligation are consistent with the amounts the Company would expect to receive for each performance obligation.

For performance obligations which consist of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation in order to determine whether the combined performance obligation is satisfied over time or at a point in time. The Company determines the appropriate method of measuring progress of combined performance obligations satisfied over time for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The estimated remaining costs is highly subjective, as the research is novel, therefore efforts to be successful may be significantly different than the estimated costs made at the balance sheet date. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company will recognize revenue from non-refundable, up-front fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. The Company receives payments from customers based on billing schedules established in each contract. Up-front payments and fees are recorded as deferred revenue upon receipt or when due until the Company performs its obligations under these arrangements. 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 accompanying consolidated 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. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional. Amounts recognized as revenue, but not yet received or invoiced, are generally recognized as contract assets.

*Exclusive Licenses –*If the license granted in the arrangement is determined to be distinct from the other promises or performance obligations identified in the arrangement, which generally include research and development services, the Company recognizes revenue from non-refundable, upfront fees allocated to the license when the license is transferred to

the customer and the customer is able to use and benefit from the license. In assessing whether a license is distinct from the other promises, the Company considers relevant facts and circumstances of each arrangement, including the research and development capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the collaboration partner can benefit from the license for its intended purpose without the receipt of the remaining promise, whether the value of the license is dependent on the unsatisfied promise, whether there are other vendors that could provide the remaining promise, and whether it is separately identifiable from the remaining promise. For licenses that are combined with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. 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 arrangement.

Research and Development Services –The promises under the Company’s collaboration and license agreements generally include research and development services to be performed by the Company on behalf of the collaboration partner. For performance obligations that include research and development services, the Company generally recognizes revenue allocated to such performance obligations based on an appropriate measure of progress. The Company utilizes judgment to determine the appropriate method of measuring progress for purposes of recognizing revenue, which is generally an input measure, such as costs incurred. The Company evaluates the measure of progress each reporting period as described underExclusive Licensesabove. Reimbursements from the partner that are the result of a collaborative relationship with the partner, instead of a customer relationship, such as co-development activities, are generally recorded as a reduction to research and development expense.

*Customer Options –*The Company’s arrangements may provide a collaborator with the right to certain optional purchases, such as the right to license a target either at the inception of the arrangement or within a pre-defined option period. Under these agreements, fees may be due to the Company (i) at the inception of the arrangement as an upfront fee or payment or (ii) upon the exercise of an option to acquire a license. 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 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 inception of the arrangement. The Company allocates the transaction price to material rights based on the relative stand-alone selling price, which is determined based on the identified discount, and the probability that the customer will exercise the option. Amounts allocated to a material right are not recognized as revenue until, at the earliest, the option is exercised or expires.

*Milestone Payments –*At the inception of each arrangement that includes milestone payments based on certain events, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The Company evaluates factors such as the scientific, clinical, regulatory, commercial, and other risks that must be overcome to achieve the particular milestone in making this assessment. There is considerable judgment involved in determining whether it is probable that a significant revenue reversal would not occur. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. If a milestone or other variable consideration relates specifically to the Company’s efforts to satisfy a single performance obligation or to a specific outcome from satisfying the performance obligation, the Company generally allocates the milestone amount entirely to that performance obligation once it is probable that a significant revenue reversal would not occur.

*Royalties –*For arrangements that include sales-based royalties, including milestone payments based on a level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements.

Research and Development Expenses and Related Accruals/Prepaids

Research and development expenses are expensed as incurred and consist of costs incurred in performing research and development activities, including compensation related expenses for research and development personnel, preclinical and clinical activities including cost of clinical drug supply, overhead expenses including facilities expenses, materials and supplies, amounts paid to consultants and outside service providers, and depreciation of equipment. Upfront license payments related to acquired technologies which have not yet reached technological feasibility and have no alternative future use are also included in research and development expense.

The Company has entered into various research and development service arrangements under which vendors perform various services. The Company records accrued expenses for estimated costs incurred under the arrangements in excess of vendor invoices received while cash payments to vendors, including those that are nonrefundable, in excess of estimated costs incurred are recorded as prepaid expenses. Prepaid expenses are expensed as the related services are performed or goods are received. When evaluating the adequacy and accuracy of the accrued and prepaid expenses, the Company reviews open contracts and purchase orders, the level of service performed, invoices received, contracted costs, and progress of studies, clinical trials or other activities based on communication with internal and/or external personnel. Significant judgments and estimates are made in determining the accrued and prepaid expense balances at the end of each reporting period, and payments for these activities are due based on the terms of individual arrangements, which may differ from the pattern of costs incurred.

Equity-Based Compensation

The Company accounts for equity awards, including restricted stock units, and common stock options, granted as equity award compensation in accordance with ASC Topic 718, Compensation — Stock Compensation ("ASC 718"). ASC 718 requires all stock-based payments to employees, which includes grants of employee equity awards, to be recognized as expense in the statements of operations based on their grant date fair values.

The fair value of each restricted stock unit is based on the fair value of the Company’s common stock less any purchase price, if applicable. The fair value of each stock option award is estimated using the Black-Scholes option-pricing model, which uses as inputs the fair value of the Company’s common stock and certain subjective assumptions, including the expected stock price volatility, the expected term of the award, the risk-free rate, and expected dividends. Through the second quarter of 2024, expected volatility was calculated based on a blend of the Company’s reported volatility data for the length of time that market data was available for the Company’s stock and the historical data for a representative group of publicly traded companies, for which historical information was available. As of the third quarter of 2024, the Company’s own volatility data covered a period of time that was sufficient to meet the expected term of the granted awards and the blended approach was no longer needed. The historical volatility is generally calculated based on a period of time commensurate with the expected term assumptions. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant commensurate with the expected term assumption. The Company uses the simplified method, under which the expected term is presumed to be the midpoint between the vesting date and the end of the contractual term. The Company utilizes this method due to lack of historical exercise data and the plain nature of its stock-based awards. The expected dividend yield is assumed to bezero as the Company has never paid dividends and has no current plans to pay any dividends on common stock.

Compensation expense related to equity awards to employees that are subject to graded vesting is recognized on a straight-line basis, based on the grant date fair value, over the requisite service period of the award, which is generally the vesting term. For awards subject to performance conditions, the Company recognizes equity award compensation expense using an accelerated recognition method over the remaining service period when management determines that

achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date.

The Company classifies equity-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.

The Company accounts for forfeitures when they occur.

Comprehensive Loss

Comprehensive loss is the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. Comprehensive loss includes net loss and the change in accumulated other comprehensive income (loss) for the period. Accumulated other comprehensive income (loss) consisted entirely of unrealized gains and losses on available-for-sale marketable securities during the period ending December 31, 2024 and 2023.

Net Loss per Share

The Company applies the two-class method to compute basic and diluted net loss per share because it has issued shares that meet the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income (losses) available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to share in the earnings as if all income (losses) for the period had been distributed. During periods of loss, there is no allocation required under the two-class method since the participating securities do not have a contractual obligation to fund the losses of the Company.

The Company calculates basic net loss per share by dividing net loss by the weighted average number of common shares outstanding, including pre-funded warrants and excluding restricted common stock. The Company calculates diluted net loss per share by dividing net loss by the weighted average number of common shares outstanding, as applicable, after giving consideration to the dilutive effect of restricted stock units, warrants, pre-funded warrants, and stock options that are outstanding during the period.

Income Taxes

Income taxes are recorded in accordance with ASC Topic 740, Income Taxes ("ASC 740"), which provides for deferred taxes using an asset and liability approach. Under this method, deferred income tax assets and liabilities are recognized based on future income tax consequences attributable to differences between the financial statement carrying amount of existing assets and liabilities, and their respective income tax basis. Deferred income tax assets and liabilities are measured using enacted income tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled.

The Company provides reserves for potential payments of tax to various tax authorities related to uncertain tax positions, as necessary. The tax benefits recorded are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is "more likely than not" to be realized following resolution of any uncertainty related to the tax benefit, assuming that the matter in question will be raised by the tax authorities.

The Company is open to examination by the Internal Revenue Service for the tax years ended December 31, 2013 to December 31, 2024. Since the Company is in a U.S. loss carryforward position, carryforward tax attributes generated in prior years may still be adjusted upon future examination if they have or will be used in a future period. The Company is currently not under examination by the Internal Revenue Service or any other jurisdictions for any tax years. The Company has not recorded any interest or penalties on any unrecognized tax benefits since its inception.

Recently Adopted Accounting Pronouncements

In November 2023, the FASB issued ASU 2023-07,Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The standard requires disclosure of incremental segment information on an annual and interim basis and allows for multiple measures of a segment’s profit or loss provided that one of those measures is consistent with GAAP. The amendments in this update do not change how a public company identifies its operating segments, aggregates those operating segments, or applies the quantitative thresholds to determine its reportable segments, but rather requires public entities to disclose significant segment expenses and other segment items on an annual and interim basis and provide in interim periods all disclosures about a reporting segment’s profit or loss and assets that are currently required annually. ASU 2023-07 becomes effective for the annual period starting on January 1, 2024, and for interim periods starting on January 1, 2025 (see Note 16).

Recently Issued Accounting Pronouncements

In December 2023, the FASB issued ASU 2023-09,Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which enhances the transparency of income tax disclosures to provide information to investors to better assess how a company’s operations and related tax risks, tax planning and operational opportunities affect its tax rate and prospects for future cash flows. This requires public entities to disclose additional categories in the rate reconciliation regarding federal and state income taxes and provide more details surrounding reconciling items if a quantitative threshold is met. The effective date for public companies is for annual periods starting on January 1, 2025. Early adoption is permitted for annual financial statements that have not yet been issued or made available for issuance, however, the Company has decided not to early adopt, does not anticipate a material impact to its net financial position, and is still evaluating the impact on its disclosures in future years as a result of the adoption of ASU 2023-09.

In November 2024, the FASB issued ASU No. 2024-03,Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40):Disaggregation of Income Statement Expenses, and in January 2025, the FASB issued ASU No. 2025-01,Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date. ASU 2024-03 requires additional disclosure of the nature of expenses included in the income statement as well as disclosures about specific types of expenses included in the expense captions presented in the income statement. ASU 2024-03, as clarified by ASU 2025-01, is effective for public companies for annual periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is still evaluating the impact on its disclosures in future years as a result of the adoption of ASU 2024-03.

3. Fair Value of Financial Assets and Liabilities

The following tables summarize the assets and liabilities measured at fair value on a recurring basis at December 31, 2024 and 2023 (in thousands):

Cash, cash equivalents and marketable securities are Level 1 assets and include investments in money market funds, U.S. treasury obligations and government agency securities that are valued using quoted market prices. Accordingly, money market funds and government funds are categorized as Level 1 as of December 31, 2024 and 2023. There wereno transfers of assets between fair value measurement levels during the years ended December 31, 2024 and 2023.

The carrying amounts reflected in the balance sheets for prepaid expenses and other current assets, accounts payable, and accrued expenses approximate their fair values at December 31, 2024 and 2023, due to their short-term nature.

The Company believes the terms of its debt reflect current market conditions for an instrument with similar terms and maturity, therefore the carrying value of the Company's debt approximates its fair value based on Level 3 of the fair value hierarchy.

4. Marketable Securities

The following table summarizes the Company’s investments as of December 31, 2024 (in thousands):

The following table summarizes the Company’s investments as of December 31, 2023 (in thousands):

Amortized cost approximated fair value for money market funds and U.S. treasury obligations included in cash and cash equivalents. The aggregate fair value of marketable securities with unrealized losses was $23.9 million and $11.9 million at December 31, 2024 and 2023, respectively.** **At December 31, 2024 and 2023,12 investments andthree investments, respectively, were in an unrealized loss position. All such investments have been in an unrealized loss position for less than a year and these losses are considered temporary. The Company has the ability and intent to hold these investments until a recovery of their amortized cost, which may not occur until maturity.

The Company believes that U.S. treasury obligations and government agency securities are subject to minimal credit risk. As a result, the Company did not record any charges for credit-related impairments for its available-for-sale securities for the year ended December 31, 2024.

5. Prepaid Expenses and Other Assets

At December 31, 2024 and 2023, prepaid expenses and other current assets consist of the following (in thousands):

At December 31, 2024 and 2023, other long-term assets consist of the following (in thousands):

6. Property and Equipment, Net

At December 31, 2024 and 2023, property and equipment consists of the following (in thousands):

Depreciation and amortization expense was $1.9 million and $2.8 million for the years ended December 31, 2024 and 2023, respectively.

7. Accrued Expenses

At December 31, 2024 and 2023, accrued expenses consist of the following (in thousands):

8. Preferred Stock

The Board of Directors or any authorized committee thereof is expressly authorized, to the fullest extent permitted by law, to provide by resolution or resolutions for, out of the unissued shares of Preferred Stock, the issuance of the shares of Preferred Stock in one or more series of such stock, and by filing a certificate of designations pursuant to applicable law of the State of Delaware, to establish or change from time to time the number of shares of each such series, and to fix the designations, powers, including voting powers, full or limited, or no voting powers, preferences and the relative, participating, optional or other special rights of the shares of each series and any qualifications, limitations and restrictions thereof.

9. Common Stock

In June 2024, the stockholders approved an amendment to the Company’s amended and restated certificate of incorporation to increase the number of authorized shares of common stock from 150,000,000 to 300,000,000.

In October 2024, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with J.P. Morgan Securities LLC, Jefferies LLC and Piper Sandler & Co., as representatives of the several underwriters named therein (the “Underwriters”), relating to the issuance and sale of an aggregate of 10,265,488 shares of the Company’s common stock at$28.25 per share and pre-funded warrants to purchase 353,983 shares of its common stock. The offering price per pre-funded warrant was$28.2499, which equals the per share public offering price for the common shares less the$0.0001 exercise price for each such pre-funded warrant. The pre-funded warrants are exercisable at any time and only expire when exercised in full. The offering closed on October 10, 2024. Pursuant to the Underwriting Agreement, the Underwriters were granted a 30-day option to purchase up to 1,592,920 additional shares (the “Option

Shares”) of common stock, which was exercised in full on October 16, 2024. Total proceeds of the transaction, including the Option Shares were approximately$324.4 million, net of underwriting discounts and estimated offering expenses.

The Company has had a sales agreement in place during various time periods with Jefferies LLC (“Jefferies”) with respect to an at-the-market (“ATM”) offering program. Under this program, the Company is able to offer and sell, from time to time at its sole discretion, shares of its common stock through Jefferies as its sales agent. In an ATM offering, exchange-listed companies incrementally sell newly issued shares into the secondary trading market through a designated broker-dealer at prevailing market prices. The current ATM agreement, established in November 2022, allows for the sale of shares of common stock having an aggregate offering price of up to$100 million. As of December 31, 2024, the Company has sold 619,290 shares, generating net proceeds of$5.2 million, under the ATM program. No sales were made under the ATM program during the year ended December 31, 2024.

The Company has issued pre-funded warrants to purchase common stock, as well as warrants to purchase common stock as part of its financing activities. Both the pre-funded warrants and warrants meet the conditions for equity classification and are recorded as a component of stockholders’ equity within additional paid-in capital. In October 2024, June 2022 and November 2020, the Company issued 353,983,25,510,205 and 2,179,487 pre-funded warrants, respectively. During the years ended December 31, 2024 and 2023,2,526,833 and 8,154,695, respectivelyof the Company’s pre-funded warrants were exercised. As of December 31, 2024, the Company has 17,362,147 pre-funded warrants outstanding. In June 2022, the Company also issued 10,459,181 warrants with an exercise price of$7.35. During the years ended December 31, 2024 and 2023,1,309,492 and 471,025, respectively of the Company’s warrants were exercised. As of December 31, 2024, the Company has 8,678,664 warrants outstanding.

Shares Reserved For Future Issuance

As of December 31, 2024, the Company had common shares reserved for issuance as follows:

10. Equity-Based Compensation

Equity Plans

As of December 31, 2024, the Company has four active equity plans, the 2018 Stock Option and Incentive Plan (the “2018 Plan”), the 2017 Stock Option and Incentive Plan (the “2017 Plan”), the 2018 Employee Stock Purchase Plan (the “2018 ESPP”) and the 2022 Inducement Equity Plan (the “2022 Inducement Plan”).

2018 Stock Option and Incentive Plan

The 2018 Plan was adopted by the Board of Directors on May 2, 2018, and approved by the Company’s stockholders on May 11, 2018. The 2018 Plan has replaced the 2017 Plan asno additional awards will be granted under that plan following the consummation of the Initial Public Offering (“IPO”).

The 2018 Plan provides for the grant of equity-based incentive awards, including incentive stock options, non-qualified stock options, restricted stock awards, unrestricted stock awards and restricted stock units to the Company’s officers, employees, directors and other key persons (including consultants). Stock options and restricted stock units granted under the 2018 Plan to employees generally vest over four years. The shares of common stock underlying any awards that are forfeited, cancelled, repurchased or are otherwise terminated by the Company under the 2018 Plan will be added back to the shares of common stock available for issuance under the 2018 Plan.

The 2018 Plan provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, beginning on January 1, 2019, by 4% of the outstanding number of shares of common stock on the immediately preceding December 31 or such lesser number of shares as determined by the Board of Directors or compensation committee (the “Annual Increase”). These limits are subject to adjustment in the event of a stock split, stock dividend or other change in the Company’s capitalization.

2017 Stock Option and Incentive Plan

The 2017 Plan provides for the grant of incentive stock options, non-qualified stock options, restricted stock awards, unrestricted stock awards and restricted stock units. Stock options granted under the 2017 Plan to employees generally vest over four years. The Company no longer issues grants from the 2017 Plan. The shares of common stock underlying any awards that are forfeited, cancelled, repurchased or are otherwise terminated by the Company under the 2017 Plan will be added back to the shares of common stock available for issuance under the 2018 Plan.

2018 Employee Stock Purchase Plan

On May 2, 2018, the Board of Directors adopted the 2018 ESPP, and it was approved by the stockholders on May 11, 2018. At December 31, 2024 there were 2,196,691 shares available to grant under the 2018 ESPP andno shares had been issued. The ESPP provides that the number of shares reserved and available for issuance will automatically increase each January 1, beginning on January 1, 2019 through January 1, 2028, by the lesser of (i)353,614 shares of common stock, (ii)1% of the outstanding number of shares of the Company’s common stock on the immediately preceding December 31 or (iii) such lesser number of shares as determined by the 2018 ESPP administrator. The number of shares reserved under the 2018 ESPP is subject to adjustment in the event of a stock split, stock dividend or other change in the Company’s capitalization.

2022 Inducement Equity Plan

The 2022 Inducement Plan was approved by the Board of Directors on June 16, 2022 and provides for thegrant of non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock units, unrestricted stock awards and dividend equivalent rights to individuals that were not previously an employee or director of the Company or individuals returning to employment after a bona fide period of non-employment with the Company. Stock options and restricted stock units granted under the 2022 Inducement Plan to employees generally vest over four years. The shares of common stock underlying any awards that are forfeited, cancelled, repurchased or are otherwise terminated by the Company under the 2022 Inducement Plan will be added back to the shares of common stock available for issuance under the 2022 Inducement Plan. The 2022 Inducement Plan was approved for 1,000,000 shares of common stock in June 2022. Since its inception and through December 31, 2024, an additional 4,000,000 shares of common stock have been added to the 2022 Inducement Plan.

Total Equity-Based Compensation Expense

The Company recorded equity-based compensation expense related to all equity-based awards, which was allocated as follows in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2024 and 2023 (in thousands):

The following table summarizes the Company’s unrecognized equity-based compensation expense as of December 31, 2024:

Restricted Stock Units

The following table summarizes the Company’s restricted stock unit activity for the current year:

The total fair value of restricted stock units vested during the year ended December 31, 2024 was $9.7 million.

Stock Options

The following table summarizes the Company’s stock option activity for the current year:

Using the Black-Scholes option pricing model, the weighted average fair value of options granted during the year ended December 31, 2024 was $11.79.

The following weighted average assumptions were used in determining the fair value of options granted in the years ended December 31, 2024 and 2023:

11. Income Taxes

The Company has not recorded a current tax provision for the years ended December 31, 2024 and 2023.

The effective income tax rate differed from the amount computed by applying the federal statutory rate to the Company’s loss before income taxes as follows:

Deferred tax assets (liabilities) consist of the following at December 31, 2024 and 2023 (in thousands):

Total Net Deferred Tax Assets

Deferred tax assets are reduced by a valuation allowance if, based on the weight of available positive and negative evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Accordingly, a full valuation allowance has been established against the net deferred tax assets as of December 31, 2024 and 2023. The valuation allowance for deferred tax assets increased by $76.5 million and $49.2 million in 2024 and 2023, respectively. This increase mainly relates to the establishment of a valuation allowance against the Company’s net domestic deferred tax assets in connection with net operating losses generated in each year, capitalized research expenses and additional tax credit carryforwards generated. Starting with tax years beginning after December 31, 2021, entities are required to capitalize all research and experimentation “R&D” expenses as defined under Section 174 of the Internal Revenue Code and amortize them over five years for domestic expenses and over fifteen years for foreign expenses. During the year, the Company capitalized $121.5 million of R&D expenses, net of current and prior year amortization deductions. The corresponding deferred tax asset as of December 31, 2024 is $80.4 million. As of December 31, 2024, the Company had approximately $512.6 million and $498.8 million of Federal and State operating loss carryforwards respectively, which begin to expire in 2032, except for $462.1 million of the Company’s federal net operating loss carryforwards, and $0.2 million of state net operating losses that do not expire. These loss carryforwards may be available to reduce future taxable income, if any. These loss carryforwards are subject to review and possible adjustment by the appropriate taxing authorities. As of December 31, 2024, the Company also had federal and state credit carryovers of $54.9 million and $7.7 million, respectively, which begin to expire in 2034 and 2025, respectively. The amount of loss and credit carryforwards that may be utilized in any future period may be limited based upon changes in the ownership of the Company’s ultimate parent. Additionally, the deductibility of federal net operating losses generated after December 31, 2017 and the indefinite state net operating losses is limited to 80% of the Company’s taxable income in any future taxable year.

The Company follows the provisions of ASC 740-10, “Accounting for Uncertainty in Income Taxes,” which specifies how tax benefits for uncertain tax positions are to be recognized, measured, and recorded in financial statements; requires certain disclosures of uncertain tax matters; specifies how reserves for uncertain tax positions should be classified on the balance sheet; and provides transition and interim period guidance, among other provisions. As of December 31, 2024 and 2023, the Company hasnot recorded any amounts for uncertain tax positions. The Company’s policy is to recognize interest and penalties accrued on any uncertain tax positions as a component of income tax expense, if any, in its statements of income.

The Company’s net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a three-year period in excess of 50 percent as defined under Section 382 and 383 of the U.S. Internal Revenue Code of 1986, respectively, as well as similar state provisions. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. The Company conducted a Section 382 study covering the period of November 26, 2013 through December 31, 2023. The study concluded that ownership changes occurred during that period which limit the amount of the Company’s net operating losses and tax credit carryforwards that can be utilized before expiring. The carryforwards disclosed represent the amount of attributes that can be utilized based on the results of the study.

All of the Company’s tax years will remain open for examination by the federal and state tax authorities to the extent that the Company's tax attributes are utilized in future years to offset income or income taxes.

12. Commitments and Contingencies

Operating Lease

In November 2019, the Company entered into a lease of office and laboratory space at 301 Binney Street in Cambridge, Massachusetts to be used as its new corporate headquarters (“the Lease”). The expiration date of the Lease was originally in August 2025 and included anoption to extend the term bytwo years. The base rent under the original Lease was $6.9 million per year, subject to an annual increase of 3.5%. Variable lease payments include the Company’s allocated share of costs incurred and expenditures made by the landlord in the operation and management of the building. The Lease included incentives of $14.1 million in the form of an allowance for tenant improvements related to the design and build out of the space. In connection with the Lease, the Company has secured a letter of credit for $2.3 million which renews automatically each year.

In May 2024, the Company entered into the First Amendment (the “Lease Amendment”) to the Lease to extend the term for approximatelytwo years, commencing on August 19, 2025 (the “First Extension Term”) with the base rent to start at approximately $6.2 million per year, followed by a 3% annual increase. Pursuant to the Lease Amendment, the Company also has anoption to extend the term of the Lease byfive years, upon the expiration of the First Extension Term.

Other information related to the Lease is as follows (in thousands, except lease term and discount rate):

The following is a maturity analysis of the annual undiscounted cash flows reconciled to the carrying value of the operating lease liabilities as of December 31, 2024 (in thousands):

The Company recorded approximately $7.0 million and $8.3 million in rent expense for the years ended December 31, 2024 and 2023, respectively.

Legal Proceedings

The Company, from time to time, may be party to litigation arising in the ordinary course of its business. The Company was not subject to any material legal proceedings during the years ended December 31, 2024 and 2023.

13. Debt

On October 16, 2020 (the “Closing Date”) the Company entered into a Loan and Security Agreement with Oxford Finance LLC (“Oxford”) and Silicon Valley Bank (“SVB”) for $50.0 million (the “Loan and Security Agreement”). Tranche 1 of $25.0 million was funded on the Closing Date. The Company had an additional $25.0 million in loan proceeds available under Tranche 2 which was funded in December 2021, in conjunction with the Company entering into the First Amendment to Loan and Security Agreement with Oxford and SVB. The Loan and Security Agreement was to mature on May 1, 2025 and required interest-only payments through November 2022, with principal payments to commence in December 2022. Pursuant to the Loan and Security Agreement, the Company was required to maintain cash in an SVB account equal to the lesser of 100% of the Company’s consolidated cash or 105% of the dollar amount of the outstanding debt.

On November 10, 2022, the Company entered into the Second Amendment to Loan and Security Agreement (“Amendment 2”) to increase the Company’s borrowing capacity under the Loan and Security Agreement to an amount up to $100.0 million, comprised of the original $50.0 million loan which remains outstanding and two additional $25.0 million tranches. The first $25.0 million tranche available under Amendment 2, was available at the Company’s discretion through December 2023 upon achievement of certain development and business performance milestones. The Company did not exercise this tranche. The second $25.0 million tranche available under Amendment 2, may be available upon the Company’s request, at Oxford and SVB’s discretion. Amendment 2 also extended the interest-only payment period for an additional 24 months through November 2024, with principal payments to commence in December 2024. The maturity of the loan was extended to November 2027.

Effective upon Amendment 2, the interest rate on the unpaid principal is the greater of the Wall Street Journal prime rate plus 4.60% or 9.35% per annum. Prepayment is permitted and may include a pre-payment fee ranging from 0% -3% (of the principal amount being prepaid), depending on when the prepayment is made. The Company is also required to make a final payment equal to 2% of the original principal amount.

In conjunction with Amendment 2, the Company was required to pay $0.9 million for the accrued portion of the final payment on the previous outstanding balance.

On March 10, 2023, SVB was closed by the California Department of Financial Protection and Innovation, which appointed the Federal Deposit Insurance Corporation (“FDIC”) as receiver. Afterward, the FDIC transferred all deposits of the former Silicon Valley Bank to Silicon Valley Bridge Bank, N.A., as operated by the FDIC. On March 27, 2023,

Silicon Valley Bridge Bank was closed by the Office of the Comptroller of the Currency, and the FDIC was appointed as receiver. First Citizens Bank then entered into an agreement with the FDIC to purchase out of FDIC receivership substantially all loans and certain other assets and assume all customer deposits and certain other liabilities of Silicon Valley Bridge Bank. On March 27, 2023, Silicon Valley Bridge Bank and its U.S. branches began operating as Silicon Valley Bank, a division of First Citizens Bank.

On April 18, 2023, the Company entered into Amendment 3 to the Loan and Security Agreement to amend certain provisions relating to the Company’s operating accounts.

On May 17, 2024, the Company entered into the Fourth Amendment to the Loan and Security Agreement (“Amendment 4”). The Company currently has $50.0 million outstanding under the Loan and Security Agreement, which was drawn down in two equal tranches. The third $25.0 million tranche is available at the Company’s discretion through December 2024, upon achievement of certain clinical and business milestones, which were amended under Amendment 4. The fourth $25.0 million tranche may be available through June 1, 2025 (or through December 1, 2025, upon achievement of certain business milestones) upon the Company’s request, at Oxford and SVB’s discretion. Amendment 4 also extends the interest-only payment period for an additional six months through May 2025, with principal payments to commence in June 2025. Additionally, upon achievement of certain business performance milestones, which were achieved in October 2024, the interest-only payment period was extended through November 2025, with principal payments to commence in December 2025.

On February 10, 2025, the Company entered into an Amended and Restated Loan and Security Agreement (the “Amended and Restated Loan and Security Agreement”) with Oxford. The Amended and Restated Loan and Security Agreement amends and restates in its entirety that certain Loan and Security Agreement, as amended.

The Amended and Restated Loan and Security Agreement provides for term loans in an aggregate principal amount of up to $200.0 million (each, a “Term Loan” and together, the “Term Loans”) subject to funding in four tranches. To date, the Company has received $50.0 million of Term Loans. The remaining three tranches, each in an amount of $50.0 million, are available to be borrowed (a) in the case of the second tranche, until December 31, 2025, (b) in the case of the third tranche, after the achievement of certain development and business performance milestones until September 30, 2026, and (c) in the case of the fourth tranche, after the achievement of certain development and business performance milestones until December 31, 2027. The Amended and Restated Loan and Security Agreement consolidates the existing outstanding loan tranches solely with Oxford and also extends the interest-only payment period through March 2029, with principal payments to commence in April 2029.

The outstanding principal of each Term Loan has an annual interest rate of (a) the greater of (i) the 1-Month CME Term SOFR on the last business day of the month that immediately precedes the month in which the interest will accrue and (ii)3% , plus (b)5.5%. Interest is payable on a monthly basis based on the principal amount outstanding during the preceding month. In addition, the Company is required to pay Oxford a final payment fee equal to 2.00% of the original principal amount of each Term Loan advanced to the Company.

Adjusted for the Amended and Restated Loan and Security Agreement entered into in February 2025, the following table shows required payments (excluding interest), during the next five years on debt outstanding at December 31, 2024 (in thousands):

The Company incurred costs on behalf of the lender recorded as a debt discount of $0.5 million and incurred debt issuance costs of $0.1 million, both of which are recorded as a deduction from the carrying amount of the debt and are being amortized as interest expense over the term of the loan. The final payment fee will be treated as an additional debt discount and accreted to the debt balance over the term.

For the years ended December 31, 2024 and 2023, the Company recorded total interest expense for the debt of $6.6 million and $6.5 million, respectively.

14. Net Loss per Share

The Company calculates basic net loss per share by dividing net loss by the weighted average number of common shares outstanding, excluding restricted common stock. The weighted average number of common shares used in the basic and diluted net loss per share calculation includes the pre-funded warrants issued in connection with the Company’s November 2020, June 2022 and October 2024 follow-on offerings as the pre-funded warrants are exercisable at any time for nominal cash consideration. As of December 31, 2024,10,681,528 pre-funded warrants have been exercised and 17,362,147 pre-funded warrants are outstanding. The Company has generated a net loss in all periods presented, so the basic and diluted net loss per share are the same, as the inclusion of the potentially dilutive securities would be anti-dilutive.

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

The following table sets forth the outstanding common stock equivalents, presented based on amounts outstanding at each period end, that have been excluded from the calculation of diluted net loss per share for the periods indicated because their inclusion would have been anti-dilutive:

15. Retirement Plan

The Company sponsors a 401(k) retirement plan, in which substantially all employees are eligible to participate upon employment. Participants may contribute a percentage of their annual compensation to this plan, subject to statutory limitations. Effective January 1, 2020, the Company adopted a policy to match 50% of the employee contributions to the 401(k) plan up to a maximum of 6% of the participating employee’s eligible earnings, resulting in a maximum company match of 3% of the participating employee’s eligible earnings subject to statutory limitations. The Company recognized $1.1 million and $0.9 million in expense related to the match during the years ended December 31, 2024 and 2023, respectively.

16. Segment Reporting

The Company operates and manages its business as asingle segment for the purposes of assessing performance and making operating decisions. The Company’s president and chief executive officer, who is the chief operating decision maker (“CODM”), reviews the Company’s financial information on a consolidated basis for purposes of evaluating financial performance and allocating resources and; therefore we have presented segment information on the same basis. When evaluating the Company’s financial performance, the CODM regularly reviews net loss, non-operating expenses and operating expenses with non-cash expenses such as depreciation and equity-based compensation expense removed. The CODM considers net loss in making decisions on how to allocate resources. The measure of segment assets is

reported on the balance sheet as total consolidated assets. All of the Company's long-lived assets are held in the United States.

The following table presents significant expense information about the Company’s operating segment:

*Consists of other segment expenses related to supplies, corporate and facilities expenses.

17. Subsequent Events

On February 10, 2025, the Company entered into the Amended and Restated Loan and Security Agreement with Oxford for up to $200.0 million of which $25.0 million from Tranche 1 was received in October 2020 and $25.0 million from Tranche 2 was received in December 2021. The Amended and Restated Loan and Security Agreement consolidates the existing outstanding loan tranches solely with Oxford and extends the interest-only payment period through March 2029, with principal payments to commence in April 2029. Additional details of the Amended and Restated Loan and Security Agreement can be found in Note 13 and as an exhibit to these financial statements.