Fulcrum Therapeutics, Inc.

1. Nature of the Business and Basis of Presentation

Fulcrum Therapeutics, Inc. (the “Company”) was incorporated in Delaware on August 18, 2015. The Company is focused on developing small molecules to improve the lives of patients with genetically-defined rare diseases in areas of high unmet medical need.

The Company is subject to a number of risks similar to other companies in the biotechnology industry, including, but not limited to, risks of failure of preclinical studies and clinical trials, dependence on key personnel, protection of proprietary technology, reliance on third party organizations, risks of obtaining regulatory approval for any product candidate that it may develop, development by competitors of technological innovations, compliance with government regulations, and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing, and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel 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 product sales.

Basis of Presentation

The accompanying consolidated financial statements have been prepared in conformity with generally accepted accounting principles in the United States of America (“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 Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”).

The accompanying consolidated financial statements and footnotes to the financial statements have been prepared on the same basis as the most recently audited annual consolidated financial statements and, in the opinion of management, reflect all normal recurring adjustments necessary for the fair presentation of the Company’s financial position as of March 31, 2026 and the results of its operations and its cash flows for the three months ended March 31, 2026 and 2025. The results for the three months ended March 31, 2026 are not necessarily indicative of results to be expected for the year ending December 31, 2026, any other interim periods, or any future year or period. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2025 included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (the “SEC”) on February 24, 2026 (the “Annual Report on Form 10-K”).

Liquidity

The Company has incurred recurring losses and negative cash flows from operations since inception and has primarily funded its operations with proceeds from the sale of shares of its capital stock and from upfront payments received from collaboration and license agreements. As of March 31, 2026, the Company had an accumulated deficit of$613.2 million. The Company expects its operating losses and negative operating cash flows to continue into the foreseeable future as it continues to advance and expand its research and development efforts. The Company expects to finance its future cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances and marketing, distribution or licensing arrangements.

The Company expects that its cash, cash equivalents, and marketable securities will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months from the date of issuance of these financial statements. However, the Company has based this estimate on assumptions that may prove to be wrong, and its operating plan may change as a result of many factors currently unknown to it. As a result, the Company could deplete its capital resources sooner than it currently expects. If the Company is unable to raise additional funds through equity or debt financings when needed, it may be required to delay, limit, reduce or terminate development or future commercialization efforts or grant rights to develop and market product candidates that it would otherwise prefer to develop and market itself.

2. Summary of Significant Accounting Policies

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiary, Fulcrum Therapeutics Securities Corp., which is a Massachusetts subsidiary created to buy, sell, and hold securities. All intercompany transactions and balances have been eliminated.

Summary of Significant Accounting Policies

The significant accounting policies and estimates used in the preparation of the accompanying consolidated financial statements are described in the Company’s audited consolidated financial statements for the year ended December 31, 2025 included in the Company’s Annual Report on Form 10-K. There have been no material changes in the Company’s significant accounting policies during the three months ended March 31, 2026.

Use of Estimates

The preparation of financial statements in accordance with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements, and the reported amount of expenses during the reported periods. Estimates inherent in the preparation of these consolidated financial statements include, but are not limited to, estimates related to accrued expenses, stock-based compensation expense, and income taxes. The Company bases its estimates on historical experience and other market specific or other relevant assumptions 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 could differ from those estimates or assumptions.

Off-Balance Sheet Risk and Concentrations of Credit Risk

The Company has no significant off-balance sheet risk such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents, marketable securities, and restricted cash. The Company’s cash, cash equivalents, and restricted cash are deposited in accounts at large financial institutions. The Company believes it is not exposed to significant credit risk due to the financial strength of the depository institutions in which the cash, cash equivalents and restricted cash are held. The Company maintains its cash equivalents in U.S. Treasury securities and money market funds that invest in U.S. Treasury securities. The Company’s marketable securities consist of U.S. Treasury securities, government agency securities, and corporate bonds, and potentially subject the Company to concentrations of credit risk. The Company has adopted an investment policy that limits the amounts the Company may invest in any one type of investment. The Company has not experienced any credit losses and does not believe it is exposed to any significant credit risk on these funds.

Recent Accounting Pronouncements

In November 2024, the FASB issued ASU No. 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures, which requires disclosure of additional information about specific expense categories in the notes to the financial statements on an interim and annual basis. The standard is effective for fiscal years beginning after December 15, 2026, and for interim periods beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the disclosure requirements related to this new standard.

3. Fair Value Measurements

The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicate the fair value hierarchy classification of such fair values as of March 31, 2026 and December 31, 2025 (in thousands):

There wereno transfers between fair value levels during thethree months ended March 31, 2026.

4. Cash Equivalents and Marketable Securities

Cash equivalents and marketable securities consisted of the following as of March 31, 2026 and December 31, 2025 (in thousands):

There wereno sales of marketable securities during thethree months ended March 31, 2026. As of March 31, 2026, the Company held 39 debt securities that were in an unrealized loss position for less than 12 months with an aggregate fair value of $204.4 million. As of March 31, 2026, the Company heldone debt security that was in an unrealized loss position for greater than 12 months with a fair value of $5.0 million. As of March 31, 2026, the aggregate fair value of marketable securities with a remaining contractual maturity of greater than one year was $53.5 million.

The Company has the intent and ability to hold its debt securities until recovery. As a result, the Company didnot record any charges for credit-related impairments for its marketable securities for the three months ended March 31, 2026.

5. Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):

Depreciation expense for the three months ended March 31, 2026 and 2025 was $0.3 million and $0.4 million, respectively.

6. Additional Balance Sheet Detail

Prepaid expenses and other current assets consisted of the following (in thousands):

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

7. Preferred Stock

As of March 31, 2026 and December 31, 2025,5,000,000 shares of undesignated preferred stock were authorized. No shares of preferred stock were issued or outstanding as of March 31, 2026 and December 31, 2025.

No dividends have been declared since inception.

8. Common Stock

As of March 31, 2026 and December 31, 2025,200,000,000 shares of common stock, $0.001 par value per share, were authorized.

Each share of common stock entitles the holder toone vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are not entitled to receive dividends, unless declared by the Company’s board of directors, subject to the preferential dividend rights of any preferred stock then outstanding. No dividends have been declared or paid by the Company since its inception.

As of March 31, 2026 and December 31, 2025, the Company has reserved for future issuance the following number of shares of common stock:

Pre-Funded Warrants

In August 2024, the Company entered into separate exchange agreements with RA Capital Healthcare Fund, L.P. (“RA Capital”) and another existing institutional stockholder, pursuant to which (i) RA Capital exchanged 8,500,000 shares of the Company's common stock for a pre-funded warrant to acquire 8,500,000 shares of the Company's common stock and (ii) the other existing institutional stockholder exchanged an aggregate of 850,000 shares of the Company's common stock, for pre-funded warrants to acquire an aggregate of 850,000 shares of the Company's common stock. The aggregate 9,350,000 shares of common stock subject to the exchange agreements were retired on the date of the exchanges. In December 2025, the Company issued and sold 1,111,193 pre-funded warrants to purchase shares of common stock, at a price to the public of $13.499 per pre-funded warrant. As of March 31, 2026,850,000 pre-funded warrants have been exercised.

The pre-funded warrants have an exercise price of $0.001 per underlying share of common stock, are immediately exercisable and have no expiration date. The number of shares of the Company’s common stock issuable upon exercise of each pre-funded warrant is subject to adjustment upon certain corporate events, including certain stock dividends and splits, combinations, reclassifications, and certain other events. The pre-funded warrants include a beneficial ownership blocker that provides that the holder may not exercise (nor may we allow the exercise) if upon giving effect to such exercise, it would cause the aggregate number ofshares of the Company’s common stock beneficially owned by the holder (together with affiliates and any other persons whose beneficial ownership of the Company’s common stock would be aggregated for the purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended) to exceed a limit agreed to with the investor, of the total number of then issued and outstanding shares of the Company’s common stock as determined in accordance with the terms of the pre-funded warrant. This threshold may be increased or decreased upon 61 days’ prior notice at the discretion of RA Capital, but not in excess of 19.99%.

The Company assessed the pre-funded warrants for appropriate classification as either equity or liability pursuant to the Company’s accounting policy described in Note 2, “Summary of Significant Accounting Policies” in the Annual Report on Form 10-K. The Company determined the pre-funded warrants are freestanding instruments that do not meet the definition of a liability pursuant to ASC 480 and do not meet the definition of a derivative pursuant to ASC 815. The pre-funded warrants are indexed to the Company’s common stock and meet all other conditions for equity classification under ASC 480 and ASC 815. Accordingly, the pre-funded warrants are classified as equity and are accounted for as a component of additional paid-in capital at the time of issuance. The Company also determined that the pre-funded warrants should be included in the determination of basic and diluted earnings per share.

9. Stock-based Compensation Expense

2016 Stock Incentive Plan

In July 2016, the Company adopted the 2016 Stock Incentive Plan (the “2016 Plan”), which provided for the grant of restricted stock awards, restricted stock units, incentive stock options, non-statutory stock options, and other stock-based awards to the Company’s eligible employees, officers, directors, consultants, and advisors. As of the effective date of the 2019 Stock Incentive Plan (the “2019 Plan”), and as of March 31, 2026, no shares remained available for future issuance under the 2016 Plan. Any options or other awards outstanding under the 2016 Plan remain outstanding and effective.

2019 Stock Incentive Plan

On July 2, 2019, the Company’s stockholders approved the 2019 Plan, which became effective on July 17, 2019. The 2019 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards to the Company’s officers, employees, directors, consultants and advisors. The number of shares initially reserved for issuance under the 2019 Plan was 2,017,142 shares, plus the shares of common stock remaining available for issuance under the 2016 Plan as of July 17, 2019. The number of shares reserved was increased on January 1, 2020 and will be increased each January 1 thereafter through January 1, 2029 by the least of (i)2,000,000 shares, (ii)4% of the number of shares of the Company’s common stock outstanding on the first day of each such year or (iii) an amount determined by the Company’s board of directors. On January 1, 2026, the number of shares reserved for issuance under the 2019 Plan was increased by 2,000,000 shares. As of March 31, 2026, there were 4,579,521 shares available for future issuance under the 2019 Plan.

The shares of common stock underlying any awards that expire, terminate, or are otherwise surrendered, cancelled, forfeited or repurchased by the Company under the 2016 Plan or the 2019 Plan will be added back to the shares of common stock available for issuance under the 2019 Plan. As of July 17, 2019, no further awards will be made under the 2016 Plan.

2022 Inducement Stock Incentive Plan

In February 2022, the Company’s board of directors adopted the 2022 Inducement Stock Incentive Plan (the “Inducement Plan”), pursuant to which the Company may grant, subject to the terms of the Inducement Plan and Nasdaq rules, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units, and other stock-based awards. The Company initially reserved a total of 1,750,000 shares of common stock for the issuance of awards under the Inducement Plan. The number of shares reserved and available for issuance under the Inducement Plan can be increased at any time with the approval of the Company’s board of directors. The Inducement Plan permits the board of directors, a delegated committee of the board of directors, or a delegated officer of the Company to grant the stock-based awards available under the Inducement Plan to attract key employees for the growth of the Company. Effective March 8, 2023, the Company’s board of directors amended the Inducement Plan to increase the number of shares reserved for issuance by 2,000,000 shares. Effective May 18, 2023, the Company’s board of directors amended the Inducement Plan to increase the number of shares reserved for issuance by 1,400,000 shares. Effective June 17, 2024, the Company’s board of directors amended the Inducement Plan to increase the number of shares reserved for issuance by 1,000,000 shares. As of March 31, 2026, there were 1,174,084 shares available for future issuance under the Inducement Plan.

Stock Options

Stock options granted by the Company typically vest over afour-year period and have aten year contractual term. Shares issued upon the exercise of stock options are issued from the Company’s pool of authorized but unissued common stock. In addition to stock options granted under the 2019 Plan and 2016 Plan, the Company has granted stock options as material inducements to employment in accordance with Nasdaq Listing Rule 5635(c)(4), which were granted outside of the 2019 Plan and 2016 Plan. The following table summarizes the Company’s stock option activity during thethree months ended March 31, 2026:

The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock as of the balance sheet date for those options that had exercise prices lower than the fair value of the Company’s common stock.

The weighted average grant date fair value of stock options granted in the three months ended March 31, 2026 and 2025 was $9.09 per share and $3.52 per share, respectively. The total intrinsic value of stock options exercised during thethree months ended March 31, 2026 and 2025 was less than $0.1 million andzero, respectively.

The fair value of stock options granted during thethree months ended March 31, 2026 and 2025 has been calculated on the date of grant using the following weighted average assumptions:

Restricted Stock Units

The Company has also granted restricted stock units. The shares of common stock underlying restricted stock units typically vest over a four-year period. The shares of common stock are recorded in stockholders’ equity as they vest.

The following table summarizes the Company’s restricted stock unit activity during thethree months ended March 31, 2026:

Stock-based Compensation Expense

The total compensation cost recognized in the statements of operations and comprehensive loss associated with all stock-based compensation awards granted by the Company is as follows (in thousands):

As of March 31, 2026, the Company had an aggregate of $40.0 million of unrecognized stock-based compensation expense, which is expected to be recognized over a weighted average period of 2.59 years.

2019 Employee Stock Purchase Plan

On July 2, 2019, the Company’s stockholders approved the 2019 Employee Stock Purchase Plan (the “ESPP”), which became effective on July 17, 2019. A total of 252,142 shares of common stock were initially reserved for issuance under the ESPP. In addition, the number of shares of common stock reserved under the ESPP was increased on January 1, 2020, and will be increased annually on each January 1 thereafter through January 1, 2029, by the least of (i)428,571 shares of common stock, (ii)1% of the number of shares of the Company’s common stock outstanding on the first day of each such year or (iii) an amount determined by the Company’s board of directors. On January 1, 2026, the number of shares reserved for issuance under the 2019 ESPP was increased by 428,571 shares. As of March 31, 2026, there were 2,459,643 shares available for future issuance under the ESPP.

10. License and Collaboration Agreements

Sanofi Agreement

In May 2024, the Company entered into a collaboration and license agreement (the “Sanofi Agreement”) with Genzyme Corporation (“Sanofi”), pursuant to which the Company granted Sanofi an exclusive license to commercialize losmapimod, an oral small molecule for the treatment of facioscapulohumeral muscular dystrophy, outside of the United States.

In September 2024, the Company discontinued development of losmapimod following topline results from the Phase 3 REACH trial. On December 18, 2024, Sanofi provided written notice of termination for convenience, and the agreement terminated in its entirety on April 17, 2025. As a result, the Company is not entitled to receive any further milestone payments, royalties, or development cost reimbursements under the agreement.

During the three months ended March 31, 2026, the Company recordedno activity related to the Sanofi Agreement. During the three months ended March 31, 2025, the Company recordeda reduction in research and development expenses of $1.0 million related to reimbursable global development activities under the agreement.

CAMP4 Agreement

In July 2023, the Company entered into a license agreement (the “CAMP4 Agreement”) with CAMP4 Therapeutics Corporation (“CAMP4”), pursuant to which the Company obtained a worldwide exclusive license to certain intellectual property related to CAMP4’s Diamond-Blackfan anemia (“DBA”) program. Under the terms of the agreement, the Company was responsible for development and commercialization of any licensed products, and CAMP4 would have been eligible to receive development, regulatory, and sales milestone payments, as well as royalties on net sales of licensed products.

In April 2025, the Company incurred a $0.6 million preclinical milestone payment, which was recorded as research and development expense during the year ended December 31, 2025.

In February 2026, the Company announced the discontinuation of its bone marrow failure syndromes program, including DBA. On April 23, 2026, the Company delivered written notice to terminate the CAMP4 Agreement for convenience. In accordance with the terms of the agreement, the termination will become effective following the applicable notice period. Upon termination, the Company will have no further obligations under the agreement, other than those that survive termination in accordance with its terms.

11. Leases

Operating Leases

26 Landsdowne Street

In November 2017, the Company entered into a lease agreement for its current corporate headquarters comprising approximately 28,731 square feet of office and laboratory space at 26 Landsdowne Street in Cambridge, Massachusetts, commencing December 2017. The Company began to occupy and use the leased space for its intended purpose in June 2018. The lease ends on June 30, 2028. The Company has the option to extend the term of the lease for an additional five-year period, at the market rate, by giving the landlord written notice of its election to exercise the extension at least nine months prior to the original expiration of the lease term. The lease has a total commitment of $25.1 million over theten year term, and includes escalating rent payments. The lease provides the Company with an allowance for normal leasehold improvements of $5.0 million. The lease agreement requires the Company to either pay a security deposit or maintain a letter of credit of $1.1 million. The Company maintains a letter of credit for this lease and has recorded the cash held to secure the letter of credit as restricted cash on the consolidated balance sheet as of March 31, 2026 and December 31, 2025. Operating lease expense associated with this lease for the three months ended March 31, 2026 was approximately $0.5 million. Variable lease expense associated with this lease for thethree months ended March 31, 2026 was approximately $0.3 million.

The future minimum lease payments associated with the 26 Landsdowne Street lease as of March 31, 2026, are as follows (in thousands):

(1)Amounts are for nine months ending December 31, 2026.

12. Commitments and Contingencies

Indemnification Agreements

Inthe ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters arising out of the relationship between such parties and the Company. In addition, the Company has entered into indemnification agreements with members of its board of directors and senior management that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs asa result of such indemnifications. The Company is not aware of any claims under indemnification arrangements, and it hasnot accrued any liabilities related to such obligations as of March 31, 2026 or December 31, 2025.

Legal Proceedings

The Company is not currently a party to any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses the costs related to its legal proceedings as they are incurred. No such costs have been incurred during the three months ended March 31, 2026.

13. Defined Contribution Plan

The Company has a defined contribution savings plan under Section 401(k) of the Internal Revenue Code (the “401(k) Plan”). The 401(k) Plan covers all employees who meet defined minimum age and service requirements, and allows participants the option to elect to defer a portion of their annual compensation on a pretax basis. As currently established, the Company is not required to make contributions to the 401(k) Plan. The Company made $0.1 million in contributions to the 401(k) Plan for thethree months ended March 31, 2026 and 2025.

14. Net (Loss) Income per Share

Basic net (loss) income per share is calculated by dividing net (loss) income by the weighted average number of common shares outstanding during the period, including the 9,611,193 shares of common stock issuable upon the exercise of pre-funded warrants that are exercisable for little or no consideration, as described in Note 8.

The following common stock equivalents were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect:

15. Segment Information

Segment reporting is prepared on the same basis that the Company'schief executive officer, who is the Company's chief operating decision maker (the “CODM”), utilizes to manage the business and makes decisions on how to allocate resources and assess performance of the business. The Company and the CODM view the Company's operations as asingle operating segment. The Company's singular focus is on developing small molecules to improve the lives of patients with genetically defined rare diseases in areas of high unmet medical need.

The Company and the CODM primarily utilize the segment's consolidated net loss, disaggregated between (a) research and development and (b) general and administrative, as the key indicator to assess the segment's performance and for allocating resources.

The Company's reportable segment operating expenses and net loss for thethree months ended March 31, 2026 and 2025 are as follows: