SYNDAX PHARMACEUTICALS, INC. (unaudited) CONSOLIDATED BALANCE SHEETS (In thousands, except share and per share data) June 30, 2026 December 31, 2025 ASSETS Current assets: Cash and cash equivalents $ 336,477 $ 134,930 Short-term investments 211,383 259,140 Accounts receivable, net 45,067 37,996 Inventory, net 33,164 32,754 Short-term deposits 6,406 19,616 Other receivables, net 2,703 6,404 Collaboration receivable, net 22,359 23,745 Prepaid expenses and other current assets 17,480 13,496 Total current assets 675,039 528,081 Long-term investments 27,217 — Property and equipment, net 212 181 Right-of-use asset, net 1,082 1,342 Restricted cash 102 102 Total assets $ 703,652 $ 529,706 LIABILITIES AND STOCKHOLDERS’ EQUITY Current liabilities: Accounts payable $ 4,874 $ 16,580 Accrued expenses and other current liabilities 94,297 103,064 Current portion of right-of-use liability 506 470 Current portion of capital lease — 2 Total current liabilities 99,677 120,116 Long-term liabilities: Royalty interest financing liability 344,026 343,909 Convertible note liability 244,090 — Right-of-use liability, less current portion 760 1,051 Total long-term liabilities 588,876 344,960 Total liabilities 688,553 465,076 Commitments and contingencies (Note 16) Stockholders’ equity: Common stock, $0.0001 par value, 200,000,000 shares authorized; 89,150,619 and 87,405,979 shares issued and outstanding at June 30, 2026 and December 31, 2025, respectively 9 9 Additional paid-in capital 1,613,846 1,570,749 Accumulated other comprehensive (loss) gain (140 ) 452 Accumulated deficit (1,598,616 ) (1,506,580 ) Total stockholders’ equity 15,099 64,630 Total liabilities and stockholders’ equity $ 703,652 $ 529,706 The accompanying notes are an integral part of these unaudited consolidated financial statements. 1 SYNDAX PHARMACEUTICALS, INC. (unaudited) CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (In thousands, except share and per share data) Three Months Ended June 30, Six Months Ended June 30, 2026 2025 2026 2025 Revenue: Product revenue, net $ 54,700 $ 28,600 $ 103,623 $ 48,642 Collaboration revenue, net 18,088 9,358 34,029 9,111 Total revenues 72,788 37,958 137,652 57,753 Operating expenses: Cost of product sales $ 3,208 $ 1,279 $ 5,841 $ 2,164 Research and development 68,036 62,227 126,881 123,863 Selling, general and administrative 41,539 43,805 79,127 84,836 Total operating expenses 112,783 107,311 211,849 210,863 Loss from operations (39,995 ) (69,353 ) (74,197 ) (153,110 ) Other (expense) income, net: Royalty interest expense (12,119 ) (7,854 ) (23,965 ) (15,903 ) Convertible note interest expense (555 ) — (555 ) — Other interest expense (2 ) (4 ) (2 ) (6 ) Interest income 3,746 5,950 7,307 13,133 Other expense (438 ) (586 ) (624 ) (807 ) Total other (expense) income, net (9,368 ) (2,494 ) (17,839 ) (3,583 ) Net loss $ (49,363 ) $ (71,847 ) $ (92,036 ) $ (156,693 ) Other comprehensive loss: Unrealized (loss) gain on marketable securities (151 ) (242 ) (592 ) 122 Other comprehensive loss (49,514 ) (72,089 ) (92,628 ) (156,571 ) Net loss per share: Basic and diluted loss per share attributable to common stockholders $ (0.55 ) $ (0.83 ) $ (1.04 ) $ (1.82 ) Weighted-average common shares used in calculating: Basic and diluted loss per share attributable to common stockholders 88,991,317 86,337,237 88,625,508 86,255,020 The accompanying notes are an integral part of these unaudited consolidated financial statements. 2 SYNDAX PHARMACEUTICALS, INC. (unaudited) CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (In thousands, except share and per share data) Six months ended June 30, 2026 (In thousands, except share data) Common Stock $0.0001 Par Value Additional Paid-In Capital Accumulated Other Comprehensive (Loss)/Income Accumulated Deficit Total Stockholders’ Equity Shares Amount Balance as of December 31, 2025 87,405,979 $ 9 $ 1,570,749 $ 452 $ (1,506,580 ) $ 64,630 Stock-based compensation expense — — 12,188 — — 12,188 Unrealized loss on investments — — — (441 ) — (441 ) Stock purchase under ESPP 120,458 — — — — — Employee withholdings ESPP — — 458 — — 458 Vesting of RSUs 506,135 — — — — — Proceeds from exercise of stock options 511,309 — 7,460 — — 7,460 Net loss — — — — (42,673 ) (42,673 ) Balance as of March 31, 2026 88,543,881 $ 9 $ 1,590,855 $ 11 $ (1,549,253 ) $ 41,622 Stock-based compensation expense — — 14,069 — — 14,069 Unrealized loss on investments — — — (151 ) — (151 ) Vesting of RSUs 44,250 — — — — — Employee withholdings ESPP — — 167 — — 167 Proceeds from exercise of stock options 562,488 — 8,755 — — 8,755 Net loss — — — — (49,363 ) (49,363 ) Balance as of June 30, 2026 89,150,619 9 1,613,846 (140 ) (1,598,616 ) 15,099 The accompanying notes are an integral part of these unaudited consolidated financial statements. 3 SYNDAX PHARMACEUTICALS, INC. (unaudited) CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (In thousands, except share and per share data) Six months ended June 30, 2025 (In thousands, except share data) Common Stock $0.0001 Par Value Additional Paid-In Capital Accumulated Other Comprehensive (Loss)/Income Accumulated Deficit Total Stockholders’ Equity Shares Amount Balance as of December 31, 2024 85,694,443 $ 9 $ 1,509,110 $ 163 $ (1,221,158 ) $ 288,124 Stock purchase under ESPP 104,115 — — — — — Stock-based compensation expense — — 10,487 — — 10,487 Unrealized gain on investments — — — 364 — 364 Vesting of RSUs 205,527 — — — — — Employee withholdings ESPP — — 545 — — 545 Proceeds from exercise of stock options 42,947 — 385 — — 385 Net loss — — — — (84,846 ) (84,846 ) Balance as of March 31, 2025 86,047,032 $ 9 $ 1,520,527 $ 527 $ (1,306,004 ) $ 215,059 Stock-based compensation expense — — 13,903 — — 13,903 Unrealized loss on investments — — — (242 ) — (242 ) Vesting of RSUs 417 — — — — — Employee withholdings ESPP — — 468 — — 468 Proceeds from exercise of stock options 11,628 — 83 — — 83 Net loss — — — — (71,847 ) (71,847 ) Balance as of June 30, 2025 86,059,077 $ 9 $ 1,534,981 $ 285 $ (1,377,851 ) $ 157,424 The accompanying notes are an integral part of these unaudited consolidated financial statements. 4 SYNDAX PHARMACEUTICALS, INC. (unaudited) CONSOLIDATED STATEMENTS OF CASH FLOWS (In thousands) Six Months Ended June 30, 2026 2025 CASH FLOWS FROM OPERATING ACTIVITIES: Net loss $ (92,036 ) $ (156,693 ) Adjustments to reconcile net loss to net cash used in operating activities: Depreciation 9 — Accretion of investments (1,568 ) (6,810 ) Non-cash operating lease expense 260 393 Stock-based compensation 26,067 24,167 Non-cash interest on convertible note 555 — Amortization of debt issuance costs 359 167 Changes in operating assets and liabilities: Accounts receivable (7,071 ) (11,852 ) Inventory, net (220 ) (17,107 ) Prepaid expenses and other assets 9,226 (4,778 ) Collaboration receivable (payable), net 1,386 (31,547 ) Other receivable 3,701 6 Accounts payable (11,706 ) 5,727 Accrued expenses and other liabilities (9,579 ) 15,370 Net cash used in operating activities (80,617 ) (182,957 ) CASH FLOWS FROM INVESTING ACTIVITIES: Purchases of property, plant, and equipment (40 ) — Purchases of short and long-term investments (125,261 ) (102,251 ) Proceeds from sales and maturities of short-term investments 146,777 238,280 Net cash provided by investing activities 21,476 136,029 CASH FLOWS FROM FINANCING ACTIVITIES: Proceeds from convertible note 250,000 — Issuance costs of convertible note (6,152 ) — Proceeds from Employee Stock Purchase Plan 625 1,013 Proceeds from stock option exercises 16,215 468 Net cash provided by financing activities 260,688 1,481 NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH 201,547 (45,447 ) CASH, CASH EQUIVALENTS AND RESTRICTED CASH—beginning of period 135,032 154,300 CASH, CASH EQUIVALENTS AND RESTRICTED CASH —end of period $ 336,579 $ 108,853 SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION: Cash paid for royalty interest financing $ 15,332 $ 1,879 The accompanying notes are an integral part of these unaudited consolidated financial statements. 5 SYNDAX PHARMACEUTICALS, INC. (unaudited) NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 1. Nature of Business Syndax Pharmaceuticals, Inc. is a commercial-stage biopharmaceutical company advancing innovative cancer therapies. We currently have two commercially approved products and a robust pipeline of late- and early-stage development programs. We were incorporated in Delaware in 2005. We have operations in New York, NY, and we operate in one segment. References in these notes to unaudited consolidated financial statements to “Syndax,” “the Company,” “we,” “us” or “our” refer to Syndax Pharmaceuticals, Inc. and its wholly owned subsidiaries. 2. Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles, or U.S. GAAP. Any reference in these notes to applicable guidance is meant to refer to U.S. GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Updates, or ASU, of the Financial Accounting Standards Board, or FASB. In the opinion of management, the accompanying unaudited interim financial statements include all normal and recurring adjustments (which consist primarily of accruals and estimates that impact the financial statements) considered necessary to present fairly the Company’s financial position as of June 30, 2026 and its results of operations for the three and six months ended June 30, 2026 and 2025 and cash flows for the six months ended June 30, 2026 and 2025. Operating results for the three and six months ended June 30, 2026 are not necessarily indicative of the results that may be expected for the year ending December 31, 2026. The unaudited interim financial statements presented herein do not contain the required disclosures under U.S. GAAP for annual financial statements. The accompanying unaudited interim financial statements should be read in conjunction with the annual audited financial statements and related notes as of and for the year ended December 31, 2025 contained in the Company’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission, or SEC, on February 26, 2026. In 2011, the Company established a wholly owned subsidiary in the United Kingdom, which the Company dissolved in June 2024. In 2014, the Company established a wholly owned U.S. subsidiary, which the Company dissolved in July 2025. In 2021, the Company established a wholly owned subsidiary in the Netherlands. To date, there have been no material activities for these entities. All intercompany balances and transactions have been eliminated in consolidation. 3. Summary of Significant Accounting Policies The Company’s significant accounting policies, which are disclosed in the audited consolidated financial statements for the year ended December 31, 2025, and the notes thereto are included in the Company’s Annual Report on Form 10-K that was filed with the SEC on February 26, 2026. Since the date of filing, there have been no material changes to the Company’s significant accounting policies, except as noted below. Use of Estimates The preparation of the unaudited consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the unaudited consolidated financial statements and the reported amounts of costs and expenses during the reporting period. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. The Company evaluates its estimates and assumptions on an ongoing basis. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. As of the date of issuance of these unaudited consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, assumptions and judgments or revise the carrying value of its assets or liabilities. These estimates may change as new events occur and additional information is obtained and are recognized in the unaudited consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the Company’s unaudited consolidated financial statements. Income taxes In accordance with Topic ASC 270, Interim Reporting, and Topic ASC 740, Income Taxes, the Company is required at the end of each interim period to determine the best estimate of its annual effective tax rate and then apply that rate in providing for income taxes on a current year-to-date (interim period) basis. For the six months ended June 30, 2026 and 2025, the Company 6 recorded no tax expense or benefit due to the expected current year loss and its historical losses. As of June 30, 2026 and December 31, 2025, the Company concluded that a full valuation allowance would be necessary for all of its net deferred tax assets. The Company had no amounts recorded for uncertain tax positions, interest or penalties in the accompanying unaudited consolidated financial statements. On July 4, 2025, the One Big Beautiful Bill Act, or OBBBA, was enacted in the United States. The OBBBA includes significant changes to the Internal Revenue Code of 1986, such as the permanent extension of certain expiring provisions of the Tax Cuts and Jobs Act of 2017, modifications to certain aspects of the international tax framework and the restoration of favorable tax treatment for certain business expense provisions. The OBBBA introduced several U.S. tax law changes, including the ability to immediately expense domestic research and experimental, or R&E, expenditures starting in 2025, and an election to accelerate any unamortized domestic R&E expenditures over a one or two year period beginning with the 2025 tax year. In accordance with ASC 740, Accounting for Income Taxes, the impacts of the OBBBA did not affect the Company’s U.S. deferred tax assets or liabilities, as the Company continues to maintain a full valuation allowance against those balances. Other comprehensive income Comprehensive loss consists of two components, net loss and other comprehensive loss, net of tax. The Company’s other comprehensive loss, net of tax, consists of unrealized gains (losses) on the Company’s investments. Collaboration revenue, net In September 2021, the Company entered into the Incyte License and Collaboration Agreement, or the Incyte License, with Incyte, covering the worldwide development and commercialization of axatilimab. In August 2024, the U.S. Food and Drug Administration, or FDA, approved Niktimvo for the treatment of chronic graft-versus host disease, or cGVHD, after failure of at least two prior lines of systemic therapy in adult and pediatric patients weighing at least 40 kg (88.2 lbs). See Note 4 — Significant Collaborative Research and License Agreements — Incyte Collaboration for further details on the Incyte License and Collaboration Agreement. In accordance with Topic ASC 808, Collaboration Arrangements, Incyte has been identified as the principal in product sales, therefore, the Company will recognize its share of any profits or losses in the amount of net product sales less cost of goods sold and shared commercial costs, royalties and other expenses, in the period in which the underlying sales and costs are recognized. The Company’s share of net profits in connection with commercialization of products will be presented as “Collaboration revenue, net” and its share of net losses will be presented as “Collaboration loss, net” within operating expenses. The year to date “Collaboration revenue, net” or “Collaboration loss, net” will be presented as the net cumulative amount for all periods reported on in the financial statements. The Company will continue to recognize the costs associated with ongoing development services in the R&D operating expense line, including any cost-sharing components with Incyte. Recently Issued and Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other accounting standard setting bodies that we adopt as of the specified effective date. Unless otherwise discussed below, we do not believe that the adoption of recently issued standards have or may have a material impact on our unaudited consolidated financial statements or disclosures. In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, or ASU 2024-03. Among other items, the requirements include expanded disclosures around employee compensation and selling expenses. ASU 2024-03 will be effective for the Company for the year ending December 31, 2027. The Company is still evaluating the impact of this new guidance on its unaudited consolidated financial statements but expects the adoption to result in disclosure changes only. 4. Significant Collaborative Research and License Agreements Incyte Collaboration In September 2021, the Company entered into the Incyte License with Incyte, covering the worldwide development and commercialization of axatilimab. Also in September 2021, the Company entered into a share purchase agreement with Incyte, or the Incyte Share Purchase Agreement. These agreements are collectively referred to as the Incyte Agreements. Under the terms of the Incyte Agreements, Incyte received exclusive commercialization rights outside of the United States, subject to certain royalty payment obligations set forth below. In the United States, Incyte and the Company are co-commercializing and co-promoting axatilimab as 7 Niktimvo™ (axatilimab-csfr). The Company and Incyte share equally the profits and losses from co-commercialization efforts in the United States. The Company and Incyte have agreed to continue to co-develop axatilimab and to share development costs associated with global and additional U.S.-specific clinical trials, with Incyte responsible for 55% of such costs and the Company responsible for 45% of such costs. Each company will be responsible for funding any of its own independent development activities. Incyte is responsible for 100% of future development costs for trials that are specific to ex-U.S. countries. All development costs related to the collaboration will be subject to a joint development plan. Under the terms of the Incyte Agreements, in December 2021, Incyte paid the Company a non-refundable cash payment of $117.0 million and the Company issued 1,421,523 shares of common stock with an aggregate purchase price of $35.0 million, or $24.62 per share. Additionally, under the terms of the Incyte Agreements, the Company is eligible to receive up to $220.0 million in future contingent development and regulatory milestones and up to $230.0 million in commercialization milestones as well as tiered royalties ranging in the mid-teens percentage on net sales of the licensed product comprising axatilimab in Europe and Japan and low double digit percentage in the rest of the world outside of the United States. The Company’s right to receive royalties in any particular country will expire upon the last to occur of (a) the expiration of licensed patent rights covering the licensed product in that particular country, (b) a specified period of time after the first post-marketing authorization sale of a licensed product in that country, and (c) the expiration of any regulatory exclusivity for that licensed product in that country. In August 2024, the FDA approved Niktimvo for the treatment of cGVHD after failure of at least two prior lines of systemic therapy in adult and pediatric patients weighing at least 40 kg (88.2 lbs). As a result of the approval of Niktimvo, the Company earned a revenue milestone of $12.5 million, which was received in the third quarter of 2024. Upon the achievement of $150.0 million in net sales of Niktimvo, the Company recognized a $5.0 million milestone receivable in the fourth quarter of 2025, which was received in the first quarter of 2026. For the three and six months ended June 30, 2026, the Company has recognized collaboration revenue of $18.1 million and $34.0 million, respectively. For the three and six months ended June 30, 2025, the Company recognized $9.4 million and $9.1 million of collaboration revenue, respectively. As of June 30, 2026, the Company has recorded approximately $26.4 million as a collaboration receivable due from Incyte related to the Company's portion of the profit share, commercialization and development costs under the Incyte Agreements and has recorded approximately $4.0 million as a collaboration payable due to Incyte for development and commercialization costs incurred by Incyte. As of December 31, 2025, the Company has recorded $28.1 million as a collaboration receivable due from Incyte related to the Company's portion of the profit share, commercialization and development costs under the Incyte Agreements and has recorded approximately $4.4 million as a collaboration payable due to Incyte for development and commercialization costs incurred by Incyte. The Company’s share of collaboration profit or loss is based on net sales of Niktimvo and the collaborative commercialization expenses. Vitae Pharmaceuticals, Inc. In October 2017, the Company entered into a license agreement, or the Vitae License Agreement, with Vitae Pharmaceuticals, Inc., or Vitae, a subsidiary of AbbVie, Inc., or AbbVie, under which the Company was granted an exclusive, sublicensable, worldwide license to a portfolio of preclinical, orally available, small molecule inhibitors of the Menin–KMT2A binding interaction, or the Menin Assets. Upon execution of the Vitae License Agreement, the Company agreed to pay Allergan (the predecessor in interest to AbbVie) up to $99.0 million in one-time development and regulatory milestone payments over the term of the Vitae License Agreement, subject to the achievement of certain milestone events. In the event that the Company or any of its affiliates or sublicensees commercializes the Menin Assets, the Company will also be obligated to pay Vitae low single to low double-digit percentage royalties on sales, subject to reduction in certain circumstances, as well as up to an aggregate of $70.0 million in potential one-time, sales-based milestone payments based on achievement of certain annual sales thresholds. The Company is solely responsible for the development and commercialization of the Menin Assets. Each party may terminate the Vitae License Agreement for the other party’s uncured material breach or insolvency, and the Company may terminate the Vitae License Agreement at any time upon advance written notice to Vitae. Vitae may terminate the Vitae License Agreement if the Company or any of its affiliates or sublicensees institutes a legal challenge to the validity, enforceability, or patentability of the licensed patent rights. Unless terminated earlier in accordance with its terms, the Vitae License Agreement will continue on a country-by-country and product-by-product basis until the later of: (i) the expiration of all of the licensed patent rights in such country; (ii) the expiration of all regulatory exclusivity applicable to the product in such country; and (iii) 10 years from the date of the first commercial sale of the product in such country. 8 As of the date of the Vitae License Agreement, the asset acquired had no alternative future use nor had it reached a stage of technological feasibility. As the processes or activities that were acquired along with the license do not constitute a “business,” the transaction has been accounted for as an asset acquisition. As a result, in 2017, the upfront payment of $5.0 million was recorded as research and development expense in the consolidated statements of operations. Since the inception of the Vitae License Agreement, the Company achieved certain development and regulatory milestones resulting in $38.0 million in expense, which includes an $18.0 million milestone expense in 2024 and a $12.0 million expense in 2025, related to the submission of a supplemental New Drug Application, or sNDA, for Revuforj and the first United States sale of Revuforj in its second indication. UCB Biopharma Sprl In 2016, the Company entered into a license agreement, or the UCB License Agreement, as amended from time to time, with UCB Biopharma Sprl, or UCB, under which UCB granted to the Company a worldwide, sublicensable, exclusive license to UCB6352, which the Company refers to as axatilimab, an anti-CSF-1R monoclonal antibody. Upon execution of the agreement, the Company agreed to pay UCB up to $119.5 million in one-time development and regulatory milestone payments over the term of the UCB License Agreement, subject to the achievement of certain milestone events. In the event that the Company or any of its affiliates or sublicensees commercializes axatilimab, the Company will also be obligated to pay UCB low double-digit percentage royalties on sales, subject to reduction in certain circumstances, as well as up to an aggregate of $250.0 million in potential one-time, sales-based milestone payments based on achievement of certain annual sales thresholds. Under certain circumstances, the Company may be required to share a percentage of non-royalty income from sublicensees, subject to certain deductions, with UCB. The Company is solely responsible for the development and commercialization of axatilimab, except that UCB was responsible for performing a limited set of transitional chemistry, manufacturing and control tasks related to axatilimab. Each party may terminate the UCB License Agreement for the other party’s uncured material breach or insolvency, and the Company may terminate the UCB License Agreement at any time upon advance written notice to UCB. UCB may terminate the UCB License Agreement if the Company or any of its affiliates or sublicensees institutes a legal challenge to the validity, enforceability, or patentability of the licensed patent rights. Unless terminated earlier in accordance with its terms, the UCB License Agreement will continue on a country-by-country and product-by-product basis until the later of: (i) the expiration of all of the licensed patent rights in such country; (ii) the expiration of all regulatory exclusivity applicable to the product in such country; and (iii) 10 years from the date of the first commercial sale of the product in such country. As of the date of the UCB License Agreement, the asset acquired had no alternative future use nor had it reached a stage of technological feasibility. As the processes or activities that were acquired along with the license do not constitute a “business,” the transaction has been accounted for as an asset acquisition. As a result, in 2016, the upfront payment of $5.0 million was recorded as research and development expense in the consolidated statements of operations. In connection with its most recent amendment of the UCB License Agreement, in the second quarter of 2022 the Company paid UCB $5.8 million, which was recognized as a milestone expense. Since the effective date of the license agreement, the Company achieved certain development and regulatory milestones and has recorded $41.0 million as research and development expense, which includes a $15.0 million milestone paid during the third quarter of 2024 upon the approval of Niktimvo and a $10.0 million milestone recognized in the first quarter of 2025 for the first patient dosed in a Phase III study with the compound in a combination with another agent. The Company also recognized a $10.0 million commercial milestone expense in the fourth quarter of 2025 upon the achievement of $150.0 million in net sales of Niktimvo. 9 5. Net Loss per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period. Because the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company: Three Months Ended June 30, Six Months Ended June 30, 2026 2025 2026 2025 (In thousands, except share and per share data) (In thousands, except share and per share data) Numerator—basic and diluted: Net loss $ (49,363 ) $ (71,847 ) $ (92,036 ) $ (156,693 ) Net loss attributable to common stockholders—basic and diluted $ (49,363 ) $ (71,847 ) $ (92,036 ) $ (156,693 ) Net loss per share attributable to common stockholders—basic and diluted $ (0.55 ) $ (0.83 ) $ (1.04 ) $ (1.82 ) Denominator—basic and diluted: Weighted-average number of common shares used to compute net loss per share attributable to common stockholders—basic and diluted 88,991,317 86,337,237 88,625,508 86,255,020 The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported (in common stock equivalent shares): June 30, 2026 2025 Options to purchase common stock 13,389,854 13,933,003 Employee Stock Purchase Plan 54,887 88,999 Non-vested restricted stock units (RSUs) 3,348,409 2,577,678 Conversion of convertible notes 10,097,350 — For additional information related to the Company’s common stock see Note 14 — Stock Based Compensation. 6. Other Receivables, net In April 2024, entinostat received marketing approval in China, and as a result, the Company recorded $3.5 million of milestone revenue in 2024. The Company had recorded a $3.7 million receivable related to milestones (plus accrued interest) under the license agreement with Eddingpharm in 2025, which remains outstanding as of June 30, 2026. As the receivable remains outstanding, and the Company has assessed the amount as non-recoverable, the Company recorded a full reserve against the asset as a selling, general and administrative expense in 2025. The Company has recorded $2.7 million in receivables related to employee stock option exercises in which the cash payment was outstanding as of June 30, 2026. 7. Fair Value Measurements The carrying amounts of cash and cash equivalents, restricted cash, accounts payable, and accrued expenses approximated their estimated fair values due to the short-term nature of these financial instruments. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value are performed in a manner to maximize the use of observable inputs and minimize the use of unobservable inputs. The accounting standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value, which are the following: Level 1— Quoted prices (unadjusted) in active markets that are accessible at the market date for identical unrestricted assets or liabilities. 10 Level 2— Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs for which all significant inputs are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3— Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The table below presents information about the Company’s assets and liabilities that are regularly measured and carried at fair value and indicate the level within the fair value hierarchy of valuation techniques the Company utilized to determine such fair values (in thousands): Fair Value Measurements Using Quoted Prices Significant (unadjusted) Other Significant Total in Active Observable Unobservable Carrying Markets Inputs Inputs Value (Level 1) (Level 2) (Level 3) (In thousands) June 30, 2026 Assets: Cash and cash equivalents $ 336,477 $ 336,477 $ — $ — Short-term investments 211,383 — 211,383 — Long-term investments 27,217 — 27,217 — Total assets $ 575,077 $ 336,477 $ 238,600 $ — December 31, 2025 Assets: Cash and cash equivalents $ 115,358 $ 115,358 $ — $ — Short-term investments 259,140 — 259,140 — Long-term investments — — — — Total assets $ 374,498 $ 115,358 $ 259,140 $ — There have been no material impairments of our assets measured and carried at fair value during the periods ended June 30, 2026 and 2025. In addition, there have been no changes in valuation techniques during the periods ended June 30, 2026 and 2025. The fair value of Level 1 instruments classified as cash equivalents are valued using quoted market prices in active markets. The fair value of Level 2 instruments classified as short- and long-term investments are determined based on quoted prices in active markets, which are either directly or indirectly observable as of the reporting date with fair value being determined using models or other valuation methodologies. The Company’s short and long-term investments are classified as available-for-sale securities. As of June 30, 2026, the remaining contractual maturities of the available-for-sale securities were 1 to 23 months, and the balance in the Company’s accumulated other comprehensive loss was comprised solely of activity related to the Company’s available-for-sale securities. There were no realized gains or losses recognized on the sale or maturity of available-for-sale securities, during the three and six months ended June 30, 2026 and 2025. As a result, the Company did not reclassify any amounts out of accumulated other comprehensive gain for the same periods. The following table summarizes the available-for-sale securities: 11 Amortized Unrealized Unrealized Cost Gains Losses Fair Value (In thousands) June 30, 2026 Commercial paper $ 84,572 $ — $ (100 ) $ 84,471 Corporate bonds 36,356 — (36 ) 36,319 US Treasury 117,813 — (4 ) 117,810 $ 238,741 $ — $ (140 ) $ 238,600 December 31, 2025 Commercial paper $ 86,066 $ 15 $ — $ 86,081 Corporate bonds 28,227 30 — 28,257 US Treasury 144,395 407 — 144,802 $ 258,688 $ 452 $ — $ 259,140 8. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): June 30, 2026 December 31, 2025 Prepaid insurance $ 1,841 $ 1,590 Interest receivable on investments 2,656 2,146 Prepaid subscriptions 1,900 2,221 Prepaid state and local taxes — 13 Prepaid rent 54 55 Prepaid inventory 8,605 6,252 Other 2,424 1,219 Total prepaid expenses and other current assets $ 17,480 $ 13,496 9. Inventory, net Inventory, net consisted of the following (in thousands): June 30, 2026 December 31, 2025 Raw materials $ 29,201 $ 29,027 Work-in-process 2,434 2,112 Finished goods 1,529 1,615 Total Inventory, net $ 33,164 $ 32,754 Inventories are stated at the lower of cost or net realizable value, as determined on a first-in, first-out basis. Prior to the FDA's approval of Revuforj in November 2024, all costs for the manufacturing of product to support clinical development and commercial launch, including pre-launch inventory, were expensed as research and development costs. The pre-launch inventory will continue to be used in commercial production until it is depleted. 10. Property and Equipment, net 12 Property and equipment, net, consisted of the following (in thousands): June 30, December 31, 2026 2025 Equipment $ 311 $ 271 Leasehold improvements 167 167 Furniture and fixtures 134 134 Office and computer equipment 34 34 Total property and equipment 646 606 Accumulated depreciation (434 ) (425 ) Property and equipment, net $ 212 $ 181 Depreciation expense was $5,000 and $9,000 for the three and six months ended June 30, 2026. There was no depreciation expense for the three and six months ended June 30, 2025. 11. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): June 30, 2026 December 31, 2025 Product revenue allowances $ 11,115 $ 9,810 Accrued clinical study and trial costs 20,878 18,977 Accrued selling, general, and administrative costs 6,483 6,316 Accrued compensation and related costs 11,384 24,352 Accrued milestone costs — 10,000 Accrued royalty payable 8,183 7,372 Accrued interest - royalty interest financing 34,149 25,516 Accrued interest - convertible note 555 — Other 1,550 721 Total accrued expenses and other current liabilities $ 94,297 $ 103,064 12. Royalty Interest Financing Liability On November 4, 2024, the Company entered into a Purchase and Sale Agreement, or the Purchase and Sale Agreement, with Royalty Pharma Development Funding, LLC, or Royalty Pharma, pursuant to which Royalty Pharma purchased rights to certain revenue streams from net sales of products comprising or containing axatilimab (including Niktimvo™) by the Company, its affiliates and its licensees in the United States and its respective territories, districts, commonwealths and possessions (including Guam and Puerto Rico) in exchange for an upfront fee of $350 million. Pursuant to the Purchase and Sale Agreement, Royalty Pharma purchased the right to receive a percentage of net sales equal to a royalty rate of 13.8% on quarterly net sales of Niktimvo in the United States and its respective territories; provided that the royalty rate is subject to certain adjustments based on future aggregate net sales of the product in the United States and its respective territories, or the Revenue Participation Right. Aggregate payments made to Royalty Pharma in respect of the Revenue Participation Right will be capped at $822.5 million, or the Royalty Cap. The Purchase and Sale Agreement contains customary representations, warranties and indemnities of the Company and Royalty Pharma and customary covenants relating to the royalty payments, including the grant of a back-up security interest in the purchased royalties and certain assets related to the product and restrictions on the incurrence of additional indebtedness and on the existence of liens on the Company’s assets related to the product. Upon a change of control, the Company will have the right, but not the obligation, to repurchase the Revenue Participation Right at a repurchase price set forth in the Purchase and Sale Agreement. In addition, the Purchase and Sale Agreement provides that if certain events of default occur, including certain bankruptcy events or certain termination events with respect to the Company’s license agreement with UCB Biopharma Srl, Royalty Pharma may require the Company to repurchase Royalty Pharma’s interests in the Revenue Participation Right at a repurchase price equal to the Royalty Cap. The Company assessed the Purchase and Sale Agreement and identified it as a sale of future revenue in the form of a debt instrument to be accounted for as a liability under Topic ASC 470, Borrower’s Accounting for Debt Modifications. The Company has elected to use the prospective method in its calculation of its effective interest rate and will update this calculation quarterly when there are changes in the projected sales. Issuance costs pursuant to the Purchase and Sale Agreement consisted primarily of bank and 13 legal fees and totaled $6.3 million. These issuance costs were recorded as a direct deduction to the carrying amount of the liability and will be amortized under the effective interest method over the estimated period the liability will be repaid. For the period ended June 30, 2026, the Company estimated an effective annual interest rate of approximately 13.02%. Over the course of the Purchase and Sale Agreement, the annual interest rate will be affected by the amount and timing of net Niktimvo revenue recognized and change in timing of forecasted net Niktimvo revenue. On a quarterly basis, the Company reassesses the expected timing of the net Niktimvo revenue, recalculates the amortization and effective interest rate, and adjusts the accounting prospectively, as needed. For the three and six months ended June 30, 2026, the Company recognized royalty interest expense of $12.1 million and $24.0 million, respectively. The Company made $15.3 million of payments pursuant to the Purchase and Sale Agreement during the six month period ended June 30, 2026. June 30, 2026 December 31, 2025 Current portion of royalty interest financing liability $ — $ — Royalty interest financing liability, less current portion 350,000 350,000 Debt issuance costs (5,974 ) (6,091 ) Total royalty interest financing liability, net $ 344,026 $ 343,909 13. Convertible Notes In June 2026, the Company issued $250.0 million aggregate principal amount of 2.25% Convertible Senior Notes due 2031, or the 2031 Notes, in a private placement to institutional accredited investors that are qualified institutional buyers under Rule 144A in reliance on the exemption from registration provided by Section 4(a)(2) of the Securities Act. The 2031 Notes are senior, unsecured obligations of the Company and bear interest at 2.25% per annum, payable semi-annually in arrears on June 15 and December 15, beginning December 15, 2026. The 2031 Notes mature on June 15, 2031, unless earlier converted, redeemed, or repurchased. The initial conversion rate is 40.3894 shares of common stock per $1,000 principal amount (equivalent to an initial conversion price of approximately $24.76 per share), subject to customary anti-dilution adjustments under certain circumstances in accordance with the terms of the indenture relating to the 2031 Notes. Upon conversion, the Company will pay or deliver, at its election, cash, shares of its common stock, or a combination of cash and shares of common stock. Before March 15, 2031, the 2031 Notes are convertible only upon the satisfaction of specified conditions; thereafter, the 2031 Notes are convertible at any time until the second scheduled trading day before maturity. The Company may redeem for cash all or any portion of the 2031 Notes (subject to certain limitations) on or after June 20, 2029 if the last reported sale price of its common stock exceeds 130% of the conversion price for a specified period at a redemption price equal to 100% of the principal amount of the 2031 Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. If the Company undergoes a fundamental change (as defined in the indenture governing the 2031 Notes), holders may require the Company to repurchase their 2031 Notes for cash at a price equal to 100% of the principal amount plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. Initially, a maximum of 13,631,400 shares of common stock may be issued upon conversion of the 2031 Notes based on the initial maximum conversion rate of 54.5256 shares of common stock per $1,000 principal amount of 2031 Notes, which is subject to customary anti-dilution adjustment provisions. The 2031 Notes are classified as a long-term liability under ASC 470 and are presented net of unamortized debt issuance costs, which are amortized to interest expense over the term of the 2031 Notes using the effective interest method. Accrued interest related to the 2031 Notes is recorded under the accrued expenses and other current liabilities line of the balance sheet. As of June 30, 2026, the net carrying amount of the 2031 Notes was $244.1 million, unamortized debt issuance costs were $5.9 million, and the effective interest rate was 2.733%. June 30, 2026 Current portion of convertible note liability $ — Convertible note liability, less current portion 250,000 Debt issuance costs (5,910 ) Total convertible note liability, net $ 244,090 14. Stock-Based Compensation In January 2026, the number of shares of common stock available for issuance under the Company’s 2015 Omnibus Incentive Plan, or the 2015 Plan, was increased by 3,496,239 shares of common stock due to the automatic annual provision to increase shares of common stock available under the 2015 Plan. In March 2026, the 2015 Plan expired. In June 2026, the 2026 Equity Incentive Plan, or 2026 Plan, was approved. The maximum number of shares of the Company’s common stock that may be issued under the 2026 Plan is 17,134,916 shares, which is the sum of (i) 7,200,000 newly authorized shares, plus (ii) up to 9,934,916 shares of common stock 14 subject to outstanding stock awards granted under the 2015 Plan that, on or after the 2026 Plan becomes effective, expire or otherwise terminate prior to exercise or settlement. As of June 30, 2026, there were 424,326 shares of common stock available for issuance under the 2023 Plan and 7,448,808 shares of common stock available for issuance under the 2026 Plan. The Company recognized stock-based compensation expense related to the issuance of stock option awards and restricted stock units to employees and non-employees and related to the Company’s 2015 Employee Stock Purchase Plan, or ESPP, in the consolidated statements of comprehensive loss as follows: Three Months Ended June 30, Six Months Ended June 30, 2026 2025 2026 2025 Research and development $ 4,510 $ 4,196 $ 8,537 $ 7,864 Selling, general and administrative 9,504 9,591 17,530 16,303 Total $ 14,014 $ 13,787 $ 26,067 $ 24,167 Compensation expense by type of award in the three and six months ended June 30, 2026 and 2025 was as follows: Three Months Ended June 30, Six Months Ended June 30, 2026 2025 2026 2025 Stock options $ 8,178 $ 8,707 $ 15,739 $ 16,392 RSUs 5,624 4,757 9,905 7,332 ESPP 212 323 423 443 Total $ 14,014 $ 13,787 $ 26,067 $ 24,167 In addition, stock-based compensation expense of $0.1 million and $0.2 million was capitalized to inventory for the three and six months ended June 30, 2026, respectively, which represents the stock-based compensation expense incurred related to employees involved in the manufacturing process of finished goods and samples. For the three and six months ended June 30, 2025, $0.1 million and $0.2 million of stock compensation expense was capitalized to inventory. As of June 30, 2026, there were $103.4 million of unrecognized compensation costs related to employee and non-employee unvested stock options and RSUs granted under the Inducement Plan, 2015 Plan, 2026 Plan, and the Company’s 2007 Stock Plan, which are expected to be recognized over a weighted-average remaining service period of 2.67 years. Employee Benefit Plan The Company maintains a defined contribution 401(k) retirement plan. For the three and six months ended June 30, 2026, the Company made $0.3 million and $2.8 million, respectively, of contributions to the plan. For the three and six months ended June 30, 2025, the Company made $0.3 million and $2.6 million, respectively, of contributions to the plan. The Company’s contributions were made in cash. 15. Stockholders’ Equity Pre-Funded Warrants In December 2021, the Company sold pre-funded warrants to purchase 1,142,856 shares of common stock. As of June 30, 2026, 285,714 pre-funded warrants were issued and outstanding. 16. Commitments and Contingencies License Agreements The Company is obligated to pay royalties pursuant to the Vitae License Agreement and the UCB License Agreement as a percentage of net product sales for direct licensed products, such as Revuforj and Niktimvo. The obligation to pay royalties expires, on a country-by-country basis and licensed product-by-licensed product basis at the later of (i) the expiration of all of the licensed patent 15 rights in such country; (ii) the expiration of all regulatory exclusivity applicable to the product in such country; and (iii) 10 years from the date of the first commercial sale of the product in such country. These fees were recorded as cost of product sales. From time to time, the Company may be subject to various claims and proceedings in the ordinary course of business. If the potential loss from any claim, asserted or unasserted, or proceeding is considered probable and the amount is reasonably estimable, the Company will accrue a liability for the estimated loss. There were no contingent liabilities recorded as of June 30, 2026. 17. Segment Reporting The Company manages its business activities on a consolidated basis and operate as a single operating and reportable segment: Syndax Pharmaceuticals. The Company primarily derives revenue in the United States through milestone revenue and product sales on the approved products, Revuforj® (revumenib) and Niktimvo™ (axatilimab-csfr). The accounting policies of the segment are the same as those described in Note 3 – Summary of Significant Accounting Policies. To assess performance, the Company’s Chief Operating Decision Maker, or CODM, Michael Metzger, uses consolidated net loss as the segment’s measure of segment profit or loss. The CODM uses net loss in the budget and forecasting process and considers budget-to actual variances on a quarterly basis when making decisions about the allocation of operating and capital resources. The following table provides the operating financial results of our biopharmaceutical cancer therapeutics segment: Three Months Ended June 30, Six Months Ended June 30, 2026 2025 2026 2025 June 30, 2026 Total Revenue $ 72,788 $ 37,958 $ 137,652 $ 57,753 Less: Significant and other segment expenses Cost of product sales 3,208 1,279 5,841 2,164 Research and development expenses Revumenib-related costs 35,493 28,155 61,218 48,960 Axatilimab-related costs 8,682 9,053 18,315 28,764 Other R&D programs 1,043 1,826 1,205 2,747 Personnel cost and other expenses 18,308 18,997 37,606 35,528 General and administrative expenses Commercial-related expenses 9,869 9,914 17,590 20,739 Personnel cost and other expenses 16,298 19,307 32,999 38,389 Other SG&A expenses 5,868 4,993 11,008 9,405 Stock-based compensation 14,014 13,787 26,067 24,167 Royalty interest expense 12,119 7,854 23,965 15,903 Convertible note interest expense 555 — 555 — Interest expense (income), net (3,744 ) (5,946 ) (7,305 ) (13,127 ) Other expense, net 438 586 624 807 Segment net loss $ (49,363 ) $ (71,847 ) $ (92,036 ) $ (156,693 ) 16