Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations

The following discussion and analysis should be read in conjunction with our consolidated financial statements and related notes included elsewhere in this Annual Report. This discussion and analysis and other parts of this Annual Report contain forward-looking statements based upon current beliefs, plans and expectations that involve risks, uncertainties and assumptions, such as statements regarding our plans, objectives, expectations, intentions and projections. Our actual results and the timing of selected events could differ materially from those anticipated in these forward-looking statements as a result of several factors, including those set forth under “Risk Factors” and elsewhere in this Annual Report. You should carefully read the “Risk Factors” section of this Annual Report to gain an understanding of the important factors that could cause actual results to differ materially from our forward-looking statements. Please also see the section entitled “Special Note Regarding Forward-Looking Statements.”

For the discussion of the financial condition and results of operations for the year ended December 31, 2022 compared to the year ended December 31, 2021, refer to "Management's Discussion and Analysis of Financial Condition and Results of Operations—Results of Operations" and "—Liquidity and Capital Resources" included in the Annual Report on Form 10-K filed with the SEC on February 28, 2023.

Overview

We are a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies. Our two lead product candidates are revumenib, and axatilimab. We are developing revumenib, a potent, selective, small molecule inhibitor of the menin-MLL binding interaction for the treatment of KMT2A rearranged, or KMT2Ar, also known as mixed lineage leukemia rearranged or MLLr, acute leukemias including acute lymphoblastic leukemia, or ALL, and acute myeloid leukemia, or AML, and necleophosmin 1, also known as NPM1, mutant AML. We are also exploring the use of revumenib as a treatment in solid tumors, specifically its activity in metastatic colorectal cancer. We are developing axatilimab, a monoclonal antibody that blocks the colony stimulating factor 1 receptor, or CSF-1, in chronic graft-versus-host disease, or cGVHD, as well as idiopathic pulmonary fibrosis, or IPF. We plan to continue to leverage the technical and business expertise of our management team and scientific collaborators to license, acquire and develop additional therapeutics to expand our pipeline.

We have no products approved for commercial sale and have not generated any product revenues from product sales to date. We continue to incur significant research and development and other expenses related to our ongoing operations. Except for 2021, we have not been profitable and have incurred losses in each period since our inception in 2005. For the years ended December 31, 2023 and 2022, we reported a net loss of $209.4 million and $149.3 million, respectively. For the year ended December 31, 2021, we reported a net profit of $24.9 million. As of December 31, 2023, we had an accumulated deficit of $902.4 million, which included non-cash charges for stock-based compensation, preferred stock accretion and extinguishment charges. As of December 31, 2023, we had cash, cash equivalents and short-term and long-term investments of $600.5 million.

Significant Risks and Uncertainties

The current inflationary environment may materially affect our business and operating results by increasing the cost of our clinical trial materials and supplies, driving the U.S. Federal Reserve system to increase interest rates, which in turn increased our overhead costs. Rising interest rates could make it more difficult for us to obtain traditional financing on acceptable terms, if at all. Additionally, the ongoing recession risk together with the foregoing, could result in further economic uncertainty and volatility in the capital markets in the near term and, as a result could negatively affect our operations. Furthermore, such economic conditions have produced downward pressure on share prices. Although we do not believe that inflation has had a material impact on our financial position or results of operations to date, additional high inflation could increase our operating costs, including our labor costs and research and development costs. These costs may also be negatively impacted due to supply chain constraints, global geopolitical tensions as a result of the ongoing war between Russia and Ukraine and the war in Israel, worsening macroeconomic conditions and employee availability and wage increases, which may result in additional stress on our working capital.

Additionally, we are subject to other challenges and risks specific to our business and our ability to execute on our strategy, as well as risks and uncertainties common to companies in the pharmaceutical industry with

development and commercial operations, including, without limitation, risks and uncertainties associated with: obtaining regulatory approval of our late-stage product candidate; identifying, acquiring or in-licensing additional products or product candidates; pharmaceutical product development and the inherent uncertainty of clinical success; the challenges of protecting and enhancing our intellectual property rights; and complying with applicable regulatory requirements.

Financial Overview

Revenue

To date, we have not generated any product revenues. Our ability to generate revenue and become profitable depends upon our ability to obtain marketing approval of and successfully commercialize our product candidates. Our revenues for the year ended December 31, 2021, have been solely derived from our license, development and commercialization agreements with Kyowa Kirin Co., Ltd., or KKC, and with Incyte Corporation, or Incyte. We generated no revenue during the years ended December 31, 2023 and 2022.

In September 2021, we entered into a collaboration and license agreement with Incyte or the Incyte Collaboration Agreement, with Incyte for the worldwide development and commercialization of axatilimab. Additionally, in September 2021, we entered into a share purchase agreement with Incyte, or the Incyte Share Purchase Agreement. Under the terms of the Incyte Collaboration Agreement, Incyte received exclusive commercialization rights outside of the United States, and we and Incyte will, subject to the exercise of our co-promotion option, have co-commercialization rights in the United States, with respect to axatilimab. Incyte is responsible for leading commercialization strategy and booking all revenue from worldwide sales of axatilimab, subject to its royalty payment obligations set forth below. The parties will share equally the profits and losses from the co-commercialization efforts. We and Incyte are co-developing axatilimab and sharing development costs associated with global and U.S.-specific clinical trials, with Incyte responsible for 55% of such costs and we are responsible for 45% of such costs. Each company is responsible for funding any independent development activities. All development costs related to the collaboration are subject to a joint development plan. A joint development committee between us and Incyte will govern future development of axatilimab. 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. In December 2021, we received an upfront cash payment of $117 million and issued 1,421,523 shares of common stock for an aggregate purchase price of $35 million. We allocated $126.6 million of the total consideration received to the license, and such amount was recognized as license revenue upon transfer of license to Incyte.

We granted KKC an exclusive license to develop and commercialize entinostat in Japan and Korea, or the KKC license agreement. In 2015, we received a $25.0 million upfront payment from KKC, inclusive of an equity investment. We allocated $17.3 million of the upfront payment to the license fee, and such fee is being recognized as revenue ratably over our expected performance period (expected to be through 2029). The balance of the upfront payment of $7.7 million was allocated to KKC’s purchase of shares of our convertible preferred stock. In September 2021, KKC informed us that they discontinued the entinostat program and cancelled the license to develop and commercialize entinostat. As a result, we recognized $12.4 million in revenue which was previously deferred in the third quarter of 2021.

Research and Development

Since our inception, we have primarily focused on our clinical development programs. Research and development expenses consist primarily of costs incurred for the development of our product candidates and include:

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expenses incurred under agreements related to our clinical trials, including the costs for investigative sites and contract research organizations, or CROs, that conduct our clinical trials;

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employee-related expenses associated with our research and development activities, including salaries, benefits, travel and non-cash stock-based compensation expenses;

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manufacturing process-development, clinical supplies and technology-transfer expenses;

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license fees and milestone payments under our license agreements;

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consulting fees paid to third parties;

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allocated facilities and overhead expenses; and

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costs associated with regulatory operations and regulatory compliance requirements.

Internal and external research and development costs are expensed as they are incurred. Cost-sharing amounts received by us are recorded as reductions to research and development expense. Costs for certain development activities, such as clinical trials, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations or other information provided to us by our vendors.

Research and development activities are central to our business model. Drug candidates in late stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of late-stage clinical trials. We plan to continue to spend a significant amount of our resources on research and development activities for the foreseeable future as we continue to advance the development of our drug candidates. The amount of research and development expenses allocated to external spending will continue to grow, while we expect our internal spending to grow at a slower and more controlled pace.

It is difficult to determine, with certainty, the duration and completion costs of our current or future preclinical programs, research studies and clinical trials of our product candidates. The duration, costs and timing of research studies and clinical trials of our product candidates will depend on a variety of factors that include, but are not limited to, the following:

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per patient costs;

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the number of patients that participate;

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the number of clinical trial sites;

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the countries in which the trials are conducted;

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the length of time required to enroll eligible patients;

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the potential additional safety monitoring or other studies requested by regulatory agencies;

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the duration of patient monitoring;

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the efficacy and safety profile of the product candidates; and

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timing and receipt of any regulatory approvals.

In addition, the probability of success for each drug product candidate will depend on numerous factors, including competition, manufacturing capability and commercial viability. The successful development of our product candidates is highly uncertain. At this time, we cannot reasonably estimate the nature, timing or costs of the efforts that will be necessary to complete the remainder of the development of our product candidates for the period, if any, in which material net cash inflows from these potential product candidates may commence. Clinical development timelines, the probability of success and development costs can differ materially from expectations.

Selling, General and Administrative

Selling, general and administrative expenses consist primarily of employee-related expenses, including salaries, benefits, non-cash stock-based compensation and travel expenses, for our employees in executive, finance, human resources, business development and support functions. Other selling, general and administrative expenses include facility-related costs not otherwise allocated to research and development expenses and accounting, tax, legal, information technology and consulting services. We anticipate that our selling, general and administrative expenses will further increase in the future as we continue to increase our headcount to support our continued research and development and anticipated commercialization of our product candidates. Additionally, in anticipation of expected regulatory approvals of the our drug candidates, we expect an increase in employee-related expenses and other commercial expenses in 2024 as a result of our preparation for the commercial launch, especially as it relates to the sales and marketing of our drug product candidates.

Interest Expense

Interest expense consists primarily of interest expense on our operational and capital leases and in prior years consisted of our term loan, which was paid off in 2022.

Interest Income

Interest income consists of income earned on our cash, cash equivalents and short and long-term investment balances.

Other (Expense) Income, net

Other (expense) income net includes income (expense), net consisting of revaluation of foreign currency related to trade payables.

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, or FASB, or other standard setting bodies and adopted by us as of the specified effective date. Unless otherwise discussed in "Summary of Significant Accounting Policies" (Note 3) to our audited consolidated financial statements included in this Annual Report, we believe that the impact of recently issued standards that are not yet effective will not have a material impact on our financial position or results of operations upon adoption.

Critical Accounting Estimates

The preparation of our consolidated financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States, or U.S. GAAP, requires us to make estimates, judgments and assumptions that may affect the reported amounts of assets, liabilities, equity, revenue and expense and related disclosure of contingent assets and liabilities. On an ongoing basis we evaluate our estimates, judgments and assumptions. We base our estimates on historical experience, known trends and events and various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. In making estimates and judgments, management employs critical accounting policies. Other significant accounting policies are outlined in "Summary of Significant Accounting Policies" (Note 3) to our consolidated financial statements included in this Annual Report.

We have listed below our critical accounting estimates that we believe to have the greatest potential impact on our consolidated financial statements. Historically, our assumptions, judgments and estimates relative to our critical accounting estimates have not differed materially from actual results.

Revenue from Contracts with Customers

We enter into license agreements for the development and commercialization of our product candidates. License agreements may include non-refundable upfront payments, contingent payments based on the occurrence of specified events under our license arrangements, partial or complete reimbursement of research and development expenses, license fees and royalties on sales of entinostat if they are successfully approved and commercialized. Our performance obligations under the license agreements may include the transfer of intellectual property rights in the form of licenses, obligations to provide research and development services and related materials and participation on certain development and/or commercialization committees.

Revenue is recognized when, or as, performance obligations are satisfied, which occurs when control of the promised products or services is transferred to customers. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring products or services to a customer, or the transaction price. To the extent that the transaction price includes variable consideration, we estimate the amount of variable consideration that should be included in the transaction price utilizing the most likely amount method. Variable consideration is included in the transaction price if, in our judgment, it is probable that a significant future reversal of cumulative revenue under the contract will not occur. Estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on an assessment of our anticipated performance and all information (historical, current and forecasted) that is reasonably available.

We assessed the promises to determine if they are distinct performance obligations. Once the performance obligations are determined, the transaction price is allocated based on a relative standalone selling price basis. Milestone payments and royalties are typically considered variable consideration at the outset of the contract and are recognized in the transaction price either upon occurrence or when the constraint of a probable reversal is no longer applicable.

As of December 31, 2021, we recorded revenue of $126.6 million relating to the Incyte Collaboration Agreement and $13.3 million relating to the KKC Agreement. For the years ended December 31, 2023 and 2022, no revenue has been recognized relating to either agreement.

We applied significant judgment to our Incyte Collaboration Agreement. We evaluated whether our contractual obligations represented distinct performance obligations. Such evaluation required judgment since it was made from the customer’s perspective. We determined that the transfer of the license to Incyte was a distinct performance obligation, separate from the ongoing collaboration activities. As such, we estimated the standalone selling price to be $126.6 million which we recognized as $126.6 million of license revenue for the year ended December 31, 2021.

We applied significant judgment to our KKC Agreement. We evaluated whether our contractual obligations represented distinct performance obligations. Such evaluation required judgment since it was made from the customer’s perspective. We determined that our performance obligations under the collaboration at contract inception were not distinct and represented a single performance obligation. In September 2021, KKC informed us, that they have discontinued the entinostat program and have cancelled the license to develop and commercialize entinostat. As a result, we recognized $12.4 million in revenue, which was previously deferred in the third quarter of 2021.

Accrued Research and Development Expenses

As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued research and development expenses. This process involves reviewing contracts and vendor agreements, communicating with our applicable personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of actual cost. We make estimates of our accrued and prepaid clinical expenses as of each balance sheet date in our consolidated financial statements based on facts and circumstances known to us at that time. Examples of estimated accrued research and development expenses include fees paid to contract research organizations, or CROs, and investigative sites in connection with clinical studies and to vendors related to product manufacturing and development of clinical supplies.

We base our expenses related to clinical study and trial costs on our estimates of the services received and efforts expended pursuant to contracts with multiple research institutions and CROs that conduct and manage clinical studies on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows and expense recognition. Payments under some of these contracts depend on factors out of our control, such as the successful enrollment of patients and the completion of clinical trial milestones. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from our estimate, we adjust the accrual accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, if our estimates of the status and timing of services performed differ from the actual status and timing of services performed, we may report amounts that are too high or too low in any particular period. To date, we have not experienced any significant adjustments to our estimates.

Results of Operations

Comparison of the years ended December 31, 2023, 2022 and 2021:

Revenues:

Operating expenses:

Other income (expense):

Research and Development

The following table summarizes the research and development expenses for the full years ended December 31, 2023, 2022 and 2021:

For the year ended December 31, 2023, our total research and development expenses increased by $44.5 million or 38 % from the prior year. The increase is primarily due to:

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An increase in $16.8 million in revumenib related costs due to increases in expenses associated with registrational trials, the initiation of frontline/combination trials, clinical diagnostic test development costs, and regulatory expenses associated with New Drug Applications, or NDA, submission.

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A decrease of $1.2 million in axatilimab-related costs is due to lower registrational trial costs, lower costs for the IPF trial that were driven by start-up costs in 2022, and lower CMC-related expenses, net of expense reimbursement from Incyte, our co-development partner, of $12.3 million in 2023 and $25.9 million in 2022.

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An increase of $29.8 million in personnel costs, including non-cash stock-based compensation, and other expenses related to increases in headcount to support of on-going clinical trials and regulatory expenses, NDA activities and related expenses and overhead expenses (e.g. information technology and facilities).

The following table summarizes the internal and external research and development expenses for the full years ended December 31, 2023 and 2022:

Years EndedDecember 31, Increase(Decrease)

We expect research and development expenses to fluctuate from quarter to quarter depending on the timing of clinical trial activities, clinical manufacturing, and other development activities.

Selling, General and Administrative

The following table summarizes the selling, general and administrative expenses for the full years ended December 31, 2023, 2022 and 2021:

For the year ended December 31, 2023, our total selling, general and administrative expenses increased by $33.7 million, or 101%, from the prior year. The increase primarily is due to:

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An increase of $11.0 million in commercialization activities for the revumenib and axatilimab programs.

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An increase of $4.3 million related to increases in rent, information technology, human resources and legal related expenses.

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An increase of $18.4 million in personnel costs, including non-cash stock-based compensation, and related costs related to increases in headcount to support a growing research and development organization and preparation for commercial launch.

Interest Expense and Income

For the year end December 31, 2023, interest expense decreased by $2.9 million, or 93%, from the prior year. The decrease is primarily due to the elimination of interest expense related to the amended loan agreement by and between the Company and Hercules, which was terminated in September 2022.

For the year ended December 31, 2023, interest income increased by $15.3 million, or 260%, from the prior year. This increase was primarily due to higher interest rates and increased average balance on cash equivalents and short and long-term investments.

Other (Expense) Income, net

For the year ended December 31, 2023, the total other (expense) income, net increased from the comparable period in the prior year primarily due to an increase in revaluation of foreign currency related to trade payables.

Liquidity and Capital Resources

Overview

As of December 31, 2023, we had cash, cash equivalents and short-term and long-term investments totaling $600.5 million. Since our inception, our operations have been primarily financed by net proceeds from our public stock offerings, and revenue from our license agreements. We believe that our cash, cash equivalents and short and long-term investments as of December 31, 2023, will fund our projected operating expenses and capital expenditure requirements for at least the next 12 months. In addition to our existing cash, cash equivalents, short and long-term investments, we are eligible to receive research and development funding and to earn milestone and other contingent payments for the achievement of defined collaboration objectives and certain development, regulatory and commercial milestones, and royalty payments under our collaboration agreements. Our ability to earn these milestone and contingent payments and the timing of achieving these milestones is primarily dependent upon the outcome of our collaborators’ research and development activities and is uncertain at this time.

Loan and Security Agreement

In February 2020, we entered into a loan and security agreement, with Hercules, as amended in December 2021, which we refer to as the Amended Loan Agreement. We terminated the Amended Loan Agreement in September 2022. On September 23, 2022, we made a prepayment of $21.5 million to satisfy in full all of our principal and interest obligations and related fees under the Amended Loan Agreement. The payoff amount paid by us in connection with the termination of the Amended Loan Agreement was pursuant to a payoff letter with Hercules and included payment of (a) $1.0 million as an end-of term fee and (b) $0.4 million as a pre-payment fee. Hercules released all security interests held on our assets.

For additional details on our Amended Loan Agreement, see "Loan Payable" (Note 14) to our consolidated financial statements in this Annual Report.

Future Funding Requirements

We believe that our available cash, cash equivalents, short-term and long-term investments are sufficient to fund existing and planned cash requirements. Our primary uses of capital are, and we expect will continue to be, compensation and related expenses, third-party clinical research and development services, clinical costs, legal and other regulatory expenses and general overhead costs. We have based our estimates on assumptions that may prove to be incorrect, and we could use our capital resources sooner than we currently expect.

Additionally, the process of testing drug candidates in clinical trials is costly, and the timing of progress in these trials is uncertain. We cannot estimate the actual amounts necessary to successfully complete the development and commercialization of our product candidates or whether, or when, we may achieve profitability. Our future capital requirements will depend on many factors, including:

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the initiation, progress, timing, costs and results of clinical trials of our product candidates;

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the outcome, timing and cost of seeking and obtaining regulatory approvals from the FDA and comparable foreign regulatory authorities, including the potential for such authorities to require that we perform more trials than we currently expect;

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the cost to establish, maintain, expand and defend the scope of our intellectual property portfolio, including the amount and timing of any payments we may be required to make, or that we may receive, in connection with licensing, preparing, filing, prosecuting, defending and enforcing any patents or other intellectual property rights;

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market acceptance of our product candidates;

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the cost and timing of selecting, auditing and developing manufacturing capabilities, and potentially validating manufacturing sites for commercial-scale manufacturing;

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the cost and timing for obtaining pricing and reimbursement, which may require additional trials to address pharmacoeconomic benefit;

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the cost of establishing sales, marketing and distribution capabilities for our product candidates if either candidate receives regulatory approval and we determine, in the case of revumenib to commercialize it ourselves, or in the case of axatilimab to co-commercialize it with Incyte;

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the costs of acquiring, licensing or investing in additional businesses, products, product candidates and technologies;

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the interruption of key clinical trial activities, such as clinical trial site monitoring;

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the cost of disruption to our supply chain and operations, and associated delays in the manufacturing and supply of our products, which would adversely impact our ability to continue our clinical trial operations;

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the effect of competing technological and market developments; and

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our need to implement additional internal systems and infrastructure, including financial and reporting systems, as we grow our company.

We have no products approved for commercial sale and have not generated any product revenues from product sales to date. Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings and additional funding from license and collaboration arrangements. Except for any obligations of our collaborators to reimburse us for research and development expenses or to make milestone or royalty payments under our agreements with them, we will not have any committed external source of liquidity.

Our material cash requirements include the following contractual obligations as of December 31, 2023, and the effects that such obligations are expected to have on our liquidity and cash flows in future periods. For additional information, see our consolidated financial statements.

(in thousands) Total Less than1 Year 1 to 3Years 3 to 5Years More than5 Years

Operating leases for office space (1) $ 1,802 $ 1,196 $ 606 $ — $ —

Capital lease for office equipment (2) 26 14 12 — —

(1)

In August 2021, we signed a 36-month extension of the lease for the office space in Waltham, MA. In August 2022, we signed a 36-month extension of the lease for the office space in New York, NY. In May 2023, we

signed a 27-month lease for an additional space in New York, NY. The minimum lease payments above do not include any related common area maintenance charges or real estate taxes.

(2)

In January 2022, we entered into two four-year non-cancelable leases for office equipment. In June 2023, we entered into one two-year non-cancelable lease for office equipment. All three leases are accounted for as a capital lease. The leased assets are included in property, plant and equipment, at cost.

We have incurred losses and cumulative negative cash flows from operations since our inception, excluding year ending December 31, 2021. As of December 31, 2023, we had an accumulated deficit of $902.4 million. We anticipate that we will continue to incur significant losses for at least the next several years. We expect that our research and development and selling, general and administrative expenses will continue to increase. As a result, we will need additional capital to fund our operations, which we may raise through a combination of the sale of equity, debt financings, or other sources, including potential collaborations. To the extent that we raise additional capital through the future sale of equity or debt, the ownership interest of our stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our existing common stockholders. If we raise additional funds through collaboration arrangements in the future, we may have to relinquish valuable rights to our technologies, future revenue streams or drug candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market drug candidates that we would otherwise prefer to develop and market ourselves.

At-the-Market Offering Program

In March 2021, we entered into a sales agreement with Cowen and Company, LLC, or TD Cowen, under which we could, from time to time, issue and sell shares of our common stock having aggregate sales proceeds of up to $75.0 million, in a series of one or more at-the-market, or ATM, equity offerings, or the 2021 ATM Program. On May 26, 2023, we terminated the 2021 ATM Program. Prior to termination, we sold shares under the 2021 ATM Program for aggregate net proceeds of approximately $25.0 million.

In May 2023, we entered into a new sales agreement with TD Cowen under which we could, from time to time, issue and sell shares of our common stock having aggregate sales proceeds of up to $200.0 million, in a series of one or more ATM equity offerings, or the 2023 ATM Program. TD Cowen is not required to sell any specific share amounts but acts as the Company’s sales agent, using commercially reasonable efforts consistent with its normal trading and sales practices. Pursuant to the sales agreement, shares will be sold under the shelf registration statement on Form S-3ASR (Registration No. 333-254661), which became automatically effective upon the filing on March 24, 2021. Our common stock will be sold at prevailing market prices at the time of the sale, and as a result, prices may vary. As of December 31, 2023, we sold 2,719,744 shares of common stock under the 2023 ATM Program for net proceeds of approximately $42.1 million.

Cash Flows

The following is a summary of cash flows:

Years Ended December 31,

Net Cash (Used in) Provided by Operating Activities

Net cash used in operating activities for the year ended December 31, 2023, was $160.6 million and primarily consisted of our net loss of $209.4 million adjusted for non-cash items including stock-based compensation of $31.0 million, an investment increase of $14.8 million, a net increase in operating assets and liabilities of $32.0 million and non-cash operating lease expense of $0.7 million. The significant items in the increase in operating assets and

liabilities include an increase in accrued expenses and other liabilities of $14.9 million, an increase in collaboration payable of $10.7 million, an increase in accounts payable of $5.7 million, and an increase in prepaid expenses and other assets of $0.7 million.

Net cash used in operating activities for the year ended December 31, 2022 was $133.7 million and primarily consisted of our net loss of $149.3 million adjusted for non-cash items including stock-based compensation of $16.0 million, an investment increase of $3.4 million, a net increase in operating assets and liabilities of $1.7 million, an increase in interest expense associated with the term loan of $1.1 million, and non-cash operating lease expense of $0.4 million. The significant items in the increase in operating assets and liabilities include an increase in accrued expenses and other liabilities of $9.4 million, an increase in collaboration receivable of $3.5 million, partially offset by a decrease in prepaid expenses and other assets of $3.0 million, and a decrease in accounts payable of $1.3 million.

Net Cash Provided by (Used in) Investing Activities

Net cash provided by in investing activities for the year ended December 31, 2023 was $117.6 million and was due to $472.2 million in proceeds from the maturities of available-for-sale marketable securities, partially offset by the purchase of $354.6 million of available-for-sale marketable securities.

Net cash used in investing activities for the year ended December 31, 2022, was $186.2 million and was primarily due to the purchase of $495.3 million of available-for-sale marketable securities partially offset by $308.9 million in proceeds from the maturities of available-for-sale marketable securities.

Net Cash Provided by Financing Activities

Net cash provided by financing activities for the year ended December 31, 2023, was $264.1 million and was primarily due to proceeds of $215.9 million from the issuance of common stock in a follow-up offering, $42.1 million from the issuance of common in at-the-market offering, and $6.0 million of proceeds from the stock option exercises and ESPP purchases.

Net cash provided by financing activities for the year ended December 31, 2022, was $172.3 million and was primarily due proceeds of $162.0 million from the issuance of common stock in a public offering, $19.4 million of proceeds from at-the-market offerings, and $11.9 million of proceeds from the stock option exercises and ESPP purchases, partially offset by payment on the term loan of $21.0 million.

Net Operating Loss and Research and Development Tax Credit Carryforwards

At December 31, 2023, we had federal and state tax net operating loss carryforwards, or NOLs, of approximately $136.4 million and $63.5 million, respectively. We have generated federal NOLs of $114.3 million and state NOLs of $0.9 million which have an indefinite carryforward period. The remaining $22.1 million of federal NOLs and the $62.6 million of state NOLs will begin to expire at various dates starting in 2026. At December 31, 2023, we had available income tax credits of approximately $12.7 million, with $8.9 million attributable to Federal R&D Credits and $3.8 million attributable to state R&D Credits, which are available to reduce future income taxes, if any. These income tax credits began to expire in 2024.

Utilization of the net operating losses and credits may be subject to a substantial annual limitation due to ownership change limitations provided by the Internal Revenue Code of 1986, as amended. The annual limitation may result in the expiration of our net operating losses and credits before we can use them. We have recorded a valuation allowance on all of our deferred tax assets, including our deferred tax assets related to our net operating loss and research and development tax credit carryforwards.

Item 7A. Quantitative and Qualitative Disclosures about Market Risk

The market risk inherent in our financial instruments and in our financial position represents the potential loss arising from adverse changes in interest rates. As of December 31, 2023, we had cash, cash equivalents and short-term and long-term investments of $600.5 million, consisting of overnight investments, interest-bearing money market funds and highly rated federal bonds and short and long-term investments including commercial paper, highly rated corporate bonds and treasuries. Our primary exposure to market risk is interest rate sensitivity, which is affected by changes in the general level of U.S. interest rates. The primary objectives of our investment activities are

to ensure liquidity and to preserve principal while at the same time maximizing the interest income, we receive from our marketable securities without significantly increasing risk. We have established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity. Due to the relative short-term maturities of our cash equivalents and the low risk profile of our short and long-term investments, an immediate 100 basis point change in interest rates would not have a material effect on the fair market value of our cash equivalents and short and long-term investments. We have the ability to hold our investments until maturity, and therefore, we would not expect our operating results or cash flows to be affected to any significant degree by the effect of a change in market interest rates on our investment portfolio.

We do not believe that inflation and changing prices had a significant impact on our results of operations for any periods presented herein.

Item 8. Financial Statements and Supplementary Data

Our consolidated financial statements, together with the report of our independent registered public accounting firm, appear in this Annual Report on Form 10-K beginning on page F-1.

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

None.

Item 9A. Controls and Procedures

Evaluation of our Disclosure Controls and Procedures

Our management, with the participation of our principal executive officer and our principal financial officer, evaluated, the effectiveness of our disclosure controls and procedures as of December 31, 2023. The term “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended, or the Exchange Act, means controls and other procedures of a company that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act are recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to our management, including our principal executive and principal financial officers, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and our management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on an evaluation of our disclosure controls and procedures as of December 31, 2023, our principal executive officer and principal financial officer concluded that, as of such date, our disclosure controls and procedures were effective at the reasonable assurance level.

Management’s Annual Report on Internal Control Over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Rules 13a-15(f) and 15d-15(f) promulgated under the Exchange Act as a process designed by, or under the supervision of, the company’s principal executive and principal financial officers to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Therefore, even those systems determined to be effective can provide only reasonable assurance with respect to financial statement preparation and presentation. Projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Our management assessed the effectiveness of our internal control over financial reporting as of December 31, 2023. In making this assessment, management used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (COSO) in Internal Control – Integrated Framework (2013). Based on

that assessment, our management concluded that, as of December 31, 2023, our internal control over financial reporting was effective.

Attestation Report of the Registered Public Accounting Firm

Deloitte & Touche LLP, the independent registered public accounting firm that audited the consolidated financial statements included in this Annual Report on Form 10-K, has issued an attestation report on the effectiveness of internal control over financial reporting as of December 31, 2023, included herein.

Changes in Internal Control Over Financial Reporting

No change in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) occurred during the fiscal quarter ended December 31, 2023 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the stockholders and the Board of Directors of Syndax Pharmaceuticals, Inc.

Opinion on Internal Control over Financial Reporting

We have audited the internal control over financial reporting of Syndax Pharmaceuticals, Inc. and subsidiaries (the “Company”) as of December 31, 2023, based on criteria established in Internal Control — Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). In our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2023, based on criteria established in Internal Control — Integrated Framework (2013) issued by COSO.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the consolidated financial statements as of and for the year ended December 31, 2023, of the Company and our report dated February 27, 2024, expressed an unqualified opinion on those financial statements.

Basis for Opinion

The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management's Annual Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

Definition and Limitations of Internal Control over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

/s/ Deloitte & Touche LLP

Boston, Massachusetts

February 27, 2024

Item 9B. Other Information

Change in Control Arrangements

On February 27, 2024, several of our named executive officers entered into amendments to their employment agreements providing, in part, for increases in their change in control benefits. For Mr. Metzger, in the event of an involuntary termination without cause or resignation for good reason within three (3) months prior to, or within twelve (12) months following, a change in control, he will receive (i) an amount equal to 24 months of base salary, payable in a lump sum, (ii) an amount equal to 24 months of the target annual incentive award, payable in a lump sum, and (iii) continuation of health benefits for 24 months. For Drs. Gallagher and Madigan and Messrs. Albrecht and Goldan, in the event of an involuntary termination without cause or resignation for good reason within three (3) months prior to, or within twelve (12) months following, a change in control, each will receive (i) an amount equal to 18 months of base salary, payable in a lump sum, (ii) an amount equal to 18 months of the target annual incentive award, payable in a lump sum, and (iii) continuation of health benefits for 18 months.

Trading Arrangements

During our last fiscal quarter, none of our directors and officers (as defined in Rule 16a-1(f) under the Exchange Act) adopted or terminated a “Rule 10b5-1 trading arrangement” or a “non-Rule 10b5-1 trading arrangement,” as defined in Regulation S-K Item 408 for the purchase or sale of our securities, except as set forth below:

defense of Rule 10b5–1(c)

(1) Termination of Rule 10b5-1 trading arrangement, each of which the reporting person terminated prior to the sale of all plan securities.

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

Not Applicable

PART III

Certain information required by Part III is omitted from this Annual Report because we will file with the SEC a definitive proxy statement pursuant to Regulation 14A, or the 2024 Proxy Statement, no later than 120 days after the end of our fiscal year ended December 31, 2023, and certain information included therein is incorporated herein by reference.

Item 10. Directors, Executive Officers, and Corporate Governance

The information required by this item is incorporated by reference to the information set forth in the sections titled “Information About Our Board of Directors,” “Executive Officers” and “The Board of Directors and Its Committees” and “Delinquent Section 16(a) Reports,” if applicable, in our 2024 Proxy Statement.

Item 11. Executive Compensation

The information required by this item is incorporated by reference to the information set forth in the sections titled "Compensation Discussion and Analysis", “Executive Officer” and “Director Compensation”, "Pay Versus Performance" and "The Board of Directors and its Committees-Compensation Committee Interlocks and Insider Participation" in our 2024 Proxy Statement.

Information regarding our Code of Business Conduct and Ethics, or the Code of Conduct, required by this item will be contained in our 2024 Proxy Statement under the caption “The Board of Directors and Its Committees – Code of Business Conduct and Ethics,” and is hereby incorporated by reference. If we make any substantive amendments to the Code of Conduct or grants any waiver from a provision of the Code of Conduct to any executive officer or director, we will promptly disclose the nature of the amendment or waiver on its website. The full text of our Code of Conduct is available at the investors section of our website at www.syndax.com. The reference to our website address does not constitute incorporation by reference of the information contained at or available through our website, and you should not consider it to be a part of this Annual Report.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

The information required by this item is incorporated by reference to the information set forth in the section titled “Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters” and "Securities Authorized for Issuance Under Equity Compensation Plans" in our 2024 Proxy Statement.

Item 13. Certain Relationships and Related Transactions and Director Independence

The information required by this item is incorporated by reference to the information set forth in the sections titled “The Board of Directors and Its Committees – Board Independence” and “Certain Relationships and Related Party Transactions” in our 2024 Proxy Statement.

Item 14. Principal Accountant Fees and Services

The information required by this item is incorporated by reference to the information set forth in the sections titled “Independent Registered Public Accounting Firm Fees” and “Pre-Approval Policies and Procedures” contained in Proposal 3 in our 2024 Proxy Statement.

PART IV

Item 15. Exhibits and Financial Statement Schedules

(a)(1) Financial Statements.

Pages

Report of Independent Registered Public Accounting Firm (PCAOB ID 34) F-2

Consolidated Balance Sheets as of December 31, 2023 and 2022 F-4

Notes to Consolidated Financial Statements F-10

(a)(2) Financial Statement Schedules.

All schedules have been omitted because they are not required or because the required information is given in the Consolidated Financial Statements or Notes thereto.

(a)(3) Exhibits.

ExhibitNo. Description

4.3 Description of Capital Stock.

ExhibitNo. Description

10.16* Syndax Pharmaceuticals, Inc. 2023 Inducement Plan.

ExhibitNo. Description

23.1 Consent of Independent Registered Public Accounting Firm.

24.1 Power of Attorney (included on the signature page to this report).

ExhibitNo. Description

97 Incentive Compensation Recoupment Policy.

101.INS Inline XBRL Instance Document.

101.SCH Inline XBRL Taxonomy Extension Schema Document.

101.CAL Inline XBRL Taxonomy Extension Calculation Linkbase Document.

101.DEF Inline XBRL Taxonomy Extension Definition Linkbase Document

101.LAB Inline XBRL Taxonomy Extension Label Linkbase Document.

101.PRE Inline XBRL Taxonomy Extension Presentation Linkbase Document.

* Indicates a management contract or compensatory plan.

+ Furnished herewith and not deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act.

† Confidential treatment has been granted for certain portions of this exhibit. These portions have been omitted and filed separately with the SEC.

Item 16. Form 10-K Summary

Not applicable.

SIGNATURES

Pursuant to the requirements of Section 13 of 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

SYNDAX PHARMACEUTICALS, INC.

Date: February 27, 2024 By: /s/ Michael A. Metzger

Michael A. Metzger

Chief Executive Officer

POWER OF ATTORNEY

Each person whose individual signature appears below hereby authorizes and appoints Michael A. Metzger and Luke J. Albrecht, and each of them, with full power of substitution and resubstitution and full power to act without the other, as his or her true and lawful attorney-in-fact and agent to act in his or her name, place and stead and to execute in the name and on behalf of each person, individually and in each capacity stated below, and to file any and all amendments to this report on Form 10-K, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing, ratifying and confirming all that said attorneys-in-fact and agents or any of them or their or his or her substitute or substitutes may lawfully do or cause to be done by virtue thereof.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

Signature Title Date

Michael A. Metzger

Keith Goldan

/s/ Dennis G. Podlesak Chairman of the Board of Directors February 27, 2024

Dennis G. Podlesak

/s/ Martin H. Huber, M.D. Director February 27, 2024

Martin H. Huber, M.D.

/s/ Jennifer Jarrett Director February 27, 2024

Jennifer Jarrett

/s/ Keith A. Katkin Director February 27, 2024

Keith A. Katkin

/s/ Pierre Legault Director February 27, 2024

Pierre Legault

/s/ William Meury Director February 27, 2024

William Meury

/s/ Briggs W. Morrison, MD. Director February 27, 2024

Briggs W. Morrison, MD.

Syndax Pharmaceuticals, Inc.

Index to Consolidated Financial Statements

Pages

Report of Independent Registered Public Accounting Firm (PCAOB ID 34) F-2

Consolidated Balance Sheets as of December 31, 2023 and 2022 F-4

Notes to Consolidated Financial Statements F-10

F-1

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the stockholders and Board of Directors of Syndax Pharmaceuticals, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Syndax Pharmaceuticals, Inc. and subsidiaries (the "Company") as of December 31, 2023 and 2022, the related consolidated statements of operations, comprehensive (loss) income, stockholders' equity, and cash flows, for each of the three years in the period ended December 31, 2023, and the related notes (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2023 and 2022, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2023, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2023, based on criteria established in Internal Control — Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 27, 2024, expressed an unqualified opinion on the Company's internal control over financial reporting.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Prepaid and Accrued Clinical Costs— Refer to Notes 3 and 11 to the financial statements

Critical Audit Matter Description

The Company recognizes research and development expenses as incurred, which include costs relating to clinical trial and clinical study activities performed by the CROs. Expenses related to clinical trials and studies are based on estimates of the services received and efforts expended pursuant to contracts with each of the contract research organizations (“CROs”). Tracking the progress of the clinical study and trial activities, including payments made by

F-2

the Company and by the CROs, allows the Company to record the appropriate expense, prepayments, and accruals under the terms of the agreements with the CROs.

We identified the estimates for research and development accrued and prepaid CRO expenses, including costs incurred by CROs as a critical audit matter due to the judgments necessary for management to estimate the level of services provided and the costs incurred for the service when the Company has not yet been invoiced or otherwise notified of actual costs. Prepaid CRO expenses are recorded within the balance of short-term deposits on the consolidated balance sheet, while accrued CRO expenses are recorded within the balance of accrued expenses and other current liabilities on the consolidated balance sheet. This required a high degree of auditor judgment and an increased extent of effort when performing audit procedures to audit management's estimates of such accrued and prepaid CRO expenses.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to prepaid and accrued clinical costs included the following, among others:

•

We tested the effectiveness of internal controls over the estimation of accrued CRO and prepaid CRO expense calculations, including management’s controls over the assessment and estimation of the costs incurred for significant research and development activities performed by CROs.

•

For a sample of contracts, we read the related contracts, purchase orders, statements of work and other contractual documentation. We tested the completeness and accuracy of the information used to develop the estimates and evaluated the significant assumptions used by management to estimate the recorded amounts by performing the following:

Performed corroborating inquiries with the Company’s research and development personnel to understand the nature and progress of the studies conducted by the CROs.

Inspected information from third-party service provider CRO.

Obtained corresponding invoices and evidence of payment to third-party service provider CROs.

Compared the estimated accrual balance as of December 31, 2023, to the invoices received after year-end to evaluate the Company’s ability to estimate the accrual.

/s/ Deloitte & Touche LLP

Boston, Massachusetts

February 27, 2024

We have served as the Company’s auditor since 2008.

F-3

SYNDAX PHARMACEUTICALS, INC.

CONSOLIDATED BALANCE SHEETS

(In thousands, except share and per share data)

December 31,

ASSETS

Current assets:

Collaboration receivable, net — 3,474

Prepaid expenses and other current assets 3,293 1,915

Property and equipment, net 8 20

LIABILITIES AND STOCKHOLDERS' EQUITY

Current liabilities:

Collaboration payable, net 7,232 —

Accrued expenses and other current liabilities 39,856 24,276

Current portion of right-of-use liability 1,035 434

Current portion of capital lease 12 5

Long-term liabilities:

Right-of-use liability, less current portion 578 709

Capital lease, less current portion 10 13

Total long-term liabilities 588 722

Commitments and contingencies (Note 16)

Stockholders' equity:

Accumulated other comprehensive income (loss) 218 (806 )

Total liabilities and stockholders' equity $ 612,880 $ 497,236

The accompanying notes are an integral part of these consolidated financial statements.

F-4

SYNDAX PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except share and per share data)

Years Ended December 31,

Revenues:

Operating expenses:

Other income (expense):

Net (loss) income Per Share:

Weighted-average common shares used in calculating:

The accompanying notes are an integral part of these consolidated financial statements.

F-5

SYNDAX PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME

(In thousands)

Years Ended December 31,

Other comprehensive gain (loss):

Unrealized gain (loss) on marketable securities, net of tax 1,024 (851 ) 49

The accompanying notes are an integral part of these consolidated financial statements.

F-6

SYNDAX PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF

STOCKHOLDERS’ EQUITY

(In thousands, except share and per share data)

Shares Amount Capital (Loss) Income Deficit (Deficit)

Stock purchase under ESPP 26,878 — — — — —

Pre-funded warrant cashless exercise 725,784 — — — — —

Stock-based compensation expense — — 13,317 — — 13,317

Unrealized gain on investments — — — 49 — 49

Vesting of RSU 5,500 — — — — —

Employee withholdings ESPP — — 367 — — 367

Stock purchase under ESPP 28,999 — — — — —

Pre-funded warrant cashless exercise 2,832,151 — — — — —

Stock-based compensation expense — — 16,019 — — 16,019

Vesting of RSU 38,749 — — — — —

Unrealized loss on investments — — — (851 ) — (851 )

Employee withholdings ESPP — — 401 — 401

Stock-based compensation expense — — 30,951 — — 30,951

Unrealized gain on investments — — — 1,024 — 1,024

Stock purchase under ESPP 34,797 — — — — —

Employee withholdings ESPP — — 910 — — 910

Pre-funded warrant cashless exercise 857,131 — — — — —

Vesting of RSU 9,102 — — — — —

The accompanying notes are an integral part of these consolidated financial statements.

F-7

SYNDAX PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(In thousands)

Years Ended December 31,

CASH FLOWS FROM OPERATING ACTIVITIES:

(Accretion) amortization of investments (14,803 ) (3,382 ) 644

Non-cash interest income (expense) — 1,103 (225 )

Changes in fair value of derivative liability — (187 ) (389 )

Other — — (1 )

Changes in operating assets and liabilities:

Collaboration payable/receivable, net 10,706 (3,474 ) —

Deferred revenue — — (13,133 )

CASH FLOWS FROM INVESTING ACTIVITIES:

Purchases of property and equipment — — (129 )

Proceeds from sales of equipment — 225 —

CASH FLOWS FROM FINANCING ACTIVITIES:

Payment on term loan — (20,996 ) —

The following table provides a reconciliation of cash, cash equivalents, and restricted cash equivalents reported within the consolidated balance sheets that sum to the total of the amounts shown in the consolidated statements of cash flows:

Years Ended December 31,

(In thousands)

Supplemental disclosures of cash flow information (Note 17).

F-8

The accompanying notes are an integral part of these consolidated financial statements.

F-9

SYNDAX PHARMACEUTICALS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

1. Nature of Business

Syndax Pharmaceuticals, Inc. (“the Company” or “Syndax”) is a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies. The Company's two lead product candidates are revumenib and axatilimab. The Company is developing revumenib, a potent, selective, small molecule inhibitor of the menin-MLL binding interaction for the treatment of KMT2A rearranged, (“KMT2Ar”), also known as mixed lineage leukemia rearranged, (“MLLr”), acute leukemias including acute lymphoblastic leukemia, (“ALL”), and acute myeloid leukemia, or AML, and nucleophosmin 1, also known as NPM1, mutant AML. The Company is also exploring the use of revumenib as a treatment in solid tumors, specifically its activity in metastatic colorectal cancer. The Company is developing axatilimab, a monoclonal antibody that blocks the colony stimulating factor 1 receptor, (“CSF-1R”), in chronic graft-versus-host disease, (“cGVHD”), as well as idiopathic pulmonary fibrosis, (“IPF”). The Company plans to continue to leverage the technical and business expertise of its management team and scientific collaborators to license, acquire and develop additional therapeutics to expand its pipeline.

Since its inception, the Company has devoted its efforts principally to research and development and raising capital. The Company is subject to risks common to companies in the development stage, including, but not limited to, successful development of therapeutics, obtaining additional funding, protection of proprietary therapeutics, compliance with government regulations, fluctuations in operating results, dependence on key personnel and collaborative partners, and risks associated with industry changes. The Company’s long-term success is dependent upon its ability to successfully develop and market its product candidates, expand its oncology drug pipeline, earn revenue, obtain additional capital when needed, and ultimately, achieve profitable operations. The Company anticipates that it will be several years before any of its product candidates is approved, if ever, and the Company begins to generate revenue from sales of such product candidates. Accordingly, management expects to incur substantial losses on the ongoing development of its product candidates and does not expect to achieve positive cash flow from operations for the foreseeable future, if ever. As a result, the Company will continue to require additional capital to move forward with its business plan. While certain amounts of this additional capital were raised in the past, there can be no assurance that funds necessary beyond these amounts will be available in amounts or on terms sufficient to ensure ongoing operations.

The Company’s management believes that the cash, cash equivalents and short-term investments balances as of December 31, 2023, should enable the Company to maintain its planned operations for at least 12 months from the issuance date of these financial statements. The Company’s ability to fund all of its planned operations internally beyond that date, including the completion of its ongoing and planned clinical trial activities, may be substantially dependent upon whether the Company can obtain sufficient funding on terms acceptable to the Company. Proceeds from additional capital transactions would allow the Company to accelerate and/or expand its planned research and development activities. In the event that sufficient funds were not available, the Company may be required to delay or reduce expenditures to conserve cash, which could involve scaling back or curtailing development and selling, general and administrative activities.

The Company is subject to challenges and risks specific to its business and ability to execute on the strategy, as well as risks and uncertainties common to companies in the pharmaceutical industry with development and commercial operations, including, without limitation, risks and uncertainties associated with: obtaining regulatory approval of the Company’s late-stage product candidate; delays or problems in the supply of the Company’s products, loss of single source suppliers or failure to comply with manufacturing regulations; identifying, acquiring or in-licensing additional products or product candidates; pharmaceutical product development and the inherent uncertainty of clinical success; and the challenges of protecting and enhancing the Company’s intellectual property rights; complying with applicable regulatory requirements.

2. Basis of Presentation

The Company has prepared the accompanying consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”).

F-10

3. Summary of Significant Accounting Policies

Estimates

The preparation of 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 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. The Company’s actual results may differ from these estimates under different assumptions or conditions.

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 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 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 consolidated financial statements.

Cash Equivalents

Cash equivalents include all highly liquid investments maturing within 90 days or less from the date of purchase. Cash equivalents include money market funds, corporate debt securities, U.S. government agency notes, and overnight deposits.

Restricted Cash

The Company classifies as restricted cash all cash pledged as collateral to secure long-term obligations and all cash whose use is otherwise limited by contractual provisions. Amounts are reported as non-current unless restrictions are expected to be released in the next 12 months.

Marketable Securities

All investments in marketable securities are classified as available-for-sale and are reported at fair value with unrealized gains and losses excluded from earnings and reported net of tax in accumulated other comprehensive income, which is a component of stockholders’ equity. Unrealized losses that are determined to be other-than-temporary, based on current and expected market conditions, are recognized in earnings. Declines in fair value determined to be credit related are charged to earnings. The cost of marketable securities sold is determined by the specific identification method.

Segment Reporting

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions regarding resource allocation and assessing performance. The Company has one operating segment.

Concentrations of Credit Risk

Cash and cash equivalents, restricted cash, and short and long-term investments are financial instruments that potentially subject the Company to concentrations of credit risk. Substantially all of the Company’s cash, cash equivalents, and short and long-term investments were deposited in accounts at two financial institutions, and at times, such deposits may exceed federally insured limits. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company’s available-for-sale investments primarily consist of government money market funds, corporate debt securities, commercial paper, credit card asset-backed securities and overnight deposits and potentially subject the Company to concentrations of credit risk.

F-11

Property and Equipment

Property and equipment are recorded at cost. Depreciation is recorded using the straight-line method over the estimated useful lives of the assets (three to five years). Assets under capital leases are amortized over the shorter of their useful lives or lease term using the straight-line method. Major replacements and improvements are capitalized, while general repairs and maintenance are expensed as incurred.

Impairment of Long-Lived Assets

Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. When such events occur, the Company compares the carrying amounts of the assets to their undiscounted expected future cash flows. If this comparison indicates that there is impairment, the amount of impairment is calculated as the difference between the carrying value and fair value. To date, no such impairments have been recognized.

Revenue Recognition

The Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which we expect to receive in exchange for those goods or services. The Company recognize revenue following the five – step model prescribed under FASB Accounting Standards Codification (ASC 606), Revenue from Contracts with Customers: (i) identify contract(s) with customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) we satisfy the performance obligations.

Licenses of Intellectual Property: Revenue from non-refundable, up-front fees allocated to the licenses related to the Company's intellectual property, are recognized as the license is transferred to the customer and the customer is able to use and benefit from the license. This generally takes place over the related know-how transfer period, or if applicable, over the term of transfer of future updates to the intellectual property.

Development Milestone Payments: The Company evaluates whether milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant 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 generally not considered probable of being achieved until those approvals are received. The transaction price is then 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. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related 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 license fees and earnings in the period of adjustment.

Commercial Milestone Payments and Royalties: For arrangements that include sales-based royalties, including milestone payments based on the level of commercial sales, and the license is deemed to be the predominant item to which the royalties or commercial milestones relate, the Company will recognize revenue at the later of when the related sales occur or when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date no commercial milestone payments or royalties have been achieved.

When no performance obligations are required of the Company, or following the completion of the performance obligation period, such amounts are recognized as revenue upon transfer of control of the goods or services to the customer. Generally, all amounts received or due other than sales-based milestones and royalties are classified as license fees.

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Deferred revenue arises from amounts received in advance of the culmination of the earnings process and is recognized as revenue in future periods as performance obligations are satisfied. Deferred revenue expected to be recognized within the next twelve months is classified as a current liability. Upfront payment contract liabilities resulting from the Company’s license agreements do not represent a financing component as the payment is not financing the transfer of goods or services, and the technology underlying the licenses granted reflects research and development expenses already incurred by the Company.

For additional information on our collaboration and license arrangements, please read Note 4, Collaborative Research and License Agreements, to these consolidated financial statements.

Research and Development

Research and development costs are expensed as incurred. Research and development expenses include payroll and personnel expenses, consulting costs, external contract research and development expenses, and allocated overhead, including rent, equipment depreciation, and utilities. Research and development costs that are paid in advance of performance are capitalized as a prepaid expense and amortized over the service period as the services are provided. The Company expenses upfront license payments related to acquired technologies that have not yet reached technological feasibility and have no alternative future use.

In instances where the Company enters into cost-sharing arrangements, all research and development costs reimbursed by the collaborators are accounted for as reductions to research and development expense. During the years ended December 31, 2023 and 2022, the Company has incurred external costs related to Incyte cost-sharing collaboration. During the year ended December 31, 2021, the Company incurred no external costs related to cost-sharing collaborations.

Clinical Costs

Clinical study and trial costs are a component of research and development expenses. The Company expenses clinical trial activities performed by third parties based on an evaluation of the progress to completion of specific contract tasks using data such as patient enrollment, clinical site activations, or other information provided to us by our vendors. Depending on the progression of the contract and timing of invoicing and payment the research and development expense can be an accrued expense or a prepaid expense. Prepaid clinical study and trial costs are included in short-term deposits on the accompanying consolidated balance sheet.

Income Taxes

The Company records deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the Company’s financial statement carrying amounts and the tax bases of assets and liabilities and for loss and credit carryforwards using enacted tax rates expected to be in effect in the years in which the differences reverse. A valuation allowance is provided to reduce the net deferred tax assets to the amount that will more likely than not be realized. The Company determines whether it is more likely than not that a tax position will be sustained upon examination. If it is not more likely than not that a position will be sustained, none of the benefit attributable to the position is recognized. The tax benefit to be recognized for any tax position that meets the more-likely-than-not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the contingency. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes.

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Guarantees and Indemnifications

As permitted under Delaware law, the Company indemnifies its officers, directors, and employees for certain events or occurrences that happen by reason of the relationship with, or position held at, the Company. The Company has standard indemnification arrangements under office leases (as described in Note 5, Leases to these consolidated financial statements) that require it to indemnify the landlord against all costs, expenses, fines, suits, claims, demands, liabilities, and actions directly resulting from any breach, violation, or nonperformance of any covenant or condition of the Company’s lease. Through December 31, 2023, the Company had not experienced any losses related to these indemnification obligations and no claims were outstanding. The Company does not expect significant claims related to these indemnification obligations, and consequently, concluded that the fair value of these obligations is negligible, and no related reserves were established.

Stock-Based Compensation

The Company accounts for all stock option awards granted to employees and non-employees using a fair value method. Stock-based compensation is measured at the grant date fair value of the stock option grants and is recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis. For equity awards that have a performance condition, the Company recognizes compensation expense based on its assessment of the probability that the performance condition will be achieved. The Company accounts for forfeitures as they occur.

(Loss) Earnings Per Share

Basic earnings per share is computed by dividing undistributed net income attributable to Syndax by the weighted-average number of common shares outstanding during the period. Diluted earnings per share is computed based on the treasury method by dividing net income by the weighted-average number of common shares outstanding during the period plus potentially dilutive common equivalent shares outstanding.

Recently Issued and Adopted Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board 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 consolidated financial statements or disclosures.

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4. Collaborative Research and License Agreements

Incyte Collaboration

In September 2021, the Company entered into license and collaboration agreement (the "Incyte License and Collaboration Agreement") with Incyte Corporation ("Incyte") covering the worldwide development and commercialization of axatilimab. Also, in September 2021 the Company entered into a share purchase agreement with Incyte, ("Incyte Share Purchase Agreement" and together with Incyte License and Collaboration Agreement, the Incyte Agreements"). Under the terms of the Incyte Agreements, Incyte will receive exclusive commercialization rights outside of the United States, subject to its royalty payment obligations set forth below. In the United States, Incyte and the Company will co-commercialize axatilimab, with the Company having the right to co-promote axatilimab with Incyte, subject to the Company’s exercise of its co-promotion option. Incyte will be responsible for leading all aspects of commercialization of axatilimab in the United States. The Company and Incyte will share equally the profits and losses from co-commercialization efforts in the United States. The Company and Incyte have agreed to co-develop axatilimab and to share development costs associated with global and 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 with Incyte 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.

The Incyte Agreement and the Incyte Share Purchase Agreement were executed on the same date and negotiated simultaneously. Management therefore concluded that the Incyte Agreements are to be combined for accounting purposes and therefore allocated the total consideration to the units of account identified. The common stock issued to Incyte was recorded at fair value of $24.8 million. Pursuant to the Letter Agreement, Incyte is permitted to terminate the Incyte Agreement, under circumstances under which the upfront payment of $117 million would be returned to Incyte and a cash settlement on the sale of the Company's common stock would be made to make the parties whole (the “Letter Agreement”). In connection with the closing of this transaction in December 2021, the Company determined that the cash settlement feature of the Letter Agreement represented an embedded derivative requiring bifurcation and separate accounting recognition at fair value. The Letter Agreement terminated in March 2022. Accordingly, the Company initially allocated $0.6 million of the total consideration received to the derivative liability. As of December 31, 2022, the fair value of the derivative is zero.

The Company evaluated the terms of the Incyte Agreement and determined it is within the scope of Accounting Standard Update 2018-18, Collaborative Arrangements (Topic 808), and has elements that are within the scope of Topic 606 and Topic 808.

The Company identified the following promises in the Incyte Agreements that were evaluated under the scope of Topic 606: (i) delivery of a license for axatilimab to develop, commercialize, and conduct medical affairs and (ii) services to be performed in accordance with the development plan. The Company also evaluated whether certain options outlined within the Incyte Agreements represented material rights that would give rise to a performance obligation and concluded that none of the options convey a material right to Incyte and therefore are not considered separate performance obligations within the Incyte Agreements.

The Company assessed the above promises and determined that the license for axatilimab represents the only performance obligation within the scope of Topic 606. The license for axatilimab is considered functional

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intellectual property and distinct from other promises under the contract as Incyte can benefit from the license on its own or together with other readily available resources. The services performed by the Company to obtain regulatory approval of axatilimab are not complex or specialized, could be performed by another qualified third party, are not expected to significantly modify or customize the license given that axatilimab is late-stage intellectual property that has completed its Phase 1/2 trial and is currently enrolling in a global pivotal Phase 2 trial, and the services are expected to be performed over a short period of time. Therefore, the license represents a separate performance obligation within a contract with a customer under the scope of Topic 606 at contract inception.

The Company considers the collaborative research and development activities and manufacturing activities to be separate units of account within the scope of Topic 808 and are not deliverables under Topic 606. The Company and Incyte are both active participants in the activities and are exposed to significant risks and rewards that are dependent on the commercial success of the activities in the arrangement.

Under the scope of Topic 606, the Company identified contract promises for the license of intellectual property and know-how rights for axatilimab. The Company determined that the license was capable of being distinct from the ongoing collaboration activities. After the allocation to the common stock and derivative liability, the total transaction price to be allocated to the Incyte Agreement is $126.6 million. The Company estimated the standalone selling price of the license to be the entire $126.6 million, based on an application of the income approach by measuring the fair value of the discounted cash flows from commercialization. Significant assumptions included in the valuation included judgments relating to the probability of achieving both regulatory and commercial milestones, forecasted future cash flows and the election of the discount rate. As the Company concluded the license was distinct, revenue of $126.6 million was recognized upon transfer of the license to Incyte in the year ended December 31, 2021.

The Company used the most likely amount method to estimate variable consideration and estimated that the most likely amount for each potential preclinical, development, and regulatory variable consideration milestone payment under this agreement is zero, as achievement of those milestones is uncertain and highly susceptible to factors outside the Company’s control. Accordingly, all such milestone payments were excluded from the transaction price. Management will reevaluate the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur, will adjust the transaction price as necessary. Sales based royalties, including milestones based on the level of sales, were also excluded from the transaction price, as the license is deemed to be the predominant item to which the royalties relate. The company will recognize such 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).

Company considers the collaborative research and development activities and manufacturing activities to be separate units of account within the scope of Topic 808 and are not deliverables under Topic 606. The Company and Incyte are both active participants in the activities and are exposed to significant risks and rewards that are dependent on the commercial success of the activities in the arrangement.

As of December 31, 2023, the Company has recorded $2.2 million as a collaboration receivable due from Incyte related to the Company's development and pre-commercialization costs under the Incyte Agreements and has recorded approximately $9.5 million as a collaboration payable due to Incyte for development and pre-commercialization costs incurred by Incyte as of December 31, 2023. Both expenses and cost offset are recorded as part of research and development and selling, general and administrative expense.

5. Leases

Leases

The Company accounts for leases in accordance with ASC 842, Leases, and determines whether an arrangement is a lease at inception. Operating lease right-of-use (“ROU”) assets and lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. Lease agreements with lease and non-lease components are accounted for separately. For leases that do not provide an implicit rate, the Company uses the incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The ROU asset also includes any lease

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payments made and excludes lease incentives and initial direct costs incurred. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Leases with an initial term of 12 months or less are not recorded on the balance sheet as the Company has elected to apply the short-term lease exemption. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term.

The Company identified three existing long-term building leases under ASC 842 that are classified as operating leases. In September 2016, the Company entered into a five-year operating lease for 12,207 square feet of office space in Waltham, MA, with a lease commencement date of March 1, 2017. On August 17, 2021, the Company signed a 36-month extension to the lease for the Waltham, MA office with aggregate payments of $1.6 million, with a lease commencement date of March 1, 2022.

In December 2015, the Company entered into a 62-month operating lease for 4,039 square feet of space in New York, NY, which commenced on January 1, 2016. In February 2021, the Company signed an 18-month extension to the lease for the New York office, which commenced on March 1, 2021. In August 2022, the Company signed a 36-month extension to the lease for the New York office, with aggregate payments of $689,000, with a lease commencement date of September 1, 2022.

In May 2023, the Company entered into a 27-month operating lease for an additional 12,217 square feet of space in New York, NY, with aggregate payments of $1.6 million, with a lease commencement date of June 1, 2023.

The remaining lease terms as of December 31, 2023, for the facility in Waltham, MA and the two facilities in New York, NY, were 14 months and 20 months, respectively.

As of December 31, 2023, the consolidated balance sheet includes a $1.5 million operating lease ROU asset and a $1.6 million ROU liability. The Company used a weighted average discount rate of 14% to calculate its lease obligations, and an increase or decrease in the rate does not have a significant impact on the ROU asset or ROU liability. The ROU asset is amortized on a straight-line basis over the remainder of the lease term. For the year ended December 31, 2023, the Company recorded approximately $743,000 in operating lease expense and made approximately $924,000 in lease payments.

Future minimum lease payments under the Company’s operating leases, were as follows:

Maturity of lease liabilities As of

(in thousands) December 31, 2023

Thereafter —

Total lease payments $ 1,802

Less: imputed interest (189 )

Total operating lease liability $ 1,613

Future minimum lease payments under the Company’s capital leases as of December 31, 2023 and 2022, were $25,864 and $22,441, respectively.

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6. (Loss) Earnings per Share

Basic and diluted (loss) earnings per share are calculated as follows (in 000s):

Years Ended December 31,

Numerator:

Denominator:

Effective of Dilutive Securities

Options to purchase common stock — — 1,429

Non - vested restricted stock units (RSUs) — — 118

ESPP to purchase common stock — — 11

Dilutive potential common shares — - 1,558

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, in 000s):

December 31,

ESPP to purchase common stock 35 17 —

For additional information related to the Company's common stock see Note 12, Common Stock to these consolidated financial statements.

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7. Significant Agreements

Vitae Pharmaceuticals, Inc.

In October 2017, the Company entered into a license agreement (the “Allergan License Agreement”) with Vitae Pharmaceuticals, Inc., a subsidiary of Allergan (“Allergan”), under which Allergan granted the Company an exclusive, sublicensable, worldwide license to a portfolio of preclinical, orally available, small molecule inhibitors of the interaction of menin with Mixed Lineage Leukemia (“MLL”) protein (the “Menin Assets”). The Company made a nonrefundable upfront payment of $5.0 million to Allergan in the fourth quarter of 2017. Additionally, subject to the achievement of certain milestone events, the Company may be required to pay Allergan up to $99.0 million in one-time development and regulatory milestone payments over the term of the Allergan License Agreement. 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 Allergan low single to low double-digit 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. Under certain circumstances, the Company may be required to share a percentage of non-royalty income from sublicensees, subject to certain deductions, with Allergan. The Company is solely responsible for the development and commercialization of the Menin Assets. Each party may terminate the Allergan License Agreement for the other party’s uncured material breach or insolvency; and the Company may terminate the Allergan License Agreement at will at any time upon advance written notice to Allergan. Allergan may terminate the Allergan 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 Allergan 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 Allergan 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 agreement, the Company achieved certain development and regulatory milestones resulting in $8.0 million in expense, which included $2.0 million paid in the first quarter of 2023.

UCB Biopharma Sprl

In July 2016, the Company entered into a license agreement (the “UCB License Agreement”) with UCB Biopharma Sprl (“UCB”), under which UCB granted to the Company a worldwide, sublicensable, exclusive license to UCB6352, which the Company refers to as axatilimab, an Investigational New Drug Application-ready anti-CSF-1R monoclonal antibody. The Company made a nonrefundable upfront payment of $5.0 million to UCB in the third quarter of 2016. Additionally, subject to the achievement of certain milestone events, the Company may be required to pay UCB up to $119.5 million in one-time development and regulatory milestone payments over the term of the UCB License Agreement. 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 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 will be solely responsible for the development and commercialization of axatilimab, except that UCB is 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 will 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.

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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. Since the start of the license agreement, the Company achieved certain development and regulatory milestones and has recorded $6.0 million as research and development expense. Additionally, 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 is recognized as a milestone expense. In the fourth quarter of 2023, UCB achieved a development and regulatory milestone resulting in a $10.0 million expense, which has been recorded in accrued expenses as of December 31, 2023. The Company paid the amount to UCB in the first quarter of 2024.

Bayer Pharma AG (formerly known as Bayer Schering Pharma AG)

In March 2007, the Company entered into a license agreement (the “Bayer Agreement”) with Bayer Schering Pharma AG (“Bayer”) for a worldwide, exclusive license to develop and commercialize entinostat and any other products containing the same active ingredient. Under the terms of the Bayer Agreement, the Company paid a nonrefundable up-front license fee of $2.0 million and is responsible for the development and marketing of entinostat. The Company recorded the $2.0 million license fee as research and development expense during the year ended December 31, 2007, as it had no alternative future use. The Company will pay Bayer royalties on a sliding scale based on net sales, if any, and make future milestone payments to Bayer of up to $150.0 million in the event that certain specified development and regulatory goals and sales levels are achieved.

8. Property and Equipment, net

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

December 31,

Office and computer equipment 34 34

Total property and equipment 419 419

Accumulated depreciation (411 ) (399 )

Property and equipment, net $ 8 $ 20

Depreciation expense was $12,000 and $33,000 for the years ended December 31, 2023 and 2022, respectively.

9. 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.

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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.

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

Assets:

There have been no material impairments of our assets measured and carried at fair value during the years ended December 31, 2023, and 2022. In addition, there have been no changes in valuation techniques during the years ended December 31, 2023, and 2022. 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 cash equivalents and short and long-term investments was determined other than quoted prices in active markets, which are either directly or indirectly observable as of the reporting date and fair value is determined using models or other valuation methodologies.

The short-term and long-term investments are classified as available-for-sale securities. As of December 31, 2023, the remaining contractual maturities of the available-for-sale securities were 1 to 15 months, and the balance in the Company’s accumulated other comprehensive income 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 years ended December 31, 2023. As a result, the Company did not reclassify any amounts out of accumulated other comprehensive income for the same periods. The Company has a limited number of available-for-sale securities in insignificant loss positions as of December 31, 2023, which the Company does not intend to sell and has concluded will not be required to sell before recovery of the amortized cost for the investment at maturity.

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The following table summarizes the available-for-sale securities (in thousands):

AmortizedCost UnrealizedGains Unrealized(Losses) FairValue

10. Prepaid Expenses and Other Current Assets

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

December 31,

Interest receivable on investments 1,227 583

Prepaid state and local taxes 264 3

Total prepaid expenses and other current assets $ 3,293 $ 1,915

11. Accrued Expenses and Other Current Liabilities

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

December 31,

Accrued clinical study and trial costs $ 16,346 $ 14,375

Accrued compensation and related costs 11,172 5,945

Total accrued expense and other current liabilities $ 39,856 $ 24,276

12. Common Stock

The Company is authorized to issue 200,000,000 shares of common stock. The holders of each share of common stock are entitled to one vote per share held and are entitled to receive dividends, if and when declared by the Board, and to share ratably in the Company’s assets available for distribution to stockholders, in the event of liquidation.

In March 2021, the Company entered into a sales agreement with Cowen and Company, LLC, or TD Cowen, under which the Company could, from time to time, issue and sell shares of its common stock having aggregate sales proceeds of up to $75.0 million, in a series of one or more at-the-market, or ATM, equity offerings, or the 2021

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ATM Program. On May 26, 2023, the Company terminated the 2021 ATM Program. Prior to termination the Company sold shares under the 2021 ATM Program for net proceeds of approximately $25.0 million.

In May 2023, the Company entered into a new sales agreement with TD Cowen under which the Company could, from time to time, issue and sell shares of its common stock having aggregate sales proceeds of up to $200.0 million, in a series of one or more ATM equity offerings, or the 2023 ATM Program. TD Cowen is not required to sell any specific share amounts but acts as the Company’s sales agent, using commercially reasonable efforts consistent with its normal trading and sales practices. Pursuant to the new sales agreement, shares will be sold pursuant to the previous shelf registration statement on Form S-3ASR (Registration No. 333-254661), which became automatically effective upon filing on March 24, 2021. The Company’s common stock will be sold at prevailing market prices at the time of the sale, and as a result, prices may vary. In the year ended December 31, 2023, the Company sold 2,719,744 common shares of common stock under the 2023 ATM Program, with net proceeds of approximately $42.1 million.

In December 2021, the Company issued 3,802,144 shares of common stock and pre-funded warrants to purchase 1,142,856 shares of common stock. The offering price for the securities was $17.50 per share or $17.4999 for each Pre-Funded Warrant,with net proceeds of approximately $81.2 million. On January 24, 2023, 86,000 pre-funded warrants were exercised for 85,998 shares of common stock, under a cashless exercise. On April 12, 2023, 273,000 pre-funded warrants were exercised for 272,996 shares of common stock, under a cashless exercise. On May 9, 2023, 498,142 pre-funded warrants were exercised for 498,137 shares of common stock, under a cashless exercise. As of December 31, 2023, 285,714 pre-funded warrants were considered issued and outstanding.

In December 2021, in connection with the Incyte License and Collaboration Agreement and Share Purchase Agreement, the Company issued 1,421,523 shares of common stock, with net proceeds of approximately $35.0 million. The Company recorded the equity issuance at a fair value of $24.8 million based on the market price of the stock on the date of issuance.

In December 2022, the Company issued 7,840,909 shares of common stock. The offering price for the securities was $22.00 per share, with gross proceeds of approximately $172.5 million, offset by $10.5 million of issuance cost.

In December 2023, the Company issued 12,432,431 shares of common stock. The offering price for the securities was $18.50 per share, with gross proceeds of approximately $230.0 million, offset by $14.0 million of issuance cost.

The Company has reserved for future issuance the following shares of common stock pursuant to the following outstanding securities or equity plans:

SNDX US Equity

SNDX · 10-K · period ended 2023-12-31

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations

Item 7A. Quantitative and Qualitative Disclosures about Market Risk

Item 8. Financial Statements and Supplementary Data

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

Item 9A. Controls and Procedures

Item 9B. Other Information

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

Item 10. Directors, Executive Officers, and Corporate Governance

Item 11. Executive Compensation

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

Item 13. Certain Relationships and Related Transactions and Director Independence

Item 14. Principal Accountant Fees and Services

Item 15. Exhibits and Financial Statement Schedules

Item 16. Form 10-K Summary

SNDX US Equity☆

SNDX · 10-K · period ended 2023-12-31

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations

Item 7A. Quantitative and Qualitative Disclosures about Market Risk

Item 8. Financial Statements and Supplementary Data

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

Item 9A. Controls and Procedures

Item 9B. Other Information

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

Item 10. Directors, Executive Officers, and Corporate Governance

Item 11. Executive Compensation

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

Item 13. Certain Relationships and Related Transactions and Director Independence

Item 14. Principal Accountant Fees and Services

Item 15. Exhibits and Financial Statement Schedules

Item 16. Form 10-K Summary

SNDX US Equity