sndx-10k_20211231.htm

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the Fiscal Year Ended December 31, 2021

For the Transition Period from to

Commission File Number: 001-37708

Syndax Pharmaceuticals, Inc.

(Exact name of Registrant as specified in its charter)

35 Gatehouse Drive, Building D, Floor 3

Waltham, Massachusetts02451

(781) 419-1400

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol(s) Name of each exchange on which registered

Common Stock SNDX The Nasdaq Stock Market, LLC

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes☒ No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Securities Act. Yes ☐No☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to the filing requirements for the past 90 days. Yes☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large Accelerated Filer ☒ Accelerated Filer ☐

Non-accelerated Filer ☐ Smaller Reporting Company ☒

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act.) Yes ☐ No ☒

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☒

As of June 30, 2021, the last day of the registrant’s most recently completed second fiscal quarter, the aggregate market value of the Common Stock held by non-affiliates of the registrant was approximately $833.4 million, based on the closing price of the registrant’s common stock on June 30, 2021. Shares of the registrant’s common stock held by each officer and director and stockholders that the registrant has concluded are affiliates of the registrant. This determination of affiliate status is not a determination for other purposes.

As of February 25, 2022, there were 55,012,245 shares of common stock outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s definitive proxy statement for its 2022 Annual Meeting of Stockholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year ended December 31, 2021, are incorporated by reference into Part III of this Annual Report on Form 10-K.

TABLE OF CONTENTS

Page

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS ii

PART I

Item 1. Business 1

Item 1A. Risk Factors 23

Item 1B. Unresolved Staff Comments 55

Item 2. Properties 55

Item 3. Legal Proceedings 55

Item 4. Mine Safety Disclosures 55

PART II

Item 6. Selected Financial Data 57

Item 7A. Quantitative and Qualitative Disclosures about Market Risk 69

Item 8. Financial Statements and Supplementary Data 70

Item 9A. Controls and Procedures 70

Item 9B. Other Information 72

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 72

PART III

Item 10. Directors, Executive Officers and Corporate Governance 73

Item 11. Executive Compensation 73

Item 14. Principal Accountant Fees and Services 73

PART IV

Item 15. Exhibit and Financial Statement Schedules 74

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements other than statements of historical fact are “forward-looking statements” for purposes of this Annual Report on Form 10-K. In some cases, you can identify forward-looking statements by terminology such as “anticipate,” “believe,” “could,” “estimate,” “expects,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “will,” “would” or the negative or plural of those terms, and similar expressions.

Forward-looking statements include, but are not limited to, statements about:

• our ability to replicate results in future clinical trials;

• the market adoption of our product candidates by physicians and patients;

• developments relating to our competitors and our industry; and

Factors that may cause actual results to differ materially from current expectations include, among other things, those set forth in Part I, Item 1A, “Risk Factors,” below and for the reasons described elsewhere in this Annual Report on Form 10-K. Any forward-looking statement in this Annual Report on Form 10-K reflects our current view with respect to future events and is subject to these and other risks, uncertainties and assumptions. Given these uncertainties, you should not rely on these forward-looking statements as predictions of future events. Although we believe that the expectations reflected in the forward-looking statements are reasonable, our information may be incomplete or limited and we cannot guarantee future results. Except as required by law, we assume no obligation to update or revise these forward-looking statements for any reason, even if new information becomes available in the future.

This Annual Report on Form 10-K also contains estimates, projections and other information concerning our industry, our business and the markets for certain drugs and consumer products, including data regarding the estimated size of those markets, their projected growth rates and the incidence of certain medical conditions. Information that is based on estimates, forecasts, projections or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information. Unless otherwise expressly stated, we obtained these industry, business, market and other data from reports, research surveys, studies and similar data prepared by third parties, industry, medical and general publications, government data and similar sources and we have not independently verified the data from third party sources. In some cases, we do not expressly refer to the sources from which these data are derived.

In this Annual Report on Form 10-K, unless otherwise stated or as the context otherwise requires, references to “Syndax,” “the Company,” “we,” “us,” “our” and similar references refer to Syndax Pharmaceuticals, Inc. and its wholly owned subsidiaries. This Annual Report on Form 10-K also contains references to our trademarks and to trademarks belonging to other entities. Solely for convenience, trademarks and trade names referred to, including logos, artwork and other visual displays, may appear without the ® or TM symbols, but such references are not intended to indicate, in any way, that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto. We do not intend our use or display of other companies’ trade names or trademarks to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

iii

PART I

Item 1. BUSINESS

Our Company

We are a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies. Our two lead product candidates are SNDX-5613 and SNDX-6352, or axatilimab. We are developing SNDX-5613, targeting the binding interaction of menin with the mixed lineage leukemia 1, or MLL1, protein for the treatment of MLL-rearranged, or MLLr, acute leukemias and nucleophosmin 1, or NPM1, mutant acute myeloid leukemia, or AML, as well as axatilimab, a monoclonal antibody that blocks the colony stimulating factor 1, or CSF-1 receptor. We have deprioritized the development of entinostat, our once-weekly, oral, small molecule, Class I HDAC inhibitor, to focus resources on advancing our existing pipeline and expanding it with new assets. 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.

Our Strategy

Our clinical-stage pipeline includes SNDX-5613, a highly selective inhibitor of the menin–MLL binding interaction, axatilimab, a monoclonal antibody that blocks the CSF-1 receptor, and entinostat, a Class I HDAC inhibitor.

We are developing SNDX-5613 in acute leukemias and axatilimab for use in cGVHD and potentially other fibrotic-macrophage driven diseases as single agents and in combination with approved drugs. We have deprioritized the development of entinostat but may opportunistically explore potential disease areas where entinostat could play an important therapeutic role. Key elements of our strategy include:

Our Pipeline

SNDX-5613

Our first clinical-stage product candidate, SNDX-5613, is a potent, orally active inhibitor of the high affinity interaction site on menin with the protein MLL1. This specific interaction is a key driver for two genetically defined acute leukemias: (i) MLLr and (ii) NPM1c AML. Both diseases have a poor prognosis. In preclinical testing, SNDX-5613 has demonstrated benefit in leukemic models of disease. Initial clinical evidence with SNDX-5613 also supports the hypothesis that disruption of the menin-MLL interaction can lead to responses in acute leukemias.

We are developing SNDX-5613 as a targeted therapy to potentially treat two genetically defined acute leukemias: (i) a genetically defined subset of acute leukemias with chromosomal rearrangements in the mixed lineage leukemia gene, known as MLLr; and (ii) AML, with a somatic mutation in the nucleophosmin 1, or NPM1, gene, also known as NPM1c. Our near-term focus is to rapidly establish proof-of-concept that SNDX-5613 is a targeted therapy that can potentially provide meaningful clinical benefit to adult and pediatric leukemia patients having relapsed or refractory MLLr or NPM1c acute leukemias. Our investigational new drug, or IND, application for SNDX-5613 took effect with the U.S. Food and Drug Administration, or FDA, in the second quarter of 2019 and we commenced AUGMENT-101, a clinical trial consisting initially of a Phase 1 dose escalation portion to determine the maximum tolerated dose, or MTD, and recommended Phase 2 dose of SNDX-5613 in patients with acute leukemia. We are conducting the trial at multiple centers in the United States. We are completing the Phase 1 portion of the trial and have initiated the pivotal Phase 2 portion of the trial with patients to be enrolled in three

indication-specific expansion cohorts to determine the efficacy, short- and long-term safety, and tolerability of SNDX-5613 in MLLr ALL, MLLr AML and NPM1c AML.

In September 2021, we participated in a meeting with the FDA to discuss the results of the Phase 1 portion of our AUGMENT-101 trial. At the meeting, the FDA agreed with our recommended Phase 2 dose and confirmed that we may initiate the Phase 2 registration-directed cohorts of AUGMENT-101. Additionally, the FDA agreed with our proposed statistical design and endpoints for each of the three Phase 2 expansion cohorts.

Additionally, we announced that we will initiate a frontline trial of SNDX-5613 in combination with venetoclax and azacytidine in newly diagnosed AML patients unable to tolerate induction chemotherapy. The trial will be conducted as part of the Leukemia & Lymphoma Society’s Beat AML Master Clinical Trial, and SNDX-5613 is the first menin inhibitor to be included in the Beat AML Master Clinical Trial. We also announced that we will initiate a trial to assess the anti-leukemic efficacy of SNDX-5613 in MLLr or NPM1 patients with measurable residual disease progression following anti-leukemic treatment. This trial will be conducted as part of the Australian Leukemia and Lymphoma Group INTERCEPT Master Clinical Trial, a collaborative clinical trial investigating novel therapies to target early relapse and clonal evolution as pre-emptive therapy in AML. SNDX-5613 is the first menin inhibitor to be included in the INTERCEPT AML Master Clinical Trial. Lastly, we announced that we will initiate a new trial to assess the safety, tolerability, and preliminary anti-leukemic efficacy of SNDX-5613 in combination with chemotherapy in patients with relapsed or refractory MLLr or mNPM1 acute leukemias. We expect that the Phase 1b trial, which we refer to as AUGMENT-102, will enroll up to 27 patients.

In December 2021, we presented positive date from the Phase 1 portion of our AUGMENT-101 trial in heavily pretreated patients with MLLr or NPM1c mutations in an oral presentation during the American Society of Hematology (ASH) Virtual Annual Meeting. The following table summarizes select efficacy and safety data that has been presented by us throughout 2021.

* Overall Response Rate = CR + CRh + CRp + CRi + MLFS

In the data that we presented at ASH, SNDX-5613 was well tolerated, with no discontinuations due to treatment-related adverse events observed. The only dose limiting toxicity observed was Grade 3 QT prolongation, which occurred in 7% (n=3/43) of patients treated at the four doses that met the study’s pre-defined recommended Phase 2 dose criteria.

In January 2020, the FDA granted SNDX-5613 Orphan Drug Designation, or ODD, for the treatment of adult and pediatric AML and in June 2021, the FDA granted Fast Track Designation to SNDX-5613 for the treatment of adult and pediatric patients with relapsed or refractory acute leukemias harboring a MLLr or NPM1 mutation. In December 2021, we announced that the European Commission granted ODD to SNDX-5613 for the treatment of AML.

SNDX-5613

Rationale for Targeting MLLr

MLLr leukemias arise by rare, spontaneous translocations at the MLL1 locus (11q23). It is estimated that approximately 10% of AML and ALL harbor this MLL-re-arrangement with a worldwide incidence of approximately 5,000 to 7,000 cases per year. These translocations generate oncogenic fusion proteins with more than 90 different MLL fusions currently known. All MLL fusion proteins bind with high affinity to the chromatin associated protein menin through a conserved N-terminal sequence. This specific interaction with menin enables an aberrant transcription program that drives leukemic transformation. In pre-clinical animal models, small molecule inhibitors of the menin-MLL interaction have demonstrated deep and durable single agent treatment effects in multiple leukemic xenografts harboring MLL fusions. Inhibiting the menin-MLL1 interaction represents a novel targeted strategy for the treatment of MLLr leukemias.Today, the first choice therapy for both MLLr AML and MLLr ALL still relies heavily on intensive chemotherapy, if a patient can tolerate such treatment. Despite these patients being routinely diagnosed, there are currently no targeted therapies approved to treat patients with MLLr acute leukemias. Currently there are several other clinical-stage menin-inhibitors in development for the treatment of MLLr AML and MLLr ALL.

Rationale for Targeting Nucleophosmin 1 Mutant AML

NPM1 is among the most frequently mutated genes in AML, found in approximately 30% of AML cases for an incidence of approximately 20,000 cases per year. Mutations in NPM1 lead to the aberrant cytoplasmic localization of the mutants, termed NPM1c. Loss of NPM1c from the nucleus leads to suppression of differentiation and enables a leukemic transcription program that relies critically on the menin-MLL1 complex to drive and maintain the program. As a result, NPM1c harboring cells are sensitive to menin-MLL interaction inhibitors. In NPM1c cells, inhibition of the menin-MLL interaction suppresses the leukemic transcription program, causing growth arrest, terminal differentiation and cell death. In animal models, small molecule inhibitors of the menin-MLL interaction have demonstrated deep and durable single agent treatment effects in multiple NPM1c xenografts. Based on these findings, blocking the menin-MLL1 interaction represents a novel targeted strategy for the treatment of NPM1c AML.

Like MLLr, NPM1 is readily diagnosed as part of the standard AML patient work-up today, and yet there are no approved targeted therapies approved to treat patients with a NPM1 mutant AML. There are several additional clinical stage agents currently advancing as potential treatments for NPM1 mutant AML.

Axatilimab

We are also developing axatilimab a monoclonal antibody targeting the colony stimulating factor-1 receptor, or CSF-1R, a cell surface protein thought to control the survival and function of monocytes and macrophages. Axatilimab binds with high affinity to CSF-1R and blocks the binding of the two known CSF-1R ligands CSF-1 and IL-34. CSF-1R is expressed on the surface of specific immune cells known as macrophages and their precursor cells known as monocytes. CSF-1R signaling on these cells has been demonstrated in preclinical studies conducted in animal models of skin and lung chronic graft versus host disease, or cGVHD, to be the key regulatory pathway involved in the expansion and infiltration of the macrophages that mediate fibrosis and the cGVHD disease process. Blocking CSF-1R activity with an experimental CSF-1R antibody in these studies was shown to prevent and treat the symptoms of cGVHD. We believe that by inhibiting CSF-1R activation on monocytes and macrophages, axatilimab has the potential to be used to treat cGVHD as well as other fibrotic diseases where monocyte-derived macrophages have been shown to play a significant role.

Our near-term focus is to rapidly establish that axatilimab can provide meaningful clinical benefit in patients with advanced cGVHD where prior therapies are no longer effective and to establish proof-of-concept of using axatilimab to treat other fibrotic diseases where monocyte-derived macrophages have been shown to play a role.

We announced that following our end of Phase 1 meeting with the FDA, we have aligned on a regulatory path for axatilimab for the treatment of cGVHD. We commenced a pivotal Phase 2 trial, AGAVE-201, to assess the safety and efficacy of different doses and schedules of axatilimab for the treatment of patients with cGVHD. The primary endpoint is the objective response rate based on the 2014 NIH consensus criteria for GVHD with key secondary endpoints including duration of response and improvement in modified Lee Symptom Scale score. We anticipate releasing topline data in 2023. We completed enrollment of the Phase 1/2 trial evaluating axatilimab for the treatment of patients with cGVHD in the second quarter of 2021.

In December 2021, we presented positive data from the Phase 1/2 trial of axatilimab in patients with recurrent or refractory chronic cGVHD despite two or more prior lines of therapy in an oral presentation during the American Society of Hematology at ASH. During the presentation, and in a press release that we issued on the presentation date, we shared that as of October 22, 2021 (data cutoff) a total of 40 patients were treated in the SNDX-6352-503 trial, who received a median of four prior systemic therapies. There were 31 evaluable patients treated at 1mg/kg every 2 weeks or 3mg/kg every 4 weeks, the doses that we are testing in the ongoing AGAVE-201 global pivotal study. Of the evaluable patients, responses were observed in 68% (n=21/31) of patients, with a best ORR (complete response (CR) plus partial response) of 72% (n=18/25) at 1mg/kg every two weeks and 50% (n=3/6) at 3mg/kg every four weeks. Responses observed across a range of organ systems with difficult to treat manifestations such as lung (n=5/15), skin (n=3/28), and joints and fascia (n=16/24). Fifty-three percent of patients (n=16/30) reported clinically meaningful improvement as measured by at least a 7-point decrease in Lee Symptom Scale score. As of data cutoff 43% (n=17/40) of patients remained on treatment.

In the data that we presented at ASH, axatilimab was well-tolerated with a favorable safety profile. The most common observed adverse events were consistent with on-target effects on liver enzyme pharmacology. There was no incidence of cytomegalovirus or other viral reactivation and no apparent increases in risk for infection. Enrollment remains ongoing in the global pivotal Phase 2 AGAVE-201 trial of axatilimab in patients with cGVHD, with topline data expected in 2023.

In March and April of 2021, we announced that the FDA granted Orphan Drug Designation to axatilimab for the treatment of patients with cGVHD and idiopathic pulmonary fibrosis, or IPF. In addition to the ongoing AGAVE-201 trial, we and Incyte expect to initiate additional trials of axatilimab in patients with cGVHD in 2022, including a Phase 2 trial in combination with a JAK inhibitor in patients with steroid-refractory cGVHD. Beyond cGVHD, we plan to commence a Phase 2 proof-of-concept trial of axatilimab in the first half of 2022 in patients with IPF.

Axatilimab in GVHD

cGVHD, an immune response of the donor-derived hematopoietic cells against recipient tissues, is a serious, potentially life-threatening complication of allogeneic hematopoietic stem cell transplantation, or HSCT, that can last for years. cGVHD is estimated to develop in approximately 40% of transplant recipients and affects approximately 14,000 patients in the United States. cGVHD typically manifests across multiple organ systems, with the skin and mucosa being commonly involved, and is characterized by the development of fibrotic tissue

The first line of therapy for cGVHD is typically corticosteroids, though approximately 50% of patients may require treatment with additional systemic therapies, such as extracorporeal photopheresis, cytostatic agents such as mycophenolate moftetil, methotrexate, and immunmodulators such as rituximab, IL-2. Imbruvica® (ibrutinib), a BTK inhibitor, was the first FDA-approved therapy for cGVHD and is indicated for use after one or more lines of therapy. Imbruvica received approval based on Phase 1/2 clinical trial data that showed a 68% overall response rate, with 48% of responses lasting 20 weeks or longer and reduced dependence on steroids for most patients. While approved agents have shown a benefit in improving symptoms of this disease, none have demonstrated an improvement in long-term outcomes and a significant unmet medical need still remains for this patient population. Additionally, all currently approved agents are believed to exert their effect through T- and B-cells, with minimal impact on macrophages. By inhibiting the work of monocyte-derived macrophages, Axatilimab, provides a differentiated way to treat cGVHD, which we expect is ultimately expected to have a more pronounced impact on the fibrotic process. We also believe that shifting CSF-1R inhibition earlier in the treatment phase of cGVHD, to minimize formation of fibrotic tissue, could have a meaningful long-term impact on the disease process itself.

Entinostat

Entinostat is our oral, small molecule product candidate that has direct effects on both cancer cells and immune regulatory cells, potentially enhancing the body’s immune response to tumors. In May 2020, we reported final results of E2112, the Phase 3 clinical trial conducted by ECOG-ACRIN Cancer Research Group and sponsored by the National Cancer Institute, that evaluated the investigational compound entinostat plus exemestane in patients with advanced hormone receptor positive, human epidermal growth factor receptor 2 negative (HR+, HER2-) breast cancer. The trial did not achieve the primary endpoint of demonstrating a statistically significant overall survival benefit over hormone therapy alone.

We have deprioritized the development of entinostat, but may opportunistically explore potential disease areas where entinostat could play an important therapeutic role.

Collaborations

Incyte Collaboration and License Agreement

In September 2021, we entered into a collaboration and license agreement, or the Incyte Agreement, with Incyte for the development and commercialization of axatilimab. Additionally, in September 2021 the Company entered into a share purchase agreement with Incyte, or Incyte Share Purchase Agreement. Collectively referred to as the Incyte Agreements. Under the terms of the Incyte 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.

In addition, we and Incyte entered into a Letter Agreement memorializing how the parties would work together in the event that the government intervened in the proposed collaboration and the parties are forced to terminate and unwind the collaboration. Pursuant to the Letter Agreement, the parties agreed, in part, (i) to permit Incyte to terminate the Incyte Agreement through September 2022 if, prior to March 23, 2022, either party for the

first time receives a formal request from either the Federal Trade Commission or the Department of Justice, Antitrust Division, regarding the Incyte Agreement, which we refer to as the Termination Right, and (ii) to provide the parties with a mechanism to settle any gain or loss related to Incyte’s equity investment in the Company solely in the event that Incyte exercises its Termination Right. If Incyte exercises its Termination Right, (x) we will refund to Incyte the $117 million upfront license fee and any payments made by Incyte for royalties, milestones and development costs and any other amounts paid by Incyte to us under the Incyte Agreement, and (y) we will waive any remaining lock-up restrictions and Incyte may sellmaythe shares of our common stock that it purchased in connection with its equity investment pursuant to the Incyte Agreement. Following a sale of its shares, Incyte will remit to us any gain that it received, or, alternatively, we will repay Incyte for any loss that it incurred in each case in connection with the sale of the shares. The Termination Right expires if the parties do not receive a formal request before March 23, 2022. To date, the parties have not received any formal request from either the Federal Trade Commission or the Department of Justice, Antitrust Division.

Upon signing the Letter Agreement in December 2021 both the Incyte Agreement and Incyte Share Purchase Agreement became effective. As a result, we received an upfront fee of $117 million and we issued 1,421,523 shares of common stock for an aggregate purchase price of $35 million, or $24.62 per share. We are eligible to receive up to $230 million in commercialization milestones as well as tiered royalties ranging in the mid-teens on sales outside of the United States.

NCI and Investigator Collaborations

Collaborative Research and Development Agreement with the NCI related to Entinostat

Our collaboration with the NCI is governed by a CRADA between us and the NCI. The CRADA was originally signed by Mitsui Pharmaceuticals, Inc., or Mitsui, and was then assigned to Schering AG following Schering AG’s acquisition of Mitsui. In 2007, Schering AG, then known as Bayer Schering Pharma AG, agreed to assign the CRADA to us in connection with the execution of a license, development and commercialization agreement, or the Bayer license agreement, with Bayer.

Under the CRADA, as amended, the NCI sponsors clinical studies on entinostat using researchers at the NCI as well as NCI-funded researchers at other institutions, including ECOG-ACRIN and JHU. In return, we receive access to the data generated in these clinical studies, and we are obligated to supply the clinical trial sites with sufficient quantities of entinostat. Additionally, we are required to make an annual payment to a particular NCI laboratory to help support certain research studies related to this and other clinical trial. We have no other payment obligations under the CRADA.

We own any intellectual property generated in the course of the collaboration with the NCI, or Collaboration IP, to the extent that Collaboration IP is generated by our employees. We also have an exclusive option to obtain an exclusive or non-exclusive commercialization license under Collaboration IP generated by the NCI. With respect to any Collaboration IP that is owned by or licensed to us, we have agreed to grant the United States government a non-exclusive license to practice or have practiced this Collaboration IP throughout the world by or on behalf of the government for research or other government purposes.

Either party may terminate the CRADA either by mutual consent or unilaterally upon advance written notice to the other party. Absent such early termination, the CRADA will expire on May 21, 2023. As we have in the past, we expect to renew the CRADA at that time.

Collaborative Research and Development Agreement with the NCI related to Axatilimab and Entinostat

In September 2016, we entered into an additional collaboration with the NCI related to both entinostat and axatilimab. Under the CRADA, the NCI sponsors preclinical and clinical studies on entinostat and axatilimab using researchers at the NCI as well as NCI-funded researchers at other institutions. In return, we receive access to the data generated in these preclinical and clinical studies and we are obligated to supply the laboratories and clinical trial sites with sufficient quantities of entinostat and axatilimab. Additionally, we are required to make an annual payment to a particular NCI laboratory to help support certain research studies related to this and other preclinical and clinical trials. We have no other payment obligations under the CRADA.

We own all intellectual property generated during the collaboration with the NCI, or Axatilimab Collaboration IP, to the extent that Axatilimab Collaboration IP is generated by our employees. We also have an exclusive option to obtain an exclusive or non-exclusive commercialization license under Axatilimab Collaboration IP generated by the NCI. With respect to any Axatilimab Collaboration IP that is owned by or licensed to us, we have agreed to grant the U.S. government a non-exclusive license to practice or have practiced this Axatilimab Collaboration IP throughout the world by or on behalf of the government for research or other government purposes.

License Agreements

Vitae Pharmaceuticals, Inc.

We have a license agreement with Vitae Pharmaceuticals, Inc., a subsidiary of AbbVie plc, or the AbbVie License Agreement, under which Vitae granted us an exclusive, sublicenseable, worldwide license to, preclinical, orally-available, small molecule inhibitors of the interaction of menin with the MLL protein, or the Menin Assets. We are solely responsible for the development and commercialization of the Menin Assets.

Subject to the achievement of certain milestone events, we may be required to pay Vitae up to an aggregate of $99 million in one-time development and regulatory milestone payments over the term of the AbbVie License Agreement. In the event that we or any of its affiliates or sublicensees commercializes the Menin Assets, we will also be obligated to pay Vitae 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, we may be required to share a percentage of non-royalty income from sublicensees, subject to certain deductions, with Vitae. In June 2019, we achieved certain development and regulatory milestones resulting in a $4.0 million payment, which was paid with interest in May 2020. In January 2022, we dosed the first patient in our pivotal phase 2 study, consequently completing our phase 1 study. Completion of the phase 1 study requires us to pay AbbVie a $2.0 million development milestone. We anticipate paying this milestone in the first quarter of 2022.

Each party may terminate the AbbVie License Agreement for the other party’s uncured material breach or insolvency; and we may terminate the AbbVie License Agreement at will at any time upon advance written notice to Vitae. Vitae may terminate the AbbVie License Agreement if we 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 AbbVie 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.

UCB

We have a license agreement with UCB, or the UCB license agreement, under which UCB granted us a worldwide, sublicenseable, exclusive license to UCB6352, which the Company refers to as axatilimab. The UCB license agreement permits us to use axatilimab or other licensed products for all human uses, including treatment, prevention and diagnostic uses, in all indications, diseases, conditions or disorders, and we are obligated to use commercially reasonable efforts to develop, obtain regulatory approval and commercialize a certain licensed product. We are solely responsible for the development and commercialization of axatilimab.

Subject to the achievement of certain milestone events, we 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 we or any of our affiliates or sublicensees commercializes axatilimab, we 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, we may be required to share a percentage of non-royalty income from sublicensees, subject to certain deductions, with UCB. During the year ended December 31, 2020 and 2021, we were required to pay $2.0 million and $4.0 million, respectively, due to the achievement of certain development and regulatory milestones. As of December 31, 2021, $2.0 million is recorded as an accrued expense.

Each party may terminate the UCB license agreement for the other party’s uncured material breach or insolvency; and we 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 we or any of our 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.

Bayer Pharma AG

We have a license agreement with Bayer Pharma AG, or Bayer, pursuant to which we obtained a worldwide, exclusive license to develop and commercialize entinostat and any other products containing the same active ingredient. The Bayer license agreement, as amended, permits us to use entinostat or other licensed products for the treatment of any human disease, and we are obligated to use commercially reasonable efforts to develop, manufacture and commercialize licensed products for all commercially reasonable indications. Initially, Bayer manufactured and supplied our requirements of entinostat, but effective May 2012, manufacturing rights and responsibility for entinostat was transferred to us, by mutual agreement of the parties.

We are obligated to pay up to approximately $50.0 million in the aggregate upon obtaining certain milestones in the development and marketing approval of entinostat, assuming that we pursue at least two different indications for entinostat or any other licensed product. We are also obligated to pay Bayer up to $100.0 million in aggregate sales milestones, and a tiered single-digit royalty on net sales by us, our affiliates and sublicensees of entinostat and any other licensed products under the Bayer license agreement. We are obligated to pay Bayer these royalties on a country-by-country basis for the life of the relevant licensed patents covering such product or 15 years after the first commercial sale of such product in such country, whichever is longer. We cannot determine the date on which our royalty payment obligations to Bayer would expire because no commercial sales of entinostat have occurred and the last-to-expire relevant patent covering entinostat in a given country may change in the future.

The Bayer license agreement will remain in effect until the expiration of our royalty obligations under the agreement in all countries. Upon expiration of the agreement our licenses become fully paid-up and irrevocable. Either party may terminate the Bayer license agreement in its entirety or with respect to certain countries in the event of an uncured material breach by the other party. Either party may terminate the Bayer license agreement if voluntary or involuntary bankruptcy proceedings are instituted against the other party, if the other party makes an assignment for the benefit of creditors, or upon the occurrence of other specific events relating to the insolvency or dissolution of the other party. Bayer may terminate the Bayer license agreement if we seek to revoke or challenge the validity of any patent licensed to us by Bayer under the Bayer license agreement or if we procure or assist a third party to take any such action.

Eddingpharm International Company Limited

We have a license, development and commercialization agreement with Eddingpharm International Company Limited, or Eddingpharm, under which we granted Eddingpharm an exclusive license under our intellectual property rights to develop and commercialize entinostat in China and certain other Asian countries. This license includes a sublicense under the rights we received under the Bayer license agreement. If we acquire or develop any other anti-cancer drug that, like entinostat, is a selective inhibitor of Class I HDAC, such drug will be included in this license as well. Eddingpharm is manufacturing entinostat during the term of the agreement or through termination of the agreement for our breach. During the term of the agreement, subject to certain exceptions, each party is prohibited from commercializing in China and certain other Asian countries any other selective inhibitor of Class I HDACs for the same indication as entinostat, with all forms of cancer being treated as the same indication.

We are eligible to receive up to $10.0 million in development and regulatory milestone payments as well as royalty payments based on revenue targets. Royalty payment obligations will be payable in each country in the Eddingpharm territory until the later to occur of (i) the date that all valid claims of the last effective license patent in such country expires or is abandoned, withheld or otherwise invalidated and (ii) 15 years from the date of first commercial sale of entinostat in such country. Any payments owed to Bayer as a result of Eddingpharm’s

development of entinostat in the Eddingpharm territory will be made by us out of the payments we receive from Eddingpharm.

The agreement with Eddingpharm will expire with respect to each country in the Eddingpharm territory upon the expiration of all royalty payment obligations in such country. In addition, we may terminate the agreement in its entirety upon written notice to Eddingpharm if Eddingpharm or any affiliate commences any action or proceeding that challenges the validity, enforceability or scope of any licensed patent in the Eddingpharm territory. Eddingpharm may terminate the agreement in its entirety for convenience at any time upon advance notice to us. Either party may terminate the agreement for the other party’s uncured material breach, or bankruptcy or related actions or proceedings. If we commit an uncured material breach of certain provisions of the agreement, Eddingpharm may, instead of terminating the agreement, elect to continue the agreement in full force and effect except certain payments to us will be reduced.

Sales and Marketing

Given our stage of development, we have not yet established a commercial organization or distribution capabilities. We intend to build a commercial infrastructure to support sales of our product candidates in the United States. Our targeted sales force will focus on a well-defined group of medical oncologists, primarily in the non-hospital and academic settings, who are responsible for the care and treatment of cancer patients. We expect to manage sales, marketing and distribution through internal resources and third-party relationships. While we may commit significant financial and management resources to commercial activities, we would also consider collaborating with one or more pharmaceutical companies to enhance our commercial capabilities. Outside the United States, we plan to rely on our current partners and may seek additional pharmaceutical partners for sales and marketing activities.

Manufacturing

We do not own or operate manufacturing facilities for the production of axatilimab, SNDX-5613 or entinostat, and we do not have plans to develop our own manufacturing operations in the foreseeable future. We currently rely on third-party contract manufacturers for all of our required raw materials, active pharmaceutical ingredients and finished product for our preclinical research and clinical trials. We do not have any current contractual relationship for the manufacture of commercial supplies. If axatilimab, SNDX-5613 or entinostat is approved by any regulatory agency, we intend to enter into agreements with a third-party contract manufacturer and one or more backup manufacturers for the commercial production of such product. Development and commercial quantities of any products that we develop will need to be manufactured in facilities, and by processes, that comply with the requirements of the FDA and the regulatory agencies of other jurisdictions in which we are seeking approval.

Intellectual Property

Patents and Property Rights

Through licensed intellectual property and our owned intellectual property, we seek patent protection in the United States and internationally for our product candidates, their methods of use and processes for their manufacture, as well as for other technologies, where appropriate. Our policy is to actively seek to protect our proprietary position by, among other things, filing patent applications in the United States and abroad claiming our proprietary technologies that are important to the development of our business. We also rely on trade secrets, know-how, continuing technological innovation and in-licensing opportunities to develop and maintain our proprietary position.

We cannot be sure that patents will be granted with respect to any of our owned or licensed pending patent applications or with respect to any patent applications filed by us or our licensors in the future, nor can we be sure that any of our existing owned or licensed patents or any patents that may be granted to us or to our licensors in the future will protect our technology. Our success will depend significantly on our ability to obtain and maintain patent and other proprietary protection for the technologies that we consider important to our business, defend our patents, preserve the confidentiality of our trade secrets, operate our business without infringing the patents and proprietary rights of third parties, and prevent third parties from infringing our proprietary rights.

Axatilimab Patent Portfolio

We in-licensed from UCB a patent portfolio directed to axatilimab. As of December 31, 2021, the axatilimab composition-of-matter patent portfolio included two granted U.S. patents, seven allowed non-U.S. applications, fourteen granted non-U.S. patents, including a granted EP patent which has been validated in 37 countries, and 19 non-U.S. pending patent applications. The in-licensed granted patents covering axatilimab, and any non-U.S. pending applications should they issue, will expire in August 2034 or later should patent term extension be granted.

Our in-licensed patent portfolio also includes pending U.S. and non-U.S. patent applications directed to methods for the treatment and/or prophylaxis of fibrotic disease by administration of an inhibitor of CSF-1R activity, methods for the treatment and/or prophylaxis of inflammatory bowel disease, or IBD, by administration of an inhibitor of CSF-1R activity, and liquid pharmaceutical compositions of anti-CSF-1R antibodies. If these pending applications were to issue as one or more patents, these patents would expire between November 2024 and February 2036 or later should patent term extension be granted. Further, the in-licensed portfolio includes three non-U.S. patents directed to methods of treating solid tumors by administration of an inhibitor of CSF-1R activity. The three patents expired in October 2020.

Our owned axatilimab patent portfolio includes one pending U.S. patent application and six non-U.S. patent application directed to combinations of entinostat and axatilimab. If any one of these applications were to issue as one or more patents, these patents would expire in May 2038 or later should patent term extension be granted. Our owned axatilimab patent portfolio also consists of one pending international patent application under the Patent Cooperation Treaty, or PCT, directed to the treatment regimens and methods of using axatilimab. If this PCT application were to issue as one or more patents, these patents would expire in December 2040 or later should patent term extension be granted.

Menin Asset Patent Portfolio

We in-licensed from Vitae Pharmaceuticals, Inc., a subsidiary of AbbVie plc, a patent portfolio directed to a series of selective preclinical inhibitors targeting the binding interaction of menin with MLL-r. As of December 31, 2021, the in-licensed portfolio includes two granted U.S. patents, U.S. Patent Nos. 10,683,302 and 10,899,758, six granted non-U.S patents, including a granted European patent, which was validated in 30 member states, two pending U.S. applications and 28 non-U.S. pending patent applications covering composition of matter and methods of treating, e.g., MLL. The granted patents based on the in-licensed applications is expected to expire June 2037 or later should patent term extension be granted. If the in-licensed application were to issue as one or more patents, these patents would expire between June 2037 and September 2037.

Our owned menin patent portfolio consists of one pending international patent application under the Patent Cooperation Treaty, or PCT, directed to combinations of a menin inhibitor and a CYP3A inhibitor for the treatment of various cancers. Our owned menin patent portfolio also consists of two U.S. provisional applications directed to menin inhibitors and combinations with various other compounds. If any applications arising from the PCT or provisional applications were to issue as one or more patents, these patents would expire between April 2041 and May 2042 or later should patent term extension be granted.

Entinostat Patent Portfolio

We strive to protect entinostat with multiple layers of patents. As of December 31, 2021, our portfolio included four owned pending U.S. non-provisional patent applications, one owned granted U.S. patent, U.S. Patent No. 10,226,472, which expires in August 2032 or later should patent term extension be granted, one allowed U.S. non-provisional patent application directed to methods of treating a patient with combinations of entinostat and

pembrolizumab, eight granted non-U.S. patents (including one Canadian patent jointly owned with The Regents of the University of Colorado, which will expire in April 2029), and 49 owned non-U.S. pending patent applications. Also, we have filed national phase applications in the Eurasia Regional Patent Office, Ukraine and Georgia based on our owned PCT application directed to treatment of selected breast cancer patients with a combination of entinostat and exemestane. We have assigned our rights to the application we filed in the Eurasia Regional Patent Office to Domain Russia Investments Limited, or DRI. We have also assigned our rights to the applications we filed in Ukraine and Georgia to NovaMedica LLC, or NovaMedica. Our owned entinostat patent portfolio includes pending U.S. and ex-U.S. patent applications directed to methods of treating cancer patients by administration of entinostat and exemestane, methods of treating cancer patients by administration of entinostat in combination with an HER2 inhibitor, treatments with entinostat combined with anti PD-1 or anti PD-L1 antibodies, entinostat and CSF-1 or CSF-1R combination therapies (also discussed above in the Axatilimab Patent Portfolio) and patient selection for combination therapy comprising entinostat and a second therapeutic agent. If our owned pending U.S. applications and non-U.S. filings were to issue as one or more patents, these patents would expire between August 2032 and May 2039.

The patent portfolio we licensed from Bayer contains a number of issued U.S. and foreign patents as well as patent applications pending outside the United States. A number of the patents and patent applications we licensed from Bayer are directed to entinostat while other patents and patent applications are directed to compounds other than entinostat. As of December 31, 2019, the portfolio we licensed from Bayer included seven issued U.S. patents, 62 granted non-U.S. patents and 17 patent applications pending in non-U.S. patent offices. For example, the portfolio we licensed from Bayer includes reissue U.S. Patent RE39,754, which covers a genus of benzamide compounds including entinostat or SNDX-275. RE39,754 is a composition of matter patent having an initial term which expired in September 2017.

The portfolio we licensed from Bayer also includes U.S. Patent 7,973,166, or the ’166 patent, which covers a crystalline polymorph of entinostat which is referred to as crystalline polymorph B, the crystalline polymorph used in the clinical development of entinostat. Many compounds can exist in different crystalline forms. A compound which in the solid state may exhibit multiple different crystalline forms is called polymorphic, and each crystalline form of the same chemical compound is termed a polymorph. A new crystalline form of a compound may arise, for example, due to a change in the chemical process or the introduction of an impurity. Such new crystalline forms may be patented. By comparison, the U.S. Patent RE39,754, which expired in September 2017, covers the chemical entity of entinostat and any crystalline or non-crystalline form of entinostat. On March 7, 2014, our licensor Bayer applied for reissue of the ‘166 patent. The reissue application sought to add three additional inventors to the ‘166 patent. The reissue was granted as RE45,499 on April 28, 2015, at which time the original ‘166 patent was surrendered. The reissue patent has the same force and effect as the original ‘166 patent and the same August 2029 expiration date.

Of the unexpired foreign-granted patents we licensed from Bayer, there are 33 granted foreign counterparts of the ‘166 patent (now RE45,499) that cover crystalline polymorph B, including the European patent and Eurasian patent. The granted European patent comprises 37 national countries that have all been validated, and the granted Eurasian patent comprises nine countries that have all been validated. Likewise, there are 3 pending foreign counterparts of the ‘166 crystalline polymorph B patent. Other patents and patent applications in the licensed Bayer portfolio are expired and cover methods of treatment by administration of entinostat. For example, U.S. Patent 7,317,028, which expired in October 2017, covers methods of treating selected cancers by administration of entinostat; U.S. Patent 7,687,525, which also expired in September 2017, covers methods of treating autoimmune disease by administration of entinostat; U.S. Patent 6,320,078, which expired in July 2019, covers methods of manufacturing entinostat; U.S. Patent No. 8,026,239, which expired in September 2017, covers methods of treating certain malignant tumors by administration of a compound within a subgenus of benzamide compounds including entinostat; U.S. Patent RE40,703, which expired in September 2017, covers a subgenus of benzamide compounds that does not include entinostat; and U.S. Patent 6,794,392, which expired in September 2017, covers a subgenus of benzamide compounds that does not include entinostat.

Patent Term

The term of individual patents depends upon the legal term of the patents in the countries in which they are obtained. In most countries in which we file, the patent term is 20 years from the date of filing the earliest non-provisional application or PCT application.

In the United States, a patent’s term may be lengthened by patent term adjustment, which compensates a patentee for administrative delays by the USPTO in granting a patent, or may be shortened if a patent is terminally disclaimed over an earlier-filed patent. The term of a patent that covers an approved drug may also be eligible for patent term extension, which permits patent term restoration as compensation for the patent term lost during the development and regulatory review process. To obtain a patent extension in the United States, the term of the relevant patent must not have expired before the extension application, the patent cannot have been extended previously under this law, an application for extension must be submitted, the product must be subject to regulatory review prior to its commercialization, and the permission for the commercial marketing or use of the product after such regulatory review period is the first permitted commercial marketing or use of the product. If our future products contain active ingredients which have not been previously approved, we may be eligible for a patent term extension in the United States. In the United States, we expect to seek extension of patent terms under the Drug Price Competition and Patent Term Restoration Act of 1984, which permits a patent term extension of up to five years beyond the expiration of the patent for patent claims covering a new chemical entity. If patent extensions are available to us outside of the United States, we would expect to file for a patent term extension in applicable jurisdictions.

Confidential Information and Inventions Assignment Agreements

We require our employees and consultants to execute confidentiality agreements upon the commencement of employment, consulting or collaborative relationships with us. These agreements provide that all confidential information developed or made known during the course of the relationship with us be kept confidential and not disclosed to third parties except in specific circumstances.

In the case of employees, the agreements provide that all inventions resulting from work performed for us, utilizing our property or relating to our business and conceived or completed by the individual during employment shall be our exclusive property to the extent permitted by applicable law. Our consulting and service agreements also provide for assignment to us of any intellectual property resulting from services performed for us.

Government Regulation and Product Approval

United States Government Regulation

In the United States, the FDA regulates drugs and biologics under the Federal Food, Drug, and Cosmetic Act, or FDCA, the Public Health Service Act, and related regulations. Drugs and biologics are also subject to other federal, state and local statutes and regulations. The FDA and comparable regulatory agencies in state and local jurisdictions impose substantial requirements upon, among other things, the testing, development, manufacture, quality control, safety, purity, potency, labeling, storage, distribution, record keeping and reporting, approval, import and export, advertising and promotion, and postmarket surveillance of drugs and biologics.

Biopharmaceutical Product Development Process

The process required by the FDA before biopharmaceutical products may be marketed in the United States generally involves the following:

Before testing any compounds with potential therapeutic value in humans, the product candidate enters the preclinical testing stage. Preclinical tests include laboratory evaluations of product chemistry and formulation, as well as animal studies to assess the potential safety, toxicity profile and activity of the product candidate. The conduct of the preclinical tests must comply with federal regulations and requirements including GLPs.

Prior to commencing the first clinical trial in humans, an IND must be submitted to the FDA, and the IND must become effective. A sponsor must submit preclinical testing results to the FDA as part of the IND and the FDA must evaluate whether there is an adequate basis for testing the drug in humans. The IND automatically becomes effective 30 days after receipt by the FDA unless the FDA within the 30-day time period raises concerns or questions about the submitted data or the conduct of the proposed clinical trial and places the IND on clinical hold. In such case, the IND application sponsor must resolve any outstanding concerns with the FDA before the clinical trial may begin. A separate submission to the existing IND application must be made for each successive clinical trial to be conducted during product development. Further, an independent Institutional Review Board, or IRB, for each site proposing to conduct the clinical trial must review and approve the protocol and informed consent for any clinical trial before it commences at that site. Informed consent must also be obtained from each study subject. Regulatory authorities, an IRB, a data safety monitoring board or the trial sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the participants are being exposed to an unacceptable health risk.

Human clinical trials are typically conducted in three sequential phases that may overlap:

Post-approval studies, or Phase 4 clinical trials, may be conducted after initial marketing approval. These studies may be required by the FDA as a condition of approval and are used to gain additional experience from the treatment of patients in the intended therapeutic indication. The FDA also has express statutory authority to require post-market clinical studies to address safety issues.

Some clinical trials are overseen by an independent group of qualified experts organized by the clinical trial sponsor, known as a data monitoring board or committee. This group provides recommendations for whether or not a trial may move forward at designated checkpoints based on access to certain data from the study. A sponsor may also suspend or terminate a clinical trial based on evolving business objectives and/or competitive climate.

Concurrent with clinical trials, companies usually complete additional animal studies and must also develop additional information about the chemistry and physical characteristics of the product candidate as well as finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the drug candidate and, among other things, must include developed methods for testing the identity, strength, quality and purity of the finished product. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the product candidate does not undergo unacceptable deterioration over its shelf life.

FDA Review and Approval Processes

In order to obtain approval to market a biopharmaceutical product in the United States, a marketing application must be submitted to the FDA that provides data establishing to the FDA’s satisfaction the safety and effectiveness of the investigational drug for the proposed indication. Each NDA or BLA submission requires a substantial user fee payment unless a waiver or exemption applies. The application includes all relevant data available from pertinent nonclinical studies and clinical trials, including negative or ambiguous results as well as positive findings, together with detailed information relating to the product’s chemistry, manufacturing, controls and proposed labeling, among other things. Data can come from company-sponsored clinical trials intended to test the safety and effectiveness of a use of a product, or from a number of alternative sources, including studies initiated by investigators.

The FDA will initially review an NDA or BLA for completeness before it accepts it for filing. The FDA has 60 days from its receipt of an application to determine whether the application will be accepted for filing based on the agency’s threshold determination that the application is sufficiently complete to permit substantive review. If it is not, the FDA may refuse to file the application and request additional information, in which case the application must be resubmitted with the supplemental information, and review of the application is delayed. After an NDA or BLA submission is accepted for filing, the FDA reviews the application to determine, among other things, whether the proposed product is safe and effective for its intended use, and whether the product is being manufactured in accordance with cGMP to assure and preserve the product’s identity, strength, quality and purity. The FDA may refer applications for novel drug products or drug products that present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved and, if so, under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.

Upon the filing of an NDA or BLA, the FDA may grant a priority review designation to a product, which sets the target date for FDA action on the application at 6 months, rather than the standard 10 months. Priority review is given for drug that treats a serious condition and, if approved, would provide a significant improvement in safety or effectiveness. Priority review designation does not change the scientific or medical standard for approval or the quality of evidence necessary to support approval.

Before approving an NDA or BLA, the FDA will inspect the facilities at which the product is manufactured. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving an NDA or BLA, the FDA may inspect one or more clinical sites to assure compliance with GCP.

After the FDA completes its initial review of an NDA or BLA, it will communicate to the sponsor that the product is approved, or it will issue a complete response letter to communicate that the application will not be approved in its current form and inform the sponsor of changes that must be made or additional clinical, nonclinical or manufacturing data that must be received before the application can be approved.

Even if a product candidate receives regulatory approval, the approval may be limited to specific disease states, patient populations and dosages, or might contain significant limitations on use in the form of warnings, precautions or contraindications, or in the form of onerous risk management plans, restrictions on distribution, or post-marketing study requirements. For example, the FDA may require Phase 4 testing, which involves clinical trials designed to further assess a drug’s safety and effectiveness and may require testing and surveillance programs to

monitor the safety of approved products that have been commercialized. The FDA may also determine that a risk evaluation and mitigation strategy, or REMS, is necessary to assure the safe use of the drug. If the FDA concludes a REMS is needed, the sponsor of an NDA must submit a proposed REMS, and the FDA will not approve an NDA without an approved REMS, if required.

Expedited Review Programs

Among other programs, the FDA may expedite the review of a product candidate designated as a breakthrough therapy, which is intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. A sponsor may request the FDA to designate a drug as a breakthrough therapy at the time of, or any time after, the submission of an IND application for the drug. If the FDA designates a drug as a breakthrough therapy, it must take actions appropriate to expedite the development and review of the application, which may include holding meetings with the sponsor and the review team throughout the development of the drug; providing timely advice to, and interactive communication with, the sponsor regarding the development of the drug to ensure that the development program to gather the nonclinical and clinical data necessary for approval is as efficient as practicable; involving senior managers and experienced review staff, as appropriate, in a collaborative, cross-disciplinary review; assigning a cross-disciplinary project lead for the FDA review team to facilitate an efficient review of the development program and to serve as a scientific liaison between the review team and the sponsor; and taking steps to ensure that the design of the clinical trials is as efficient as practicable, when scientifically appropriate, such as by minimizing the number of patients exposed to a potentially less efficacious treatment. The FDA may rescind a breakthrough therapy designation in the future if further clinical development later shows that the criteria for designation are no longer met.

Breakthrough therapy designation does not change the standards for approval but may expedite the development or review process.

Post-Approval Requirements

If and when approved, any products manufactured or distributed by us or on our behalf will be subject to continuing regulation by the FDA, including requirements for record-keeping, reporting of adverse experiences and submitting annual reports.

Biopharmaceutical manufacturers are required to register their facilities with the FDA and certain state agencies, and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with cGMPs, which impose certain quality processes, manufacturing controls and documentation requirements upon us and our third-party manufacturers in order to ensure that the product is safe, has the identity and strength, and meets the quality and purity characteristics that it purports to have. The FDA and certain states also impose requirements on manufacturers and distributors to establish the pedigree of product in the chain of distribution, including technology capable of tracking and tracing product as it moves through the distribution chain. We cannot be certain that we or our present or future suppliers will be able to comply with the cGMP and other FDA regulatory requirements. If our present or future suppliers are not able to comply with these requirements, the FDA may halt our clinical trials, fail to approve any application, shut down manufacturing operations or withdraw approval of an application, or we may recall the product from distribution. Noncompliance with cGMP or other requirements can result in issuance of warning letters, civil and criminal penalties, seizures and injunctive action.

The FDA closely regulates the labeling, marketing and promotion of drugs and biologics. While doctors are free to prescribe any drug approved by the FDA for any use based on the doctor’s independent medical judgement, a company can only make claims relating to safety and efficacy of a drug that are consistent with FDA approval, and the company is allowed to actively market a drug only for the particular use and treatment approved by the FDA. In addition, any claims we make for our products in advertising or promotion must be appropriately balanced with important safety information and otherwise be adequately substantiated. Failure to comply with these requirements can result in adverse publicity, warning letters, corrective advertising, injunctions and potential civil and criminal penalties. Government regulators recently have increased their scrutiny of the promotion and marketing of drugs.

Coverage and Reimbursement

In both domestic and foreign markets, sales of any products for which we may receive regulatory approval will depend in part upon the availability of coverage and adequate reimbursement to healthcare providers from third-party payors. Such third-party payors include government health programs, such as Medicare and Medicaid, as well as managed care organizations, private health insurers and other organizations. Coverage decisions may depend upon clinical and economic standards that disfavor new drug products when more established or lower cost therapeutic alternatives are available. Assuming coverage is granted, the reimbursement rates paid for covered products might not be adequate. Even if favorable coverage status and adequate reimbursement rates are attained, less favorable coverage policies and reimbursement rates may be implemented in the future. The marketability of any products for which we may receive regulatory approval for commercial sale may suffer if the government and other third-party payors fail to provide coverage and adequate reimbursement to allow us to sell such products on a competitive and profitable basis. For example, under these circumstances, physicians may limit how much or under what circumstances they will prescribe or administer such products, and patients may decline to purchase them. This, in turn, could affect our ability to successfully commercialize our products and impact our profitability, results of operations, financial condition, and future success.

In the United States, the European Union and other potentially significant markets for our product candidates, government authorities and third-party payors are increasingly attempting to limit or regulate the price of medical products and services, particularly for new and innovative products and therapies. Such pressure, along with the increased emphasis on managed healthcare in the United States and on country and regional pricing and reimbursement controls in the European Union, will likely put additional downward pressure on product pricing, reimbursement and usage, which may adversely affect our future product sales and results of operations. These pressures can arise from rules and practices of managed care groups, judicial decisions, governmental laws and regulations related to government healthcare programs, healthcare reform, and pharmaceutical coverage and reimbursement policies.

The market for any product candidates for which we may receive regulatory approval will depend significantly on the degree to which these products are listed on third-party payors’ drug formularies or lists of medications for which third-party payors provide coverage and reimbursement to the extent products for which we may receive regulatory approval are covered under a pharmacy benefit or are otherwise subject to a formulary. The industry competition to be included on such formularies often leads to downward pricing pressures on pharmaceutical companies. Also, third-party payors may refuse to include a particular branded drug on their formularies or otherwise restrict patient access to a branded drug when a less costly generic equivalent or other alternative is available. In addition, because each third-party payor individually approves coverage and reimbursement levels, obtaining coverage and adequate reimbursement is a time-consuming and costly process. Further, one payor’s determination to provide coverage for a drug product does not assure that other payors will also provide coverage for the drug product. We may be required to provide scientific and clinical support for the use of any product to each third-party payor separately with no assurance that approval would be obtained, and we may need to conduct expensive pharmacoeconomic studies in order to demonstrate the cost-effectiveness of our products. We cannot be certain that our product candidates will be considered cost-effective. This process could delay the market acceptance of any product candidates for which we may receive approval and could have a negative effect on our future revenues and operating results.

Federal and State Fraud and Abuse and Data Privacy and Security Laws and Regulations

In addition to FDA restrictions on marketing of pharmaceutical products, federal and state laws restrict business practices in the pharmaceutical industry. These laws include anti-kickback and false claims laws and regulations as well as data privacy and security laws and regulations. The laws that will affect our operations include, but are not limited to:

We may also be subject to federal and state laws that govern the privacy and security of other personal information, including federal and state consumer protection laws, state data security laws, and data breach notification laws. A data breach affecting sensitive personal information, including health information, could result in significant legal and financial exposure and reputational damages.

Because of the breadth of these laws and the narrowness of available statutory and regulatory exemptions, it is possible that some of our business activities could be subject to challenge, investigation or legal action under one or more of such laws. If our operations are found to be in violation of any of the federal and state laws described above or any other governmental regulations that apply to us, we may be subject to significant civil, criminal, and administrative penalties, including, without limitation, damages, fines, imprisonment, disgorgement, exclusion from participation in government healthcare programs, additional reporting requirements and oversight if we become subject to a corporate integrity agreement or similar agreement to resolve allegations of non-compliance with these laws, and the curtailment or restructuring of our operations.

To the extent that any of our product candidates receive approval and are sold in a foreign country, we may be subject to similar foreign laws and regulations, which may include, for instance, applicable post-marketing requirements, including safety surveillance, anti-fraud and abuse laws, international data protection laws (including the General Data Protection Directive ((EU) 2016/679) on the protection of individuals with regard to the processing of personal data and on the free movement of such data as well as EU member state implementing legislation), and implementation of corporate compliance programs and reporting of payments or transfers of value to healthcare professionals.

Healthcare Reform

In the United States and some foreign jurisdictions, there have been a number of legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval of our product candidates, restrict or regulate post-approval activities and affect our ability to profitably sell any product candidates for which we obtain marketing approval. Among policy makers and payors in the United States and elsewhere, there is significant interest in promoting changes in healthcare systems with the stated goals of containing healthcare costs, improving quality and expanding access. In the United States, the pharmaceutical industry has been a particular focus of these efforts and has been significantly affected by major legislative initiatives. In March 2010, then President Obama signed into law the Affordable Care Act, which substantially changed the way healthcare will be financed by both governmental and private insurers, and significantly impacts the pharmaceutical industry. Among the provisions of the Affordable Care Act of importance to our business, including, without limitation, our ability to commercialize, and the prices we may obtain for, any of our product candidates that are approved for sale, are the following:

• extension of manufacturers’ Medicaid rebate liability;

• expansion of eligibility criteria for Medicaid programs;

There have been executive, judicial and Congressional challenges to certain aspects of the Affordable Care Act. For example, the Tax Cuts and Jobs Act of 2017, or Tax Act, included a provision which repealed, effective January 1, 2019, the tax-based shared responsibility payment imposed by the Affordable Care Act on certain individuals who fail to maintain qualifying health coverage for all or part of a year that is commonly referred to as the “individual mandate”. In addition, the 2020 federal spending package permanently eliminated, effective January 1, 2020, the Affordable Care Act’s mandated “Cadillac” tax on high-cost employer-sponsored health coverage and medical device tax and, effective January 1, 2021, also eliminated the health insurer tax. On June 17, 2021, the U.S. Supreme Court dismissed a challenge on procedural grounds that argued the Affordable Care Act is unconstitutional in its entirety because the “individual mandate” was repealed by Congress. Thus, the Affordable Care Act will remain in effect in its current form. Prior to the U.S. Supreme Court ruling, on January 28, 2021, President Biden issued an executive order that initiated a special enrollment period for purposes of obtaining health insurance coverage through the Affordable Care Act marketplace. The executive order also instructed certain governmental agencies to review and reconsider their existing policies and rules that limit access to healthcare, including among others, reexamining Medicaid demonstration projects and waiver programs that include work requirements, and policies that create unnecessary barriers to obtaining access to health insurance coverage through Medicaid or the Affordable Care Act. It is possible that the PPACA will be subject to judicial or Congressional challenges in the future. It is unclear how any such challenges and the healthcare reform measures of the Biden administration will impact the Affordable Care Act.

Further, there has been increasing legislative and enforcement interest in the United States with respect to specialty drug pricing practices. Specifically, there have been several recent U.S. Congressional inquiries, Presidential executive orders, and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to drug pricing, review the relationship between pricing and manufacturer patient programs, reduce the cost of drugs under Medicare, and reform government program reimbursement methodologies for drugs. At the federal level, the Trump administration used several means to propose or implement drug pricing reform, including through federal budget proposals, executive orders and policy initiatives. For example, on July 24, 2020 and September 13, 2020, the Trump administration announced several executive orders related to prescription drug pricing that seek to implement several of the administration’s proposals. As a result, the FDA released a final rule and guidance in September 2020, providing pathways for states to build and submit importation plans for drugs from Canada. Further, on November 20, 2020, the U.S. Department of Health & Human Services, or HHS, finalized a regulation removing safe harbor protection for price reductions from pharmaceutical manufacturers to plan sponsors under Medicare Part D, either directly or through pharmacy benefit managers, unless the price reduction is required by law. The implementation of the rule has been delayed by the Biden administration from January 1, 2022 to January 1, 2023 in response to ongoing litigation. The rule also creates a new safe harbor for price reductions reflected at the point-of-sale, as well as a new safe harbor for certain fixed fee arrangements between pharmacy benefit managers and manufacturers, the implementation of which have also been delayed until January 1, 2023. On December 27, 2021, CMS issued a final rule that rescinded an interim final rule implementing the Trump administration’s Most Favored Nation executive order, which would tie Medicare Part B payments for certain physician-administered drugs to the lowest price paid in other economically advanced countries. In July 2021, the Biden administration released an executive order, “Promoting Competition in the American Economy,” with multiple provisions aimed at prescription drugs. In response to Biden’s executive order, on September 9, 2021, the U.S. Department of Health and Human Services, or HHS, released a Comprehensive Plan for Addressing High Drug Prices that outlines principles for drug pricing reform and sets out a variety of potential legislative policies that Congress could pursue as well as potential administrative actions HHS can take to advance these principles. No legislation or administrative actions have been finalized to implement these principles. Congress is also considering additional health reform measures. At the state level, legislatures are increasingly passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk

purchasing. It is also possible that additional governmental action will be taken in response to the COVID-19 pandemic.

The full impact on our business of the Affordable Care Act and other new laws is uncertain but may result in additional reductions in Medicare and other healthcare funding. Nor is it clear whether other legislative changes will be adopted, if any, or how such changes would affect the demand for our products once commercialized.

Regulations Outside of the United States

In addition to regulations in the United States, we will be subject to a variety of foreign regulations governing clinical trials and commercial sales and distribution of our product candidates to the extent we choose to sell any products outside of the United States. Whether or not we obtain FDA approval for a product, we must obtain approval of a product by the comparable regulatory authorities of foreign countries before we can commence clinical trials or marketing of the product in those countries. The approval process varies from country to country and the time may be longer or shorter than that required for FDA approval. The requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary greatly from country to country. As in the United States, post-approval regulatory requirements, such as those regarding product manufacture, marketing, or distribution would apply to any product that is approved outside the United States.

Other Regulations

We are also subject to numerous federal, state and local laws relating to such matters as safe working conditions, manufacturing practices, environmental protection, fire hazard control, and disposal of hazardous or potentially hazardous substances. We may incur significant costs to comply with such laws and regulations now or in the future.

Employees and Human Capital Resources

As of February 25, 2022, we had 59 full-time employees. Of the full-time employees, 41 were primarily engaged in research and development activities and 15 have an M.D. or Ph.D. degree. None of our employees are represented by labor unions or covered by collective bargaining agreements. We consider our relationship with our employees to be good.

Our human capital resources objectives include, as applicable, identifying, recruiting, retaining, incentivizing and integrating our existing and additional employees. The principal purposes of our equity incentive plans are to attract, retain and motivate selected employees, consultants and directors through the granting of equity-based compensation awards and cash-based compensation awards, in order to increase stockholder value and the success of our company by motivating such individuals to perform to the best of their abilities and achieve our objectives.

Compensation and Benefits

We consider a number of measures and objectives in managing our human capital assets, including, among others, employee engagement, development, and training, talent acquisition and retention, employee safety and wellness, diversity and inclusion, and compensation and pay equity. We provide our employees with salaries and bonuses intended to be competitive for our industry, opportunities for equity ownership, development programs that enable continued learning and growth and a robust benefits package to promote well-being across all aspects of their lives, including health care, retirement planning and paid time off. In addition, we have conducted employee surveys to gauge employee engagement and identify areas of future focus for our human capital practices and benefits offerings.

Diversity, Equity and Inclusion (DEI)

We believe that a diverse workforce is critical to our success and we are fundamentally committed to creating and maintaining a work environment in which employees are treated fairly, with dignity, decency, respect and in accordance with all applicable laws. We understand that varied perspectives lead to the best ideas and outcomes. We believe that by creating a workplace where every individual can feel welcome and valued, we will be better able

to achieve our corporate objectives. All employees must adhere to a code of business conduct and ethics and our employee handbook, which combined, define standards for appropriate behavior and are annually trained to help prevent, identify, report, and stop any type of discrimination and harassment. Our recruitment, hiring, development, training, compensation, and advancement is based on qualifications, performance, skills, and experience without regard to gender, race, or ethnicity.

Corporate and Other Information

We were incorporated in Delaware in 2005. In 2011, we established a wholly owned subsidiary in the United Kingdom, in 2014 we established a wholly owned U.S. subsidiary, and in 2021, we established a wholly owned subsidiary in the Netherlands. There have been no material activities for these entities to date. We currently operate in one segment.

Our principal executive offices are located at 35 Gatehouse Drive, Building D, Floor 3, Waltham, Massachusetts 02451 and our telephone number is (781) 419-1400. Our corporate website address is www.syndax.com. Information contained on or accessible through our website is not a part of this Annual Report on Form 10-K, and the inclusion of our website address in this Annual Report on Form 10-K is an inactive textual reference only.

We file electronically with the SEC, our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act. We make available on our website at www.syndax.com, under “Investors,” free of charge, copies of these reports as soon as reasonably practicable after filing or furnishing these reports with the SEC.

Item 1A. Risk Factors

This Annual Report on Form 10-K contains forward-looking information based on our current expectations. Because our business is subject to many risks and our actual results may differ materially from any forward-looking statements made by or on behalf of us, this section includes a discussion of important factors that could affect our business, operating results, financial condition and the trading price of our common stock. You should carefully consider these risk factors, together with all of the other information included in this Annual Report on Form 10-K as well as our other publicly available filings with the Securities and Exchange Commission.

Summary of Selected Risks

Our business is subject to numerous risks and uncertainties, of which you should be aware before making a decision to invest in our securities. These risks and uncertainties include, among others, the following:

Risks Related to Our Business and Industry

The ongoing COVID-19 pandemic could adversely impact our business, including our clinical trials.

The ongoing COVID-19 pandemic has resulted in travel and other restrictions in order to reduce the spread of the disease, including state and local orders across the United States and other countries worldwide, which, among other things, direct individuals to shelter at their places of residence, direct businesses and governmental agencies to cease non-essential operations at physical locations, prohibit certain non-essential gatherings, and order cessation of non-essential travel. In response to these public health directives and orders, we have implemented work-from-home policies for our employees. The effects of executive orders may disrupt our business and delay our clinical programs and timelines, the magnitude of which will depend, in part, on the length and severity of the restrictions and other limitations on our ability to conduct our business in the ordinary course. These and similar, and perhaps more severe, disruptions in our operations could negatively impact our business, operating results and financial condition.

While the COVID-19 pandemic has not yet had a material impact on our business operations, quarantines and various government orders related to the pandemic, including its variants, may adversely impact our business operations and the business operations of our contract research organizations conducting our clinical trials and our third-party manufacturing facilities in the United States and other countries. In particular, if the pandemic continues to persist for an extended period of time and continues to impact essential distribution systems such as FedEx and postal delivery or if it results in facility closures facility closures for cleaning and/or insufficient staff, these ongoing constraints associated with the pandemic could cause disruptions to our supply chain and operations, including associated delays in the manufacturing and supply of our products, which would adversely impact our ability to continue our clinical trial operations.

In addition, our clinical trials may be affected by the COVID-19 pandemic. For example, we have experienced delays in clinical site initiation and patient enrollment due to prioritization of hospital resources toward the COVID-19 pandemic. Patients may not be able to comply with clinical trial protocols if quarantines impede patient movement or interrupt healthcare services. Similarly, our ability to recruit and retain patients and principal investigators and site staff who, as healthcare providers, may have heightened exposure to COVID-19, could be limited, which in turn could adversely impact our clinical trial operations. As a result, we may face delays in meeting our anticipated timelines for our ongoing and planned clinical trials.

The spread of COVID-19, including its variants, has caused a broad impact globally and may materially affect us economically. While the full extent of the economic impact brought by, and the duration of, the pandemic may be difficult to assess or predict, it has resulted in uncertainty in macroeconomic conditions and result in significant disruption of global financial markets, reducing our ability to access capital, which could in the future negatively affect our liquidity. In addition, a recession or market correction resulting from the pandemic could materially affect our business and the value of our common stock.

COVID-19 continues to evolve rapidly, and multiple variants of the virus that cause COVID-19 are circulating globally. The extent to which the COVID-19 pandemic impacts our business, our clinical development and regulatory efforts will depend on future developments that are highly uncertain and cannot be predicted with confidence, such as the duration of the outbreak, travel restrictions, quarantines, social distancing requirements, business closures in the United States and other countries, the rollout of mass vaccinations for COVID-19 and the effectiveness of other actions taken in the United States and other countries to contain and treat the disease. While vaccines have been approved and are being deployed, the timing of achieving widespread vaccination remains uncertain, and the vaccines may be less effective against new variants, potentially leading to the reimpositions of restrictions in an effort to mitigate risks to public health, especially as more infectious variants of the virus emerge for a prolonged period of time, further delaying the return of the global economy to pre-pandemic levels.

Accordingly, we do not yet know the full extent of potential delays or impacts on our business, our clinical and regulatory activities, healthcare systems or the global economy as a whole. However, these impacts could adversely affect our business, financial condition, results of operations and growth prospects.

In addition, to the extent the ongoing COVID-19 pandemic adversely affects our business and results of operations, it may also have the effect of heightening many of the other risks and uncertainties described in this “Risk Factors” section.

We are currently developing several product candidates. If we are unable to successfully complete clinical development of, obtain regulatory approval for and commercialize our product candidates, our business prospects will be significantly harmed.

Our financial success will depend substantially on our ability to effectively and profitably commercialize our product candidates. In order to commercialize our product candidates, we will be required to obtain regulatory approvals by establishing that each of them is sufficiently safe and effective. The clinical and commercial success of our product candidates will depend on a number of factors, including the following:

• timely completion of any future clinical trials of SNDX-5613 and axatilimab;

If we fail to obtain regulatory approval for our product candidates, we will not be able to generate product sales, which will have a material adverse effect on our business and our prospects.

SNDX-5613 has undergone limited clinical testing and we may fail to show that the drug is well tolerated and provides sufficient clinical benefit for patients.

Research suggests that certain acute leukemias, such as mixed lineage leukemia-rearranged, or MLLr, leukemias and nucleophosmin 1, or NPM1, mutant acute myeloid leukemia, or AML, are driven by the interaction of menin, a nuclear protein involved in transcription, with the N-terminus of MLL1 protein, a histone methyl transferase. In NPM1 mutant AML the interaction with menin occurs via the wild type MLL1 protein, and in MLLr acute leukemias, the interaction occurs via a mutant form of MLL1, a fusion protein known as MLLr. MLLr results from a rare, spontaneous fusion between the N-terminus of the mixed lineage leukemia protein-1, or MLL1, and a host of signaling molecules and nuclear transcription factors. This fusion produces an aberrant transcription program that drives leukemic transformation. In pre-clinical animal models, small molecule inhibitors of the menin-MLLr interaction, such as SNDX-5613, which bind to, and block the interaction of menin with either MLLr or MLL1, have demonstrated deep and durable single agent treatment effects in multiple leukemic xenograft models harboring MLL fusions or NPM1 mutations. Our strategy for developing SNDX-5613 is to conduct a Phase 1/2 clinical trial in relapsed/refractory patients with MLLr and NPM1 mutant acute leukemias and determine if the observed clinical efficacy supports further development. The Phase 1 portion of the trial is assessing the safety, tolerability and pharmacokinetics of SNDX-5613, and seeks to establish a recommended Phase 2 dose. It is open label, and we have released and may in the future release results from time to time that reflect small numbers of patients which may not be accurately predictive of safety or efficacy results later in the trial or in subsequent trials. The Phase 2 portion is evaluating the efficacy of SNDX-5613 across three expansion cohorts enrolling pediatric and adult patients with MLLr acute lymphoblastic leukemia, or ALL, MLLr acute myeloid leukemia, or AML, and NPM1 mutant AML. While we believe that we have established sufficient efficacy to warrant continued development in these indications, we have not yet sufficiently demonstrated a favorable risk-benefit of SNDX-5613 in patients.

Axatilimab has undergone limited clinical testing and we may fail to show that this drug is well tolerated and provides a clinical benefit for patients.

Preclinical studies suggest that CSF-1/CSF-1R signaling may be the key regulatory pathway involved in the expansion and infiltration of donor derived macrophages that mediate the disease processes involved in cGVHD and other fibrotic or inflammatory diseases. Nonclinical studies and analysis of patient samples indicates that the cGVHD inflammatory disease process is a result of a complex interaction between host and donor immune cells including B cells, and regulatory T cells with M2 differentiated macrophages in target tissue appearing to represent the common distal mediator of fibrosis. Therefore, we hypothesize that a CSF-1R signal inhibitor such as axatilimab may play a meaningful role as a monotherapy agent in the treatment of cGVHD. Our approach is to conduct a Phase 1/2 clinical trial with axatilimab in subjects with active cGVHD who have failed at least two prior lines of therapy. Following our end of Phase 1 meeting with the FDA, we have aligned on a regulatory path for axatilimab for the treatment of cGVHD and commenced a pivotal Phase 2 trial, AGAVE-201, to assess the safety and efficacy of different doses and schedules of axatilimab for the treatment of patients with cGVHD. While we believe that we have established sufficient efficacy to warrant continued development in this indication, we have not yet sufficiently demonstrated a favorable risk-benefit of axatilimab in patients.

Interim top-line and preliminary data from our clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data.

From time to time, we may publish interim top-line or preliminary data from our clinical trials. For example, in April and December 2021, we announced interim data from our Phase 1/2 clinical trial of SNDX-5613. Interim data from clinical trials that we may complete are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available. Preliminary or top-line data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. Preliminary or top-line data may include, for example, data regarding a small percentage of the patients enrolled in a clinical trial, and such preliminary data should not be viewed as an indication, belief or guarantee that other patients enrolled in such clinical trial will achieve similar

results or that the preliminary results from such patients will be maintained. As a result, interim and preliminary data should be viewed with caution until the final data are available. Differences between preliminary or interim data and final data could significantly harm our business prospects and may cause the trading price of our common stock to fluctuate significantly.

We may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of any of our product candidates.

Before obtaining marketing approval from regulatory authorities for the sale of any of our product candidates, we or our collaborators must conduct extensive trials to demonstrate the safety and efficacy of the product candidates in humans. Clinical testing is expensive and difficult to design and implement, can take many years to complete and is inherently uncertain as to the outcome. A failure of one or more trials can occur at any stage of testing. The outcome of preclinical studies and early clinical trials may not accurately predict the success of later trials, and interim results of a trial do not necessarily predict final results. For example, in May 2020, we announced that ECOG-ACRIN advised us that the E2112 trial did not achieve the primary endpoint of demonstrating a statistically significant overall survival benefit over hormone therapy alone in the Phase 3 clinical trial and we decided to deprioritize the entinostat program to focus resources on advancing the remainder of our pipeline. A number of companies in the pharmaceutical and biotechnology industries have suffered significant setbacks in advanced trials due to lack of efficacy or unacceptable safety profiles, notwithstanding promising results in earlier trials.

We are dependent upon our collaboration with Incyte to further develop and commercialize axatilimab. If we or Incyte fail to perform as expected or if the collaboration is terminated as a result of actions by the Federal Trade Commission or the Department of Justice, the potential for us to generate future revenues under the collaboration could be significantly reduced, the development and/or commercialization of axatilmab may be terminated or substantially delayed, and our business could be adversely affected.

We are subject to numerous risks related to the Incyte Agreement to collaborate on the development and commercialization of axatilimab.

For example, there is no assurance that the parties will achieve any of the regulatory development or sales milestones, that we will receive any future milestone or royalty payments under the collaboration agreement or that the collaboration will not be unwound as a result of actions by the Federal Trade Commission or the Department of Justice. Incyte’s activities may be influenced by, among other things, the efforts and allocation of resources by Incyte, which we cannot control. If Incyte does not perform in the manner we expect or fulfill its responsibilities in a timely manner, or at all, the clinical development, manufacturing, regulatory approval, and commercialization efforts related to axatilimab could be delayed or terminated. In addition, our license with Incyte may be unsuccessful due to other factors, including, without limitation, the following:

We cannot ensure that the potential strategic benefits and opportunities expected from this collaboration with be realized on our anticipated timeline or at all.

If we or our collaborators are unable to enroll patients in clinical trials, these clinical trials may not be completed on a timely basis or at all.

The timely completion of clinical trials largely depends on patient enrollment. Many factors affect patient enrollment, including:

• direct and indirect effects of the ongoing COVID-19 pandemic;

• evolving standard of care in treating cancer patients;

• the number and location of clinical trial sites enrolled;

• the eligibility and exclusion criteria for the trial;

• the design of the trial;

• ability to obtain and maintain patient consent; and

• risk that enrolled subjects will drop out before completion.

As a result of the above factors, there is a risk that our or our collaborators’ clinical trials may not be completed on a timely basis or at all.

We may be required to relinquish important rights to and control over the development and commercialization of our product candidates to our current or future collaborators.

Our collaborations, including any future strategic collaborations we enter into, could subject us to a number of risks, including:

• we may be required to assume substantial actual or contingent liabilities;

• strategic collaborators may experience financial difficulties;

We may explore strategic collaborations that may never materialize or may fail.

We periodically explore a variety of possible strategic collaborations in an effort to gain access to additional product candidates or resources. At the current time, we cannot predict what form such a strategic collaboration might take. We are likely to face significant competition in seeking appropriate strategic collaborators, and strategic collaborations can be complicated and time consuming to negotiate and document. We may enter into strategic collaborations that we subsequently no longer wish to pursue, and we may not be able to negotiate strategic collaborations on acceptable terms, or at all. We are unable to predict when, if ever, we will enter into any additional strategic collaborations because of the numerous risks and uncertainties associated with establishing them.

The regulatory approval processes of the FDA and foreign regulatory authorities are lengthy, time-consuming and inherently unpredictable. Our inability to obtain regulatory approval for our product candidates could harm our business.

The time required to obtain approval by the FDA and foreign regulatory authorities is unpredictable, but typically takes many years following the commencement of preclinical studies and clinical trials and depends upon numerous factors, including the substantial discretion of the regulatory authorities. In addition, approval policies, regulations, or the type and amount of clinical data necessary to gain approval may change during the course of a product candidate’s clinical development and may vary among jurisdictions. We have not obtained regulatory approval for any of our product candidates, and it is possible that we will never obtain regulatory approval for our existing product candidates or any future product candidates.

Due to the ongoing COVID-19 pandemic, it is possible that we could experience delays in the timing of our interactions with regulatory authorities due to absenteeism by governmental employees, inability to conduct planned physical inspections related to regulatory approval, or the diversion of regulatory authority efforts and attention to approval of other therapeutics or other activities related to COVID-19, which could delay anticipated approval decisions and otherwise delay or limit our ability to make planned regulatory submissions or obtain new product approvals. In addition, our product candidates could fail to receive regulatory approval from the FDA or foreign regulatory authorities for other reasons, including but not limited to:

• failure to demonstrate that our product candidates are safe and effective;

The FDA or foreign regulatory authorities may require more information, including additional preclinical or clinical data, to support approval, which may delay or prevent approval and our commercialization plans, or may cause us to decide to abandon our development program. Even if we were to obtain approval, regulatory authorities may approve one or more of our product candidates for a more limited patient population than we request, may grant approval contingent on the performance of costly post-marketing trials, may impose a risk evaluation and mitigation strategy, or REMS, or foreign regulatory authorities may require the establishment or modification of a similar strategy that may, for instance, restrict distribution of one or more of our product candidates and impose burdensome implementation requirements on us, or may approve it with a label that does not include the labeling claims necessary or desirable for the successful commercialization of one or more of our product candidates, all of which could limit our ability to successfully commercialize our product candidates.

Our product candidates may not achieve adequate market acceptance among physicians, patients, healthcare payors and others in the medical community to be commercially successful.

Even if our product candidates receive regulatory approval, they may not gain sufficient market acceptance among physicians, patients, healthcare payors and others in the medical community. Our commercial success also depends on coverage and adequate reimbursement by third-party payors, including government payors, which may be difficult or time-consuming to obtain, may be limited in scope and may not be obtained in all jurisdictions in which we may seek to market our product candidates. The degree of market acceptance will depend on a number of factors, including:

• the efficacy and safety profile as demonstrated in trials;

• the timing of market introduction as well as competitive products;

• the clinical indications for which the product candidate is approved;

• the cost of treatment in relation to alternative treatments;

• relative convenience and ease of administration;

• the frequency and severity of adverse events;

• the effectiveness of sales and marketing; and

• unfavorable publicity relating to our product candidates.

If our product candidates are approved but do not achieve an adequate level of acceptance by physicians, hospitals, healthcare payors and patients, we may not generate sufficient revenue to become or remain profitable.

We rely on third-party suppliers to manufacture and distribute our clinical drug supplies for our product candidates, we intend to rely on third parties for commercial manufacturing and distribution of our product candidates and we expect to rely on third parties for manufacturing and distribution of preclinical, clinical and commercial supplies of any future product candidates.

We do not currently have, nor do we plan to acquire, the infrastructure or capability to manufacture or distribute preclinical, clinical or commercial quantities of drug substance or drug product, including our existing product candidates. While we expect to continue to depend on third-party manufacturers for the foreseeable future, we do not have direct control over the ability of these manufacturers to maintain adequate manufacturing capacity and capabilities to serve our needs, including quality control, quality assurance and qualified personnel. In additional, public health epidemics, such as the COVID-19 pandemic, may impact the ability of our existing or future manufacturers to perform their obligations to us.

We are dependent on our third-party manufacturers for compliance with cGMPs and for manufacture of both active drug substances and finished drug products. Facilities used by our third-party manufacturers to manufacture drug substance and drug product for commercial sale must be approved by the FDA or other relevant foreign regulatory agencies pursuant to inspections that will be conducted after we submit our NDA or relevant foreign regulatory submission to the applicable regulatory agency. If our third-party manufacturers cannot successfully manufacture materials that conform to our specifications and/or the strict regulatory requirements of the FDA or foreign regulatory agencies, they will not be able to secure and/or maintain regulatory approval for their manufacturing facilities. Furthermore, these third-party manufacturers are engaged with other companies to supply and/or manufacture materials or products for such companies, which also exposes our third-party manufacturers to regulatory risks for the production of such materials and products. As a result, failure to meet the regulatory requirements for the production of those materials and products may also affect the regulatory clearance of a third-party manufacturers’ facility. If the FDA or a foreign regulatory agency does not approve these facilities for the manufacture of our product candidates, or if it withdraws its approval in the future, we may need to find alternative manufacturing facilities, which would impede or delay our ability to develop, obtain regulatory approval for or market our product candidates, if approved.

Even if our product candidates receive regulatory approval, they may still face future development and regulatory difficulties.

Even if we obtain regulatory approval for our product candidates, they would be subject to ongoing requirements by the FDA and foreign regulatory authorities governing the manufacture, quality control, further development, labeling, packaging, storage, distribution, safety surveillance, import, export, advertising, promotion, recordkeeping and reporting of safety and other post-market information. The FDA and foreign regulatory authorities will continue to monitor closely the safety profile of any product even after approval. If the FDA or foreign regulatory authorities become aware of new safety information after approval of a product candidate, they may require labeling changes or establishment of a REMS or similar strategy, impose significant restrictions on its indicated uses or marketing, or impose ongoing requirements for potentially costly post-approval studies or post-market surveillance.

In addition, manufacturers of drug products and their facilities are subject to continual review and periodic inspections by the FDA and other regulatory authorities for compliance with cGMP regulations and standards. If we or a regulatory agency discover previously unknown problems with a product, such as adverse events of unanticipated severity or frequency, or problems with the facility where the product is manufactured, a regulatory agency may impose restrictions on that product, the manufacturing facility or us, including withdrawal of the product from the market or suspension of manufacturing, or we may recall the product from distribution. If we, or our third-party manufacturers, fail to comply with applicable regulatory requirements, a regulatory agency may:

• issue warning letters or untitled letters;

• seek an injunction or impose civil or criminal penalties or monetary fines;

• suspend or withdraw regulatory approval;

• suspend any ongoing clinical trials;

The occurrence of any event or penalty described above may inhibit our ability to commercialize and generate revenue from the sale of our product candidates.

Advertising and promotion of any product candidate that obtains approval in the United States will be heavily scrutinized by the FDA, the Department of Justice, the Department of Health and Human Services’ Office of Inspector General, state attorneys general, members of Congress, other government agencies and the public. While physicians may prescribe products for off-label uses as the FDA and other regulatory agencies do not regulate a physician’s choice of drug treatment made in the physician’s independent medical judgment, they do restrict promotional communications from companies or their sales force with respect to off-label uses of products for which marketing clearance has not been issued. Companies may only share truthful and not misleading information that is otherwise consistent with a product’s FDA approved labeling. Violations, including promotion of our products for unapproved (or off-label) uses, may be subject to enforcement letters, inquiries and investigations, and civil and criminal sanctions by the government. Additionally, foreign regulatory authorities will heavily scrutinize advertising and promotion of any product candidate that obtains approval in their respective jurisdictions.

In the United States, engaging in the impermissible promotion of our products for off-label uses can also subject us to false claims litigation under federal and state statutes, which can lead to administrative, civil and criminal penalties, damages, monetary fines, disgorgement, individual imprisonment, exclusion from participation in Medicare, Medicaid and other federal healthcare programs, curtailment or restructuring of our operations and agreements that materially restrict the manner in which a company promotes or distributes drug products. These false claims statutes include, but are not limited to, the federal civil False Claims Act, which allows any individual to bring a lawsuit against an individual or entity, including a pharmaceutical or biopharmaceutical company on behalf of the federal government alleging the knowing submission of false or fraudulent claims, or causing to present such false or fraudulent claims, for payment or approval by a federal program such as Medicare or Medicaid. These False Claims Act lawsuits against pharmaceutical and biopharmaceutical companies have increased significantly in number and breadth, leading to several substantial civil and criminal settlements regarding certain sales practices, including promoting off-label drug uses involving fines in excess of $1.0 billion. This growth in litigation has increased the risk that a pharmaceutical company will have to defend a false claim action, pay settlement fines or restitution, agree to comply with burdensome reporting and compliance obligations, and be excluded from participation in Medicare, Medicaid and other federal and state healthcare programs. If we, or any partner that we may engage, do not lawfully promote our approved products, we may become subject to such litigation, which may have a material adverse effect on our business, financial condition and results of operations.

Our product candidates may cause undesirable side effects or have other properties that could delay or prevent their regulatory approval, limit the commercial scope of their approved use, or result in significant negative consequences following any marketing approval.

Undesirable side effects caused by our product candidates could cause the interruption, delay or halting of the trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other foreign regulatory authorities. Results of the clinical trials may reveal a high and unacceptable severity and prevalence of side effects or other unexpected characteristics. In such event, the trials could be suspended or terminated, or the FDA or foreign regulatory authorities could deny approval of our product candidates for any or all targeted indications. Drug-related side effects could affect patient recruitment or the ability of enrolled subjects to complete the trial or result in potential product liability claims. Any of these occurrences may harm our business, financial condition and prospects.

Additionally, if our product candidates receive marketing approval, and we or others later identify undesirable side effects, a number of potentially significant negative consequences could result, including:

• we may suspend marketing of, or withdraw or recall, the product;

• regulatory authorities may withdraw approvals;

• regulatory authorities may require additional warnings on the product labels;

• regulatory authorities may require that we conduct post-marketing studies;

• we could be sued and held liable for harm caused to subjects or patients; and

• our reputation may suffer.

Any of these events could prevent us from achieving or maintaining market acceptance of our product candidates for use in targeted indications or otherwise materially harm its commercial prospects, if approved, and could harm our business, results of operations and prospects.

Our failure to obtain regulatory approval in international jurisdictions would prevent us from marketing our product candidates outside the United States.

In order to market and sell our product candidates in other jurisdictions, we must obtain separate marketing approvals for those jurisdictions and comply with their numerous and varying regulatory requirements. We may not obtain foreign regulatory approvals on a timely basis, or at all. The approval procedure varies among countries and can involve additional testing. The time required to obtain approval may differ substantially from that required to obtain FDA approval. The regulatory approval process outside the United States generally includes all of the risks associated with obtaining FDA approval. In addition, in many countries outside the United States, product reimbursement approvals must be secured before regulatory authorities will approve the product for sale in that country. Obtaining foreign regulatory approvals and compliance with foreign regulatory requirements could result in significant delays, difficulties and costs for us and could delay or prevent the introduction of our product candidates in certain countries. Further, clinical trials conducted in one country may not be accepted by regulatory authorities in other countries and regulatory approval in one country does not ensure approval in any other country, while a failure or delay in obtaining regulatory approval in one country may have a negative effect on the regulatory approval process in others. Our failure to obtain approval of our product candidates by foreign regulatory authorities may negatively impact the commercial prospects of such product candidates and our business prospects could decline. Also, if regulatory approval for our product candidates is granted, it may be later withdrawn. If we fail to comply with the regulatory requirements in international jurisdictions and receive applicable marketing approvals, our target market will be reduced and our ability to realize the full market potential for our product candidates will be harmed and our business may be adversely affected.

We face significant competition from other biotechnology and pharmaceutical companies, and our operating results will suffer if we fail to compete effectively.

Even if any of our product candidates received regulatory approval, such product candidates would face competition from other therapies in the relevant indication. For example, chronic graft versus host disease has historically been managed by off-label treatments. However, in the past five years, the FDA has approved three drugs, ibrutinib (Imbruvica®), belomosidil (Rezurock®) and ruxolitinib (Jakafi®), for use in patients with cGVHD after failure of one or more lines of systemic therapy. All three of these drugs may compete with axatilimab in patients diagnosed with cGVHD.

SNDX-5613 is being developed for the treatment of adult and pediatric patients with MLLr ALL, MLLr AML and NPM1 mutant AML. At this time, there are no drugs approved for these defined populations and patients are managed using the standard of care treatment regimens developed for general AML and ALL populations. While there are other agents in early development for similar populations, SNDX-5613 has the potential to be the first defined therapy for patients with MLLr ALL, MLLr AML and/or NPM1 mutant AML.

Many of our existing or potential competitors have substantially greater financial, technical and human resources than we do and significantly greater experience in the discovery and development of product candidates, obtaining FDA and other regulatory approvals of products and the commercialization of those products. Our competitors may be more successful than us in obtaining FDA approval for drugs and achieving widespread market acceptance. Our competitors’ drugs may be more effective or more effectively marketed and sold than any drug we may commercialize and may render our product candidates obsolete or non-competitive before we can recover the expenses of developing and commercializing any of our product candidates. Our competitors may also obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for ours. We anticipate that we will face intense and increasing competition as new drugs enter the market and advanced technologies become available.

We believe that our ability to successfully compete will depend on, among other things:

Even if we obtain regulatory approval of our product candidates, the availability and price of our competitors’ products could limit the demand and the price we are able to charge. We may not be able to implement our business plan if the acceptance of our product candidates is inhibited by price competition or the reluctance of physicians to switch from existing methods of treatment, or if physicians switch to other new drug or biologic products or choose to reserve our drugs for use in limited circumstances.

The actions of Eddingpharm Investment Company Limited, or Eddingpharm, and any other current or future sublicensees could adversely affect our business.

We currently exclusively sublicense entinostat to Eddingpharm for development and commercialization of entinostat in China and select Asian countries. In December 2021, Eddingpharm announced that the results of its multi-center, randomized, double-blinded, placebo-controlled Phase III registration trial, which was designed to evaluate entinostat plus exemestane compared to placebo plus exemestane in patients with locally advanced or metastatic HR positive, HER2 negative breast cancer who have previously progressed on hormone therapy, showed that entinostat plus exemestane improved progression free survival, overall response rate and disease control rate, compared with placebo plus exemestane in patients with advanced HR positive, HER2 negative breast cancer who had progressed after previous endocrine therapy. Nonetheless, it is possible that any future clinical trials conducted by Eddingpharm, including the forthcoming overall survival data in its ongoing Phase III registration trial, and trials by other current or future sublicensees in their respective jurisdictions could have negative results, which in turn could have a material adverse effect on the development of entinostat for development and commercialization in the United States and the rest of the world.

We are dependent on UCB Biopharma Sprl, or UCB, to comply with the terms of our license agreement for axatilimab.

Our commercial success also depends upon our ability to develop, manufacture, market and sell axatilimab. In July 2016, we entered into the UCB license agreement pursuant to which we obtained a worldwide, sublicenseable, exclusive license to axatilimab, an IND-ready anti-CSF-1R monoclonal antibody. Certain of the rights licensed to us under the UCB license agreement are in-licensed by UCB from third parties. We are dependent on UCB maintaining the applicable third-party license agreements in full force and effect, which may include activities and performance obligations that are not within our control. If any of these third-party license agreements terminate, certain of our rights to develop, manufacture, commercialize or sell axatilimab may be terminated as well. The occurrence of any of these events could adversely affect the development and commercialization of axatilimab, and materially harm our business.

Our employees, consultants and collaborators may engage in misconduct or other improper activities, including insider trading and non-compliance with regulatory standards and requirements.

We are exposed to the risk that our employees, consultants, distributors, and collaborators may engage in fraudulent or illegal activity. Misconduct by these parties could include intentional, reckless or negligent conduct or disclosure of unauthorized activities to us that violates the regulations of the FDA and non-U.S. regulators, including those laws requiring the reporting of true, complete and accurate information to such regulators, manufacturing

standards, healthcare fraud and abuse laws and regulations in the United States and abroad or laws that require the true, complete and accurate reporting of financial information or data. In particular, sales, marketing and business arrangements in the healthcare industry, including the sale of pharmaceuticals, are subject to extensive laws and regulations intended to prevent fraud, misconduct, kickbacks, self-dealing and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, sales commission, customer incentive programs and other business arrangements. It is not always possible to identify and deter misconduct by our employees and other third parties, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to comply with these laws or regulations. If any such actions are instituted against us and we are not successful in defending ourselves or asserting our rights, those actions could result in the imposition of significant fines or other sanctions, including the imposition of civil, criminal and administrative penalties, damages, monetary fines, disgorgement, individual imprisonment, possible exclusion from participation in Medicare, Medicaid and other federal healthcare programs, additional reporting obligations and oversight if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws, contractual damages, reputational harm, diminished profits and future earnings and curtailment of operations, any of which could adversely affect our ability to operate our business and our results of operations. Whether or not we are successful in defending against such actions or investigations, we could incur substantial costs, including legal fees, and divert the attention of management in defending ourselves against any of these claims or investigations.

We must attract and retain additional highly skilled employees in order to succeed.

To succeed, we must recruit, retain, manage and motivate qualified clinical, scientific, technical and management personnel and we face significant competition for experienced personnel. If we do not succeed in attracting and retaining qualified personnel, particularly at the management level, it could adversely affect our ability to execute our business plan and harm our operating results. In particular, the loss of one or more of our executive officers could be detrimental to us if we cannot recruit suitable replacements in a timely manner. The competition for qualified personnel in the pharmaceutical industry is intense and as a result, we may be unable to continue to attract and retain qualified personnel necessary for the development of our business or to recruit suitable replacement personnel.

Many of the other pharmaceutical companies that we compete against for qualified personnel have greater financial and other resources, different risk profiles and a longer history in the industry than we do. They also may provide more diverse opportunities and better chances for career advancement. Some of these characteristics may be more appealing to high-quality candidates than what we have to offer. If we are unable to continue to attract and retain high-quality personnel, the rate and success at which we can discover and develop product candidates and our business will be limited.

Even if we commercialize our product candidates, they or any other product candidates that we develop, may become subject to unfavorable pricing regulations or third-party coverage or reimbursement practices, which could harm our business.

Our ability to successfully commercialize our existing product candidates, or any other product candidates that we develop, will depend in part on the extent to which coverage and adequate reimbursement for these products and related treatments will be available from third-party payors, including government healthcare programs, private health insurers, managed care plans and other organizations. Third-party payors determine which medications they will cover and establish reimbursement levels. Third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. Increasingly, third-party payors are requiring that drug companies provide them with predetermined discounts from list prices and are challenging the prices charged for medical products.

We cannot be sure that coverage and reimbursement will be available for any product that we commercialize and, if reimbursement is available, what the level of reimbursement will be. Limitation on coverage and reimbursement may impact the demand for, or the price of, and our ability to successfully commercialize any product candidates that we develop.

There may be significant delays in obtaining coverage and reimbursement for newly approved drugs, and coverage may be more limited than the indications for which the drug is approved by the FDA or foreign regulatory

authorities. Moreover, eligibility for coverage and reimbursement does not imply that a drug will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution expenses. Interim reimbursement levels for new drugs, if applicable, may also not be sufficient to cover our costs and may only be temporary. Reimbursement rates may vary according to the use of the drug and the clinical setting in which it is used, may be based on reimbursement levels already set for lower cost drugs and may be incorporated into existing payments for other services. Net prices for drugs may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors and by any future relaxation of laws that presently restrict imports of drugs from countries where they may be sold at lower prices than in the United States.

Private payors often follow decisions by the Centers for Medicare & Medicaid Services, or CMS, regarding coverage and reimbursement to a substantial degree. However, one payor’s determination to provide coverage for a drug product does not assure that other payors will also provide coverage for the drug product. As a result, the coverage determination process is often a time-consuming and costly process that will require us to provide scientific and clinical support for the use of our products to each payor separately, with no assurance that coverage and adequate reimbursement will be applied consistently or obtained in the first instance. Our inability to promptly obtain coverage and adequate reimbursement rates from both government-funded and private payors for any approved products that we develop could have an adverse effect on our operating results, our ability to raise capital needed to commercialize products and our overall financial condition.

The regulations that govern marketing approvals, coverage and reimbursement for new drug products vary widely from country to country. Current and future legislation may significantly change the approval requirements in ways that could involve additional costs and cause delays in obtaining approvals. Some countries require approval of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing or product licensing approval is granted. In some foreign markets, prescription pharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, we may obtain marketing approval for our product candidates in a particular country, but be subject to price regulations that delay our commercial launch of the product, possibly for lengthy time periods, which could negatively impact the revenues we generate from the sale of the product in that particular country. Adverse pricing limitations may hinder our ability to recoup our investment even if our product candidates obtain marketing approval.

There can be no assurance that our product candidates, if they are approved for sale in the United States or in other countries, will be considered medically reasonable and necessary for a specific indication, that it will be considered cost effective by third-party payors, that coverage and an adequate level of reimbursement will be available, or that third-party payors’ reimbursement policies will not adversely affect our ability to sell our product candidates profitably.

Current and future legislation may increase the difficulty and cost for us to commercialize our product candidates and affect the prices we may obtain.

The United States and many foreign jurisdictions have enacted or proposed legislative and regulatory changes affecting the healthcare system that could prevent or delay marketing approval of our product candidates, restrict or regulate post-approval activities and affect our ability to profitably sell any product candidate for which we obtain marketing approval. For example, then President Obama signed into law the Affordable Care Act. Among other cost containment measures, the Affordable Care Act established an annual, nondeductible fee on any entity that manufactures or imports branded prescription drugs and biologic agents, a Medicare Part D coverage gap discount program, and a formula that increased the rebates a manufacturer must pay under the Medicaid Drug Rebate Program. There have been executive, judicial and Congressional challenges to certain aspects of the Affordable Care Act. While Congress has not passed comprehensive repeal legislation, several bills affecting the implementation of certain taxes under the Affordable Care Act have been signed into law. The Tax Cuts and Jobs Act of 2017 includes a provision that repealed, effective January 1, 2019, the tax-based shared responsibility payment imposed by the Affordable Care Act on certain individuals who fail to maintain qualifying health coverage for all or part of a year that is commonly referred to as the “individual mandate.” On June 17, 2021, the U.S. Supreme Court dismissed a challenge on procedural grounds that argued the Affordable Care Act is unconstitutional in its entirety because the “individual mandate” was repealed by Congress. Thus, the Affordable Care Act will remain in effect in its current form. Moreover, prior to the U.S. Supreme Court ruling, January 28, 2021, President Biden issued an executive order that initiated a special enrollment period for purposes of obtaining health insurance coverage through the Affordable Care Act marketplace. The executive order also instructed certain governmental agencies to review and reconsider their existing policies and rules that limit access to healthcare, including among others, reexamining

Medicaid demonstration projects and waiver programs that include work requirements, and policies that create unnecessary barriers to obtaining access to health insurance coverage through Medicaid or the Affordable Care Act. It is possible that the Affordable Care Act will be subject to judicial or Congressional challenges in the future. It is unclear how any such challenges and the healthcare reform measures of the Biden administration will impact the Affordable Care Act and our business.

Other legislative changes have been proposed and adopted since the Affordable Care Act was enacted. For example, in August 2011, then President Obama signed into law the Budget Control Act of 2011, which, among other things, created the Joint Select Committee on Deficit Reduction to recommend to Congress proposals in spending reductions. The Joint Select Committee on Deficit Reduction did not agree upon a targeted deficit reduction of at least $1.2 trillion for fiscal years 2012 through 2021, triggering the legislation’s automatic reduction to several government programs. This included aggregate reductions to Medicare payments to providers of up to 2% per fiscal year, effective as of 2013. Further legislation has extended the 2% reduction to 2031 with the exception of a temporary suspension from May 1, 2020 through March 31, 2022 due to the COVID-19 pandemic, unless additional congressional action is taken. In January 2013, then President Obama signed into law the American Taxpayer Relief Act of 2012, which, among other things, reduced Medicare payments to several types of providers and increased the statute of limitations period for the government to recover overpayments to providers from three to five years.

Further, there has been increasing legislative and enforcement interest in the United States with respect to specialty drug pricing practices. Specifically, there have been several recent U.S. Congressional inquiries, Presidential executive orders, and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to drug pricing, review the relationship between pricing and manufacturer patient programs, reduce the cost of drugs under Medicare, and reform government program reimbursement methodologies for drugs. At the federal level, the Trump administration used several means to propose or implement drug pricing reform, including through federal budget proposals, executive orders and policy initiatives. For example, on July 24, 2020 and September 13, 2020, the Trump administration announced several executive orders related to prescription drug pricing that sought to implement several of the administration’s proposals. As a result, the FDA released a final rule and guidance in September 2020, providing pathways for states to build and submit importation plans for drugs from Canada. Further, on November 20, 2020, the U.S. Department of Health & Human Services, or HHS, finalized a regulation removing safe harbor protection for price reductions from pharmaceutical manufacturers to plan sponsors under Medicare Part D, either directly or through pharmacy benefit managers, unless the price reduction is required by law. The implementation of the rule has been delayed by the Biden administration from January 1, 2022 to January 1, 2023 in response to ongoing litigation. The rule also creates a new safe harbor for price reductions reflected at the point-of-sale, as well as a new safe harbor for certain fixed fee arrangements between pharmacy benefit managers and manufacturers, the implementation of which have also been delayed by the Biden administration until January 1, 2023. On November 20, 2020, the Centers for Medicare & Medicaid Services, or CMS, issued an interim final rule implementing the Trump administration’s Most Favored Nation, or MFN, executive order, which would tie Medicare Part B payments for certain physician-administered drugs to the lowest price paid in other economically advanced countries. On December 27, 2021, CMS issued a final rule that rescinded the interim final rule implementing the Trump administration’s Most Favored Nation executive order. In July 2021, the Biden administration released an executive order, “Promoting Competition in the American Economy,” with multiple provisions aimed at prescription drugs. In response to Biden’s executive order, on September 9, 2021, the U.S. Department of Health and Human Services, or HHS, released a Comprehensive Plan for Addressing High Drug Prices that outlines principles for drug pricing reform and sets out a variety of potential legislative policies that Congress could pursue as well as potential administrative actions HHS can take to advance these principles. No legislation or administrative actions have been finalized to implement these principles. Congress is also considering additional health reform measures. At the state level, legislatures are increasingly passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

It is also possible that additional governmental action is taken in response to the COVID-19 pandemic. We cannot predict the likelihood, nature or extent of government regulations that may arise from future legislation, administrative or executive action. We expect that the Affordable Care Act, as well as other current or future healthcare reform measures may result in more rigorous coverage criteria and in additional downward pressure on

the price that we receive for any approved product. This could seriously harm our future revenues. Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability or commercialize our products.

We do not currently have any sales, marketing or distribution experience or infrastructure.

In order to market any approved product candidate in the future, we must build our sales, marketing, managerial and other non-technical capabilities or make arrangements with third parties to perform these services, as we do not presently have all of these capabilities. To develop our internal sales, distribution and marketing capabilities, we must invest significant amounts of financial and management resources in the future. For drugs where we decide to perform sales, marketing and distribution functions ourselves, we could face a number of challenges, including that:

• we may not be able to attract and build an effective marketing or sales force;

• our direct or indirect sales and marketing efforts may not be successful; and

Alternatively, we may rely on third parties to launch and market our product candidates, if approved. We may have limited or no control over the sales, marketing and distribution activities of these third parties and our future revenue may depend on the success of these third parties. Additionally, if these third parties fail to comply with all applicable legal or regulatory requirements, the FDA or another governmental agency could take enforcement action that could jeopardize their ability and our ability to market our product candidates.

Product liability lawsuits against us could cause us to incur substantial liabilities and to limit commercialization of our product candidates.

SNDX US Equity

SNDX · 10-K · period ended 2021-12-31

Item 1. BUSINESS

Item 1A. Risk Factors

SNDX US Equity☆

SNDX · 10-K · period ended 2021-12-31

Item 1. BUSINESS

Item 1A. Risk Factors

SNDX US Equity