UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

SYNDAX PHARMACEUTICALS, INC.

(Exact name of Registrant as Specified in Its Charter)

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

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 financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01 Other Events.

On December 19, 2023, Syndax Pharmaceuticals, Inc. (the “Company”) issued a press release announcing the closing of its recent public offering of common stock and the exercise in full of the underwriters' option to purchase additional shares. A copy of the press release is filed herewith as Exhibit 99.1. The information contained in the press release is incorporated by reference into this Current Report on Form 8-K.

Item 9.01 Financial Statements and Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Exhibit 99.1

Syndax Announces Closing of Public Offering of Common Stock and Exercise in Full of the Underwriters' Option to Purchase Additional Shares
 

WALTHAM, Mass., December 19, 2023 /PRNewswire/ -- Syndax Pharmaceuticals, Inc. (“Syndax,” the “Company” or “we”) (Nasdaq: SNDX), a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies, today announced the closing of its previously announced underwritten public offering of 12,432,431 shares of its common stock, which includes the exercise in full of the underwriters’ option to purchase 1,621,621 additional shares. The public offering price of each share of common stock was $18.50. The aggregate gross proceeds to Syndax from this offering, before deducting underwriting discounts and commissions and estimated offering expenses, were approximately $230.0 million. Following the closing of the Offering, Syndax has 84,809,736 shares issued and outstanding as of December 19, 2023.

Goldman Sachs & Co. LLC, J.P. Morgan, TD Cowen and Stifel acted as joint book-running managers for the offering. B. Riley Securities acted as manager for the offering.

The shares were offered pursuant to a “shelf” registration statement previously filed and declared effective by the Securities and Exchange Commission (SEC). A final prospectus supplement and accompanying prospectus relating to the offering were filed with the SEC and are available on the website of the SEC at www.sec.gov. Copies of the final prospectus supplement and accompanying prospectus relating to the offering may be obtained from: Goldman Sachs and Co. LLC, Attention: Prospectus Department, 200 West Street, New York, NY 10282, telephone: 866-471-2526, facsimile: 212-902-9316 or by emailing Prospectus-ny@ny.email.gs.com; J.P. Morgan Securities LLC, c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717, telephone: (866) 803-9204, or by emailing prospectuseq_fi@jpmchase.com; Cowen and Company, LLC, 599 Lexington Avenue, New York, NY 10022, by emailing Prospectus_ECM@cowen.com or by telephone at (833) 297-2926; or Stifel, Nicolaus & Company, Incorporated, Attention: Prospectus Department, One Montgomery Street, Suite 3700, San Francisco, California 94104, by telephone at (415) 364-2720 or by emailing syndprospectus@stifel.com.

This press release shall not constitute an offer to sell, or the solicitation of an offer to buy, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Syndax

Syndax Pharmaceuticals is a clinical stage biopharmaceutical company developing an innovative pipeline of cancer therapies. Highlights of the Company's pipeline include revumenib, a highly selective inhibitor of the menin–KMT2A binding interaction, and axatilimab, a monoclonal antibody that blocks the colony stimulating factor 1 (CSF-1) receptor. For more information, please visit www.syndax.com or follow the Company on Twitter and LinkedIn.

Cautionary Note on Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “may,” “will,” “expect,” “plan,” “anticipate,” “estimate,” “intend,” “believe” and similar

expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Syndax's expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties. Actual results may differ materially from these forward-looking statements. Factors that may cause Syndax's actual results to differ from those expressed or implied in the forward-looking statements in this press release are discussed in Syndax's filings with the SEC, including the “Risk Factors” sections contained therein, as well as the risks identified in the registration statement and the final prospectus supplement relating to the offering. These forward-looking statements are based on Syndax's expectations and assumptions as of the date of this press release. Except as required by law, Syndax assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available.

Syndax Contact

Sharon Klahre

Syndax Pharmaceuticals, Inc.

sklahre@syndax.com

Tel 781.684.9827

SNDX-G