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

Date of Report (Date of earliest event reported): May 14, 2026

COLLEGIUM PHARMACEUTICAL, INC.

(Exact Name of Registrant as Specified in its Charter)

Registrant’s telephone number, including area code: (781) 713-3699

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

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 (see General Instruction A.2. below):

¨  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))

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.  ¨

On May 14, 2026, Collegium Pharmaceutical, Inc. (the “Company”) held its 2026 Annual Meeting of Shareholders (the “Annual Meeting”). A total of 32,406,969 shares of common stock of the Company were entitled to vote as of March 31, 2026, the record date for the Annual Meeting, of which 29,210,926 were present in person or by proxy at the Annual Meeting.  The following is a summary of the final voting results for each matter presented to shareholders.

PROPOSAL 1:

Election of eight Directors to hold office until the 2027 Annual Meeting of Shareholders.

Each of Rita Balice-Gordon, Garen Bohlin, Michael Donovan, John Freund, Vikram Karnani, Nancy Lurker, Carlos Paya and Gino Santini was elected by the Company’s shareholders as Directors to hold office until the 2027 Annual Meeting of Shareholders.

PROPOSAL 2:

Approval of, on an advisory basis, the compensation of the Company’s named executive officers.

On an advisory basis, the Company’s shareholders approved the compensation of the Company’s named executive officers.

PROPOSAL 3:

Ratification of the appointment of Deloitte & Touche LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026.

Proposal 3 was approved by the Company’s shareholders.

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.