Management Change/Compensation (Form 8-K)

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Resignation of Principal Financial Officer

On September 22, 2026, Gianluca Fuggetta, Senior Vice President of Finance, principal financial officer, and principal accounting officer of Gain Therapeutics, Inc. (the "Company"), notified the Company of his intention to resign from his positions with the Company, with such resignation to be effective September 30, 2026, in order to pursue other opportunities.

Appointment of Interim Chief Financial Officer

On September 24, 2026, the Company's board of directors appointed Gene Mack, the Company's current President and Chief Executive Officer, to serve as the Company's interim Chief Financial Officer, effective as of October 1, 2026. In connection with this appointment, Mr. Mack will continue in his roles as President and Chief Executive Officer and will assume the duties of the Company's principal financial officer and principal accounting officer until his successor is appointed or until his earlier resignation or removal, and until such time as a permanent replacement is named. The Company is engaged in an ongoing search for a permanent replacement to serve as its principal financial officer and principal accounting officer.

Mr. Mack's biographical information is set forth in the Company's Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 26, 2026, and is incorporated by reference herein. The compensatory and other material terms of Mr. Mack's employment with the Company will remain unchanged in connection with the foregoing.

There are no arrangements or understandings between Mr. Mack and any other persons pursuant to which Mr. Mack was selected as the Company's interim Chief Financial Officer. Mr. Mack does not have any family relationship with any of the Company's other directors or executive officers or any persons nominated or chosen by the Company to be a director or executive officer. Mr. Mack does not have any direct or indirect interest in any transaction or proposed transaction required to be reported under Item 404(a) of Regulation S-K.