Material Event (Form 8-K)

Item 8.01. Other Events.

On June 29, 2026, Gain Therapeutics, Inc. (the "Company") announced that the U.S. Food and Drug Administration ("FDA") has authorized the Company's Investigational New Drug application for GT-02287. FDA's decision will allow initiation of the Company's Phase 2 clinical development of GT-02287 in Parkinson's disease with or without a GBA1 mutation in the U.S. Both the Phase 1a and Phase 1b studies of GT-02287 were conducted in Australia. The sites in Australia are expected to also participate in the Phase 2 study along with new sites in the U.S. and select European centers. The initiation of the Phase 2 study of GT-02287 is anticipated to occur during the third quarter of 2026.

The planned Phase 2a study of oral GT-02287 in treated and untreated participants with early Parkinson's disease is expected to enroll participants across sites in the United States, Australia, and Europe. The Company expects initiation of the Phase 2a in the third quarter of 2026.