Company: GANX
Filing Date: 2025-11-28
Form Type: 424B5
Source: 0001104659-25-116944
Chunk: 6

Company: Gain Therapeutics, Inc.
Filing Date: 2025-11-28
Form: 424B5
Chunk 6
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Case activity in dried blood spots increased approximately 53% in subjects who received 13.5 mg/kg GT-02287 (the highest dose cohort and the only dose cohort analyzed for GCase activity) but not in those who received placebo, demonstrating target engagement and modulation of GCase enzyme. GCase activity continued to increase 12 hours post-dose at 14 days, the furthest time point analyzed in the study. We believe these results support the continued development of GT-02287 and its potential as a biology-modifying treatment for Parkinson’s disease. Importantly, the favorable safety and tolerability profile at oral dose levels that resulted in therapeutic plasma levels, CNS exposure, and target engagement further strengthens GT-02287’s potential to be a lead treatment for Parkinson’s disease in patients with or without a GBA1 mutation.

In December 2024, we received approval in Australia to initiate a Phase 1b trial for GT-02287 in people with Parkinson’s disease with or without the GBA1 mutation. We are working with local Parkinson’s disease (PD) advocacy groups in Australia to support enrollment and expect enrollment to complete in the summer

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of 2025 with interim data from the study expected by mid-2025. The Phase 1b open-label trial will assess the safety and tolerability of 13.5 mg/kg/day of GT-02287 for three months in patients with GBA1-PD or idiopathic Parkinson’s disease. Secondary endpoints include pharmacokinetics, GCase modulation, levels of GCase substrates, and other biomarkers in plasma and cerebrospinal fluid. The primary goal of the Phase 1b trial is to assess the safety and tolerability of GT-02287. Upon successful completion we expect to begin planning a Phase 2 study during the second half of 2025.

In preparation for the treatment of Parkinson’s disease patients, we initiated a chronic (6 months in rodents and 9 months in non-rodents) preclinical toxicity study in July 2024, enabling the conduct of clinical studies in patients with a GT-02287 treatment duration beyond three months. The 6- and 9-month studies were completed in the second quarter of 2025 and the third quarter of 2025, respectively.

In October 2025, the Company presented early results from its Phase 1b clinical study in patients with Parkinson’s Disease at the International Congress of Parkinson’s