Gain Therapeutics reports 12-month open-label data for rexaceract in Parkinson's disease

Gain Therapeutics, Inc. issued a press release on October 1, 2026 tied to a poster presented at the International Congress of Parkinson's Disease and Movement Disorders, held October 4-8, 2026 in Seoul, Korea, according to an 8-K filed the same day. The poster presents long-term open-label extension data from the Phase 1b study of rexaceract, showing stabilization of MDS-UPDRS scores over 360 days of dosing and what the company described as supporting disease-modifying potential in Parkinson's disease.¹

By August 31, 2026, enrollment status showed that 12 of 13 evaluable patients had finished the full 12-month dosing period in the open-label extension, with one more participant expected to complete dosing in November 2026.¹ Among the 12 evaluable patients, motor scores on the MDS-UPDRS stayed stable across the 12 months, with no clinically meaningful worsening on Parts II and III of the scale.¹ For context, the filing notes that a clinically meaningful worsening is typically defined as roughly a 6-point combined increase in MDS-UPDRS Parts II and III over a year, matching the average annual decline seen in early-stage Parkinson's patients.¹

The filing also reported biomarker findings: patients with both high and low baseline cerebrospinal fluid levels of glucosylsphingosine (GluSph) showed stable MDS-UPDRS scores at 12 months, and those starting with high GluSph saw a sharp drop toward normal levels within 90 days along with a faster initial response to treatment.¹

On safety, the company said preliminary long-term data indicate rexaceract is safe and generally well tolerated over 12 months, with no new safety signals and fewer treatment-emergent adverse events in the nine-month extension than in the initial three-month phase.¹

Gain said it plans to submit a new Phase 2 protocol to the FDA in the coming weeks and start a Phase 2 trial of rexaceract in Parkinson's disease patients in the first quarter of 2027.¹