Bial Halts GBA1-Targeted Parkinson's Drug After Phase 2b Trial Misses Its Marks

The ACTIVATE study of BIA 28-6156, an oral enzyme activator designed for Parkinson's patients carrying a GBA1 gene mutation, did not slow disease progression compared with placebo. Portuguese drugmaker Bial has stopped further development of the drug for this use.

Bial, the Portugal-based biopharmaceutical company developing BIA 28-6156 (also known as pariceract), announced on June 8, 2026 that its Phase 2b ACTIVATE trial did not meet its primary endpoint or its key secondary efficacy endpoint, and that the company has discontinued development of the drug for Parkinson's disease linked to the GBA1 gene. The trial, registered as NCT05819359 on ClinicalTrials.gov, enrolled 273 people with Parkinson's disease and a confirmed pathogenic variant in GBA1 across 85 sites in 11 countries in Europe and North America, randomizing participants to one of two daily doses (10 mg or 60 mg) of the drug or placebo for roughly 18 months.

GBA1 mutations are among the most common known genetic risk factors for Parkinson's disease, and people who carry them tend to develop symptoms earlier and see faster progression than those with the more common, non-genetic form of the disease. BIA 28-6156 was designed as a brain-penetrant small molecule that binds to and activates glucocerebrosidase (GCase), the lysosomal enzyme that GBA1 encodes; reduced GCase activity has been linked in research to the buildup of misfolded proteins inside nerve cells. The therapy's rationale, boosting a genetically deficient enzyme to potentially slow the underlying disease process rather than just treat symptoms, made it one of several genetically targeted approaches to Parkinson's now in testing, alongside separate efforts aimed at the LRRK2 gene and at the protein alpha-synuclein.

According to Bial's announcement and to trade press coverage of the topline results, the primary endpoint measured time to clinically meaningful progression on motor aspects of daily living, and BIA 28-6156 did not separate from placebo on that measure or on the key secondary efficacy endpoint. The company reported that the drug was generally well tolerated, with no unexpected safety concerns identified in the trial. Bial said it plans to present detailed findings from ACTIVATE at scientific meetings and in a peer-reviewed publication; as of this report, full trial data, including endpoint-by-endpoint results and dosing comparisons, had not been made public beyond the topline summary.

Bial said it is continuing a separate study of BIA 28-6156 in people with varying degrees of kidney impairment, unrelated to the Parkinson's efficacy question; the company has not announced plans for a new therapy targeting GBA1-associated Parkinson's disease.