One-year safety and tolerability profile of pridopidine in patients with Huntington disease.

Abstract

To assess the 1-year safety profile of the dopaminergic stabilizer pridopidine in patients with Huntington disease. Patients received pridopidine 45 mg/day for 4 weeks then pridopidine 90 mg/day for 22 weeks in this 6-month open-label extension (OLE) of the 6-month MermaiHD randomized controlled trial (RCT). Any adverse events (AEs) were recorded. Patients were categorized by their RCT treatment group (placebo, pridopidine 45 mg/day, pridopidine 90 mg/day). Of the 386 patients who completed the RCT, 353 entered the OLE and 305 (86.4%) completed. In 1 year, similar percentages of patients from each group reported ≥1 AE (placebo, 79.6% [n = 90/113]; 45 mg/day, 80.8% [n = 101/125]; 90 mg/day, 82.6% [n = 95/115]) and ≥1 serious AE (8.0% [n = 9/113], 12.8% [n = 16/125], and 8.7% [n = 10/115], respectively). The AE profile across both studies was similar; falls and worsening of chorea were most commonly reported. During the OLE, more patients previously receiving pridopidine reported ≥1 AE (67.9% [n = 163/240]) than those who had received placebo (56.6% [n = 64/113]). Early in the RCT, small increases in heart rate were reported in patients receiving pridopidine. During 1 year, no clinically meaningful changes in laboratory parameters or EKG-related safety concerns were identified. Pridopidine (≤90 mg/day) has an acceptable safety profile and is well-tolerated for 1 year. This study provides Class IV evidence that pridopidine (≤90 mg/day) is generally safe and well-tolerated in patients with Huntington disease for up to 1 year.