Q07Long-term safety and tolerability of pridopidine in patients with huntington's disease (HD): results of the mermaihd study open-label extension

• Published in: Journal of neurology, neurosurgery and psychiatry Vol. 83; no. Suppl 1; pp. A56 - fu-A57
• Main Authors: Squitieri, F, Landwehrmeyer, B, Reilmann, R, Rosser, A, Garcia de Yebenes, J, Prang, A, Ivkovic, J
• Format: Journal Article
• Language: English
• Published: 01.09.2012
• ISSN: 0022-3050
• DOI: 10.1136/jnnp-2012-303524.177

BackgroundThe MermaiHD study was a 6-month randomised placebo-controlled trial (RCT) examining the efficacy and safety of pridopidine (Huntexil registered , NeuroSearch A/S, Ballerup, Denmark) in patients with HD.AimsTo perform a 6-month open-label extension (OLE) to the RCT, to assess the long-term safety and tolerability of pridopidine.MethodsOLE eligible patients must have completed the RCT on treatment (placebo, pridopidine 45 or 90mg/day). All OLE patients received pridopidine 45mg/day (weeks 1-4) then 90mg/day (weeks 5-22). Exposure, AEs, withdrawals, dose de-escalation, vital signs, electrocardiogram data and laboratory parameters were recorded.ResultsSimilar numbers from each RCT group entered the OLE (n=113, 125 and 115 for placebo, 45mg/day and 90mg/day), of whom 86% completed the OLE. RCT baseline demographics (gender, race, age, height, weight and BMI) were similar between patients who did/did not enter the OLE, whereas treatment-emergent AEs were more common in those who did not enter (includes placebo group). Over the course of both studies, similar percentages from each group reported greater than or equal to 1 AE and greater than or equal to 1 SAE (80%, 81%, 83%; and 8%, 13%, 9%; for placebo, 45mg/day and 90mg/day) The AE profile during both studies was similar, with falls and worsening of chorea most common. In the OLE, the proportion of patients reporting greater than or equal to 1 AE was higher in those who received pridopidine in the RCT than received placebo (68% vs 57%). Worsening of chorea was more common in patients who received pridopidine in the RCT than received placebo (12.5% vs 6.2%), although in 9/30 pridopidine patients, worsening occurred after treatment discontinuation. After 52weeks of treatment, no clinically meaningful effects or safety concerns were identified for laboratory parameters and electrocardiogram results. In the first 12weeks of the RCT, a small but transitory increase in heart rate occurred in patients on pridopidine.ConclusionsPridopidine (up to 90mg/day) has a good safety profile and is well tolerated, for up to 1year of treatment.