Efficacy and Safety of the Dopaminergic Stabilizer Pridopidine (ACR16) in Patients With Huntington's Disease.

OBJECTIVES:: To evaluate the efficacy and safety of the dopaminergic stabilizer pridopidine (ACR16) in patients with Huntington's disease (HD). METHODS:: In a randomized, double-blind, placebo-controlled, 4-week trial, patients with HD received pridopidine (50 mg/d, n = 28) or placebo (n = 30). The primary outcome measure was the change from baseline in weighted cognitive score, assessed by cognitive tests (Symbol Digit Modalities, verbal fluency, and Stroop tests). Secondary outcome measures included changes in the Unified Huntington's Disease Rating Scale, Hospital Anxiety and Depression Scale, Leeds Sleep Evaluation Questionnaire, Reitan Trail-Making Test A, and Clinical Global Impression of Change. Safety assessments were also performed. RESULTS:: There was no significant difference between pridopidine and placebo in the change from baseline of the weighted cognitive score. However, secondary measures such as affective symptoms showed trends toward improvement, and there was significant improvement in voluntary motor symptoms compared with placebo (P < 0.05). Pridopidine was well tolerated, with a safety profile similar to placebo. CONCLUSIONS:: Pridopidine shows promise as a treatment for some of the symptoms of HD. In this small-scale study, the most notable effect was improvement in voluntary motor symptoms. Larger, longer-term trials are warranted.