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.