The study met the primary endpoint of reduction in severity of chorea, the cardinal motor feature in Huntington disease, as measured by change in the Unified Huntington’s Disease Rating Scale (UHDRS®) Total Maximal Chorea (TMC) score from baseline to the average score at weeks 10 and 12.
In the randomized, double-blind, placebo-controlled KINECT-HD study, treatment with valbenazine resulted in a placebo-adjusted mean reduction in the TMC score of 3.2 units (p < 0.0001), indicating a highly statistically significant improvement in chorea. The TMC score is part of the motor assessment of the UHDRS® and measures chorea in seven different body parts, including the face, oral-buccal-lingual region, trunk and each limb independently. The TMC score is the sum of the individual scores and ranges from 0 to 28. The secondary endpoints of Clinical Global Impression of Change (CGI-C) Response Status and Patient Global Impression of Change (PGI-C) Response Status were also statistically significant in favor of valbenazine treatment.
The treatment emergent adverse events observed in this trial were consistent with the known safety profile of valbenazine. No suicidal behavior or worsening of suicidal ideation was observed in the valbenazine-treated subjects in this study. Data from the Phase 3 KINECT-HD study will be presented at a medical conference in 2022.
HD impacts an estimated 30,000 adults in the United States. Chorea, an involuntary movement disorder characterized by irregular and unpredictable movements, is one of the most common symptoms, affecting roughly 90% of those diagnosed with Huntington disease over the course of disease progression.
KINECT-HD2 is an open-label study to evaluate the long-term safety and tolerability of valbenazine for the treatment of chorea in Huntington disease.