Valbenazine Shows Long-Term Efficacy for Patients With Huntington Disease Chorea

Valbenazine has shown promise as a treatment for Huntington disease (HD) chorea with long-term efficacy, according to study findings presented at the Huntington Study Group (HSG) 2023 Annual Meeting, held from November 2 to 4 in Phoenix, Arizona.

KINETIC-HD2 (ClinicalTrials.gov Identifier: NCT04400331) is an ongoing randomized, double-blind, placebo-controlled phase 3 open-label study designed to evaluate the long-term safety and tolerability of valbenazine in patients with HD chorea. Researchers included patients who completed the KINECT-HD trial (ClinicalTrials.gov Identifier: NCT04102579). The study included 127 adults aged 18 to 75 who have been diagnosed with genetically confirmed motor-manifest HD with sufficient chorea symptoms. Patients received valbenazine 40 mg once daily — with a target daily maintenance dose of 80 mg — for up to 156 weeks.

Efficacy outcomes include mean changes from baseline in the Unified Huntington Disease Rating Scale Total Maximal Chorea (TMC) and response status for Clinical Global Impression of Change (CGC-I) and Patient Global Impression of Change (PGI-C).

Among patients who received valbenazine 40 mg (n=118), the researchers observed a reduction in mean TMC score [SD] by week 2 (-3.4 [3.1]). This reduction was sustained in patients who received valbenazine 80 mg or lower from week 8 (-5.6 [3.6]; n=110) through week 50 (-5.8 [4.1]; n=66). At week 50, 76.9% (n=50/65) of CGI-C responders and 74.2% (49/66) of PGI-C responders rated symptoms as “much improved” or better.

Among 125 participants who received treatment, 119 reported at least 1 treatment-emergent adverse event (falls, 30.4%; fatigue, 24.0%; somnolence, 24.0%), which resulted in 17 participants to discontinue treatment.

The researchers concluded that “long-term treatment with once-daily valbenazine was well tolerated and provided clinically meaningful improvement in chorea severity for up to [approximately] 1 year.”