Impact of Chorea on Self-care Activity, Employment, and Health-care Resource Use in Patients with Huntington's Disease

Safety and efficacy of valbenazine for the treatment of chorea associated with Huntington's disease (KINECT-HD): a phase 3, randomised, double-blind, placebo-controlled trial

BACKGROUND

Valbenazine is a highly selective vesicular monoamine transporter 2 (VMAT2) inhibitor approved for treatment of tardive dyskinesia. To address the ongoing need for improved symptomatic treatments for individuals with Huntington's disease, valbenazine was evaluated for the treatment of chorea associated with Huntington's disease.

METHODS

KINECT-HD (NCT04102579) was a phase 3, randomised, double-blind, placebo-controlled trial, performed in 46 Huntington Study Group sites in the USA and Canada. The study included adults with genetically confirmed Huntington's disease and chorea (Unified Huntington's Disease Rating Scale [UHDRS] Total Maximal Chorea [TMC] score of 8 or higher) who were randomly assigned (1:1) via an interactive web response system (with no stratification or minimisation) to oral placebo or valbenazine (≤80 mg, as tolerated) for 12 weeks of double-blinded treatment. The primary endpoint was a least-squares mean change in UHDRS TMC score from the screening and baseline period (based on the average of screening and baseline values for each participant) to the maintenance period (based on the average of week 10 and 12 values for each participant) in the full-analysis set using a mixed-effects model for repeated measures. Safety assessments included treatment-emergent adverse events, vital signs, electrocardiograms, laboratory tests, clinical tests for parkinsonism, and psychiatric assessments. The double-blind placebo-controlled period of KINECT-HD has been completed, and an open-label extension period is ongoing.

FINDINGS

KINECT-HD was performed from Nov 13, 2019, to Oct 26, 2021. Of 128 randomly assigned participants, 125 were included in the full-analysis set (64 assigned to valbenazine, 61 assigned to placebo) and 127 were included in the safety-analysis set (64 assigned to valbenazine, 63 assigned to placebo). The full-analysis set included 68 women and 57 men. Least-squares mean changes from the screening and baseline period to the maintenance period in the UHDRS TMC score were -4·6 for valbenazine and -1·4 for placebo (least-squares mean difference -3·2, 95% CI -4·4 to -2·0; p<0·0001). The most commonly reported treatment-emergent adverse event was somnolence (ten [16%] with valbenazine, two [3%] with placebo). Serious treatment-emergent adverse events were reported in two participants in the placebo group (colon cancer and psychosis) and one participant in the valbenazine group (angioedema because of allergic reaction to shellfish). No clinically important ch anges in vital signs, electrocardiograms, or laboratory tests were found. No suicidal behaviour or worsening of suicidal ideation was reported in participants treated with valbenazine.

INTERPRETATION

In individuals with Huntington's disease, valbenazine resulted in improvement in chorea compared with placebo and was well tolerated. Continued research is needed to confirm the long-term safety and effectiveness of this medication throughout the disease course in individuals with Huntington's disease-related chorea.

FUNDING

Neurocrine Biosciences.

Huntington's disease influences employment before and during clinical manifestation: A systematic review

Huntington's disease (HD) is an inherited neurodegenerative disease. People at risk for HD can choose to get predictive testing years before the clinical onset. HD is characterized by motor, cognitive and psychiatric symptoms and has a mean age at onset between 30 and 50 years, an age at which people are usually still working. This systematic review focuses on summarizing which disease-specific characteristics influence employment and working capacity in HD. Twenty-three studies were identified and showed that while employment and working capacity in HD are negatively influenced by cognitive decline and motor impairments, apathy already plays a role in the prodromal stage. Moreover, the influence of HD transcends the clinical manifestation of the disease, as some people at risk are already experiencing the impact of HD on employment through fear of or actual genetic discrimination. Employment and working capacity are not influenced by predictive testing for HD in and of itself.