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.

Subthalamic nucleus deep brain stimulation for severe idiopathic dystonia: impact on severity, neuropsychological status, and quality of life.

OBJECT: Medically refractory dystonia has recently been treated using deep brain stimulation (DBS) targeting the globus pallidus internus (GPI). Outcomes have varied depending on the features of the dystonia. There has been limited literature regarding outcomes for refractory dystonia following DBS of the subthalamic nucleus (STN). METHODS: Four patients with medically refractory, predominantly cervical dystonia underwent STN DBS. Intraoperative assessments with the patients in a state of general anesthesia were performed to determine the extent of fixed deformities that might predict outcome. Patients were rated using the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) preoperatively and 3 and 12 months following surgery by a rater blinded to the study. Mean changes and standard errors of the mean in scores were calculated for each subscore of the two scales. Scores were also analyzed using analysis of variance and probability values were generated. Neuropsychological assessments and quality of life ratings using the 36-Item Short Form Health Survey (SF-36) were evaluated longitudinally. RESULTS: Significant improvements were seen in motor (p = 0.04), disability (p = 0.02), and total TWSTRS scores (p = 0.03). Better outcomes were seen in those patients who did not have fixed deformities. There was marked improvement in the mental component score of the SF-36. Neuropsychological function was not definitively impacted as a result of the surgery. CONCLUSIONS: Deep brain stimulation of the STN is a novel target for dystonia and may be an alternative to GPI DBS. Further studies need to be performed to confirm these conclusions and to determine optimal candidates and stimulation parameters.

Long-term outcomes of bilateral subthalamic nucleus stimulation in patients with advanced Parkinson's disease.

BACKGROUND: In patients with advanced Parkinson's disease (PD), deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been shown to improve motor function and decrease medication requirements in the short term. However, the long-term benefits of DBS are not yet established. OBJECTIVE: It was the aim of this study to evaluate long-term outcomes of patients with PD treated with bilateral DBS of the STN. DESIGN AND METHODS: Thirty-three subjects who had bilateral STN DBS were followed prospectively after surgery. We evaluated subjects, using the Unified Parkinson's Disease Rating Scale (UPDRS), preoperatively, 12 months after surgery and at a long-term follow-up visit. Ratings were performed on and off dopaminergic medications. We compared postoperative UPDRS scores, dyskinesia ratings and medication dosages with preoperative values. RESULTS: Twenty-seven subjects had evaluations beyond 18 months (median 33.7 months). Total UPDRS scores in the 'medication-off' state were improved by 37% (p < 0.001) at 12 months and 17.7% (p = 0.0051) at the long-term evaluation. Medication-off state UPDRS part III scores were significantly improved at both 1 year and at the last evaluation (37.6 and 29.3%; p < 0.001). Dopaminergic medication requirements were decreased by 35.3% (p < 0.001) during the first postoperative year and remained below preoperative levels at the long-term evaluation. Average duration of 'off' time remained decreased by about 40% at both 1 year and at the time of last evaluation. Subjects had a sustained reduction in dyskinesia severity (88.6% at 1 year and 68.8% at last evaluation). CONCLUSIONS: In this cohort of subjects with advanced PD, bilateral STN stimulation improved 'off' medication motor function, reduced time spent in the medication-off state and reduced medication requirements for up to 4 years after surgery. We conclude that STN DBS is an effective long-term therapy for selected patients with advanced PD.