Huntington’s Disease Drug Greatly Lowers Chorea Symptoms

According to a recent international study led by UTHealth Houston researcher Erin Furr Stimming, MD, who served as principal investigator on behalf of the KINECT-HD Huntington Study Group, the drug valbenazine statistically improves chorea, a movement disorder commonly associated with Huntington’s disease, when compared to a placebo.

The study results—which were published in The Lancet Neurology—come one year after Furr Stimming, professor of neurology and Memorial Hermann Chair with McGovern Medical School at UTHealth Houston, presented an early abstract of the findings at the American Academy of Neurology 2022 Annual Meeting in Seattle.

“Positive study results remind us there is a reason for hope,” said Furr Stimming, who is also director of the Huntington’s Disease Society of America Center of Excellence at UTHealth Houston Neurosciences. “Chorea associated with Huntington’s disease can negatively impact quality of life and functional independence; therefore, studying additional medications to address this hallmark motor symptom is imperative.”

The 128-person Phase III, randomized, double-blind, placebo-controlled KINECT-HD research was aimed to assess the efficacy of valbenazine as a once-daily treatment to diminish chorea associated with Huntington disease, as well as the drug’s safety and tolerability. Valbenazine is a selective vesicular monamine transporter 2 (VMAT 2) inhibitor that has not yet received FDA approval. Chorea is an uncontrollable, irregular movement that is the hallmark of Huntington’s disease.

In patients with Huntington’s disease, valbenazine showed a statistically significant reduction in chorea symptoms and improvement in total chorea severity when compared to placebo. Improvement could be evident as early as the second week of the study, when subjects completed the lowest study dose (40 mg), with continuously better improvement compared to the placebo in all following visits as the dose was modified in intervals. By the end of the 12-week experiment, 82% of those given valbenazine were taking 80 mg.

Notably, KINECT-HD was the first Phase III trial to use the Huntington’s Disease Health Index (HD-HI). The HD-HI is a patient-reported outcome measure used to assess clinically significant changes in Huntington’s disease function in response to therapeutic interventions. In comparison to the placebo group, patients who received valbenazine reported greater mobility and hand/arm function, as well as a lower load from aberrant motions.

“We are incredibly grateful to the participants and care partners for their dedication to this study,” Furr Stimming said.

Neurocrine Biosciences, a biopharmaceutical company, submitted a supplementary New Drug Application to the FDA in December 2022 for valbenazine as a treatment for chorea associated with Huntington’s disease. By August 20, 2023, the organization is scheduled to react to the submission. The study’s findings were disclosed in the filing.

Huntington’s disease is a rare, genetic disease that normally manifests itself in a person’s 30s or 40s and causes nerve cells in the brain to degrade over time. Around 40,000 people in the United States have the lethal condition, and another 200,000 are at danger of inheriting it. There is no cure, although drugs as well as physical, speech, and occupational therapy can help control symptoms.

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