Interim Data from KINECT-HD2 Study Indicates Ingrezza Treatment Leads to Sustained Long-Term Improvements in Chorea Symptoms Associated with Huntingdon Disease

Researchers reported that Ingrezza treatment was associated with long-term improvements through 50 weeks in patients with chorea symptoms associated with Huntington disease (HD). Results from this analysis of interim data from the KINECT-HD2 (NCT04400331) open-label extension (OLE) study were presented at the 30th Annual Meeting of the Huntington Study Group.

KINECT-HD2 is a phase 3, randomized, double-blind, placebo-controlled OLE study evaluating the long-term safety and tolerability of Ingrezza as a treatment for chorea associated with HD. The majority of the participants (n=98) were carried over from the phase 3 KINECT-HD clinical trial (NCT04102579), which found that treatment with Ingrezza was associated with significant reductions in severity and frequency of chorea symptoms from weeks 2 to 12. The positive results from KINECT-HD were the basis of the Food and Drug Administration (FDA) decision to approve Ingrezza in August 2023.

In KINECT-HD2, the primary outcome measure is the number of participants experiencing treatment-emergent adverse events (TEAEs) up to 156 weeks, with change from baseline in Unified Huntington’s Disease Rating Scale (UHDRS) Total Maximum Chorea (TMC) score measured as a secondary outcome to assess chorea symptoms. According to interim data, participants who received Ingrezza showed a mean change from baseline in TMC score of -3.4 points at week 2, which was the lowest dose period (40 mg). Participants showed continued improvement up to 50 weeks with an average change in TMC score of -5.8, at which point they received doses of ≤ 80 mg.

At week 6, 60.9% of participants and 58.9% of investigators rated symptoms as either much improved or very much improved, which increased to 74.2% of participants and 76.9% of investigators by week 50. The most common TEAEs reported were falls, fatigue, and somnolence, which were consistent with those reported in KINECT-HD. Ingrezza’s prescribing information contains a black box warning for the risk of depression and suicidal ideation.

“These interim data provide insight on the clinically meaningful and sustained improvements participants are experiencing with INGREZZA for the treatment of chorea,” said Eiry W. Roberts, MD, Chief Medical Officer at Neurocrine Biosciences. “We look forward to analyzing additional data as they become available.”