The primary efficacy endpoint in this study was the Total Maximal Chorea (TMC) score from the UHDRS at week 80 compared with baseline TMC score. TMC score at week 80 was also compared to TMC score at week 81 following the washout period. The UHDRS is a validated rating system used to measure the severity of Huntington's disease. The rating system ranges from 0 units (absent chorea symptoms) to 28 units (marked/prolonged chorea).

Data from this study demonstrate a statistically significant reduction in chorea in patients compared to baseline who completed 80 weeks of Xenazine treatment, with a mean reduction in the TMC score of 4.6 UHDRS units. At week 81, following a one week washout period, the mean TMC score increased 5.3 UHDRS units compared to week 80 (p<0.001), suggesting that continued use of Xenazine at an individualized dose maintains reduction of chorea associated with HD for up to 80 weeks and confirming results from the pivotal study where discontinuation of Xenazine treatment was associated with the return of chorea, but without significant worsening compared to baseline.

When mild and unrelated adverse events (AEs) were excluded, the most common AEs in this study reported in >5% of subjects (three or more) were sedation/somnolence, depressed mood, anxiety, insomnia, akathisia, fatigue, agitation, fall, dysphagia and dystonia. Thirty-nine patients reported at least one AE during the titration phase compared to 20 patients during the maintenance period. Insomnia, somnolence and diarrhea emerged during titration and resolved during the maintenance period. Twelve serious AEs were reported including two falls, two cancer diagnoses, a single suicide attempt, pneumonia, elective hip replacement with post-op agitation, agitation, anxiety, akathisia, and one abnormal CA 27-29 titer in a patient who later died due to metastatic breast cancer.

SOURCE Lundbeck Inc.