Secondary End Point: CGI Global Improvement Scale
Physicians rated 69% of patients receiving Xenazine® (tetrabenazine)
as significantly improved on the Clinical Global Impression (CGI) Global Improvement
scale compared with 24% of patients receiving placebo (p=0.0063).3
Distribution of CGI Global Improvement ratings at Week 12 (end of maintenance phase)
by treatment group. Scores range from 1 for very much improved to 7 for very much
Change in Global Improvement Scores From Baseline3,4
CGI Global Improvement Scale5
- 7-point, physician-related scale that measures disease severity and patient’s improvement
or change relative to baseline state at beginning of intervention
- Physicians rate patients based on the following:
- “Rate total improvement whether or not in your judgment it is due entirely to drug
treatment. Compared to his condition at admission to the project, how much has he
Additional outcome measures
In general, measures of functional capacity and cognition showed no difference between
Xenazine and placebo. However, one functional measure (Part 4 of the UHDRS) showed
a decrement for patients treated with Xenazine compared with placebo, a difference
that was nominally statistically significant.2
A 3-item cognitive battery specifically developed to assess cognitive function in
patients with HD (Part 2 of the UHDRS) also showed a decrement for patients treated
with Xenazine compared with placebo, but the difference was not statistically significant.2
Pivotal study exploratory outcomes4
- Xenazine had no significant impact on the UHDRS Total Motor Scores
- Xenazine had an adverse impact on the UHDRS Functional Checklist, with the Xenazine
group worsening by 0.8 units and the placebo group improving by 0.4 units (p=0.02)
- Xenazine had no significant impact on UHDRS gait assessment, UHDRS parkinsonism
score, or any other exploratory outcome measures (Total Functional Capacity, Functional
Impact Scale, Independence Scale)
- Xenazine had no significant impact on the Barnes Akathisia Scale, UHDRS Behavioral
Assessment, Unified Parkinson’s Disease Rating Scale (UPDRS) swallowing, or UPDRS
- Xenazine had an adverse impact on Stroop word reading but not on other UHDRS measures
of cognitive function
- Xenazine and placebo had an improvement on the 17-itme HAM-D, but results favored
placebo over Xenazine
- "FDA Approves First Drug for Treatment of Chorea in Huntington's Disease", FDA News Release, August 15, 2008: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/2008/ucm116936.htm. Updated April 15, 2013. Accessed August 17, 2015.
- Xenazine [package insert]. Deerfield, IL: Lundbeck; June 2015.
- Tetrabenazine: briefing document for peripheral and central nervous system advisory
committee. Food and Drug Administration Web site. www.fda.gov/ohrms/dockets/ac/07/briefing/2007-4328b1-02-Prestwick.pdf
December 6, 2007. Accessed February 15, 2010.
- Huntington Study Group. Tetrabenazine as antichorea therapy in Huntington disease:
a randomized controlled trial. Neurology. 2006; 66(3):366-372.
- Guy W, ed. Clinical Global Impression (CGI). ECDEU Assessment Manual for Psychopharmacology.
Rockville, MD: US Department of Health, Education, and Welfare; 1976.