Trial status: This trial was completed and after a long FDA review has been approved for use in treating chorea of Huntington's disease.

Trial name:  TETRA-HD

FDA phase: Approved drug

Sponsor: Prestwick sponsored the trial but transferred the right to the drug to Ovation Pharmaceuticals

Trial design:  A randomized, double-blind, placebo-controlled, 12-week study conducted in 84 HD patients with significant chorea, at 16 study sites.

Outcome measures: Improvement in chorea and in doctors' general impressions of patient well-being (using the Unified Huntington's Disease Rating Scale and Clinical Global Improvement scale, respectively)

Results:  Compared to placebo, tetrabenazine reduced chorea on average by about 25 percent, with many patients experiencing greater improvement. Patients who received the medication were six times as likely to be considered considerably improved by their doctors.  Side effects included fatigue, sleepiness, risk of falls, depression, and one suicide.

Because of the risk of depression and possible increased risk of suicide a black box warning was required with marketing of tetrabenazine