This study was a two-part, multicenter, double-blind study in subjects with ALS to evaluate the safety and tolerability of dexpramipexole treatment, as well as the preliminary effects on measures of clinical function and mortality of dexpramipexole treatment.
In part 1, 102 subjects with ALS were randomized at 20 US sites to receive placebo, dexpramipexole at 50 mg/day; dexpramipexole at 150 mg/day; or dexpramipexole at 300 mg/day for 12 weeks. Participants who completed Part 1 were eligible to enroll into Part 2.
Part 2 was a randomized, double-blind, 2-arm, parallel-group, extension study evaluating the longer-term safety, tolerability, and clinical effects of oral administration of 2 dosage levels of dexpramipexole. In part 2, following a 4-week, placebo washout, continuing subjects received dexpramipexole at 50 mg/day or 300 mg/day as double-blind treatment for up to 72 additional weeks (Part 2 duration was up to a total of 76 weeks, including the 4 week placebo portion).
