Dexpramipexole Fails Phase III Study in ALS Patients
Development efforts halted (Jan. 3)
Disappointing results have been reported from the phase III EMPOWER trial of dexpramipexole (Biogen Idec) in patients with amyotrophic lateral sclerosis (ALS).
The study did not meet its primary endpoint (a combined analysis of function and survival), and no efficacy was seen in the individual components of function or survival. The trial also failed to show evidence of efficacy in its key secondary endpoints. Additional analyses of multiple subpopulations failed to demonstrate any efficacy among these groups. Based on these results, the development of dexpramipexole will be discontinued.
The randomized, double-blind, placebo-controlled EMPOWER trial enrolled 943 patients with ALS. The patients were randomly assigned to receive either dexpramipexole or placebo. The primary endpoint was the Combined Assessment of Function and Survival (CAFS). In addition, the trial individually evaluated functional decline, survival, and respiratory decline, among other measures.
Dexpramipexole had shown neuroprotective properties in previous in vitro and in vivo studies and was believed to work by increasing the efficiency of mitochondria — the energy-producing portion of cells. Mitochondria in the motor neurons undergo significant stress in ALS patients. In a phase II study, dexpramipexole achieved its primary safety objective. It also showed a trend toward dose-related slowing of functional decline and a trend toward extending survival at the highest dosage (150 mg twice daily).
The drug received an orphan designation for the treatment of ALS from the FDA and was granted “fast track” status.
Source: Biogen Idec; January 3, 2013.