A phase 3, double-blind, placebo-controlled trial of idebenone in friedreich ataxia.

OBJECTIVE: To assess the efficacy of idebenone on neurological function in patients with Friedreich ataxia.

DESIGN: Randomized, double-blind, placebo-controlled intervention trial.

SETTING: Children's Hospital of Philadelphia and the University of California at Los Angeles.

PARTICIPANTS: Seventy ambulatory pediatric patients (age, 8-18 years) with a baseline International Cooperative Ataxia Rating Scale (ICARS) score of 10 to 54.

INTERVENTIONS: Participants were randomized into 1 of 3 treatment arms: 450 or 900 mg of idebenone per day (in those with a body weight < or = or >45 kg, respectively; n = 22); 1350 or 2250 mg of idebenone per day (n = 24); or placebo (n = 24).

MAIN OUTCOME MEASURES: Mean change from baseline to week 24 in ICARS score was the primary efficacy variable. Mean change in Friedreich Ataxia Rating Scale (FARS) score, performance measures, and activities of daily living were the secondary efficacy variables.

RESULTS: Patients who received idebenone improved by 2.5 points on mean ICARS score compared with baseline, while patients in the placebo group improved by 1.3 points. Patients who took idebenone also improved by 1.6 points on the FARS, while patients taking placebo declined by 0.6 points. For both end points, the difference between the idebenone and placebo groups was not statistically different.

CONCLUSIONS: Idebenone did not significantly alter neurological function in Friedreich ataxia during the 6-month study. Larger studies of longer duration may be needed to assess the therapeutic potential of drug candidates on neurological function in Friedreich ataxia. Trial Registration clinicaltrials.gov Identifier: NCT00537680.