This study was a Phase III, multicenter, randomized, double-blind, placebo-controlled efficacy and safety study. DMD patients (ambulatory and non-ambulatory) at age 10-18 years were enrolled at sites in Europe and North America. Study subjects were randomized in a 1:1 ratio to receive either idebenone (900 mg/day) or placebo 3 times a day with meals for 52 weeks. The primary endpoint was the difference between Catena®/Raxone® and placebo in the change from Baseline to week 52 in Peak Expiratory Flow (PEF as percent predicted, PEF%p, a measure of respiratory muscle strength) as measured by hospital-based spirometry. PEF was also measured by the patient at home using the hand-held ASMA-1 device (secondary endpoint). Other respiratory endpoints included Forced Expiratory Volume in 1 second (as percent predicted, FEV1%p, an additional measure of respiratory muscle strength) and Forced Vital Capacity (as percent predicted, FVC%p, a measure of restrictive lung disease predictive of morbidity and mortality in DMD).
The aim of this Phase III study was to assess the efficacy of idebenone on pulmonary function, motor function, muscle strength and quality of life in patients with DMD. Furthermore, the safety and tolerability of idebenone was assessed.