Long-term Edaravone Efficacy in ALS: Post-hoc Analyses of Study 19 (MCI186-19).

Background In a Phase 3 study, amyotrophic lateral sclerosis (ALS) patients experienced significantly less physical functional decline with 24-week edaravone vs placebo, followed by open-label treatment for an additional 24 weeks. Methods Outcome (the change in ALS Functional Rating Scale-Revised, ALSFRS-R, from baseline) was projected for placebo patients through 48 weeks and compared with 48-week edaravone or 24-week edaravone after switching from placebo. Results A total of 123 patients received open-label treatment (65 edaravone-edaravone; 58 placebo-edaravone). The projected ALSFRS-R decline for placebo from baseline through week 48 was greater than for 48-week edaravone (P < .0001). For patients switching from placebo to edaravone, ALSFRS-R slope approached that of continued edaravone for 48 weeks. ALSFRS-R decline did not differ between actual and projected edaravone through week 48. Conclusions Compared with placebo, these analyses suggest that edaravone is beneficial in ALS patients even after 6 mo of receiving placebo, and efficacy is maintained for up to 1 year.