Phase 3b Extension Study MT‐1186‐A04 to Evaluate the Continued Efficacy and Safety of Edaravone Oral Suspension for Up to an Additional 48 Weeks in Patients With Amyotrophic Lateral Sclerosis

INTRODUCTION/AIMS: An On/Off dosing regimen of intravenous (IV) edaravone and edaravone oral suspension is currently approved in the US for treatment of amyotrophic lateral sclerosis (ALS). Placebo-controlled clinical trials showed that IV edaravone slows physical functional decline. Study MT-1186-A04 continued to examine the efficacy and safety of investigational once daily and approved on/off dosing of edaravone oral suspension in patients with ALS. METHODS: Study MT-1186-A04 (NCT05151471) was a phase 3b, multicenter, randomized, double-blind, parallel group extension study for up to an additional 48 weeks following 48-week Study MT-1186-A02 that randomized patients to investigational once daily or approved 105-mg on/off dosing of edaravone oral suspension. Patients who met Study MT-1186-A04 eligibility criteria, including Study MT-1186-A02 completion, continued in the same treatment regimen as Study MT-1186-A02. The primary efficacy endpoint for MT-1186-A04 was time from randomization in Study MT-1186-A02 to a ≥ 12-point decrease in ALS Functional Rating Scale-Revised (ALSFRS-R) or death, whichever happened first. RESULTS: Over 96 weeks, including Study MT-1186-A02, daily dosing did not show a statistically significant difference vs. approved on/off dosing for the primary endpoint (p = 0.78). Edaravone oral suspension was well tolerated, and no new safety concerns were identified in either group. DISCUSSION: Similar to Study MT-1186-A02, once daily edaravone oral suspension in extension Study MT-1186-A04 did not show superiority in terms of the primary efficacy endpoint, but had equivalent efficacy, safety, and tolerability, compared with the approved On/Off regimen. The results reinforce the appropriateness of the approved dosing regimen.