Abstract
While randomized controlled trials (RCTs) are the gold standard for evaluating the efficacy of therapies in amyotrophic lateral sclerosis (ALS), post hoc analyses can provide critical insights into clinical effectiveness, treatment durability, and subpopulation responses. Several post hoc analyses of Study MCI186‐19 (Study 19), the pivotal phase 3 RCT that supported the United States Food and Drug Administration approval of intravenous edaravone, have been performed to explore the broader clinical impact of this therapy. These analyses assessed the long‐term treatment efficacy, changes in individual ALS Functional Rating Scale–Revised item scores, survival and additional milestone events, and the impact of edaravone in patient subgroups defined by disease progression trajectories using latent class analysis. Collectively, these findings reinforce the long‐term clinical benefit of edaravone and demonstrate that edaravone may offer benefits across a spectrum of ALS disease trajectories, beyond those defined in the original study criteria. These studies help address questions not captured in the original RCT and may inform future trial design and treatment decisions.