Abstract
FORTITUDE-ALS was a study evaluating reldesemtiv in people living with ALS. Post-hoc analysis identified larger treatment effects in those with symptom onset ≤24 months and baseline ALSFRS-R ≤ 44 (24/44 criteria). Using the ENCALS risk score (RS), we analyzed how the 24/44 criteria changed the eligible population. Of the 272 participants meeting the 24/44 criteria, 73% had very short to intermediate RS compared to 18% not meeting the criteria. Though the 24/44 criteria enriched the FORTITUDE-ALS population with rapidly progressing patients, they did not completely exclude all patients with a very long predicted survival.