Ventilatory Investigation of Tirasemtiv and Assessment of Longitudinal Indices After Treatment for a Year

CY 4031 was a multi-national, double-blind, randomized, placebo-controlled, stratified, parallel group study of tirasemtiv in patients with ALS. The study had three phases: an open-label phase (2 weeks), a double-blind, placebo-controlled phase (48 weeks), and a double-blind, placebo-controlled tirasemtiv withdrawal phase (4 weeks). Patients who completed 2 weeks of treatment with open-label tirasemtiv (125 mg twice daily) were randomized 3:2:2:2 to placebo or one of three dose levels of tirasemtiv (250 mg/day, 375 mg/day, or 500 mg/day). Approximately 600 patients were planned to be enrolled into the open-label treatment phase. Patients taking riluzole at study entry could continue use of riluzole during the study as long as they had been on a stable dose for at least 30 days prior to study screening. In addition, for patients randomized to tirasemtiv, the riluzole dose was reduced to half the approved dose (ie, reduced to 50 mg once daily) because administration of tirasemtiv approximately doubles the exposure to concomitant riluzole. Patients randomized to placebo continued riluzole at 50 mg twice daily. This was accomplished without unmasking the study's blind as follows: 1. All patients on riluzole took their morning 50 mg dose of riluzole from their personal riluzole supply. 2. The sponsor supplied the evening riluzole dose as double-blind study medication, as follows: (a) for patients randomized to placebo, the double-blind, evening riluzole dose was 50 mg of active riluzole; (b) for patients randomized to tirasemtiv, the double-blind, evening riluzole dose was a matching placebo for riluzole.