Tirasemtiv: Additional Phase IIb data

Cytokinetics reported secondary endpoint data from the double-blind, placebo-controlled, international Phase IIb BENEFIT-ALS trial in 711 patients with ALS evaluating twice-daily oral tirasemtiv at the American Academy of Neurology meeting in Philadelphia. Tirasemtiv significantly reduced the decline of slow vital capacity - a measure of the strength of the skeletal muscles responsible for breathing - vs. placebo (p=0.0006 for the difference in slope of decline). Additionally, declines in slow vital capacity were significantly less in patients receiving tirasemtiv at week 8 (2.85% vs. 5.81%, p=0.004) and at week 12 (3.12% vs. 8.66%, p<0.0001) vs. placebo. Cytokinetics also said that muscle strength mega-score - a measure of strength combining data from several muscle groups - declined more slowly in patients receiving tirasemtiv compared to placebo (p=0.016 for the difference in slope of decline), but there were no significant differences on the endpoint between treatment groups at any time point (p=0.61 at week 8 and p=0.205 at week 12). Additionally, the rate of decline for SNIP scores was not significantly different between treatment groups (p=0.21 for the difference in slope of decline) and there were no significant differences between treatment groups in MVV or hand grip fatigue scores.

Serious adverse events during the double-blind portion of the trial were reported more frequently in the tirasemtiv arm vs. the placebo arm (9% vs. 5.4%). The most common serious adverse event was respiratory failure which occurred in 1 patient receiving tirasemtiv and 3 patients receiving placebo. Confusional state and delirium occurred in 2 patients receiving tirasemtiv vs. 0 patients receiving placebo. The most common adverse events reported in the tirasemtiv arm compared to the placebo arm were dizziness, fatigue and nausea. ...