Cytokinetics plummets on tirasemtiv miss

Cytokinetics Inc. (NASDAQ:CYTK) fell $8.40 (65%) to $4.59 on Friday after the company said tirasemtiv, its lead unpartnered compound, missed the primary endpoint in the Phase IIb BENEFIT-ALS trial to treat amyotrophic lateral sclerosis (ALS). Twice-daily oral tirasemtiv (formerly CK-2017357) did not improve mean ALS Functional Rating Scale-Revised (ALSFRS-R) total score from baseline to week 12 vs. placebo (p=0.11). Cytokinetics said tirasemtiv "produced mixed results" on secondary endpoints of respiratory function and other measures of skeletal muscle function. The double-blind, international trial enrolled 711 ALS patients. Data are slated to be presented at the American Academy of Neurology meeting next week.

Cytokinetics said it will fully evaluate the BENEFIT-ALS data before determining next steps for tirasemtiv. The fast skeletal muscle troponin activator has also completed Phase IIa trials to treat myasthenia gravis and claudication associated with peripheral artery disease (PAD). ...