Tirasemtiv: Phase IIa data

The double-blind, crossover, U.S. Phase IIa CY 4023 trial in 32 patients with generalized myasthenia gravis showed that single doses of 250 and 500 mg oral tirasemtiv significantly and dose-dependently improved QMG scores vs. placebo at 6 hours post-treatment (0.49-point reduction per 250 mg; p=0.02 for the trend compared to placebo). Cytokinetics said it has not yet reported data comparing each individual dose of tirasemtiv to placebo. According to the company, CY 4023 was a hypothesis-generating trial with no pre-specified single primary endpoint. The trial evaluated multiple assessments of skeletal muscle function and fatigue using QMG, pulmonary function test and MMT scores. Cytokinetics also said that tirasemtiv significantly increased percent predicted forced vital capacity (FVC) by 2.2% per 250 mg at 6 hours post-treatment vs. placebo (p=0.04 for the trend compared to placebo). Both doses of tirasemtiv were well tolerated with no premature terminations or serious adverse events reported. The most common adverse event reported was dizziness, which increased in frequency with dose. ...