In a Phase 2b clinical trial evaluating the safety, tolerability and efficacy of Cytokinetics' (CYTK) tirasemtiv in ALS patients versus placebo, the drug fails to meet its primary efficacy endpoint of the mean change from baseline in the ALS Functional Rating Scale in its revised form (ALSFRS-R) compared to the average of the scores at eight and twelve weeks versus placebo (-2.98 points in the tirasemtiv group versus -2.40 in the placebo group, p=0.11).
The test group did, however, demonstrate a statistically significant reduction in the decline of Percent Predicted Slow Vital Capacity (SVC) (a measure of the strength of the skeletal muscles responsible for breathing). The SVC declined in the control group by 8.66% versus 3.12% in the tirasemtiv group.
The Muscle Strength Mega-Score, a measure of strength combining the data from several muscle groups in each patient, declined more slowly in the test group but no point reached statistical significance.
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