Cytokinetics heart drug shows promise in trial, but analysts question modest benefits

Cytokinetics said on Friday detailed late-stage data showed its drug, aficamten, significantly improved symptoms and exercise capacity in patients with a genetic heart condition that currently has no approved treatments.

Its shares, however, fell 6% as Wall Street analysts focused on the treatment's modest benefits and safety concerns.

The drug is already approved as Myqorzo for oHCM or the obstructive form of the condition in which thickened heart muscles block blood flow.

The data showed that 53% of patients taking aficamten showed meaningful improvements in at least three of five key disease areas, such as stamina, symptom relief, and heart strain, compared to just 13% on a placebo, in the 517-patient study.

However, the drug did not significantly improve heart structure or delay cardiovascular events. About 10% of the patients also experienced a dangerous drop in their heart's pumping capacity, and 12 events of heart failure also occurred during the study.