Cytokinetics, Incorporated (Nasdaq: CYTK) announced that its Phase 3 ACACIA-HCM clinical trial of aficamten in patients with symptomatic non-obstructive hypertrophic cardiomyopathy (nHCM) met both dual primary endpoints, according to results presented at the European Society of Cardiology Congress 2026 in Munich, Germany, and simultaneously published in The New England Journal of Medicine.

The trial of 517 participants showed statistically significant improvements from baseline to Week 36 compared to placebo in both the Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (KCCQ-CSS) and maximal exercise performance (pVO2). The KCCQ-CSS improvement for aficamten versus placebo showed a least square mean difference of 3.0 points (p=0.021), while pVO2 showed a difference of 0.67 ml/kg/min (p=0.003).

Key ranked secondary endpoints, including New York Heart Association Functional Class improvement, a composite cardiopulmonary exercise testing score, and NT-proBNP, also reached statistical significance. Statistical significance was not achieved for change in left atrial volume index or time to first cardiovascular event.

On safety, serious adverse events occurred in 20.2% of patients on aficamten compared to 14.7% on placebo. Left ventricular ejection fraction below 50% was observed in 10.5% of aficamten patients versus 0.8% on placebo. Non-fatal adverse events leading to early drug discontinuation occurred in 7.0% of aficamten patients and 1.9% of placebo patients.

A secondary global efficacy analysis showed 53% of aficamten patients demonstrated a clinical response across three or more of five efficacy domains at 36 weeks, compared to 13% on placebo. Those results were published separately in Circulation.

Based on these results, Cytokinetics said it plans to submit a supplemental New Drug Application to the U.S. Food and Drug Administration for aficamten in symptomatic nHCM in the fourth quarter of 2026. Aficamten, marketed as MYQORZO, is already approved in the U.S., China, European Union, and United Kingdom for symptomatic obstructive hypertrophic cardiomyopathy.