Key Takeaways:
Cytokinetics' aficamten met both primary endpoints in the 517-patient ACACIA-HCM trial, the first positive Phase 3 study in non-obstructive hypertrophic cardiomyopathy.
"The results are consistent across prespecified subgroups and clinically impactful for these patients," Stephen Heitner, chief medical officer at Cytokinetics, said.
At 36 weeks, the Kansas City Cardiomyopathy Questionnaire Clinical Summary Score improved 3.0 points (95% CI 0.5-5.5, p=0.021) and maximal exercise performance, or pVO2, rose 0.67 ml/kg/min (95% CI 0.22-1.1, p=0.003) versus placebo. Both dual primary endpoints held across prespecified subgroups, including baseline ejection fraction, atrial fibrillation status and genotype. Key ranked secondary endpoints — NYHA functional class, a composite of two cardiopulmonary exercise parameters, and NT-proBNP — also reached statistical significance.
Cytokinetics plans to submit a supplemental new drug application to the FDA in the fourth quarter. The drug, already approved as MYQORZO for obstructive HCM in the U.S., China, the European Union and the United Kingdom, would become the first cardiac myosin inhibitor to treat the full spectrum of symptomatic HCM.
Aficamten was generally well tolerated. Left ventricular ejection fraction fell below 50 percent in 27 patients (10.5 percent) on aficamten versus two (0.8 percent) on placebo, with 21 of those 27 completing treatment at the same or lower doses. Serious adverse events occurred in 52 patients (20.2 percent) on aficamten versus 38 (14.7 percent) on placebo. Two participants had a serious heart failure event tied to ejection fraction below 50 percent, and all heart failure events occurred during dose titration or before week 12.
The results were presented in a Hot Line session at the European Society of Cardiology Congress 2026 in Munich and published in the New England Journal of Medicine. A global efficacy analysis showed 53 percent of aficamten patients responded in three or more of five clinical domains versus 13 percent on placebo.
The readout positions Cytokinetics to challenge Bristol Myers Squibb's Camzyos, approved for obstructive HCM in 2022, by expanding into the roughly half of HCM patients with the non-obstructive form. Shares rose 1.3 percent in premarket trading. Investors will watch the FDA filing in the fourth quarter and a potential approval decision next year.
This article is for informational purposes only and does not constitute investment advice.
