Cytokinetics’ aficamten outperformed standard of care (SoC) in a Phase III trial in patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM), marking a win for the candidate that is currently under approval review in the US
In the Phase III MAPLE-HCM trial (NCT05767346), aficamten was pitted against metoprolol, a SoC beta blocker. In the study, aficamten increased predicted peak oxygen uptake (pVO2) by 1.1mL/kg/min after 24 weeks, while patients treated with metoprolol saw a 1.2mL/kg/min decrease – a least-squares mean (LSM) difference of 2.3mL/kg/min, meeting the primary endpoint.
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Five of the six secondary endpoints were also achieved, including an improvement in functional class and a reduction in symptom burden.
Of those treated with aficamten, 51% had an improvement of one or more functional class in the New York Heart Association (NYHA) functional class compared to 26% receiving metoprolol.
Aficamten also improved resting left ventricular outflow tract gradient (LVOT-G) by -30mmHg and Valsalva LVOT-G by -35mmHg. The only endpoint that saw no significant difference was left ventricular mass index (LVMI).
The data was announced during a Hot Line Session at the European Society of Cardiology Congress 2025 in Madrid, Spain.
Cytokinetics added that adverse events (AEs) were similar between groups; however, one patient receiving aficamten, a 69-year-old woman with multiple co-morbidities, developed a viral illness and subsequently died. Three patients receiving metoprolol terminated treatment due to AEs.
The US Food and Drug Administration (FDA) is reviewing a New Drug Application (NDA) for Cytokinetics’ drug in oHCM with a Prescription Drug User Fee Act (PDUFA) date of 26 December 2025. This application was based on the successful Phase III SEQUOIA-HCM trial (NCT05186818), which compared the drug to a placebo.
Aficamten is a myosin inhibitor that acts by relaxing the heart’s left ventricle so it can sufficiently fill with blood before pumping.
Cytokinetics’ drug could become SoC in oHCM
Based on the Phase III trial showing the drug’s superiority over SoC beta blockers, Dr Pablo Garcia-Pavia, head of Hospital Universitario Puerta de Hierro’s Inherited Cardiac Diseases and Heart Failure Unit, said the data could better inform physicians’ approach to treating oHCM.
Serving as principal investigator of the study, Garcia-Pavia said: “In showing that aficamten is superior to metoprolol on all clinically relevant efficacy endpoints, these results call into question the reliance on beta-blockers as the initial treatment modality for obstructive HCM that has prevailed for over 60 years.”
GlobalData predicts that aficamten will reach blockbuster status in 2029, with $2.42bn estimated sales in 2031.
GlobalData is the parent company of Clinical Trials Arena.
Other than beta blockers, Cytokinetics’ drug will also be competing with Bristol Myers Squibb’s (BMS’s) Camzyos (mavacamten), also a myosin inhibitor, which gained approval by the FDA in April 2022.
Experts predict that while BMS holds the first to market advantage in this class, aficamten’s favourable safety profile may make it more preferable to patients. This is not, however, reflected in GlobalData’s sales forecast, which predicts BMS’s drug to reach a slightly higher $2.58bn in sales in 2031.
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