Cytokinetics has received approval from the U.S. Food and Drug Administration (FDA) for its cardiac myosin inhibitor, aficamten, which will be marketed as Myqorzo. The drug is approved for use in adults with symptomatic obstructive hypertrophic cardiomyopathy (oHCM), a genetic condition that leads to thickening of the heart muscle and can cause symptoms such as shortness of breath.
The FDA's decision follows data from the MAPLE-HCM study, presented at the 2025 European Society of Cardiology Congress. In this study, patients treated with aficamten experienced a 1.1-mL/kg/min increase in peak oxygen consumption (pVO2), a key measure of exercise capacity, after 24 weeks. In contrast, those on standard-of-care beta-blocker metoprolol saw a decrease of 1.2 mL/kg/min in pVO2 during the same period.
Analysts had anticipated Cytokinetics would secure approval but focused on details regarding the Risk Evaluation and Mitigation Strategy (REMS). The FDA delayed its review by three months earlier this year to examine Cytokinetics’ REMS proposal more closely.
Stifel analysts noted that the approved REMS aligns with expectations and differs from Bristol Myers Squibb’s Camzyos program. They highlighted that Cytokinetics’ REMS allows physicians to adjust dosing as early as two weeks after starting treatment and perform echocardiogram assessments between two and eight weeks following dose initiation or any subsequent change. This approach permits titration after each echocardiogram without delay.
Andrew Callos, chief commercial officer at Cytokinetics, told analysts: “Patients on 10 or 15 mg of Myqorzo can expect to reach their target dose as quickly as four or six weeks, respectively.”
Stifel analysts also cited advantages such as flexible titration requirements, the ability to reduce dosage rather than interrupt treatment, and no need for drug-drug interaction monitoring under the new REMS guidelines.
However, both Myqorzo and Camzyos require maintenance echocardiograms every six months. Some have questioned how much this differentiates Myqorzo from its competitor. Stifel analysts commented: “Overall, aficamten requires fewer echos with a flexible and predictable clinical profile, that allows physicians to actually manage their patients as they see fit (vs. a rigid/formal algorithm essentially with Camzyos).”
Cytokinetics plans to launch Myqorzo in the second half of January and will announce pricing before then. Callos said pricing would be set roughly in line with current market levels.
According to Stifel analysts, annual sales for Camzyos are about $1.2 billion despite less than 20% market penetration by Bristol Myers Squibb. They estimate Myqorzo could address a $4.4 billion global opportunity in oHCM and an additional $1.2 billion potential in non-obstructive forms of hypertrophic cardiomyopathy.
