Stifel analysts said the label for cardiac myosin inhibitor Myqorzo is in line with their expectations and is differentiated compared with BMS’ Camzyos.
Cytokinetics has won FDA approval of its cardiac myosin inhibitor, positioning the biotech to challenge Bristol Myers Squibb for the heart disease market.
The approval covers aficamten in adults with symptomatic obstructive hypertrophic cardiomyopathy (oHCM), an inherited disease that causes thickening of the heart muscles. People with oHCM have symptoms including shortness of breath. Cytokinetics, which calls the newly approved product Myqorzo, won approval after linking the molecule to significantly improved exercise capacity in patients with the disease.
With analysts expecting Cytokinetics to win approval, the details of the Risk Evaluation and Mitigation Strategy (REMS) were a key focus going into the decision. The FDA delayed the review by three months in May to give itself time to review the biotech’s REMS proposal.
Data from the MAPLE-HCM study, presented at the 2025 European Society of Cardiology Congress in September, showed that after 24 weeks of treatment, patients on aficamten saw a 1.1-mL/kg/min increase in pVO2, a measure of oxygen supply that indicates exercise capacity. Counterparts on the standard-of-care beta-blocker metoprolol saw a 1.2 mL/kg/min decrease in pVO2 over the same time span.
Stifel analysts said in a note to investors that the approved REMS is in line with their expectations and is differentiated compared with BMS’ Camzyos. Cytokinetics’ REMS gives physicians the flexibility to titrate as early as two weeks and perform echocardiogram assessments two to eight weeks after dose initiation and any subsequent dose change. A patient’s dosing may be titrated after each echo with no delay.
Andrew Callos, Cytokinetics’ chief commercial officer, said on a Friday call with analysts to discuss the approval that 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 listed the more flexible titration requirements alongside the ability to down-titrate, rather than interrupt treatment, and the absence of drug-drug interaction monitoring as positives of the REMS requirements.
Yet the need for Myqorzo patients to undergo maintenance echos every six months, the same cadence as people on Camzyos, has raised questions about how differentiated the new drug is versus its rival. Stifel analysts said the debate “ultimately misses the big picture,” which in their view is that the rigidity of Camzyos’ REMS is the biggest logistical burden.
“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),” the analysts said.
Cytokinetics plans to launch Myqorzo in the second half of January. Callos said the company will reveal pricing before the launch. The Cytokinetics executive reiterated the biotech’s plans to set a price that is roughly in line with current pricing in the category.
Stifel analysts said Cytokinetics can leverage BMS’ “significant market build-out, but with a best-in-class profile.” The analysts said annual Camzyos sales are around $1.2 billion, despite BMS penetrating less than 20% of the market. Myqorzo has a $4.4 billion global opportunity in oHCM, the analysts said, plus a potential $1.2 billion opportunity in the non-obstructive form of the disease.
