FDA approves new cytodynamic heart drug to compete with fast-growing BMS Med
Before the FDA makes a decision on Cytokinetics' obstructive hypertrophic cardiomyopathy drug, the open question is not whether the FDA will approve the drug, but how the product's labeling will match up with the Bristol-Myers Squibb drug first marketed in this indication.
The verdict has been rendered that the drug's label for aficamten has less restrictive safety and monitoring requirements, features that may help make the product more competitive. The FDA's approval late Friday makes the once-daily pill Cytokinetics' first commercial product. The South San Francisco-based biotech company will market the new drug under the brand name Myqorzo.
Hypertrophic cardiomyopathy (HCM) occurs when the heart muscle becomes abnormally thick, making it more difficult for the organ to pump blood. In obstructive HCM (oHCM), thicker heart muscle makes the inside of the left ventricle smaller and stiffer, limiting the heart's ability to pump blood. Symptoms include dizziness, fatigue and shortness of breath. This disease can progress to heart failure. Cytokinetics said more than 300,000 patients in the United States have been diagnosed with HCM, but noted the market may be larger, as an estimated 400,000 to 800,000 patients remain undiagnosed. Approximately half of HCM patients have oHCM.
Older heart medications, such as blood pressure-lowering beta-blockers and calcium channel blockers, can be used to treat oHCM, but they were not developed specifically for the disease and do not address its underlying causes. The thickening of the heart muscle is caused by excessive heart muscle contraction driven by a mutated version of myosin, a heart protein. Cytokinetics' Myqorzo is a small molecule inhibitor of myosin. Results from a placebo-controlled Phase 3 clinical trial suggest that the drug, taken once daily, helps increase the heart's ability to work during exercise, in addition to other measures of heart function.
BMS's Camzyos received FDA approval in 2022, making it the first drug developed specifically for adults with oHCM, validating the use of small molecules to inhibit cardiac myosin. In the first nine months of this year, BMS reported Camzyos sales of $714 million, an increase of more than 88% compared with the same period in 2024, putting it on track to achieve blockbuster status. But this drug also carries a risk of heart failure. Camzyzos causes the left ventricle to pump less blood with each contraction of the heart. A boxed warning on the product label flags this left ventricular ejection fraction (LVEF) risk. The FDA's approval of Camzyos also comes with a Risk Evaluation and Mitigation Strategy (REMS), a risk mitigation plan that requires echocardiography to monitor LVEF before starting the drug and during treatment.
The FDA's approval of Myqorzo for the treatment of adults with oHCM also highlights the risk of heart failure due to reduced LVEF, a risk outlined in the boxed warning. But analysts believe Cytokinetics' products have less restrictive labels. Leerink Partners analyst Roanna Ruiz said in a note to investors that Myqorzo's REMS requires fewer echocardiograms and offers greater flexibility in conducting echocardiograms during dosing initiation and dose titration. Cytokinetics drugs do not require pharmacy-level drug interaction screening, reducing the burden on pharmacists. Ruiz added that Myqorzo does not have the same embryo-fetal toxicity warning as Camzyos, which should allow Cytokinetics' drug to capture more women of childbearing age with oHCM. Cytodynamics highlighted these differences in its approval announcement.
“Our first FDA approval is a testament to the strength of our science and the bold, pioneering research that has established Cytokinetics as a leader in muscle biology,” said Robert Blum, president and CEO. “I am pleased that the approved label and REMS reflect Myqorzo's unique characteristics, including its simple, flexible dosing regimen, lack of monitoring for drug interactions, and predictable safety profile.”
Cytokinetics has ample capital to commercialize its new drugs. The company said in an investor presentation that it had about $1.25 billion in cash and investments as of the end of September. The company said prices for Myqorzo will be announced in January, when the new product is expected to be launched. But more clinical trials are underway, which could expand Myqorvo's label. A Phase 3 study in oHCM is testing it against standard-of-care beta-blockers; preliminary results released in May showed statistically significant improvements from baseline to week 24. Another phase 3 study is evaluating the drug in non-obstructive HCM. Success in this study could further differentiate Myqorzo from Camzyos, which failed Phase 3 testing for this indication earlier this year. Cytokinetics is also testing the drug in pediatric patients with HCM.
Myqorzo's growth opportunities extend overseas. Last week, Chinese regulators approved the drug for the treatment of oHCM. The regulatory decision triggered a landmark payment from Sanofi, which owns the rights to Cytokinetics' drug in China. Bayer owns the rights to the molecule in Japan. Cytokinetics retains European rights to Myqorzo. A key European Medicines Agency committee recently issued a positive opinion on the drug; a regulatory decision in Europe is expected in the first quarter of 2026.
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