Mavacamten (Camzyos; Bristol-Myers Squibb Company), a cardiac myosin inhibitor, demonstrates a favorable safety profile and efficacy in treating symptomatic, obstructive hypertrophic cardiomyopathy (HCM) patients under the FDA's Risk Evaluation and Mitigation Strategy (REMS) program. A recent report presented at the AHA 2024 Scientific Sessions detailed the 22-month real-world experience with mavacamten, involving over 5,500 patients in the United States.
The REMS program, mandated by the FDA, ensures that the benefits of a newer drug therapy outweigh the risks by informing patients, physicians, and pharmacies. The study focused on the incidence of ejection fraction drops, heart failure hospitalizations, and efficacy in reducing outflow tract gradients.
Key Findings from the REMS Program
The data revealed that the risk of ejection fraction drop was low, around 4.6%, and the risk of heart failure hospitalization was even lower, approximately 1%. The combined risk of ejection fraction below 50% and heart failure hospitalization was minimal, suggesting the REMS program's effectiveness in monitoring and mitigating potential risks. According to Milind Desai, MD, MBA, cardiologist, Vice Chair of the Heart Vascular Thoracic Institute at Cleveland Clinic, the results indicate that "the drug in the open market is relatively safe, as long as all the rules are followed."
Efficacy results showed that about 70% of patients achieved a left ventricular outflow tract gradient of less than 30 mmHg, demonstrating an excellent response to mavacamten. Furthermore, 75% of patients showed improved efficacy at doses of 5 and 10 mg or less, with only a small fraction requiring the highest dose. These results were consistent even in patients who had been taking the drug for more than a year.
The Future of HCM Treatment
Mavacamten is currently the only FDA-approved treatment for class II-III obstructive HCM. However, the field is rapidly evolving, with several new drugs in development. Aficamten (Cytokinetics), another cardiac myosin inhibitor, has completed a pivotal phase 3 trial and is under FDA consideration. Additionally, EDG 7500, a sarcomeric modulator, is in earlier phases of development, with pivotal trials on the horizon. Gene therapies are also emerging as potential treatments for HCM.
These drugs are also being tested in non-obstructive hypertrophic cardiomyopathy, expanding the potential treatment options for a broader range of patients. The increasing number of prospective research studies, along with advancements in artificial intelligence for drug discovery and diagnosis, signal a promising future for HCM treatment.
