FDA Delays Decision on Cytokinetics' Heart Drug, Citing Need for Safety Program

The U.S. Food and Drug Administration (FDA) has extended its review of Cytokinetics' experimental heart drug aficamten, pushing the decision date to December 26, 2025. This three-month delay comes as a result of an unusual back-and-forth regarding the necessity of a Risk Evaluation and Mitigation Strategy (REMS) program for the medication.

Unexpected REMS Requirement Causes Setback

Cytokinetics initially submitted its New Drug Application (NDA) for aficamten without a REMS plan, believing it had the FDA's approval to do so. However, the agency has now requested a REMS program "based on the inherent characteristics of aficamten," according to a statement released by the company.

The addition of a REMS plan has been classified as a "Major Amendment to the NDA," necessitating an extended review period. This development has surprised industry analysts, with Evercore ISI expressing perplexity over the initial submission without a REMS, given that such programs are common for heart disease medications.

Aficamten's Potential in the HCM Market

Aficamten, a cardiac myosin inhibitor, is being developed for the treatment of obstructive hypertrophic cardiomyopathy (HCM). This condition is characterized by the thickening of the heart's muscular wall, which reduces blood flow from the heart.

The drug aims to compete with Bristol Myers Squibb's Camzyos, the first approved treatment for HCM, which generated over $600 million in sales last year. Notably, Camzyos is also subject to a REMS program due to the risk of heart relaxation leading to potential heart failure.

Market Impact and Company Response

The news of the delay has impacted Cytokinetics' stock, with shares down approximately 10% in premarket trading. Despite this setback, the company remains optimistic about aficamten's prospects.

Robert I. Blum, Cytokinetics' President and CEO, stated, "We remain confident in the distinct benefit-risk and pharmaceutic profile of aficamten and continue to expect a differentiated label and risk mitigation profile upon its potential approval by FDA."

As the pharmaceutical industry watches this development closely, Cytokinetics has affirmed its commitment to ongoing constructive engagement with the FDA regarding the NDA for aficamten.