FDA launches decision on cell-kinetic cardiac drugs to review proposed safety plans
Cytokinetics aims to compete with the Bristol Myers Squibb cardiac drug expected to become a blockbuster seller, and the company's value proposition is that its drug candidate has potential safety advantages. Biotech will need to wait longer to see what the FDA thinks.
Cytokinetics announced after the market shutdown Thursday that the agency has delayed the September target date by the regulatory decision to review the drug's proposed safety plan. The new decision deadline is December 26.
Aficamten is under review as a treatment for obstructive hypertrophic cardiomyopathy, a disease with abnormally thick muscles that makes it harder for the heart to pump blood. Cell-dynamic drugs are small molecules designed to inhibit mutated versions of myocardial proteins that lead to this thickening.
The BMS drug Camzyos is the first of these myosin inhibitor drugs. Its 2022 FDA approval introduces an alternative to older cardiac drugs that have limited efficacy. BMS reports that Camzyos' sales in 2024 were $602 million, up from $231 million the previous year.
Camzyos tags come with a black box warning that warning about the risk of complications such as heart failure. This drug is only available under Risk Assessment and Mitigation Strategies (REMS). For drugs with serious safety risks, REMS informs prescribers and patients about risks and establishes a framework for monitoring or managing them.
Phase 3 results of cell kinetics drug showed adverse event characteristics similar to placebo, with no reported cases of heart failure. Applications seeking FDA approval include “unique risk mitigation methods specific to Aficamten”, according to Cyotkinetics’ annual report. But this method is not formal Rex.
“We believe that Aficamten's business prospects are highly dependent on whether the FDA approved Aficamten's label and/or post-business conditions, and are less challenging for prescribers and patients than REMS applicable to Camyos,” the company said in the report.
In a review by Aficamten, Cytokinetics said in an announcement Thursday that the FDA asked the company to submit REMS “based on the inherent characteristics of Aficamten.” The company complied with the request. However, the agency believes that this other information is a major amendment to the drug application. Major amendments triggered a three-month extension of drug review.
According to Cell Dynamics, the FDA does not require other clinical data or studies. In a prepared statement, Robert Blum, president and CEO of Cytokinets, said the company “has full of confidence in Aficamten's unique interest risks and drug profiles and continues to expect differentiated labels and risk mitigation measures following potential FDA approval.”
Leerink Partners analyst Roanna Ruiz said in a note sent to investors that the FDA’s request for REMS following Aficamten’s preliminary submission indicated that the agency was reevaluating its approach to managing the risk of a wider range of myosin inhibitors. She added that delays may differentiate cell dynamics from differential FDA A REM with BMS drugs. But she added that the development raises several questions, for example, the plan prompted the FDA to require a safety plan without submission.
“Despite this uncertainty, we are still constructive, which may be a procedural delay and will not fundamentally change the AFI approval prospects[camten]despite the uncertainty of what the final REM of AFI might be,” Ruiz said.
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