To REMS, or not to REMS.
That, apparently, was the question for Cytokinetics, which has seen any potential approval for its experimental heart drug delayed by an extra three months over an unusual safety program omission and addition.
Aficamten, a cardiac myosin inhibitor, had been on the books with the FDA for a potential approval by (or before) Sept. 26 for obstructive hypertrophic cardiomyopathy.
This disease, characterized by the blood flow from the heart being reduced by the thickening of the heart's muscular wall, already has an approved treatment on the market in the form of Bristol Myers Squibb’s cardiac myosin inhibitor Camzyos.
Cytokinetics was hoping to get into this market that has seen Camyzos bring in just over $600 million last year, but, now, those hopes will be on hold a while longer.
The whole issue revolves around REMS, the shorthand for the FDA's Risk Evaluation and Mitigation Strategy programs. REMS are typically demanded by the FDA for potentially risky drugs and are a common requirement for heart disease meds.
In a twist of fate, BMS also had a similar FDA REMS delay back in 2021, but its medicine was ultimately approved in 2022.
In the U.S., Camzyos can only be used via a REMS program because it can cause the heart to become too relaxed, increasing the risk of heart failure.
In its statement released after-hours Thursday, May 1, Cytokinetics said it had submitted its new drug application with the FDA without a plan for REMS, seemingly with the agency’s blessing.
But not so fast: The FDA has now looked over the application and in fact does want a REMS plan “based on the inherent characteristics of aficamten," the company explained.
While Cytokinetics has now provided the plan, the addition has been regarded as a “Major Amendment to the NDA,” according to the biotech, thus adding a mandatory three months to the review. The drug's decision is now expected by Dec. 26.
Analysts at Evercore ISI were perplexed, saying in a note to clients: “We didn’t see this one coming. The most surprising part to us is that [aficamten's] NDA was originally submitted without an accompanying REMS. Was that actually the FDA’s guidance to the company or some sort of miscommunication? We assume the former given that the application was accepted.”
The analysts added, however, that “the REMS was not expected to be the main differentiator for [aficamten]."
Shares in the biotech were down around 10% premarket.
“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,” said Robert Blum, Cytokinetics’ president and CEO, in the release.
“We look forward to continuing our constructive engagement with the FDA regarding the NDA for aficamten.”