FDA Misses Approval Deadline for Stealth Biotherapeutics' Rare Disease Drug

The pharmaceutical industry faces uncertainty as the U.S. Food and Drug Administration (FDA) has missed its approval deadline for Stealth Biotherapeutics' experimental rare disease drug, elamipretide. This delay comes amid concerns over the impact of recent FDA job cuts on drug reviews and highlights the challenges in bringing treatments for ultra-rare conditions to market.

FDA Review Delay Raises Questions

Stealth Biotherapeutics announced on Tuesday that the FDA's deadline to approve elamipretide for the treatment of Barth syndrome has passed without a decision. The agency has not yet provided a new date for when the therapy might be cleared for use in the United States. This marks the second delay in the review process, following an earlier postponement in January when the FDA extended its review to examine additional information submitted by the company.

The delay is particularly significant given that elamipretide had been granted priority review status, a designation intended to expedite the approval process for drugs that address unmet medical needs. Stealth CEO Reenie McCarthy stated that the company has been working closely with the FDA to "progress its review" and that labeling discussions had recently begun, suggesting that the process is still moving forward despite the missed deadline.

Impact of FDA Staffing Changes

The pharmaceutical industry is closely watching the FDA's ability to meet drug review deadlines in light of recent steep staff cuts at the agency. While the FDA has maintained that drug reviewers would not be affected by these cuts, the delay in elamipretide's review has heightened concerns about potential impacts on the drug approval process.

Several high-profile departures from the FDA have added to these concerns. Peter Marks, who oversaw the Center for Biologics Evaluation and Research, and Peter Stein, head of the FDA's Office of New Drugs, have both left the agency in recent months. These leadership changes, combined with the broader staffing reductions, have led to increased scrutiny of the FDA's review capabilities.

Implications for Rare Disease Drug Development

The case of elamipretide highlights the unique challenges faced by companies developing treatments for ultra-rare conditions. Barth syndrome, the target indication for elamipretide, is estimated to affect only about 150 people in the United States. This small patient population presents difficulties in conducting clinical trials and demonstrating efficacy to regulatory authorities.

Stealth Biotherapeutics' journey with elamipretide underscores these challenges. The company first brought the drug to the FDA in 2021, but the regulator declined to review it, citing insufficient evidence of effectiveness. Since then, Stealth has persevered in its pursuit of approval, culminating in a majority of FDA advisory committee members concluding that the drug was effective in testing.

Emily Mulligan, director of the non-profit Barth Syndrome Foundation, emphasized the importance of this review for the patient community, urging the FDA to "stay focused on completing this review" and provide a "clear new decision date."

As the pharmaceutical industry awaits further updates on elamipretide's review, this case serves as a reminder of the complexities involved in bringing new treatments to market, particularly for rare diseases. The outcome of this review may have significant implications for future rare disease drug development and the FDA's ability to manage its regulatory responsibilities in light of recent organizational changes.