Key Takeaways
- FDA leadership shift underscores regulatory volatility: Vinay Prasad’s resignation follows high-profile drug application rejections and safety-related restrictions, signaling increased scrutiny regarding gene therapies and accelerated approvals.
- Sarepta’s Elevidys under intensified safety review: FDA's initial pause of the shipments for the drug and subsequent clearance for ambulatory patients highlight evolving regulatory expectations for gene therapies after multiple patient deaths.
- Complete Response Letters (CRLs) raise concerns over FDA communication practices: Recent CRLs issued to Replimune and Capricor suggest possible gaps in agency-sponsor dialogue during mid- and late-cycle reviews.
Vinay Prasad, head of the FDA’s Center for Biologics Evaluation and Research (CBER), has resigned after a series of contentious decisions, including rejections of Biologics License Applications (BLAs) for rare disease therapies and enforcement of product restrictions. Prasad leaves at a time in which criticism of his short tenure grew across the political landscape, including from conservative media figures such as former US Senator Rick Santorum and influencer Laura Loomer.1
Why Did the FDA’s Top Biologics Official Step Down?
"Dr. Prasad did not want to be a distraction to the great work of the FDA in the Trump administration and has decided to return to California and spend more time with his family," a Department of Health and Human Services spokesperson said in an emailed statement to Reuters. “We thank him for his service and the many important reforms he was able to achieve in his time at FDA.”1,2
Leadership and Background
First announced as the head of CBER in May, Prasad was tasked with overseeing vaccines and biologic therapies and later assumed the position of the FDA’s chief medical and scientific officer. He replaced Peter Marks, who was forced out in March amid disagreements with Health Secretary Robert F. Kennedy Jr. Similar to other health officials appointed under the new administration, Prasad had been openly critical of the federal response and vaccination strategies during the COVID-19 pandemic.3
Sarepta and the Elevidys Controversy
Notably during Prasad’s tenure, the FDA placed restrictions on Sarepta Therapeutics’ gene therapy, Elevidys, due to multiple deaths in patients taking the drug. On July 18, 2025, the FDA requested that Sarepta suspend all Elevidys shipments and placed all limb-girdle muscular dystrophy (LGMD) gene therapy trials on clinical hold, citing safety concerns. While initially declining to stop shipments—stating that no new safety signals had emerged during trials—Sarepta’s stock fell by 36% in one day in the face of FDA pressure and the announcement of a third reported death. A few days later, the company reversed course and halted shipments.4
On Monday, the FDA removed its recommendation to halt shipments of the gene therapy for ambulatory patients, citing that the third death that was initially attributed to Elevidys turned out to have no role in the patient’s death. As a result, the company’s stock began to show signs of growth.5
Other Regulatory Disputes
Another contentious decision made during Prasad’s tenure was a Complete Response Letter (CRL) for a BLA from Replimune for RP1, an advanced melanoma treatment. According to the company, the CRL came as a shock, stating that issues that were raised in the CRL were not brought to its attention during mid- and late-cycle reviews.
Earlier this month, Capricor Therapeutics experienced a similar issue with its own CRL for an investigational Duchenne muscular dystrophy therapy. In that CRL, the FDA cited issues with the chemistry, manufacturing, and controls portion of the application, which Capricor said it had previously addressed.6
Internal Support
Previously, FDA Commissioner Marty Makary and Kennedy have defended Prasad and his decision making, with Kennedy citing his cautious approach to vaccines.1
“There’s not a political bone to his body,” Makary said in a recent interview with Politico. “He’s an impeccable scientist. I think one of the greatest scientific minds of our generation.”
In the same interview, Makary stated his belief that Prasad had done “a phenomenal job” in his role, citing that the staff loved him and credited him for an improved culture at the FDA.7
New acting leader announced
Moving forward, George Tidmarsh, MD, PhD, has been named acting director of CBER.8 The move comes a week after Tidmarsh was announced as the agency's new Director of the Center for Drug Evaluation and Research.9
References
- Top F.D.A. Official Resigns Under Pressure. New York Times. July 29, 2025. Accessed July 30, 2025. https://www.nytimes.com/2025/07/29/health/vinay-prasad-fda-resigns-loomer.html?unlocked_article_code=1.aU8._EeC.4z3uTKWTXYEK&smid=url-share
- US FDA's top vaccine official Vinay Prasad leaves agency after short stint. Reuters. July 29, 2025. Accessed July 30, 2025. https://www.reuters.com/business/healthcare-pharmaceuticals/us-fdas-top-vaccine-official-vinay-prasad-leaves-agency-after-short-stint-2025-07-30/
- Controversial FDA official Dr. Vinay Prasad departs agency. CNN. July 29, 2025. Accessed July 30, 2025. https://www.cnn.com/2025/07/29/health/vinay-prasad-fda
- Recapping the Sarepta Saga—And Implications for Industry. PharmExec. July 23, 2025. Accessed July 30, 2025. https://www.pharmexec.com/view/recapping-the-sarepta-saga-and-implications-for-industry
- Sarepta Stock On the Rise Following Resumption of Elevidys Shipments in US. PharmExec. July 29, 2025. Accessed July 30, 2025. https://www.pharmexec.com/view/sarepta-stock-rise-resumption-elevidys-shipments-us
- Replimune CRL Fallout: How Biopharma Leaders Should Manage a New Layer of FDA Uncertainty. PharmExec. July 25, 2025. Accessed July 30, 2025. https://www.pharmexec.com/view/replimune-crl-fallout-biopharma-leaders-manage-new-fda-uncertainty
- FDA commissioner Marty Makary defends Vinay Prasad | The Conversation. Politico. July 26, 2025. Accessed July 30, 2025. https://www.politico.com/video/2025/07/26/commissioner-marty-makary-defends-fdas-vinay-prasad-1690337
- FDA names drug regulator Tidmarsh acting head of biologics center after Prasad’s exit. Stats. July 30, 2025. Accessed July 30, 2025. https://www.statnews.com/2025/07/30/george-tidmarsh-fda-cber-biologics-vaccines-center-acting-director/
- FDA Appoints George Tidmarsh as Director of Center for Drug Evaluation and Research. PharmExec. July 23, 2025. Accessed July 30, 2025. https://www.pharmexec.com/view/fda-appoints-george-tidmarsh-director-center-drug-evaluation-research
