Drama continues to unfold at FDA.

Over the course of 2025, the agency and its related committees have experienced a significant amount of membership turnover. While much of this was expected, due to the new administration coming in and adjusting rosters to fit its new directives, that hasn’t always been the case.

Why was Head of CBER George Tidmarsh placed on leave?

Head of FDA’s drug center George Tidmarsh is the latest member to see his name in headlines. On Friday, October 31, FDA announced that Tidmarsh had been placed on administrative leave.¹ According to ABC News, Tidmarsh was considering stepping down at that time due to what he described as a “toxic environment” at the agency.

HHS spokesperson Emily Hilliard told ABC News that the decision to place Tidmarsh on leave was made after, “the Office of the General Counsel and the Office of the Inspector General were notified of serious concerns about his personal conduct.”

Following that, conflicting reports surfaced as to why Tidmarsh was out.

The Guardian reports that Tidmarsh was ousted due to concerns over his conduct.² This follows the filing of a lawsuit by Aurinia Pharmaceuticals, that claims that Tidmarsh used his position to pursue a personal vendetta against Aurinia’s chair of the board of directors, Kevin Tang.

Tang reportedly played a key role in ousting Tidmarsh from leadership positions at various pharmaceutical companies the two previously worked together at, including La Jolla Pharmaceuticals.

Tidmarsh reportedly posted a message critical of one of Aurinia’s products on LinkedIn in September, saying it had not been shown to provide a direct clinical benefit to patients. The post was later deleted, although Aurinia did publish a response in a press release,³ stating, “Aurinia stands behind the favorable benefit/risk profile of LUPKYNIS® (voclosporin). LUPKYNIS received full approval from the FDA in January 2021 based on a large, randomized 52-week clinical study known as AURORA 1. Furthermore, the FDA approved a supplementary new drug application for the long-term use of LUPKYNIS in April 2024 based on the results of AURORA 2, which demonstrated sustained efficacy of LUPKYNIS over a three-year period, with safety comparable to AURORA 1.”

Aurinia has filed a lawsuit against FDA over the impact of the post.

Tidmarsh, however, claims that he was placed on leave after criticizing Vinay Prasad, chief medical and scientific officer at FDA, according to ABC News.¹ Tidmarsh also criticized new regulatory processes at FDA designed to speed up the regulatory process.

Tidmarsh only joined FDA in July of this year. At the time, Director Makary said, “Dr. Tidmarsh is an accomplished physician-scientist and leader whose experience spans the full arc of drug development—from bench to bedside. His appointment to lead CDER brings exceptional scientific, regulatory, and operational expertise to the agency.”

Also in July, Vinay Prasad briefly lost his role at FDA before rejoining the agency as head of CBER a few weeks later. There were conflicting reports as to the reason for his brief departure, although some reports suggested that he had angered right-wing influencer and Trump-ally Laura Loomer.

And while she wasn’t a member of FDA, CDC Director Susan Monarez was fired from her post in late August. In response, the following leaders at CDC also stepped down at the same time:

• Dr. Debra Houry, the chief medical officer
• Dr. Demetre Daskalakis, director of the National Center for Immunization and Respiratory Diseases
• Dr. Daniel Jernigan, the director of the National Center for Emerging and Zoonotic Infectious Diseases
• Dr. Jen Layden, director of the Office of Public Health Data, Surveillance and Technology

Sources

1. FDA's top drug regulator placed on leave, considering resigning, citing 'toxic' environment. ABC News. November 2, 2025. https://abcnews.go.com/Politics/fdas-top-drug-regulator-leave-resigning-citing-toxic/story?id=127119927
2. Top FDA official quits amid inquiry into ‘serious concerns’ over his conduct. The Guardian. November 3, 2025. https://www.theguardian.com/us-news/2025/nov/03/fda-official-resigns-george-tidmarsh
3. Aurinia Responds to Now Retracted LinkedIn Post. Aurinia. September 29, 2025. Accessed November 3, 2025. https://www.auriniapharma.com/press-releases/aurinia-responds-to-now-retracted-linkedin-post