U.S. FDA’s top drug regulator resigns after federal officials probe ‘serious concerns’

The U.S. Food and Drug Administration seal is seen at the Hubert Humphrey Building Auditorium in Washington, April 22, 2025. (AP Photo/Jose Luis Magana, File)

WASHINGTON — The head of the U.S. Food and Drug Administration’s drug centre abruptly resigned Sunday after federal officials began reviewing “serious concerns about his personal conduct,” according to a government spokesperson.

Dr. George Tidmarsh, who was named to the FDA post in July, was placed on leave Friday after officials in the Department of Health and Human Services’ Office of General Counsel were notified of the issues, HHS press secretary Emily Hilliard said in an email. Tidmarsh then resigned Sunday morning.

“Secretary Kennedy expects the highest ethical standards from all individuals serving under his leadership and remains committed to full transparency,” Hilliard said.

The departure came the same day that a drugmaker connected to one of Tidmarsh’s former business associates filed a lawsuit alleging that he made “false and defamatory statements,” during his time at the FDA.

The lawsuit, brought by Aurinia Pharmaceuticals, alleges that Tidmarsh used his FDA position to pursue a “longstanding personal vendetta” against the chair of the company’s board of directors, Kevin Tang.

Tang previously served as a board member of several drugmakers where Tidmarsh was an executive, including La Jolla Pharmaceutical, and was involved in his ouster from those leadership positions, according to the lawsuit.

Messages placed to Tidmarsh and his lawyer were not immediately returned late Sunday.

Tidmarsh founded and led a series of pharmaceutical companies over several decades working in California’s pharmaceutical and biotech industries. Before joining the FDA, he also served as an adjunct professor at Stanford University. He was recruited to join the agency over the summer after meeting with FDA Commissioner Marty Makary.

Tidmarsh’s ouster is the latest in a string of haphazard leadership changes at the agency, which has been rocked for months by firings, departures and controversial decisions on vaccines, fluoride and other products.

Dr. Vinay Prasad, who oversees FDA’s vaccine and biologics centre, resigned in July after coming under fire from conservative activists close to President Donald Trump, only to rejoin the agency two weeks later at the behest of Health Secretary Robert F. Kennedy Jr.

The FDA’s drug centre, which Tidmarsh oversaw, has lost more than 1,000 staffers over the past year to layoffs or resignations, according to agency figures. The centre is the largest division of the FDA and is responsible for the review, safety and quality control of prescription and over-the-counter medicines.

In September, Tidmarsh drew public attention for a highly unusual post on LinkedIn stating that one of Aurinia Pharmaceutical’s products, a kidney drug, had “not been shown to provide a direct clinical benefit for patients.” It’s very unusual for an FDA regulator to single out individual companies and products in public comments online.

According to the company’s lawsuit, Aurinia’s stock dropped 20 per cent shortly after the post, wiping out more than US$350 million in shareholder value.

Tidmarsh later deleted the LinkedIn post and said he had posted it in his personal capacity, not as an FDA official.

Aurinia’s lawsuit also alleges, among other things, that Tidmarsh used his post at FDA to target a type of thyroid drug made by another company, American Laboratories, where Tang also serves as board chair.

The lawsuit, filed in U.S. District Court of Maryland, seeks compensatory and punitive damages and “to set the record straight,” according to the company.

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Matthew Perrone, The Associated Press