WASHINGTON – In a surprising turn of events, the head of the Food and Drug Administration’s drug center, Dr. George Tidmarsh, stepped down from his position on Sunday amid an investigation into his personal conduct. This resignation follows closely on the heels of a review initiated by federal officials, as confirmed by a government spokesperson.

Dr. Tidmarsh, who only assumed his role at the FDA in July, had been placed on leave the preceding Friday. The leave came after the Department of Health and Human Services’ Office of General Counsel was informed of the concerns surrounding his behavior, according to an email from HHS press secretary Emily Hilliard. On Sunday morning, Tidmarsh made the decision to resign.

“Secretary Kennedy is committed to upholding the highest ethical standards among all individuals working under his leadership and maintains a strong commitment to transparency,” Hilliard communicated.

This resignation coincided with a lawsuit filed the same day by Aurinia Pharmaceuticals, a company tied to one of Tidmarsh’s former business associates. The lawsuit accuses Tidmarsh of making “false and defamatory statements” during his tenure at the FDA, suggesting that he may have exploited his position for personal vendettas.

Aurinia Pharmaceuticals claims in their lawsuit that Tidmarsh targeted Kevin Tang, the chair of their board of directors, due to a longstanding personal feud. The lawsuit details Tang’s previous involvement with several drug companies where Tidmarsh held executive roles, including La Jolla Pharmaceutical, and notes his role in Tidmarsh’s removal from those positions.

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 center, 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 center, which Tidmarsh oversaw, has lost more than 1,000 staffers over the past year to layoffs or resignations, according to agency figures. The center 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% shortly after the post, wiping out more than $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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