High-ranking FDA official George Tidmarsh, M.D., Ph.D., has tendered his resignation after an unconventional LinkedIn diatribe landed the senior drug regulator at the center of a lawsuit and an internal probe.
Tidmarsh was placed on administrative leave Friday as the FDA kicked off an investigation into the Center for Drug Evaluation and Research (CDER) head over a complaint lodged by Tidmarsh’s former colleague and healthcare investor Kevin Tang, Stat reported Sunday.
Capping off the tumultuous weekend, Tidmarsh on Sunday resigned from his post outright.
“On Friday, HHS placed Dr. Tidmarsh on administrative leave after the Office of the General Counsel and the Office of the Inspector General were notified of serious concerns about his personal conduct,” an Department of Health and Human Services (HHS) spokesperson confirmed to Fierce Pharma over email. “Sunday morning, George Tidmarsh resigned effective immediately.”
An unconventional LinkedIn diatribe against Aurinia Pharmaceuticals’ lupus med earlier this fall—posted and then swiftly deleted by Tidmarsh—dredged up longstanding animosity between the CDER chief and Tang.
The investigation—and a lawsuit filed by Aurinia Sunday—hinge on concerns that Tidmarsh used his regulatory authority at the FDA to attempt to retaliate against Tang, with the two having clashed at several points in recent years, including in 2019, when Tidmarsh was still CEO of La Jolla Pharmaceuticals. Tang is currently the chair of Aurinia’s board of directors and manages Tang Capital Partners, the drugmaker’s largest shareholder.
The HHS spokesperson did not address the motivation for the probe in the statement to Fierce, although an unnamed official told The Wall Street Journal that the questionable conduct brought to the agency's attention was related to Tidmarsh’s LinkedIn post. In a New York Times interview, Tidmarsh also said he was told his leave was tied to the social media broadcast.
The HHS spokesperson stressed that HHS Secretary Robert F. Kennedy Jr. “expects the highest ethical standards from all individuals serving under his leadership and remains committed to full transparency.”
As part of the Trump administration’s new-look FDA, sitting Commissioner Marty Makary, M.D., tapped Tidmarsh to lead CDER in July, replacing acting head Jacqueline Corrigan-Curay, M.D., who herself was holding down the fort following the resignation of Patrizia Cavazzoni, M.D., at the top of the year. Cavazzoni stepped down from her post shortly before the start of President Donald Trump’s second term.
At the time, Makary said he would work with Tidmarsh to bolster the FDA’s drug programs, foster innovation and advance cross-agency initiatives to improve public health outcomes, although it wasn’t entirely clear what Tidmarsh’s priorities in the new role would be.
For some insight into the now-former CDER chief’s leanings, Tidmarsh has previously spoken about the need for the FDA to “remove harmful, useless drugs from the market” and rebuked instances of scientific misconduct and fraud in academic science.
Many of those claims have been laid out in various posts on Tidmarsh’s personal LinkedIn, a practice that appears to have come back to bite the biopharma veteran.
The social media post
In Tidmarsh’s now-deleted post on Aurinia’s lupus nephritis med Lupkynis, the former FDA official said the drug, also known as voclosporin, carries “significant toxicity,” adding that the medicine “has not been shown to provide a direct clinical benefit for patients.”
Tidmarsh went on to assert that the FDA would be “taking a close look at the use of surrogate endpoints to see where we can further accelerate promising drugs faster while requiring companies to perform the trials necessary to confirm actual clinical benefit.”
But that statement came as a bit of a non sequitur. The FDA’s early 2021 nod for Lupkynis conferred a full, standard approval, whereas the use of surrogate endpoints in drug approval applications is typically only used for accelerated green lights.
Before deleting his post, Tidmarsh clarified that the views expressed were his own and did not reflect the outlook of the FDA itself. Naturally, Aurinia sees the situation differently.
In the lawsuit brought against Tidmarsh in Maryland federal court, Aurinia and its U.S. subsidiary are accusing him of making “false and defamatory statements” against the company and its drug over a “longstanding personal vendetta against Kevin Tang.”
Lawyers for Aurinia linked the grudge to an incident in 2019, when “growing concerns over Dr. Tidmarsh’s management of La Jolla Pharmaceutical Company” prompted Tang, in his capacity as board chair, to ask for Tidmarsh’s resignation as the company’s CEO. Around that same time, Tang also requested that Tidmarsh hang up his hat at other companies where Tang chaired the board, like American Laboratories and Odonate Therapeutics, according to the lawsuit.
In the subsequent six years, Tidmarsh has “repeatedly threatened that he would exact revenge against Mr. Tang over these ousters,” Aurinia’s legal team contends. Over that span, Tidmarsh allegedly sent texts and emails to Tang and his associates threatening that the biopharma investor would “be exposed,” that there was “[m]ore bad karma to come,” that “[t]he pain is not over,” and that Tidmarsh was “[n]ot powerless,” according to the legal filing.
Aside from the Lupkynis LinkedIn post, Tidmarsh purportedly used his role at CDER to push the FDA to “effectively remove” desiccated thyroid extract (DTE) products from the U.S. market earlier this year, Aurinia’s lawyers argued. DTE products are used to treat hypothyroidism.
This move, which Aurinia’s legal team suggests was targeted, cut off a key source of income for the Tang-affiliated company American Laboratories, the lawsuit claims.
Tidmarsh then allegedly tried to leverage the situation to “extort and solicit a bribe from Mr. Tang in exchange for Dr. Tidmarsh using his power to reverse or otherwise mitigate the adverse impact on Mr. Tang, Tang Capital, and American Laboratories,” the suit continues.
The plaintiff lawyers claim Tidmarsh next targeted Aurinia on his LinkedIn account after Tang “refused to submit to this shocking abuse of power.” They argued that Tidmarsh’s statements around Lupkynis sent Aurinia’s stock price plummeting “in a matter of hours,” erasing more than $350 million of the company’s market value. Over the course of October, Aurinia's stock price recovered from the incident.
Agency in disarray
Tidmarsh, for his part, told The New York Times that he thinks the FDA review of his actions was itself retaliatory and tied to concerns he raised last week about the agency’s new national priority review voucher program.
“The effort was going to basically change the entire paradigm of the legal underpinnings of drug approvals that have for decades supported the actions on the safety and effectiveness of drugs,” Tidmarsh said in the NYT interview. “There was insufficient legal support for what they wanted to do, and so I didn’t agree.”
Tidmarsh went on to describe a “toxic environment” at the agency under the FDA’s chief science and medical officer, Vinay Prasad, M.D., and denied in the interview that he was interested in exacting revenge on his former colleague Tang.
Aside from deep staff cuts under the Trump administration’s government efficiency drive earlier this year, the FDA and HHS, more broadly, has also seen significant turnover in 2025 among high-ranking leaders.
Most recently, HHS pushed out Centers for Disease Control and Prevention (CDC) Director Susan Monarez, Ph.D.—less than a month after her confirmation—as the former director claimed she was “targeted” by Kennedy’s health department after refusing to “rubber-stamp unscientific, reckless directives and fire dedicated health experts.” Several prominent CDC leaders resigned in protest following Monarez’s forced departure.
Prasad's tenure at the FDA has also been marked by turbulence. Back in July, Prasad resigned less than three months into his role as head of the agency's Center for Biologics Evaluation and Research (CBER) after a regulatory back-and-forth involving Sarepta's gene therapy Elevidys.
Prasad was reinstated to his role at the FDA's request a little less than a week later.
Also at FDA's CBER, Prasad's predecessor, Peter Marks, M.D., Ph.D., resigned abruptly from his role in late March. In a subsequent interview with the Associated Press, Marks suggested he had been forced out for refusing to give RFK Jr.—a noted vaccine skeptic—unfettered access to the U.S.’ federal vaccine injury reporting system.
“It was pretty clear that either I was going to resign or they were going to fire me,” Marks told AP at the time.