Tidmarsh Sues Aurinia, Alleges Prasad Role in FDA Ouster

Former CDER director George Tidmarsh has filed a defamation lawsuit against Aurinia Pharmaceuticals and biotech investor Kevin Tang, alleging that they provided false accusations of bribery and abuse of regulatory authority to senior FDA officials a year ago, triggering his removal from the agency.

The 23-page complaint (see below) filed 10/30 in Maryland federal court also alleges that former CBER director Vinay Prasad may have helped instigate the accusations following an internal dispute with Tidmarsh over Prasad's involvement in CDER regulatory decisions.

According to Tidmarsh, Prasad began contacting CDER reviewers directly in early 10/2025 despite having no jurisdiction over the drug center. After Tidmarsh requested coordination, Prasad allegedly sent a 2:35 a.m. text message on 10/5/2025 threatening to fire CDER deputy director Michael Davis. Later that morning, Prasad allegedly instructed Tidmarsh to "step aside" and described the directive as his "final warning."

Tidmarsh says he reported the incidents to then-FDA commissioner Marty Makary and chief of staff Jim Traficant, but no corrective action followed.

"Upon information and belief, this conflict led Dr. Prasad to solicit the defamatory complaints from defendants," the lawsuit states. The complaint does not establish that Prasad solicited the allegations, and Prasad is not named as a defendant.

The lawsuit offers a substantially different account of the events that led to Tidmarsh's 11/2/2025 resignation after just over three months as CDER director (see earlier story).

Aurinia's original lawsuit, filed the day Tidmarsh resigned, accused him of using his FDA position to pursue a personal vendetta against Tang, with whom he had worked at several biotechnology companies (see story).

The dispute centered partly on Tidmarsh's 9/2025 LinkedIn post questioning the clinical benefit of Aurinia's lupus nephritis drug Lupkynis (voclosporin). Aurinia alleged that the statements were false and defamatory and caused its shares to plunge more than 20%, erasing approximately $350 million in market value.

Aurinia also alleged that Tidmarsh targeted another Tang-affiliated company, American Laboratories, through FDA's actions against unapproved desiccated thyroid extract products, and that Tidmarsh's attorney sought an extension of a financial agreement in exchange for favorable regulatory intervention.

Tidmarsh now denies those allegations, asserting that FDA had decided to take action against the thyroid products before he joined the agency and that the enforcement decision was handled by an FDA office outside his authority. He says he recused himself from the matter.

The complaint also contends that Tang, rather than Tidmarsh, sought regulatory intervention and that Tidmarsh's attorney explicitly told Tang on 10/9/2025 that the former CDER director was ethically prohibited from assisting American Laboratories.

Tidmarsh alleges that Aurinia and Tang provided a draft of their lawsuit to FDA leadership on or before 10/31/2025. During a meeting that day, Makary allegedly told Tidmarsh that Traficant had a copy of the forthcoming lawsuit and that he had reviewed it. The commissioner also allegedly informed Tidmarsh that Aurinia accused him of soliciting a bribe from Tang.

Tidmarsh says Makary claimed that a reporter had provided the draft complaint, an assertion the journalist subsequently denied, according to the lawsuit.

FDA placed Tidmarsh on administrative leave that evening. His agency email access was disabled 11/1, and he resigned 11/2, the same day Aurinia filed its lawsuit. Tidmarsh further alleges that an HHS attorney advised him to resign because of the "toxic environment at FDA."

The complaint argues that Aurinia's pre-litigation communications with FDA officials were defamatory and are not protected by the legal privileges ordinarily associated with statements made during judicial proceedings.

Tidmarsh is seeking compensatory and punitive damages exceeding $75,000, alleging that the accusations destroyed his FDA career, damaged his professional reputation and impaired his future earning capacity. He has demanded a jury trial.