Madrigal Pharmaceuticals’ former head of clinical development sued the company Oct. 9, alleging he was forced out after raising concerns about liver injury data and efficacy results for its MASH drug Rezdiffra, according to a complaint filed in the U.S. District Court for the Northern District of Illinois. Madrigal disputes the allegations.
Michael Charlton, MD, a hepatologist who was senior vice president and head of clinical development, alleges in the complaint that over about eight months he reported to Madrigal’s CEO and chief medical officer that the company was suppressing adverse liver injury data, presenting efficacy results he said could not be reconciled with source data and letting an unblinded board member, a former chief medical officer and major shareholder, influence the adjudication of clinical outcomes. He alleges the CEO told him to “stop looking.”
Dr. Charlton alleges Madrigal then stripped him of his title, direct reports and other duties, announced his replacement while he was on medical leave and positioned him to present efficacy data at an international conference that he had flagged internally as unverifiable. He resigned Jan. 5. The complaint also cites a 2026 analysis in Frontiers in Pharmacology of FDA adverse event reports that it says supports his concerns about liver injury.
The suit claims retaliation under the Sarbanes-Oxley Act’s whistleblower provisions. Dr. Charlton filed an administrative complaint with OSHA Dec. 12, 2025, and says he sued in court because the Labor Department did not issue a final decision within 180 days. He seeks reinstatement or front pay, back pay and compensatory damages.
Madrigal disclosed the lawsuit in its Nov. 3 quarterly filing, saying it disputes the allegations and plans to defend itself vigorously.
Rezdiffra, a once-daily oral drug, was approved in March 2024 as the first MASH therapy under the FDA’s accelerated approval pathway, and its label carries a warning for drug-induced liver toxicity. The approval is contingent on an ongoing trial to confirm its clinical benefit.
