Former Madrigal executive sues over Rezdiffra safety concerns

A former Madrigal Pharmaceuticals executive has sued the company in federal court, alleging that he was forced out after voicing internal concerns about the safety of Rezdiffra, Madrigal’s approved treatment for metabolic dysfunction-associated steatohepatitis, STAT reported Wednesday.

Michael Charlton, a physician, served as Madrigal’s senior vice president and clinical development lead from October 2024 to January 2026. The complaint, filed October 9 in the U.S. District Court for the Northern District of Illinois, claims Madrigal retaliated against him under federal whistleblower statutes and seeks either reinstatement or financial compensation, according to the report.

In the lawsuit, Charlton says his responsibility was to protect “the safety, scientific integrity and accuracy of the clinical trials and disclosures supporting Madrigal’s flagship drug.” The filing states: “He did exactly that. Madrigal punished him for it.”

The lawsuit centers on Rezdiffra, the MASH drug that Madrigal markets. STAT reported that the former executive’s complaint accuses the company of punishing him for raising safety concerns internally.

Update, November 5, 2026

Madrigal Pharmaceuticals said it will contest the whistleblower lawsuit, according to a statement the company gave Fierce Pharma on Wednesday. A Madrigal spokesperson told Fierce Pharma that the company intends to defend itself vigorously. "Rezdiffra has improved the lives of thousands of patients living with MASH, and Madrigal stands firmly behind the safety and effectiveness of our product," the spokesperson said. Madrigal also disclosed the lawsuit in its third-quarter securities filing, Fierce Pharma reported.