Ex-Madrigal Executive Sues Over Drug Safety Concerns

Former senior vice president Dr Michael Charlton alleges he was forced out after raising concerns about Rezdiffra.

Updated on Nov. 5, 2026 in Healthcare

Bold flat-color editorial illustration of a plain institutional courthouse facade with a simple geometric capsule shape in the foreground, in navy and cream with a muted red accent. — Former Madrigal Pharmaceuticals senior vice president Dr Michael Charlton has sued the company, alleging he was forced out after raising drug safety concerns about Rezdiffra. AI Illustration. Upload story photo >

Dr Michael Charlton, former senior vice president and head of clinical development at Madrigal Pharmaceuticals, has filed a whistleblower lawsuit in the US District Court for the Northern District of Illinois alleging he was forced out after raising drug safety concerns. Madrigal disclosed the suit in its quarterly Form 10-Q filing with the SEC on 3 November and said it disputes the allegations.

Why it matters

The suit centers on Rezdiffra, the first medication to obtain accelerated FDA approval for MASH in 2024 and Madrigal's only approved drug and sole source of revenue. Allegations about how safety and efficacy concerns were handled bear directly on a product that generated $1.1 billion in year-to-date net sales.

Madrigal reported $1.1 billion in year-to-date Rezdiffra net sales, with Rezdiffra as its only approved drug. Dr Charlton says he raised safety concerns with senior executives over an eight-month period before being stripped of his title and duties, and the company says it disputes those claims.

The players

Madrigal Pharmaceuticals

Madrigal Pharmaceuticals is a Pennsylvania-headquartered biopharmaceutical company whose Rezdiffra became the first FDA-approved medication for MASH.

Dr Michael Charlton

Dr Michael Charlton is a former senior vice president and head of clinical development at Madrigal Pharmaceuticals who filed the whistleblower suit.

The details

Dr Charlton alleges he was stripped of his title, leadership role and substantive duties after refusing to stop examining efficacy data and raising concerns with senior executives. He resigned, saying he did not want to lend his name to a suspected fraud, and has since worked as vice president of clinical development at Enveda since August 2026.

2024: Rezdiffra receives accelerated FDA approval for MASH.
August 2026: Dr Charlton begins work as vice president of clinical development at Enveda.
October 2026: Lawsuit is filed in the Northern District of Illinois.
3 November 2026: Madrigal discloses the lawsuit in its Form 10-Q filing with the SEC.

Market Landscape

Rezdiffra's accelerated approval for MASH gave Madrigal an early position in a newly approved treatment category, and its status as the company's sole revenue source concentrates market exposure on that single product. Allegations about how its efficacy data was handled therefore carry weight for competitive positioning in the MASH market.

For patients using Rezdiffra for MASH, the lawsuit raises questions about the safety and efficacy data underpinning the drug, though no regulatory action has been reported. Readers tracking the drug's availability should watch for any FDA or company statements responding to the allegations.

The takeaway

Whistleblower disclosures in SEC filings can surface internal disagreements over drug data before they reach regulators or the public. Readers should weigh single-product biotech companies' claims against the disclosed record as the litigation proceeds.