Novo's Wegovy Secures FDA Approval for MASH, Challenging Madrigal's Rezdiffra

The U.S. Food and Drug Administration (FDA) has granted accelerated approval to Novo Nordisk's Wegovy for the treatment of metabolic dysfunction-associated steatohepatitis (MASH), marking a significant milestone in the pharmaceutical industry. This approval positions Wegovy as the first GLP-1 agonist authorized for MASH, a condition affecting an estimated 22 million people in the United States.
Wegovy's Expanded Indication
Novo Nordisk announced that the FDA cleared Wegovy for use in adults with non-cirrhotic MASH and moderate-to-advanced liver scarring. The approval is based on Phase 3 clinical trial results demonstrating Wegovy's efficacy in improving liver scarring without worsening the condition and resolving MASH without exacerbating scarring.
The expanded indication allows for Wegovy to be used alongside diet and exercise in the management of MASH. This development comes as Wegovy has already established itself as a popular weight loss medication, generating billions in sales for Novo Nordisk.
Market Competition and Implications
Wegovy's entry into the MASH market sets the stage for intense competition with Madrigal Pharmaceuticals' Rezdiffra, which was approved in March 2024. Rezdiffra has exceeded investor expectations, generating $180 million in net sales in 2024 and $350 million in the first half of 2025.
The approval of Wegovy for MASH has impacted Madrigal's stock, with shares slumping following the FDA's decision. Analysts are now reassessing the market dynamics, considering how Wegovy's availability might affect demand for Rezdiffra.
Market Segmentation and Treatment Preferences
Despite the new competition, industry experts believe there is still a significant market for Rezdiffra. Thomas Smith, an analyst at Leerink Partners, notes that certain patient subgroups may prefer Rezdiffra over Wegovy. These include MASH patients who are already using GLP-1 drugs for other conditions, those who are considered "lean," and individuals who prefer Eli Lilly's Zepbound for obesity or Mounjaro for diabetes.
The introduction of Wegovy in the MASH space raises questions about potential changes in insurance coverage and treatment guidelines. Investors are particularly interested in whether insurers might require some patients to try Wegovy before other treatments.
References
- Novo’s Wegovy becomes first GLP-1 drug approved for MASH
The FDA clearance sets Novo’s medicine up a market battle with Madrigal Pharmaceuticals’ fast-selling Rezdiffra.
Explore Further
What were the detailed results of the Phase 3 clinical trials for Wegovy in treating MASH?
How does Wegovy's mechanism of action as a GLP-1 agonist differ from Rezdiffra in treating MASH?
What is the estimated market size and growth potential for MASH treatments in the United States?
How might Wegovy’s approval for MASH impact the sales and market strategy for Novo Nordisk?
What are the anticipated challenges in formulation such as insurance adjustments or patient adherence post-approval of Wegovy for MASH?