Historic FDA First Approval for MASH Therapy

The U.S. Food and Drug Administration (FDA) has granted accelerated approval to Rezdiffra (resmetirom), a novel drug developed by Madrigal Pharmaceuticals (MDGL), for the treatment of metabolic dysfunction-associated steatohepatitis (MASH). Approved under NDA number 217785, this once-daily oral medication is a selective thyroid hormone receptor-beta (THR-β) agonist. It offers a direct therapeutic mechanism to reduce liver fat accumulation and alleviate inflammation in patients with non-cirrhotic MASH, for whom liver transplantation was previously the only definitive option. This approval marks the first regulatory milestone in the MASH field, introducing a novel treatment option.

Efficacy Demonstrated Through Phase 3 Data

The pivotal scientific basis for the approval stems from the data of the Phase 3 MAESTRO-NASH study. In this trial, patients receiving Rezdiffra 80mg and 100mg achieved the primary endpoint of MASH resolution (improvement in MASH symptoms) without worsening of liver fibrosis, compared to the placebo group. Furthermore, the study demonstrated a simultaneous improvement in liver fibrosis by at least one stage, clearly demonstrating its therapeutic value. The FDA determined that the clinical benefit was sufficient and finalized the approval without convening a separate advisory committee (AdComm).

Surpassing $1.1 Billion in Annual Sales and Securing a Dominant Market Position

From a market perspective, Rezdiffra has significant potential, with first-quarter 2026 net sales reaching $311.3 million, already exceeding $1.1 billion in annualized sales and entering the blockbuster category. The global MASH treatment market is expected to grow rapidly at a CAGR of 17-22%, reaching up to $33 billion by the mid-2030s. Madrigal is solidifying its first-mover position by targeting approximately 460,000 diagnosed patients in the U.S. Additionally, the company is actively expanding into overseas markets, including Europe, through partnerships with global distribution partners such as Swixx BioPharma.

Differentiated Mechanism and Competition with Follow-on Drugs

While Novo Nordisk's Wegovy (semaglutide) and other GLP-1 receptor agonists are seeking to expand their indications to include MASH, their mechanisms of action differ, suggesting they may act as complementary therapies. In fact, approximately 25% of Rezdiffra-treated patients are co-administered with GLP-1-based drugs, indicating a synergistic effect rather than direct competition. Moreover, with follow-on pipeline drugs such as Akero's efruxifermin and Viking's VK2809 in development, Madrigal needs to maintain its market leadership. To this end, Madrigal is conducting an additional Phase 3 trial in patients with advanced fibrosis (F4) to expand its indications.