Mirum Pharmaceuticals Meets Phase 3 EXPAND Endpoints for LIVMARLI; sNDA Planned for 2027

Key highlights

• Primary endpoint met with a 1.81-point pruritus improvement compared to 0.83 for placebo
• Serum bile acid reduction reached 70.1 percent versus 3.5 percent in the control group
• Statistical significance achieved for all five prespecified secondary clinical endpoints
• Biliary atresia subgroup with native liver showed 2.16-point itch score reduction
• Company targets a supplemental New Drug Application submission for the first half of 2027

Phase 3 EXPAND Clinical Outcomes

Mirum Pharmaceuticals announced that its Phase 3 EXPAND trial successfully met its primary endpoint for LIVMARLI (maralixibat) in patients with ultra-rare cholestatic liver diseases. The double-blind study evaluated 52 patients, including a majority of pediatric subjects, over a 20-week period. Analysis revealed a 1.81-point improvement in the ItchRO(Obs) severity score for those treated with maralixibat, compared to a 0.83-point improvement in the placebo arm. This 0.98-point treatment difference achieved high statistical significance with a p-value of 0.0004. Furthermore, the drug demonstrated a 70.1 percent reduction in serum bile acids, significantly outperforming the 3.5 percent reduction observed in the placebo group.

Efficacy Across Subgroups

• Biliary atresia subgroup with a native liver showed a 2.16-point itch score improvement
• Serum bile acid levels in the biliary atresia subgroup dropped by 75.5 percent
• Prespecified secondary endpoints across overall and subgroup populations were met
• Safety data remained consistent with previous maralixibat studies with no new signals
• Regulatory submission will target the domestic market to expand current product labeling

Strategic Pipeline Expansion

Mirum Pharmaceuticals is a commercial-stage biotechnology firm dedicated to treating rare liver diseases through its IBAT inhibitor platform. The company currently markets LIVMARLI for Alagille syndrome and progressive familial intrahepatic cholestasis. Mirum has aggressively expanded its pipeline through the 2026 acquisition of Bluejay Therapeutics for 620 million dollars and the recent FDA approval of Atebrioz for fibrodysplasia ossificans progressiva. The EXPAND trial results represent a potential third indication for its lead asset, specifically targeting patients with biliary atresia who have not yet undergone liver transplantation.

Financial and Guidance Update

For the second quarter of 2026, Mirum reported 176.2 million dollars in revenue and subsequently raised its full-year product sales guidance to a range of 680 million to 700 million dollars. The company strengthened its balance sheet in May 2026 through a 600 million dollar private offering of zero-coupon convertible senior notes. With a market capitalization exceeding 5.5 billion dollars and an RSI of 42.4, the company maintains financial flexibility as it integrates its Bluejay acquisition. Management has reiterated expectations for additional topline readouts from its Phase 3 AZURE-4 study in late 2026.

Down 7.5% since our story on 13 Oct: $86.06 when we broke it → $79.62 at the close on 13 Oct. Daily closing prices. Source: Yahoo Finance.

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Industry Context

The market for pediatric cholestatic liver diseases is characterized by high unmet medical needs and limited surgical options like the Kasai procedure. Biliary atresia is the leading cause of liver transplantation in children, making non-surgical interventions that manage pruritus and bile acid levels highly valuable. Regulators typically prioritize treatments that demonstrate significant symptomatic relief in these ultra-rare populations. Mirum competition is evolving as pharmaceutical companies seek to expand IBAT inhibitor applications into broader hepatology segments. Success in the EXPAND trial suggests a consolidative lead for maralixibat in the rare liver disease landscape ahead of potential 2027 market expansion.

Mirum Pharmaceuticals, Inc. · financial snapshot

Share price	$86.06
Market cap	$5.6B
Revenue (annual)	$521M
1-month price change	-14.46%
Sector	HealthcareBiotechnology

Reference market data from a third-party provider, as of the story. Not a valuation or a recommendation.