Can Livmarli's Growing Patient Adoption Sustain Mirum's 2026 Revenue Momentum?

Product Performance Driving Revenue Expansion

Mirum Pharmaceuticals’ MIRM financial trajectory has been significantly shaped by Livmarli (maralixibat), an oral ileal bile acid transporter inhibitor designed for cholestatic pruritus patients. This therapeutic agent has demonstrated impressive market penetration, particularly among patients with Alagille syndrome and progressive familial intrahepatic cholestasis across multiple geographies. The introduction of a new tablet formulation has further improved treatment accessibility for adult patients, expanding the addressable market segment.

Through the first three quarters of 2025, Livmarli generated $253.6 million in net sales, representing a remarkable 70% year-over-year increase. This acceleration reflects strengthening market adoption as healthcare providers and patients increasingly recognize the drug’s clinical benefits. The company’s commercial infrastructure expansion and enhanced marketing initiatives are expected to drive continued patient uptake, positioning Livmarli as a consistent revenue anchor.

Diversification Through Strategic Acquisition

Beyond Livmarli, Mirum has fortified its commercial portfolio through the 2023 acquisition of Travere Therapeutics’ bile acid products. Cholbam capsules and Ctexli tablets now contribute materially to the revenue base, addressing distinct rare disease indications. During the nine-month period of 2025, these complementary products delivered incremental top-line support, demonstrating the strategic value of portfolio diversification.

Management has raised its full-year 2025 revenue guidance to $500-$510 million from the previous $490-$510 million range, underscoring confidence in both Livmarli’s sustained uptake trajectory and the combined performance of its acquired bile acid franchise. Looking forward, volixibat—the company’s leading pipeline candidate—is undergoing evaluation in dual phase IIb trials for primary biliary cholangitis and primary sclerosing cholangitis, potentially establishing additional revenue streams beyond 2026.

Intensifying Competitive Pressures

The company’s heavy revenue dependence on Livmarli presents inherent risk, particularly as competitive threats escalate within the IBAT inhibitor space. Albireo AB (now under Ipsen ownership) markets Bylvay, a direct functional competitor targeting identical patient populations. Both agents operate through IBAT inhibition to reduce serum bile acid accumulation, creating a competitive dynamic that could compress Mirum’s market penetration and pricing power.

GSK plc is advancing linerixibat, a proprietary IBAT inhibitor targeting cholestatic pruritus associated with primary biliary cholangitis. An FDA decision on this regulatory submission is anticipated by March 24, 2026. A potential approval would introduce formidable competition backed by GSK’s substantial resources and established market infrastructure, potentially challenging Mirum’s longer-term growth strategy.

Valuation and Market Positioning

Mirum’s equity has appreciated 35.9% over the past six months, outpacing the industry advance of 21.6% and the broader S&P 500. However, the valuation premium reflects this outperformance—the company trades at a price-to-book ratio of 11.87 versus 3.55 for the sector, and well above its historical five-year mean of 6.87.

Earnings expectations have undergone notable adjustment. The 2025 loss-per-share consensus estimate has tightened from 67 cents to 41 cents over the past 60 days. Similarly, 2026 estimates shifted from a projected 4-cent earnings-per-share gain to an anticipated 29-cent loss, signaling analyst caution regarding near-term profitability despite robust revenue growth.

Investment Outlook

Mirum currently maintains a Zacks Rank #3 (Hold) rating, reflecting the balanced interplay between Livmarli’s encouraging patient uptake and the mounting competitive landscape ahead. The trajectory of revenue growth will largely depend on the sustainability of Livmarli adoption, successful management of competitive encroachment, and the eventual contributions from its clinical-stage pipeline candidates.