Mirum’s Volixibat Hits Primary Endpoint in PSC Trial, Setting Stage for Potential First Therapy
Event summary
- Mirum’s VISTAS Phase 2b study of volixibat in primary sclerosing cholangitis (PSC) met its primary endpoint, showing a statistically significant reduction in cholestatic pruritus.
- The study enrolled 158 patients, with the primary analysis cohort (n=111) showing a 2.72-point improvement in pruritus on the Adult ItchRO scale, a 1.64-point placebo-adjusted difference (p<0.0001).
- Mirum plans to submit a New Drug Application (NDA) for volixibat in PSC in the second half of 2026, following a pre-NDA meeting with the FDA in summer 2026.
- Volixibat’s safety profile was consistent with known effects of IBAT inhibition, primarily gastrointestinal adverse events and elevations in liver laboratory parameters.
- Topline data from the VANTAGE Phase 2b study of volixibat in primary biliary cholangitis (PBC) is expected in Q1 2027.
The big picture
Mirum’s positive VISTAS results position volixibat as a potential first-in-class therapy for PSC, a rare and debilitating liver disease with no approved treatments. The success builds on Mirum’s focus on rare disease therapeutics and sets the stage for a potential NDA submission later this year. The broader implications include the validation of IBAT inhibition as a viable therapeutic approach for cholestatic diseases, which could expand Mirum’s pipeline opportunities beyond PSC and PBC.
What we're watching
- Regulatory Pathway
- Whether the FDA will accept the VISTAS data as sufficient for approval, given the historical challenges in studying PSC.
- Market Opportunity
- The potential for volixibat to capture a significant share of the PSC market, which currently lacks approved therapies.
- Pipeline Progress
- The timeline and outcomes of the VANTAGE study in PBC, which could further validate volixibat’s utility in cholestatic diseases.
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