Mirum Pharmaceuticals reported positive Phase 2b VISTAS results for volixibat in primary sclerosing cholangitis, showing significant reductions in cholestatic pruritus and supporting plans for an NDA submission in 2026.
Written By: Mahathi Palivela, PharmD
Reviewed By: Pharmacally Editorial Team
Mirum Pharmaceuticals announced positive topline results from the Phase 2b VISTAS study (NCT04663308) evaluating volixibat in patients with primary sclerosing cholangitis (PSC), with the trial meeting its primary endpoint and demonstrating statistically significant reductions in cholestatic pruritus. PSC is a rare, progressive liver disease with no approved therapies for PSC-associated pruritus.
The randomized, double-blind, placebo-controlled study enrolled 158 PSC patients who received either volixibat 20 mg twice daily or placebo, with the primary analysis focused on 111 patients who had moderate-to-severe itch at baseline.
In this cohort, volixibat produced a 2.72-point improvement in Adult ItchRO scores compared with a 1.08-point improvement for placebo, resulting in a placebo-adjusted difference of 1.64 points (p<0.0001).
More than half of patients treated with volixibat achieved at least a two-point reduction in itch severity, compared with 26.3% in the placebo group.
Improvements in pruritus were observed within two weeks of treatment initiation, while reductions in serum bile acid levels supported volixibat’s proposed mechanism as an oral ileal bile acid transporter (IBAT) inhibitor.
Safety findings were generally consistent with prior IBAT inhibitor studies, with gastrointestinal adverse events and elevations in liver laboratory values reported more frequently in the volixibat arm.
Treatment-emergent adverse events occurred in 93.5% of patients receiving volixibat and 84.0% receiving placebo. Serious adverse events were reported in 10.4% and 6.2% of patients, respectively, and no deaths occurred in the volixibat arm.
Investigators stated that serious adverse events observed in treated patients, including cholangitis, infections, abdominal pain, and pancreatitis, were not considered treatment related.
Mirum plans to hold a pre-New Drug Application meeting with the U.S. FDA in summer 2026 and expects to submit an NDA in the second half of the year.
Full study findings will be presented at the European Association for the Study of the Liver International Liver Congress 2026 on May 30, while topline data from the Phase 2b VANTAGE study evaluating volixibat in primary biliary cholangitis are expected in the first quarter of 2027.
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About the Writer
Mahathi Palivela is pursuing PharmD and has a strong interest in Clinical Pharmacy and Patient safety. She is passionate about handling and analyzing patient data, and translating clinical insights into clear, meaningful summaries. She aims to apply this interest in Medical Writing and Pharmacovigilance, focusing on improving patient outcomes through careful data interpretation and communication.