Mirum rises as volixibat Phase 2b VISTAS win keeps biotech bid alive
MIRM•Mirum Pharmaceuticals (MIRM) is trading higher as investors continue to react to positive Phase 2b VISTAS data for volixibat in primary sclerosing cholangitis-related itch, announced May 4, 2026. The company said the trial met its primary endpoint and outlined a summer 2026 FDA pre-NDA meeting and an H2 2026 NDA submission target.
1. What’s moving the stock today
Mirum Pharmaceuticals shares are pushing higher in the latest session as the market continues to price in the company’s May 4, 2026 clinical update showing volixibat met the primary endpoint in the Phase 2b VISTAS study in patients with primary sclerosing cholangitis (PSC) suffering from cholestatic pruritus. The readout reinforced expectations that volixibat could become a first-in-indication treatment for PSC-related itch, supporting a continuation bid in the name after the initial catalyst.
2. The data points investors are trading
In the primary analysis cohort, Mirum reported a 2.72-point improvement in pruritus on the Adult ItchRO scale, with a placebo-adjusted difference of 1.64 points (p<0.0001). The company also said statistically significant improvements were observed within two weeks, and it disclosed that volixibat’s safety profile was generally consistent with IBAT inhibition, with GI adverse events and liver lab elevations among key considerations.
3. What happens next (timing and catalysts)
Mirum outlined a regulatory path that includes a pre-NDA meeting with the FDA planned for summer 2026 and a targeted NDA submission in the second half of 2026 for volixibat in PSC. Beyond the headline topline results, Mirum said full VISTAS Phase 2b results are slated for a late-breaking oral presentation at the EASL International Liver Congress on May 30, 2026, which can serve as a near-term catalyst if additional detail strengthens the commercial and approvability narrative.
