Overview of Mirum Pharmaceuticals' Stock Surge#
Mirum Pharmaceuticals saw its stock price increase by 12% on Monday. This rise followed the announcement of positive results from its VISTAS Phase 2b clinical trial, which tested the drug volixibat in patients suffering from primary sclerosing cholangitis (PSC), a serious liver condition.
Trial Results and Significance#
The VISTAS study achieved its main goal, showing a significant reduction in itching, a common symptom of PSC. Specifically, patients treated with volixibat experienced an average decrease of 2.72 points from their initial scores on the Adult ItchRO scale, compared to a 1.64 point reduction for those receiving a placebo (a substance with no therapeutic effect). This result was statistically significant, meaning it is unlikely to have occurred by chance (p=0.0019).
Out of the 158 participants, 55.6% of those taking volixibat reported at least a 2-point improvement in their itching scores, compared to just 26.3% of those on placebo. Additionally, the treatment led to a notable reduction in serum bile acids, which are substances produced by the liver (p=0.0324).
Future Plans and Regulatory Steps#
Mirum Pharmaceuticals is planning a pre-New Drug Application (NDA) meeting with the U.S. Food and Drug Administration (FDA) for the summer of 2026, with the goal of submitting the NDA in the latter half of that year. Currently, there are no approved treatments for PSC, making these developments particularly significant for patients.
Safety Profile and Next Steps#
The safety profile of volixibat was generally in line with what is expected from similar treatments, with gastrointestinal issues being the most common side effects. Notably, 9.1% of patients on volixibat discontinued the study due to adverse effects, compared to 2.5% of those on placebo. Full results from the trial will be shared at the European Association for the Study of the Liver International Liver Congress on May 30. Additionally, topline data from another study involving volixibat for primary biliary cholangitis is expected in early 2027.