Volixibat Shows Positive Interim Results in VANTAGE PBC and VISTAS PSC Studies

Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM) has revealed promising interim data from two ongoing Phase 2b trials investigating volixibat, an oral ileal bile acid transporter (IBAT) inhibitor, in patients with primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC). These findings were announced in a recent press release by the company.

The VANTAGE study, which evaluates volixibat in patients with PBC, showed a statistically significant improvement in pruritus (itchiness) with a reduction of 3.82 points from baseline (p<0.0001) and a placebo-adjusted difference of -2.32 points (p=0.0026) on the Adult ItchRO scale. Furthermore, 75% of participants treated with volixibat experienced more than a 50% reduction in serum bile acids. A noteworthy enhancement in fatigue levels was also observed by week 16 in the volixibat group compared to the placebo group.

Safety profiles were consistent with previous findings, with no new adverse events reported. The most frequently encountered side effect was diarrhea, experienced by 77% of participants, which was generally mild to moderate and transient. Four serious adverse events were noted, including one in the placebo group, but no significant alterations in liver biomarkers were detected.

Statistics for the Adult ItchRO scale indicated a mean change of -3.84 for the 20 mg dose group, -3.79 for the 80 mg dose group, and -3.82 for combined doses (20+80 mg), all showing statistical significance with p-values less than 0.0001. The differences between volixibat and placebo were -2.34 (p=0.0090) for the 20 mg group, -2.29 (p=0.0075) for the 80 mg group, and -2.32 (p=0.0026) for the combined doses. Following these results, the VANTAGE trial will proceed with a 20 mg twice daily regimen of volixibat.

Simultaneously, the interim analysis for the VISTAS PSC study was reviewed by an independent data committee, which recommended the continuation of the trial with the 20 mg twice daily dose of volixibat. The decision was based on safety and meeting predefined efficacy criteria, although the interim results remain blinded to both the sponsor and investigators.

Dr. Joanne Quan, Chief Medical Officer at Mirum Pharmaceuticals, expressed optimism regarding the interim findings from the VANTAGE study, noting the significant progress in treating pruritus in PBC patients. Dr. Kris Kowdley, an investigator for both VANTAGE and VISTAS, highlighted the potential of volixibat to address bile acid-related symptoms in PBC and PSC, with anticipation for the final data.

Carol Roberts, President of the PBCers Organization, also commented on the positive implications for PBC patients, emphasizing the debilitating impact of pruritus and fatigue on their quality of life. The promising interim results of volixibat offer hope for a new therapeutic option for these patients.

Mirum Pharmaceuticals will host a conference call to discuss the interim analyses from the VISTAS and VANTAGE studies. The call is scheduled for June 17 at 8:30 a.m. ET/5:30 a.m. PT.

Volixibat is being developed as a novel orally administered treatment that selectively inhibits the ileal bile acid transporter (IBAT), potentially providing a new therapeutic approach for adult cholestatic liver diseases. In previous Phase 1 and 2 trials, volixibat demonstrated targeted fecal bile acid excretion and changes in biomarkers associated with bile acid synthesis. The current Phase 2b studies, VISTAS and VANTAGE, aim to further evaluate volixibat's efficacy and safety in treating PSC and PBC, respectively.

Mirum Pharmaceuticals, a biopharmaceutical company, focuses on developing treatments for rare diseases affecting both children and adults. The company's portfolio includes three approved medications: LIVMARLI® (maralixibat), CHOLBAM® (cholic acid), and CHENODAL® (chenodiol). LIVMARLI is used to treat cholestatic pruritus in specific liver conditions.