The drug is under evaluation in Phase IIb studies for both primary sclerosing cholangitis under the VISTAS study and PBC under the VANTAGE study.
This milestone is based on the positive interim results from the Phase IIb VANTAGE study, which indicated a statistically significant improvement in pruritus compared to placebo.
In June, Mirum reported the interim findings from the VANTAGE study. These results showed not only a significant improvement in pruritus but 75% of patients on volixibat achieved a greater than 50% reduction in serum bile acids. In addition, there was a significant improvement in fatigue at week 16 with volixibat compared to placebo.
Volixibat functions as an oral agent that minimally absorbs and selectively inhibits the ileal bile acid transporter (IBAT). By blocking IBAT, volixibat potentially offers a new method for treating adult cholestatic diseases by reducing systemic bile acids and those within the liver.
The confirmatory segment of the VANTAGE study is currently underway, with full enrolment anticipated to be completed by 2026.
Mirum chief medical officer and MD Joanne Quan said: “Breakthrough Therapy Designation for volixibat in PBC underscores the importance and urgency for a treatment to address one of the most burdensome impacts of this rare liver disease.
“We look forward to advancing our VANTAGE study with the goal of making volixibat available to patients living with PBC-related itch as quickly as possible.”