Mirum Pharmaceuticals has enrolled the first patient in its Phase IIb VISTAS study of volixibat in adult patients with primary sclerosing cholangitis (PSC), an idiopathic chronic cholestatic liver disease.

An oral minimally absorbed agent, volixibat can selectively stop apical sodium dependent bile acid transporter (ASBT).

It can potentially provide a new way of treating adult cholestatic diseases by blocking bile acid recycling through ASBT inhibition, thereby lowering bile acids systemically and in the liver.

PSC is characterised by gradual inflammation and damage of bile ducts causing serious liver disease, cancer and eventually in liver failure.

Participants in the study will randomly receive volixibat 20mg or 80 mg twice daily or placebo for 28 weeks.

Later on, all subjects will be given volixibat in the study’s open-label extension phase.

The change in pruritus from baseline for volixibat as compared with placebo will form the trial’s primary endpoint.

Safety and tolerability, quality of life measures, and serum bile acids will be the secondary endpoints.

Exploratory endpoints will include evaluation of liver fibrosis and other markers of PSC progression.

Mirum Pharmaceuticals chief medical officer Ed Tucker said: “We are excited to initiate the volixibat Phase II VISTAS study for patients with primary sclerosing cholangitis.

“Our learnings from the maralixibat development program have informed the design of our volixibat study with the hope of alleviating the burdensome effects experienced by patients with PSC.”

Presently, the company is analysing an ASBT inhibitor in ongoing studies in paediatric patients with cholestatic liver diseases.

Furthermore, Mirum has begun a rolling NDA submission to the US Food and Drug Administration (FDA) for maralixibat for treating cholestatic pruritus linked to Alagille syndrome. It is anticipated to conclude in this quarter of the year.

The company intends to launch the therapy in the US in the second half of this year on getting approval for this indication.