Mirum Pharmaceuticals advanced its primary sclerosing cholangitis (PSC) program after reporting phase IIb data from the Vistas trial of the oral IBAT inhibitor volixibat (and related follow-on dosing strategy), setting up plans for an NDA submission to the FDA in the second half of 2026. CEO Chris Peetz framed the move as entering a new phase of growth and value creation backed by the trial readout. The company’s stated development plan hinges on the phase IIb outcomes supporting efficacy and tolerability in a high-need cholestatic setting where validated endpoints and patient selection have remained crucial. For the PSC market, the planned filing signals intensifying competition among gut-targeting and bile-acid pathway therapies, where differentiation depends on durability, safety management, and labeling ambitions.