Mirum reports positive Phase 3 EXPAND data for Livmarli in cholestatic liver diseases

Mirum Pharmaceuticals disclosed on October 12, 2026 that its Phase 3 EXPAND study of LIVMARLI (maralixibat) produced topline results in patients aged 6 months or older with ultra-rare cholestatic liver diseases, including biliary atresia. According to the company, the study met its primary endpoint and achieved statistical significance across all five prespecified secondary endpoints, including the three endpoints in patients with BA and a native liver.¹

The trial enrolled 52 patients, including 46 pediatric and six adult patients, who were randomized during the 20-week double-blind period to treatment with maralixibat 285 µg/kg twice daily or placebo.¹

On the primary measure, maralixibat showed a statistically significant improvement in pruritus versus placebo in the pediatric analysis population, with a mean 1.81-point reduction in average worst-daily ItchRO(Obs) severity score from Weeks 13 to 20, versus 0.83 points for placebo, a placebo-adjusted difference of 0.98 points (p=0.0004).¹ On serum bile acids, maralixibat produced a 70.1% reduction from baseline compared with 3.5% for placebo, a 69.0% treatment effect (p<0.0001).¹

On safety, the company said findings were consistent with prior clinical experience with maralixibat, with no new safety signals observed.¹ In the safety tables, any treatment-emergent adverse event occurred in 24 of 25 (96.0%) maralixibat patients versus 26 of 27 (96.3%) on placebo, grade 3 or higher TEAEs in 6 (24.0%) versus 6 (22.2%), and serious TEAEs in 5 (20.0%) versus 5 (18.5%); diarrhea was reported in 16 (64.0%) maralixibat patients versus 3 (11.1%) on placebo.¹ No deaths occurred in either arm, per the filing.

Mirum said it intends to file a supplemental New Drug Application with US regulators in the first half of 2027, based on the Phase 3 EXPAND study results.¹