Mirum reports positive Phase 3 EXPAND results for LIVMARLI

what happened

BusinessWire reports that Mirum Pharmaceuticals released topline findings from the Phase 3 EXPAND trial of LIVMARLI® (maralixibat) in patients aged 6 months and older and adults with ultra-rare cholestatic liver diseases, including biliary atresia. The study reached its primary endpoint, while all five prespecified secondary endpoints were statistically significant. That included three measures in participants with biliary atresia and a native liver.

EXPAND randomized 52 people—46 children and six adults—during a 20-week double-blind period. Twenty-five received maralixibat at 285 µg/kg twice daily and 27 received placebo. In the main pediatric analysis, the average worst-daily ItchRO(Obs) severity score improved by 1.81 points with maralixibat versus 0.83 points with placebo, producing a 0.98-point treatment difference (p=0.0004). Pruritus improvement occurred on 86.0% of days versus 49.1% with placebo, a 36.9-percentage-point difference (p=0.0008). Total serum bile acids fell 70.1% versus 3.5%, representing a 69.0% treatment effect (p<0.0001).

Among patients with biliary atresia and a native liver, itch severity improved by 2.16 points versus 1.01 points for placebo, for a 1.15-point difference (p=0.0002). Improvement was recorded on 96.4% versus 52.2% of days, while serum bile acids declined 75.5% versus 9.0%, corresponding to a 73.1% treatment effect (p<0.0001). Safety remained consistent with earlier maralixibat experience. Treatment-emergent adverse events affected 24 of 25 maralixibat recipients and 26 of 27 placebo recipients; Grade 3 or higher events occurred in six participants in each group. Diarrhea was reported in 16 versus three patients and abdominal pain in five versus four. No deaths occurred. Mirum plans to submit a supplemental New Drug Application in the United States during the first half of 2027.

why it matters

The data support Mirum’s plan to seek broader use of LIVMARLI beyond its existing approved indications. For the company’s shares, upcoming regulatory steps and further evaluation of EXPAND remain the main market-relevant developments.

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