Positive Topline Data Announced from Mirum’s LIVMARLI Phase 3 MARCH Study in Progressive Familial Intrahepatic Cholestasis (PFIC)

• Met primary endpoint (p=0.0098); highly statistically significant effects in all PFIC subtypes.
• Significant improvements in total bilirubin and growth versus placebo at six months.
• Mirum plans to submit these data to regulatory agencies.
• Mirum to host conference call to discuss data today, October 24, at 9:00 a.m. ET/6:00 a.m. PT.

FOSTER CITY, Calif.--(BUSINESS WIRE)-- Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM) today announced positive topline results from its pivotal Phase 3 MARCH study evaluating LIVMARLI® (maralixibat) oral solution in 93 patients with progressive familial intrahepatic cholestasis (PFIC) in a broad range of subtypes, age one to 17 years. The primary endpoint of improvement in pruritus severity in PFIC2 was statistically significant (p=0.0098).

“The LIVMARLI data observed in the MARCH study showcase an unprecedented reduction in pruritus and serum bile acids. These data confirm our thesis that higher doses can result in improved efficacy and better outcomes for these patients,” said Chris Peetz, president and chief executive officer at Mirum. “We are grateful to the patients, caregivers, and healthcare providers who participated in this study and who helped make these groundbreaking results possible.”

The primary analysis was conducted in PFIC2 patients (n=31). The secondary analyses were evaluated in the All-PFIC cohort, which included PFIC2 as well as additional PFIC subtypes (n=64). The Full-Study population included All-PFIC as well as supplemental patients who had previously undergone surgery, had truncating mutations and other patients (n=93).

Topline results

PFIC2 (n=31)

*Effect size compared the difference between LIVMARLI and placebo, averaged over the last 3 time periods using a repeated measures mixed effect model. Placebo adjusted. Numbers in tables may not sum due to rounding.

All-PFIC (n=64) [PFIC1, PFIC2, PFIC3, PFIC4, PFIC6]