Mirum Presents New Data from LIVMARLI Phase 3 PFIC Study and ALGS Infant Study in Late-Breaker Presentations at The Liver Meeting of AASLD

-          Phase 3 MARCH study meets primary endpoint and demonstrates statistical significance across key endpoints in all PFIC types. Receives Best of Liver Meeting distinction. -          RISE study in infants with ALGS shows safety and tolerability of LIVMARLI for ages ≥2 months. -          Real-world evidence highlights LIVMARLI’s safety and tolerability in patients with ALGS. -          Post-AASLD conference call to discuss MARCH data on November 9, 2022 at 8am ET/5am PT

FOSTER CITY, Calif.--(BUSINESS WIRE)-- Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM), today presented new data from LIVMARLI® (maralixibat) oral solution studies, including two late-breaker presentations, at The Liver Meeting® of the American Association for the Study of Liver Diseases taking place November 4-7, 2022 in Washington, D.C.

“The MARCH-PFIC data provides comprehensive evidence that LIVMARLI is a potentially meaningful treatment option for patients with progressive familial intrahepatic cholestasis (PFIC). The statistically significant reduction in pruritus and serum bile acids, as well as improvements in bilirubin and growth, demonstrate a magnitude of treatment effect which exceeded expectations, suggesting higher doses not only improves response rates, but is also effective across PFIC types,” said Pam Vig, PhD, head of R&D at Mirum. “We look forward to discussing these data with regulatory agencies soon. In addition, interim safety data in Alagille syndrome (ALGS) underscores LIVMARLI’s safety and tolerability profile in infants as young as two months of age. We are thrilled to expand the growing body of clinical evidence for LIVMARLI in both PFIC and ALGS and to present our late breaking data at the AASLD conference.”

Oral session #5001: Efficacy and safety of maralixibat in patients with progressive familial intrahepatic cholestasis (MARCH-PFIC): a randomized placebo-controlled study **Nominated for Best of Liver Meeting** Late-breaker oral presentation by Professor Richard J. Thompson, King’s College, London

The Phase 3 MARCH study evaluated LIVMARLI 570 µg/kg BID in 93 patients across a broad range of PFIC types between ages one to 17 years old. The primary analysis (n=31) focused on patients with BSEP deficiency (PFIC2). The secondary analyses evaluated the All-PFIC cohort, which included all PFIC types (n=64). The full-study population of 93 patients was inclusive of the All-PFIC cohort, as well as a supplemental cohort of PFIC patients who had previously undergone surgery, had truncating mutations, no variants found, or other.

The primary and secondary endpoints were met with statistical significance. LIVMARLI demonstrated significant and rapid improvements in pruritus and serum bile acids, consistent across all PFIC types, with treatment effect greater than previously reported, with the higher dose tested in this study. In the All-PFIC cohort, over 60% of LIVMARLI-treated patients had a pruritus response and over half had a serum bile acid response achieving statistical significance versus placebo. The data also showed statistically significant improvements in bilirubin and growth.

Topline results

*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.