Mirum Pharmaceuticals’ maralixibat could next month become the first treatment approved by the US Food and Drug Administration (FDA) for patients with Alagille syndrome (ALGS).

Mirum recently reported on plans and trial data for the cholestatic pruritus treatment, which has a Prescription Drug User Fee Act (PDUFA) date of September 29, 2021. Maralixibat has previously received Breakthrough Therapy designation from the FDA for the treatment of pruritus in patients with ALGS and progressive familial intrahepatic cholestasis.

Chris Peetz, president and chief executive officer at Mirum, said “Alagille syndrome is a terrible disease, and we know patients and physicians are waiting for treatment options. We are launch ready in the United States and have amplified our reach to patients globally with our expanded access program and recent partnerships to accelerate potential approvals in a number of markets.”

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Pending its approval, maralixibat is currently available through an expanded access program. Mirum has also recently announced licensing agreements with GC Pharma and Cambridge Pharmaceuticals to develop and commercialize maralixibat in South Korea and China, respectively.

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The current regulatory filing is based on the results of the phase 2b ICONIC placebo-controlled drug withdrawal study that recruited 31 children with ALGS. Patients received maralixibat for 18 weeks before being randomized to receive a placebo or continue maralixibat for another 4 weeks. After the 4-week withdrawal period, all patients received maralixibat for the remainder of the 48-week trial. The trial results showed that maralixibat significantly reduced serum bile acid levels, as well as itch and xanthoma severity.

Mirum also announced it plans to submit a marketing authorization application (MAA) with the European Medicines Agency (EMA) for maralixibat in ALGS. This application will include the ICONIC study data as well as long-term event-free survival data from 2 other phase 2 ALGS trials and an open-label follow-up that includes 86 children with 6 years of follow-up. Mirum currently has an MAA under review for the use of maralixibat in patients with progressive familial intrahepatic cholestasis type 2, with a decision expected in early 2022.

The company recently presented safety data from these trials that showed that gastrointestinal (GI) events, including diarrhea and abdominal pain, were the most common adverse events but were mostly mild to moderate. The GI symptoms usually occurred within the first 4 weeks of treatment and lasted less than a week. In the studies with placebo-controlled portions, GI event rates were similar between the treatment and placebo groups. None of the 86 patients discontinued treatment due to GI symptoms.


Mirum Pharmaceuticals reports second quarter 2021 financial results and provides business update. News release. Mirum Pharmaceuticals; August 5, 2021.

Mirum Pharmaceuticals, Inc. (MIRM) CEO Chris Peetz on Q2 2021 results – earnings call transcript. Mirum Pharmaceuticals. August 8, 2021. Accessed August 16, 2021.

Mirum Pharmaceuticals presents new data demonstrating durable improvements in clinical outcome measures in patients with PFIC2 and Alagille syndrome treated with maralixibat. News release. Mirum Pharmaceuticals; April 15, 2019.

Mirum Pharmaceuticals showcases maralixibat transplant-free survival data for progressive familial intrahepatic cholestasis and long-term safety analyses for Alagille syndrome during WCPGHAN annual meeting. News release. Mirum Pharmaceuticals; June 3, 2021.

Mirum Pharmaceuticals presents analyses from its rare liver disease programs at the EASL International Liver Congress 2021. News release. Mirum Pharmaceuticals; June 23, 2021.