Mirum Pharmaceuticals Submits Supplemental New Drug Application to FDA for LIVMARLI in Patients with Cholestatic Pruritus in Progressive Familial Intrahepatic Cholestasis

FOSTER CITY, Calif.--(BUSINESS WIRE)-- Mirum Pharmaceuticals Inc. (Nasdaq: MIRM) today announced that it has submitted a supplemental New Drug Application (sNDA) for LIVMARLI^® (maralixibat) oral solution for the treatment of cholestatic pruritus in patients two months of age and older with progressive familial intrahepatic cholestasis (PFIC).

The sNDA submission is based on data from the MARCH PFIC Phase 3 study of LIVMARLI. MARCH PFIC is the largest randomized trial conducted in PFIC, with 93 patients across a range of genetic PFIC subtypes, including PFIC1, PFIC2, PFIC3, PFIC4, PFIC6 and unidentified mutational status. In the study, LIVMARLI-treated patients had statistically significant improvements in pruritus (p< 0.0001), serum bile acids (p<0.0001), bilirubin (p=0.0471), and growth as measured by weight z-score (p=0.0391), in the cohort evaluating combined genetic subtypes. The sNDA also includes data from the Phase 2 INDIGO study of PFIC2 patients demonstrating transplant-free survival in all serum bile acid responders after more than five years of treatment with LIVMARLI.

LIVMARLI is currently approved in the U.S. and Israel for the treatment of cholestatic pruritus in patients with Alagille syndrome (ALGS) one year of age and older, as well as in the European Union in the same indication, in patients two months of age and older.

“Following the groundbreaking MARCH clinical data, we are thrilled at the opportunity to provide the PFIC community in the U.S. a treatment option that significantly reduces pruritus and gives hope for a life less burdened by PFIC,” said Chris Peetz, president and chief executive officer at Mirum. “The MARCH PFIC study greatly advanced the understanding of treatment options for PFIC by including the broadest range of genetic types ever studied. We are working urgently to bring LIVMARLI to PFIC patients.”

“PFIC patients suffer greatly due to the unrelenting pruritus associated with the disease and the potential to have another treatment option available with such compelling data to support its use is really exciting,” said Emily Ventura, executive director, PFIC Network and mom to child with PFIC. “The results seen in the LIVMARLI clinical studies are encouraging as they help to show the potential benefit that patients treated with this medication may experience, which provides hope for a healthier tomorrow.”

About PFIC

Progressive familial intrahepatic cholestasis (PFIC) is a rare genetic disorder that causes progressive liver disease typically leading to liver failure. In people with PFIC, liver cells are less able to secrete bile. The resulting buildup of bile causes liver disease in affected individuals. Signs and symptoms of PFIC typically begin in infancy. Patients experience severe itching, jaundice, failure to grow at the expected rate (failure to thrive), and an increasing inability of the liver to function (liver failure). The disease is estimated to affect one in every 50,000 to 100,000 births in the United States and Europe. Six types of PFIC have been genetically identified, all of which are similarly characterized by impaired bile flow and progressive liver disease.

About LIVMARLI^® (maralixibat) oral solution

LIVMARLI^® (maralixibat) oral solution is an orally administered, once-daily, ileal bile acid transporter (IBAT) inhibitor approved by the U.S. Food and Drug Administration for the treatment of cholestatic pruritus in patients with Alagille syndrome (ALGS) one year of age and older. LIVMARLI is also approved by the European Commission for the treatment of cholestatic pruritus in patients with ALGS two months and older. It is the only approved medication to treat cholestatic pruritus associated with Alagille syndrome. For more information for U.S. residents, please visit LIVMARLI.com.

LIVMARLI is currently being evaluated in late-stage clinical studies in other rare cholestatic liver diseases including progressive familial intrahepatic cholestasis (PFIC) and biliary atresia. LIVMARLI has received Breakthrough Therapy designation for ALGS and PFIC type 2 and orphan designation for ALGS, PFIC and biliary atresia. To learn more about ongoing clinical trials with LIVMARLI, please visit Mirum’s clinical trials section on the company’s website.

IMPORTANT SAFETY INFORMATION

LIVMARLI can cause side effects, including:

Changes in liver tests. Changes in certain liver tests are common in patients with Alagille syndrome and can worsen during treatment with LIVMARLI. These changes may be a sign of liver injury and can be serious. Your healthcare provider should do blood tests before starting and during treatment to check your liver function. Tell your healthcare provider right away if you get any signs or symptoms of liver problems, including nausea or vomiting, skin or the white part of the eye turns yellow, dark or brown urine, pain on the right side of the stomach (abdomen) or loss of appetite.

Stomach and intestinal (gastrointestinal) problems. LIVMARLI can cause stomach and intestinal problems, including diarrhea, stomach pain, and vomiting during treatment. Tell your healthcare provider right away if you have any of these symptoms more often or more severely than normal for you.

A condition called Fat Soluble Vitamin (FSV) Deficiency caused by low levels of certain vitamins (vitamin A, D, E, and K) stored in body fat. FSV deficiency is common in patients with Alagille syndrome but may worsen during treatment. Your healthcare provider should do blood tests before starting and during treatment.

Other common side effects reported during treatment were bone fractures and gastrointestinal bleeding.

US Prescribing Information

EU SmPC

About Mirum Pharmaceuticals, Inc.

Mirum Pharmaceuticals, Inc. is a biopharmaceutical company dedicated to transforming the treatment of rare liver diseases. Mirum’s approved medication is LIVMARLI^® (maralixibat) oral solution which is approved in the U.S. for the treatment of cholestatic pruritus in patients with Alagille syndrome one year of age and older, and in Europe for the same indication in patients two months of age and older.

Mirum’s late-stage pipeline includes two investigational treatments for debilitating liver diseases affecting children and adults. LIVMARLI, an oral ileal bile acid transporter (IBAT) inhibitor, is currently being evaluated in clinical trials for pediatric liver diseases and includes the EMBARK Phase 2b clinical trial for patients with biliary atresia. In addition, Mirum has an expanded access program open across multiple countries for eligible patients with ALGS and PFIC.

Mirum’s second investigational treatment, volixibat, an oral IBAT inhibitor, is being evaluated in two potentially registrational studies including the VISTAS Phase 2b clinical trial for adults with primary sclerosing cholangitis and the VANTAGE Phase 2b clinical trial for adults with primary biliary cholangitis.

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Forward-Looking Statements

Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements include statements regarding, among other things, the results of Mirum’s clinical trials, the potential for Mirum’s recent FDA filings and meetings, and the regulatory approval path for maralixibat in PFIC. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Words such as “plans,” “will,” “believes,” “anticipates,” “expects,” “intends,” “goal,” “potential” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon Mirum’s current expectations and involve assumptions that may never materialize or may prove to be incorrect. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Words such as “will,” “could,” “would,” “potential” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon Mirum’s current expectations and involve assumptions that may never materialize or may prove to be incorrect. Actual results could differ materially from those anticipated in such forward-looking statements as a result of various risks and uncertainties, which include, without limitation, risks and uncertainties associated with Mirum’s business in general, the impact of the COVID-19 pandemic, and the other risks described in Mirum’s filings with the Securities and Exchange Commission. All forward-looking statements contained in this press release speak only as of the date on which they were made and are based on management’s assumptions and estimates as of such date. Mirum undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made, except as required by law.

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