LIVMARLI Now Approved in Japan for ALGS and PFIC

- LIVMARLI is the first and only treatment available for cholestatic pruritus in patients with Alagille syndrome and Progressive Familial Intrahepatic Cholestasis in Japan

Mirum Pharmaceuticals, Inc. (NASDAQ:MIRM) today announced that its partner, Takeda Pharmaceutical Company Limited, has received approval by the Japanese Ministry of Health, Labour, and Welfare for LIVMARLI^® (maralixibat) oral solution for the treatment of cholestatic pruritus in patients with Alagille syndrome (ALGS) and Progressive Familial Intrahepatic Cholestasis (PFIC) in Japan.

"We are thrilled to see LIVMARLI approved as the first and only medication available in Japan for patients living with pruritus related to ALGS and PFIC," said Chris Peetz, chief executive officer at Mirum. "Takeda is a leading global pharmaceutical company with demonstrated success in the development and commercialization of medicines for rare diseases. Under Takeda's leadership, we are confident that LIVMARLI could have a meaningful impact on the lives of patients with ALGS and PFIC in Japan."

Mirum and Takeda entered into an exclusive license agreement in September 2021 for the development and commercialization of LIVMARLI for rare cholestatic pediatric liver diseases in Japan. Under the terms of the agreement, Mirum is eligible to receive a percentage of Takeda's annual net sales.

LIVMARLI is currently approved for the treatment of pruritus related to ALGS in more than 40 countries and for PFIC in more than 30 countries worldwide.

About LIVMARLI^® (maralixibat) oral solution

LIVMARLI^® (maralixibat) oral solution is an orally administered, ileal bile acid transporter (IBAT) inhibitor approved by the U.S. Food and Drug Administration and European Medicines Agency for two pediatric cholestatic liver diseases. It is approved for the treatment of cholestatic pruritus in patients with Alagille syndrome (ALGS) in the U.S. three months of age and older and in Europe for patients two months of age and older. It is also approved in the U.S. for the treatment of cholestatic pruritus in patients with progressive familial intrahepatic cholestasis (PFIC) 12 months of age and older and in Europe for the treatment of PFIC in patients three months of age and older. For more information for U.S. residents, please visit LIVMARLI.com.

LIVMARLI is currently being evaluated in the Phase 3 EXPAND study in additional settings of cholestatic pruritus. To learn more about ongoing clinical trials with LIVMARLI, please visit Mirum's clinical trials section on the company's website.

U.S. IMPORTANT SAFETY INFORMATION

Limitation of Use: LIVMARLI is not for use in PFIC type 2 patients who have a severe defect in the bile salt export pump (BSEP) protein.

LIVMARLI can cause side effects, including:

Liver injury. Changes in certain liver tests are common in patients with Alagille syndrome and PFIC but can worsen during treatment. These changes may be a sign of liver injury. In PFIC, this can be serious or may lead to liver transplant or death. Your healthcare provider should do blood tests and physical exams 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), bloating in your stomach area, loss of appetite or bleeding or bruising more easily than normal.

Stomach and intestinal (gastrointestinal) problems. LIVMARLI can cause stomach and intestinal problems, including diarrhea and stomach pain. Your healthcare provider may advise you to monitor for new or worsening stomach problems including stomach pain, diarrhea, blood in your stool or vomiting. 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 is common in patients with Alagille syndrome and PFIC but may worsen during treatment. Your healthcare provider should do blood tests before starting and during treatment and may monitor for bone fractures and bleeding which have been reported as common side effects.

US Prescribing Information

EU SmPC

Canadian Product Monograph

About Mirum Pharmaceuticals, Inc.

Mirum Pharmaceuticals, Inc. is a biopharmaceutical company dedicated to transforming the treatment of rare diseases affecting children and adults. Mirum has three approved medications: LIVMARLI^® (maralixibat) oral solution, CHOLBAM^® (cholic acid) capsules, and CTEXLI™ (chenodiol) tablets.

LIVMARLI, an IBAT inhibitor, is approved for the treatment of two rare liver diseases affecting children and adults. It is approved for the treatment of cholestatic pruritus in patients with Alagille syndrome in the U.S. (three months and older), in Europe (two months and older), and in other regions globally. It is also approved in the U.S. in cholestatic pruritus in PFIC patients 12 months of age and older; in Europe, it is approved for patients with PFIC three months of age and older. Mirum is also initiating the Phase 3 EXPAND study, a label expansion opportunity for LIVMARLI in additional settings of cholestatic pruritus. CHOLBAM is FDA-approved for the treatment of bile acid synthesis disorders due to single enzyme deficiencies and adjunctive treatment of peroxisomal disorders in patients who show signs or symptoms of liver disease. CTEXLI is FDA-approved for the treatment of cerebrotendinous xanthomatosis (CTX) in adults.

Mirum's late-stage pipeline includes two investigational treatments for several rare diseases. Volixibat, an IBAT inhibitor, is being evaluated in two potentially registrational studies including the Phase 2 VISTAS study for primary sclerosing cholangitis (PSC) and Phase 2b VANTAGE study for primary biliary cholangitis. Volixibat has been granted Breakthrough Therapy Designation for the treatment of cholestatic pruritus in patients with PBC. Mirum is also planning for a Phase 2 study evaluating MRM-3379, a PDE4D inhibitor for the treatment of Fragile X syndrome, a rare genetic neurocognitive disorder.

To learn more about Mirum, visit mirumpharma.com and follow Mirum on Facebook, LinkedIn, Instagram and Twitter (X).

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 impact of LIVMARLI on patients in Japan, the ability of Takeda to successfully commercialize in the territory and the size of the Japanese market for LIVMARLI. 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," "can," "would," "potential," "hope," "opportunity," 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 macroeconomic and geopolitical developments, 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. A further description of risks and uncertainties can be found in Mirum's Quarterly Report on Form 10-K for the quarter ended December 31, 2024 and subsequent filings with the U.S. Securities and Exchange Commission and available at www.sec.gov.

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