FOSTER CITY, Calif.--(BUSINESS WIRE)-- Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM) today announced that the U.S. Food and Drug Administration (FDA) has approved CTEXLI™ (chenodiol) tablets, a bile acid, for the treatment of adults with cerebrotendinous xanthomatosis (CTX). CTEXLI is the first and only treatment approved for this rare, progressive and debilitating disease.

The approval is based on data from the Phase 3 RESTORE study evaluating the safety and efficacy of CTEXLI in adult patients with CTX by measurement of urine bile alcohols and other secondary measures. The primary endpoint of reduction in bile alcohols (urine 23S-pentol) was highly statistically significant (p<0.0001). At the end of the randomized double-blind withdrawal period, there was a 20-fold difference between placebo and CTEXLI treated patients in urine 23S-pentol levels.

In CTX, a deficiency of the bile acid chenodeoxycholic acid (CDCA) leads to a buildup of bile alcohols which precedes a toxic accumulation of cholestanol. Cholestanol is the key driver of symptomatic burden and disease progression, including irreversible neurologic dysfunction. Results from the RESTORE study demonstrated that treatment with CTEXLI not only improved urine bile alcohol levels but also serum cholestanol levels. Additionally, a greater proportion of patients receiving placebo required blinded rescue therapy, demonstrating the robustness of the effect.

“The FDA’s approval of CTEXLI is tremendous as it unlocks an opportunity to better identify and treat adult patients with CTX in the United States. Our hope is that patients are diagnosed sooner and have a chance to avoid some of the debilitating and lasting symptoms associated with CTX,” said Chris Peetz, chief executive officer at Mirum. “We are grateful to the clinicians, patients, advocates, and families who participated in the research that led to this approval and who have continued to provide support to this community.”

“Cerebrotendinous xanthomatosis (CTX) is a rare disease that can present with early cataracts, tendon lipid deposits, and significant neurologic disease, and the latter may be prevented with earlier diagnosis and treatment,” said Ernst J. Schaefer, MD, professor of medicine at Tufts University School of Medicine in Boston and chief medical officer and laboratory director at Boston Heart Diagnostics. “Treatment with CTEXLI has been shown to lower bile alcohols and cholestanol levels, reducing the progressive symptoms associated with CTX.”

“CTX is a devastating disease that is often diagnosed in early adulthood with progressive symptoms that can have a significant impact on a person’s quality of life,” said Jean Pickford, executive director, CTX Alliance. “We are thrilled that CTEXLI is now approved and hope that patients with this disease are diagnosed earlier and can avoid potentially irremediable disease progression and many of the debilitating symptoms associated with CTX.”

CTEXLI will be available through Mirum Access Plus (MAP), Mirum’s patient support program. Patients currently on Mirum products or those with a prescription for CTEXLI can coordinate with MAP to receive fulfillment support by dialing (855) MRM-4YOU (855-676-4968) or visiting www.ctexli.com for more information.

About Cerebrotendinous Xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is an autosomal, recessive, progressive genetic disorder resulting from a deficiency of a key enzyme in the bile acid synthesis pathway. CTX is characterized by fatty yellow nodules (xanthomas) located in the connective tissues within the brain. These deposits can cause progressive damage to the brain and other areas of the body. As the clinical course progresses, irreversible neurological deterioration leads to premature death. CTX is a rare disease affecting one to two thousand people in the United States.

About CTEXLI™ (chenodiol) tablets

CTEXLI™ (chenodiol) tablets is FDA-approved for the treatment of adults with cerebrotendinous xanthomatosis (CTX). Chenodiol is another name for chenodeoxycholic acid (CDCA). CDCA is a naturally occurring bile acid that was originally approved for the treatment of people with radiolucent stones in the gallbladder. CTEXLI was evaluated as part of the Phase 3 RESTORE study, the first and only clinical trial for CTX. CTX is a rare progressive disease that can affect the brain, spinal cord, tendons, eyes and arteries.

IMPORTANT SAFETY INFORMATION

CTEXLI can cause side effects, including:

Liver Injury: You will need to undergo laboratory testing before starting and while taking CTEXLI to check your liver function. Changes in certain liver tests may occur during treatment and may be a sign of liver injury. This can be serious. Stop taking CTEXLI immediately and tell your healthcare provider right away if you get any signs or symptoms of liver problems, including, stomach (abdomen) pain, bruising, dark-colored urine, feeling tired (fatigue), bleeding, yellowing of the skin and eyes, nausea, and itching.

Most Common Side Effects: Diarrhea, headache, stomach pain, constipation, high blood pressure, muscular weakness, and upper respiratory tract infection.

Tell your healthcare provider about all the medications that you take, as CTEXLI may interact with other medicines.

US Prescribing Information

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 potential benefitsof CTEXLI for appropriate patients, and the real life CTEXLI treated patients’ reduction of symptoms of CTX. 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-Q for the quarter ended September 30, 2024 and subsequent filings with the U.S. Securities and Exchange Commission and available at www.sec.gov .

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