Peroxisome Biogenesis Disorders

- 2024 net product sales of $336.4 million - 2025 expected global net product sales of $420 million to $435 million - VISTAS study of volixibat in PSC expected to complete enrollment in second half 2025; topline data expected 2026 - CTEXLI (chenodiol) approved in the US for cerebrotendinous xanthomatosis - Conference call to provide business updates today, February 26 at 1:30 p.m. PT/4:30 p.m. ET FOSTER CITY, Calif.--(BUSINESS WIRE)-- Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM) today reported financial results for the fourth quarter and year-end 2024 and provided a business update. “2024 was another year of significant growth and accomplishments for Mirum and in 2025 we expect this momentum to continue,” said Chris Peetz, chief executive officer of Mirum. “We continue to expand the reach of our three commercial medicines within our patient communities and look forward to another year of strong financial performance. On top of this, we are looking forward to multiple upcoming clinical and regulatory milestones, such as PSC where we’re expecting full enrollment of our VISTAS trial in the second half of the year.” Future Expectations and Milestones 2025 Guidance: expect continued revenue growth with global net product sales of approximately $420 million to $435 million and positive cash flow. Volixibat VISTAS study in primary sclerosing cholangitis (PSC) expected to complete enrollment in second half 2025; topline data expected in 2026. Volixibat VANTAGE study in primary biliary cholangitis (PBC) expected to complete enrollment in 2026. LIVMARLI EXPAND Phase 3 study for pruritus in rare cholestatic conditions expected to complete enrollment in 2026. Expect to initiate Phase 2 study for MRM-3379 in Fragile X Syndrome (FXS) in 2025. 2024 Highlights Commercial: Strong growth across all three approved medicines Total net product sales of $336.4 million in 2024. 2024 LIVMARLI net product sales totaled $213.3 million. 2024 Bile Acid Medicines net product sales totaled $123.1 million. Global LIVMARLI business grew to 30 countries with commercial access, including successful reimbursement negotiation and launch in the four major European markets. Regulatory and Pipeline: Achieved multiple significant milestones and expanded pipeline Positive interim results for volixibat in VISTAS PSC and VANTAGE PBC studies. Volixibat granted breakthrough therapy designation for treatment of cholestatic pruritus in PBC by the U.S. Food and Drug Administration (FDA). LIVMARLI approved by the FDA for cholestatic pruritus in progressive familial intrahepatic cholestasis (PFIC) patients 12 months and older and in Europe for treatment of PFIC in patients three months and older. Initiated the LIVMARLI EXPAND Phase 3 study for pruritus in rare cholestatic conditions. In-licensed global rights to PDE4D inhibitor MRM-3379 for FXS. Corporate and Financial: Strong financial performance Total net product sales for the full year ended December 31, 2024, was $336.4 million compared to $178.9 million for the full year ended December 31, 2023. Total operating expenses were $424.5 million for the full year ended December 31, 2024 compared to $295.5 million for the full year ended December 31, 2023. Total operating expenses for the full year ended December 31, 2024 included $79.4 million of non-cash stock-based compensation, intangible amortization, and other non-cash expenses compared to $48.8 million for the full year ended December 31, 2023. Cash, cash equivalents and investments of $292.8 million as of December 31, 2024 compared to $286.3 million as of December 31, 2023. Business Update Conference Call Mirum will host a conference call today, February 26 at 1:30 p.m. PT/4:30 p.m. ET, to provide business updates. Join the call using the following details: Conference Call Details: U.S./Toll-Free: +1 833 470 1428 International: +1 404 975 4839 Passcode: 126145 You may also access the call via webcast by visiting the Events & Presentations section on Mirum’s website. A replay of this webcast will be available for 30 days. 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 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 has received orphan designation for ALGS and PFIC. 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. 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 ALGS 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 Volixibat Volixibat is an oral, minimally absorbed agent designed to selectively inhibit the ileal bile acid transporter (IBAT). Volixibat may offer a novel approach in the treatment of adult cholestatic diseases by blocking the recycling of bile acids, through inhibition of IBAT, thereby reducing bile acids systemically and in the liver. Volixibat is currently being evaluated in Phase 2b studies for primary sclerosing cholangitis (PSC) (VISTAS study), and primary biliary cholangitis (PBC) (VANTAGE study). In June, Mirum announced positive interim results from the Phase 2b VANTAGE study showing statistically significant improvement in pruritus as well as meaningful reductions in serum bile acids and improvements in fatigue for patients treated with volixibat. No new safety signals were observed, and the most common adverse event was diarrhea with all cases mild to moderate. Volixibat has been granted breakthrough therapy designation for the treatment of PBC. About CHOLBAM® (cholic acid) capsules The FDA approved CHOLBAM (cholic acid) capsules in March 2015, the first FDA-approved treatment for pediatric and adult patients with bile acid synthesis disorders due to single enzyme defects, and for adjunctive treatment of patients with peroxisome biogenesis disorder-Zellweger spectrum disorder. The effectiveness of CHOLBAM has been demonstrated in clinical trials for bile acid synthesis disorders and the adjunctive treatment of peroxisomal disorders. An estimated 200 to 300 patients are current candidates for therapy. CHOLBAM® (cholic acid) Indication CHOLBAM is a bile acid indicated for Treatment of bile acid synthesis disorders due to single enzyme defects. Adjunctive treatment of peroxisomal disorders, including Zellweger spectrum disorders, in patients who exhibit manifestations of liver disease, steatorrhea, or complications from decreased fat-soluble vitamin absorption. LIMITATIONS OF USE The safety and effectiveness of CHOLBAM on extrahepatic manifestations of bile acid synthesis disorders due to single enzyme defects or peroxisomal disorders, including Zellweger spectrum disorders, have not been established. IMPORTANT SAFETY INFORMATION WARNINGS AND PRECAUTIONS – Exacerbation of liver impairment Monitor liver function and discontinue CHOLBAM in patients who develop worsening of liver function while on treatment. Concurrent elevations of serum gamma glutamyltransferase (GGT) and alanine aminotransferase (ALT) may indicate CHOLBAM overdose. Discontinue treatment with CHOLBAM at any time if there are clinical or laboratory indicators of worsening liver function or cholestasis. ADVERSE REACTIONS The most common adverse reactions (≥1%) are diarrhea, reflux esophagitis, malaise, jaundice, skin lesion, nausea, abdominal pain, intestinal polyp, urinary tract infection, and peripheral neuropathy. Please see full Prescribing Information for additional Important Safety Information. 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 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, significant increase or continued commercial results for our approved products, including continued financial growth, being on track to achieve our yearly financial guidance, delivering life changing medicines for patients suffering from rare diseases, the results, enrollment, conduct and progress of Mirum’s ongoing and planned studies for its product candidates, including newly in-licensed product candidates, the timing and results of interim analyses of our ongoing studies and the regulatory approval path for our product candidates in any indication or any specific territory. 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 “expected,” “will,” “could,” “would,” “guidance,” “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 geopolitical and macroeconomic events, and the other risks described in Mirum’s Report for the quarter ended December 31, 2024 and subsequent 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. Mirum Pharmaceuticals, Inc. Condensed Consolidated Statement of Operations Data (in thousands, except share and per share amounts) (Unaudited) Three Months Ended December 31, Year Ended December 31, 2024 2023 2024 2023 Revenue: Product sales, net $ 99,430 $ 69,554 $ 336,409 $ 178,874 License and other revenue (16 ) — 479 7,500 Total revenue 99,414 69,554 336,888 186,374 Operating expenses: Cost of sales (1) 22,780 25,020 81,643 47,039 Research and development 44,026 30,935 140,630 102,609 Selling, general and administrative 56,830 46,184 202,221 145,880 Total operating expenses (2) 123,636 102,139 424,494 295,528 Loss from operations (24,222 ) (32,585 ) (87,606 ) (109,154 ) Other income (expense): Interest income 3,204 3,775 13,792 13,735 Interest expense (3,579 ) (3,563 ) (14,311 ) (15,105 ) Loss from termination of revenue interest purchase agreement — — — (49,076 ) Other income (expense), net 231 (3,061 ) 1,213 (2,824 ) Net loss before provision for income taxes (24,366 ) (35,434 ) (86,912 ) (162,424 ) (Benefit from) provision for income taxes (576 ) 225 1,030 991 Net loss (23,790 ) (35,659 ) (87,942 ) (163,415 ) Net loss per share, basic and diluted $ (1.85 ) $ (4.00 ) Weighted-average shares of common stock outstanding, basic and diluted 47,522,594 40,885,124 (1) Amounts include intangible amortization expense as follows: Intangible amortization $ 5,894 $ 5,305 $ 22,783 $ 10,404 (2) Amounts include stock-based compensation expense as follows: Cost of sales $ 311 $ — $ 948 $ — Research and development 4,210 2,879 15,188 10,892 Selling, general and administrative 8,730 6,841 32,308 24,131 Total stock-based compensation $ 13,251 $ 9,720 $ 48,444 $ 35,023 Mirum Pharmaceuticals, Inc. Condensed Consolidated Balance Sheet Data (in thousands) (Unaudited) December 31, 2024 2023 Assets Current assets: Cash and cash equivalents $ 222,503 $ 286,326 Short-term investments 57,812 — Accounts receivable 78,286 67,968 Inventory 22,403 22,312 Prepaid expenses and other current assets 11,784 10,935 Total current assets 392,788 387,541 Restricted cash 425 — Long-term investments 12,526 — Intangible assets, net 249,819 252,925 Other noncurrent assets 15,196 6,155 Total assets $ 670,754 $ 646,621 Liabilities and Stockholders’ Equity Current liabilities: Accounts payable $ 14,618 $ 7,416 Accrued expenses 110,224 78,544 Operating lease liabilities, current 1,709 1,104 Total current liabilities 126,551 87,064 Operating lease liabilities, noncurrent 7,972 617 Convertible notes payable, net, noncurrent 308,082 306,421 Other liabilities 2,509 3,849 Total liabilities 445,114 397,951 Commitments and contingencies Stockholders’ equity: Preferred stock — — Common stock 5 5 Additional paid-in capital 870,189 803,260 Accumulated deficit (644,181 ) (556,239 ) Accumulated other comprehensive (loss) income (373 ) 1,644 Total stockholders’ equity 225,640 248,670 Total liabilities and stockholders’ equity $ 670,754 $ 646,621 Investor Contacts: Andrew McKibben ir@mirumpharma.com Media Contact: Erin Murphy media@mirumpharma.com

- 2024 net product sales of approximately $336 million exceeds upper end of guidance range; preliminary and unaudited estimate - 2025 expected global net product sales of $420 million to $435 million - VISTAS study of volixibat in primary sclerosing cholangitis expected to complete enrollment in second half 2025; topline data expected 2026 FOSTER CITY, Calif.--(BUSINESS WIRE)-- Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM) today provided its preliminary and unaudited estimates for full-year 2024 net product sales, year-end cash balance, corporate updates, and full-year 2025 outlook. “2024 marked a significant year for Mirum as we accelerated our commercial business and achieved significant development milestones,” said Chris Peetz, chief executive officer of Mirum. “We continued our leadership in cholestatic disease with a label expansion for LIVMARLI and positive interim analyses for volixibat in PSC and PBC. Additionally, we advanced our rare genetic neurology efforts with the NDA submission for chenodiol and the in-licensing of MRM-3379 for Fragile X syndrome. With proven commercial execution in ultra-rare disease and a compelling pipeline in larger indications, we believe we are well-positioned for sustained growth in the years ahead.” Future Expectations and Milestones 2025 Guidance: expect continued revenue growth with global net product sales of approximately $420 million to $435 million and positive cash flow from operations Volixibat VISTAS study in primary sclerosing cholangitis (PSC) expected to complete enrollment in second half 2025; topline data expected in 2026 Volixibat VANTAGE study in primary biliary cholangitis (PBC) expected to complete enrollment in 2026 LIVMARLI EXPAND Phase 3 study for pruritus in rare cholestatic conditions expected to complete enrollment in 2026 FDA Prescription Drug User Fee Act (PDUFA) date for chenodiol in cerebrotendinous xanthomatosis (CTX) is March 28, 2025 Expect to initiate Phase 2 study for MRM-3379 in Fragile X Syndrome (FXS) in 2025 2024 Highlights Commercial: Continued leadership in rare disease with a franchise in hepatology and genetic neurology 2024 estimated LIVMARLI net product sales of approximately $213 million and CHOLBAM and CHENODAL net product sales of approximately $123 million Total estimated net product sales of approximately $99 million in Q4 2024 including approximately $64 million in LIVMARLI net sales and approximately $35 million in net sales from CHOLBAM and CHENODAL Expanded global footprint; 30 countries with commercial access, including successful reimbursement negotiation and launch in the four major European markets Regulatory and Pipeline: Expanding Mirum’s leadership across multiple rare diseases and larger orphan settings Positive interim results for volixibat in VISTAS PSC and VANTAGE PBC studies Volixibat granted breakthrough therapy designation for treatment of cholestatic pruritus in PBC by the U.S. Food and Drug Administration (FDA) Volixibat granted orphan drug designation for the treatment of cholestatic pruritus in PBC by the FDA LIVMARLI approved by the FDA for cholestatic pruritus in progressive familial intrahepatic cholestasis (PFIC) patients 12 months and older LIVMARLI approved in Europe for treatment of PFIC in patients three months and older Initiated the LIVMARLI EXPAND Phase 3 study for pruritus in rare cholestatic conditions New Drug Application (NDA) submitted for chenodiol in CTX In-licensed global rights to PDE4D inhibitor MRM-3379 for FXS Corporate and Financial: Sustained financial strength Achieved positive cash flow from operations in Q3 2024 Cash, cash equivalents and investments of approximately $287 million as of December 31, 2024 compared to $286.3 million as of December 31, 2023 Announced the appointment of Joanne Quan, MD as Chief Medical Officer The foregoing amounts relating to 2024 financial data are unaudited and preliminary and are subject to completion of financial closing procedures. Additional information and disclosure would be required for a more complete understanding of the company’s financial position and results of operations as of December 31, 2024. Mirum will present at the 43rd annual J.P. Morgan Healthcare Conference in San Francisco on Wednesday, January 15, 2025, at 9:45 a.m. PT. The presentation and question and answer session will be webcast live and can be accessed by visiting the Investors and Media section of Mirum’s corporate website. The replay of the webcast will be available for 30 days. 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 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 has received Breakthrough Therapy designation for ALGS and PFIC type 2 and orphan designation for ALGS and PFIC. 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. 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 Volixibat Volixibat is an oral, minimally absorbed agent designed to selectively inhibit the ileal bile acid transporter (IBAT). Volixibat may offer a novel approach in the treatment of adult cholestatic diseases by blocking the recycling of bile acids, through inhibition of IBAT, thereby reducing bile acids systemically and in the liver. Volixibat is currently being evaluated in Phase 2b studies for primary sclerosing cholangitis (VISTAS study), and primary biliary cholangitis (VANTAGE study). In June, Mirum announced positive interim results from the Phase 2b VANTAGE study showing statistically significant improvement in pruritus as well as meaningful reductions in serum bile acids and improvements in fatigue for patients treated with volixibat. No new safety signals were observed, and the most common adverse event was diarrhea with all cases mild to moderate. About CHOLBAM® (cholic acid) capsules The FDA approved CHOLBAM® (cholic acid) capsules in March 2015, the first FDA-approved treatment for pediatric and adult patients with bile acid synthesis disorders due to single enzyme defects, and for adjunctive treatment of patients with peroxisome biogenesis disorder-Zellweger spectrum disorder. The effectiveness of CHOLBAM® has been demonstrated in clinical trials for bile acid synthesis disorders and the adjunctive treatment of peroxisomal disorders. An estimated 200 to 300 patients are current candidates for therapy. CHOLBAM® (cholic acid) Indication CHOLBAM is a bile acid indicated for Treatment of bile acid synthesis disorders due to single enzyme defects. Adjunctive treatment of peroxisomal disorders, including Zellweger spectrum disorders, in patients who exhibit manifestations of liver disease, steatorrhea, or complications from decreased fat-soluble vitamin absorption. LIMITATIONS OF USE The safety and effectiveness of CHOLBAM on extrahepatic manifestations of bile acid synthesis disorders due to single enzyme defects or peroxisomal disorders, including Zellweger spectrum disorders, have not been established. IMPORTANT SAFETY INFORMATION WARNINGS AND PRECAUTIONS – Exacerbation of liver impairment Monitor liver function and discontinue CHOLBAM in patients who develop worsening of liver function while on treatment. Concurrent elevations of serum gamma glutamyltransferase (GGT) and alanine aminotransferase (ALT) may indicate CHOLBAM overdose. Discontinue treatment with CHOLBAM at any time if there are clinical or laboratory indicators of worsening liver function or cholestasis. ADVERSE REACTIONS The most common adverse reactions (≥1%) are diarrhea, reflux esophagitis, malaise, jaundice, skin lesion, nausea, abdominal pain, intestinal polyp, urinary tract infection, and peripheral neuropathy. Please see full Prescribing Information for additional Important Safety Information. About Cerebrotendinous Xanthomatosis Cerebrotendinous xanthomatosis (CTX) is a rare, progressive and underdiagnosed disorder of cholesterol metabolism affecting many parts of the body. In people with CTX, the body is unable to break down cholesterol properly causing toxins (e.g., cholestanol and bile alcohols) to build up throughout the body over time. The disorder is inherited in an autosomal recessive genetic manner. Signs and symptoms of CTX include neonatal cholestasis (jaundice or bile flow interruption), chronic diarrhea, the development of bilateral cataracts before the age of 18, development of tendon xanthomas (fatty deposits in the tendons) during teenage years or later, and neurologic deterioration. The types, combinations and severity of symptoms can be different from person to person making diagnosis challenging and often delayed. About chenodiol tablets Chenodiol tablets 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. More recently, the US Food and Drug Administration (FDA) granted chenodiol orphan drug designation for cerebrotendinous xanthomatosis (CTX). CTX is a rare progressive disorder that can affect the brain, spinal cord, tendons, eyes and arteries. Chenodiol is not yet indicated for the treatment of CTX but has received a medical necessity determination in the U.S. by the FDA. About Mirum Pharmaceuticals 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 CHENODAL® (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 or liver disease. CHENODAL has received medical necessity recognition by the FDA to treat patients with cerebrotendinous xanthomatosis (CTX). Mirum's late-stage pipeline includes 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. Chenodiol, has been evaluated in a Phase 3 clinical study, RESTORE, to treat patients with CTX, with positive topline results reported in 2023. Mirum has submitted a new drug application with the FDA for the approval of chenodiol to treat CTX in the U.S. Lastly, Mirum is 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, commercial results for our approved products, including continued growth in year over year net product sales, being on track to achieve our revised financial guidance, our expected financial results as of December 31, 2024, including our net product sales and cash, cash equivalents and investments, delivering life changing medicines for patients suffering from rare diseases, the results, enrollment, conduct and progress of Mirum’s ongoing and planned studies for its product candidates, including newly in-licensed product candidates, the timing and results of interim analyses of our ongoing studies and the regulatory approval path for its product candidates globally, including the anticipated PDUFA date for chenodiol for CTX and additional international launches expected in 2025. 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 “expected,” “will,” “could,” “would,” “guidance,” “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 geopolitical and macroeconomic events, and the other risks described in Mirum’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2024 and subsequent 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. Investor Contacts: Andrew McKibben ir@mirumpharma.com Media Contact: Erin Murphy media@mirumpharma.com

Second quarter global net product sales of $77.8 million, on track to achieve full-year guidance of $310 to $320 million Positive interim results for volixibat in VISTAS PSC and VANTAGE PBC studies LIVMARLI for treatment of PFIC granted marketing authorization in Europe Initiating LIVMARLI EXPAND study for pruritus in rare cholestatic conditions Conference call to provide business updates today, August 7 at 1:30 p.m. PT/4:30 p.m. ET FOSTER CITY, Calif.--(BUSINESS WIRE)-- Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM) today reported financial results for second quarter 2024 and provided a business update. “The second quarter was marked by significant achievements across both our commercial medicines and development pipeline as we continued to execute on our strategic priorities,” said Chris Peetz, chief executive officer of Mirum. “The positive interim results of volixibat in the VISTAS PSC and VANTAGE PBC studies are exciting steps towards potential new treatment options for patients suffering from these rare liver diseases. We also achieved key regulatory milestones expanding access to LIVMARLI for patients with PFIC beginning with an approval in Europe for patients three months and older and a label expansion in the US to include patients 12 months and older, and we filed a new drug application for chenodiol in CTX. Finally, we are exploring LIVMARLI’s potential to treat cholestatic pruritus in other indications with the initiation of the EXPAND study.” Commercial: Strong growth across all three approved medicines Second quarter 2024 global net product sales of $77.8 million grew 139% compared to the second quarter 2023. LIVMARLI second quarter net sales were $47.2 million, representing 45% growth compared to the second quarter 2023. Second quarter 2024 CHOLBAM and CHENODAL net sales were $30.5 million. Regulatory and Pipeline: Achieved significant milestones and expanding pipeline Positive Interim results for volixibat in the VISTAS PSC and VANTAGE PBC studies. LIVMARLI approved in Europe for PFIC in patients three months and older. LIVMARLI approved in the US for cholestatic pruritus in PFIC in patients 12 months and older. Initiating the Phase 3 EXPAND study, a label expansion opportunity for LIVMARLI in additional settings of cholestatic pruritus in the second half of the year. New Drug Application (NDA) submitted for chenodiol in CTX. Corporate and Financial: Strong balance sheet As of June 30, 2024, Mirum had cash, cash equivalents and investments of $295.4 million compared to $286.3 million as of December 31, 2023. Uses of cash in the second quarter 2024 included a $10 million milestone payment due to Takeda for the FDA approval of LIVMARLI for PFIC. Total operating expenses were $102.1 million for the quarter ended June 30, 2024, compared to $61.8 million for the quarter ended June 30, 2023. Total operating expense included $17.7 million of non-cash stock-based compensation and depreciation and amortization expense for the quarter ended June 30, 2024, compared to $9.7 million for the quarter ended June 30, 2023. Business Update Conference Call Mirum will host a conference call today, August 7, 2024, at 1:30 p.m. PT/4:30 p.m. ET, to provide business updates. Join the call using the following details: Conference Call Details: U.S./Toll-Free: +1 833 470 1428 International: +1 404 975 4839 Passcode: 771307 You may also access the call via webcast by visiting the Events & Presentations section on Mirum’s website. A replay of this webcast will be available for 30 days. 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 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 has received Breakthrough Therapy designation for ALGS and PFIC type 2 and orphan designation for ALGS and PFIC. To learn more about ongoing clinical trials with LIVMARLI, please visit Mirum’s clinical trials section on the company’s website. 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 Volixibat Volixibat is an oral, minimally absorbed agent designed to selectively inhibit the ileal bile acid transporter (IBAT). Volixibat may offer a novel approach in the treatment of adult cholestatic diseases by blocking the recycling of bile acids, through inhibition of IBAT, thereby reducing bile acids systemically and in the liver. Phase 1 and Phase 2 studies of volixibat demonstrated on-target fecal bile acid excretion, a pharmacodynamic marker of ASBT inhibition, in addition to decreases in LDL cholesterol and increases in 7αC4 which are markers of bile acid synthesis. Volixibat has been evaluated in more than 400 individuals across multiple clinical trials. The most common adverse events reported were mild to moderate gastrointestinal events observed in the volixibat groups. Volixibat is currently being evaluated in Phase 2b studies for primary sclerosing cholangitis ( VISTAS study ), and primary biliary cholangitis ( VANTAGE study ). About CHOLBAM® (cholic acid) capsules The FDA approved CHOLBAM® (cholic acid) capsules in March 2015, the first FDA-approved treatment for pediatric and adult patients with bile acid synthesis disorders due to single enzyme defects, and for adjunctive treatment of patients with peroxisome biogenesis disorder-Zellweger spectrum disorder. The effectiveness of CHOLBAM® has been demonstrated in clinical trials for bile acid synthesis disorders and the adjunctive treatment of peroxisomal disorders. An estimated 200 to 300 patients are current candidates for therapy. CHOLBAM® (cholic acid) Indication CHOLBAM is a bile acid indicated for Treatment of bile acid synthesis disorders due to single enzyme defects. Adjunctive treatment of peroxisomal disorders, including Zellweger spectrum disorders, in patients who exhibit manifestations of liver disease, steatorrhea, or complications from decreased fat-soluble vitamin absorption. LIMITATIONS OF USE The safety and effectiveness of CHOLBAM on extrahepatic manifestations of bile acid synthesis disorders due to single enzyme defects or peroxisomal disorders, including Zellweger spectrum disorders, have not been established. IMPORTANT SAFETY INFORMATION WARNINGS AND PRECAUTIONS – Exacerbation of liver impairment Monitor liver function and discontinue CHOLBAM in patients who develop worsening of liver function while on treatment. Concurrent elevations of serum gamma glutamyltransferase (GGT) and alanine aminotransferase (ALT) may indicate CHOLBAM overdose. Discontinue treatment with CHOLBAM at any time if there are clinical or laboratory indicators of worsening liver function or cholestasis. ADVERSE REACTIONS The most common adverse reactions (≥1%) are diarrhea, reflux esophagitis, malaise, jaundice, skin lesion, nausea, abdominal pain, intestinal polyp, urinary tract infection, and peripheral neuropathy. Please see full Prescribing Information for additional Important Safety Information. About Cerebrotendinous Xanthomatosis Cerebrotendinous xanthomatosis (CTX) is a rare, progressive and underdiagnosed disorder of cholesterol metabolism affecting many parts of the body. In people with CTX, the body is unable to break down cholesterol properly causing toxins (e.g., cholestanol and bile alcohols) to build up throughout the body over time. The disorder is inherited in an autosomal recessive genetic manner. Signs and symptoms of CTX include neonatal cholestasis (jaundice or bile flow interruption), chronic diarrhea, the development of bilateral cataracts before the age of 18, development of tendon xanthomas (fatty deposits in the tendons) during teenage years or later, and neurologic deterioration. The types, combinations and severity of symptoms can be different from person to person making diagnosis challenging and often delayed. About chenodiol tablets Chenodiol tablets 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. More recently, the US Food and Drug Administration (FDA) granted chenodiol orphan drug designation for cerebrotendinous xanthomatosis (CTX). CTX is a rare progressive disorder that can affect the brain, spinal cord, tendons, eyes and arteries. Chenodiol is not yet indicated for the treatment of CTX but has received a medical necessity determination in the U.S. by the FDA. 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 CHENODAL® (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. 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 or liver disease. CHENODAL has received medical necessity recognition by the FDA to treat patients with cerebrotendinous xanthomatosis (CTX). Mirum’s late-stage pipeline includes two investigational treatments for debilitating liver 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. Lastly, chenodiol, has been evaluated in a Phase 3 clinical study, RESTORE, to treat patients with CTX, with positive topline results reported in 2023. Mirum has submitted a new drug application with the FDA for the approval of chenodiol to treat CTX in the U.S. 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, continued commercial success for our approved products, including continued growth in year over year net product sales, being on track to achieve our financial guidance, delivering life changing medicines for patients suffering from rare diseases, the results, conduct and progress of Mirum’s ongoing and planned studies for its product candidates, and the regulatory approval path for its product candidates globally. 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,” “guidance,” “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 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 Annual Report on Form 10-K for the fiscal year ended December 31, 2023 and in its subsequent reports on Form 10-Q, including in the sections thereof captioned “Risk Factors,” as well as in its subsequent reports on Form 8-K, all of which are filed with the U.S. Securities and Exchange Commission and available at www.sec.gov . Mirum Pharmaceuticals, Inc. Condensed Consolidated Statement of Operations Data (in thousands, except share and per share amounts) (Unaudited) Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Revenue: Product sales, net $ 77,760 $ 32,497 $ 146,677 $ 61,595 License and other revenue 115 5,000 420 7,500 Total revenue 77,875 37,497 147,097 69,095 Operating expenses: Cost of sales (1) 20,227 6,812 38,057 11,791 Research and development 32,672 22,009 64,894 45,557 Selling, general and administrative 49,208 32,949 94,846 63,168 Total operating expenses (2) 102,107 61,770 197,797 120,516 Loss from operations (24,232 ) (24,273 ) (50,700 ) (51,421 ) Other income (expense): Interest income 3,486 3,627 7,119 5,899 Interest expense (3,569 ) (3,726 ) (7,146 ) (7,968 ) Loss from termination of revenue interest purchase agreement — (49,076 ) — (49,076 ) Other income (expense), net 312 (274 ) 2,069 (1,085 ) Net loss before provision for income taxes (24,003 ) (73,722 ) (48,658 ) (103,651 ) Provision for income taxes 635 316 1,259 517 Net loss (24,638 ) (74,038 ) (49,917 ) (104,168 ) Net loss per share, basic and diluted $ (0.52 ) $ (1.94 ) $ (1.06 ) $ (2.75 ) Weighted-average shares of common stock outstanding, basic and diluted 47,235,080 38,107,334 47,081,315 37,892,513 (1) Amounts include intangible amortization expense as follows: Intangible amortization $ 5,593 $ 1,258 $ 10,995 $ 2,517 (2) Amounts include stock-based compensation expense as follows: Cost of sales $ 318 $ — $ 318 $ — Research and development 3,546 2,672 7,407 5,387 Selling, general and administrative 7,971 5,685 15,560 11,531 Total stock-based compensation $ 11,835 $ 8,357 $ 23,285 $ 16,918 Mirum Pharmaceuticals, Inc. Condensed Consolidated Balance Sheet Data (Unaudited) June 30, 2024 December 31, 2023 Assets Current assets: Cash and cash equivalents $ 233,245 $ 286,326 Short-term investments 45,126 — Accounts receivable 60,430 67,968 Inventory 20,438 22,312 Prepaid expenses and other current assets 8,590 10,935 Total current assets 367,829 387,541 Restricted cash 250 — Long-term investments 17,075 — Intangible assets, net 261,768 252,925 Other noncurrent assets 13,832 6,155 Total assets $ 660,754 $ 646,621 Liabilities and Stockholders’ Equity Current liabilities: Accounts payable $ 9,842 $ 7,416 Accrued expenses 101,394 78,544 Operating lease liabilities, current 1,072 1,104 Total current liabilities 112,308 87,064 Operating lease liabilities, noncurrent 8,244 617 Convertible notes payable, net 307,242 306,421 Other liabilities 3,972 3,849 Total liabilities 431,766 397,951 Commitments and contingencies Stockholders’ equity: Preferred stock — — Common stock 5 5 Additional paid-in capital 835,616 803,260 Accumulated deficit (606,156 ) (556,239 ) Accumulated other comprehensive (loss) income (477 ) 1,644 Total stockholders’ equity 228,988 248,670 Total liabilities and stockholders’ equity $ 660,754 $ 646,621 Investor Contact: Andrew McKibben ir@mirumpharma.com Media Contact: Erin Murphy media@mirumpharma.com