Peroxisome Biogenesis Disorders

- Net product sales totaled $178.9 million, and full year 2023 revenue totaled $186.4 million, delivering 142% growth over 2022 total revenue - 2024 expected global net product sales of $310 million to $320 million - LIVMARLI PFIC PDUFA date on track for March 13, 2024 - Volixibat VISTAS and VANTAGE interim analyses expected in first half of 2024 - Conference call to provide business updates today, February 28 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 2023 and provided a business update. “2023 was a landmark year for Mirum as we significantly expanded our commercial footprint, realizing $179 million in net product sales, and achieved another year of strong global LIVMARLI growth. We also successfully integrated CHOLBAM and CHENODAL into our portfolio, which strengthened our position as a leader in rare disease,” said Chris Peetz, chief executive officer at Mirum. “In 2024, we look forward to further expanding the reach of our approved medicines, potential LIVMARLI and CHENODAL label expansions and interim analyses for our volixibat adult indications. Operationally and financially, we are well positioned for this next phase of growth and remain committed to our mission of delivering life changing medicines to patients in need.” Commercial: Leading Pediatric Hepatology Franchise Net product sales totaled $178.9 million, and full year 2023 revenue totaled $186.4 million, representing 142% growth over 2022 total revenue. 2023 LIVMARLI net product sales totaled $141.8 million, representing approximately 89% growth over 2022 net product sales. International business grew to 18 countries with reimbursed access to LIVMARLI. Expect continued revenue growth across all approved medicines in 2024 with expected global net product sales of $310 million to $320 million. Regulatory & Pipeline: Multiple Upcoming 2024 Milestones U.S. Food and Drug Administration (FDA) Prescription Drug User Free Act (PDUFA) date for LIVMARLI in progressive familial intrahepatic cholestasis (PFIC) is March 13, 2024. New Drug Application (NDA) submission for CHENODAL in CTX planned in first half 2024. Volixibat VISTAS study in primary sclerosing cholangitis blinded interim analysis expected in first half 2024. Volixibat VANTAGE study in primary biliary cholangitis interim analysis expected in first half 2024. Corporate and Financial: Strong Balance Sheet, Financially Sustaining Scale Total net product sales for the full year ended December 31, 2023, was $178.9 million compared to $75.1 million for the full year ended December 31, 2022. Total operating expenses were $293.0 million for the full year ended December 31, 2023, compared to $208.3 million for the full year ended December 31, 2022. The increase in year-over-year operating expense was due to a $32.2 million increase in cost of goods sold and a $56.8 million increase in sales, general and administrative expense, partially offset by a $4.2 million decrease in research and development expense. As of December 31, 2023, Mirum had cash and cash equivalents of $286.3 million. Announced the appointment of Joanne Quan, M.D. as Chief Medical Officer. The foregoing financial information is unaudited and subject to change, and actual results may vary from the foregoing. Business Update Conference Call Mirum will host a conference call today, February 28, 2024, at 1:30 p.m. PT/4:30 p.m. ET, to discuss its financial results, guidance, and 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: 089049 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, 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) three months 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. For more information for U.S. residents, please visit LIVMARLI.com. Mirum has also submitted LIVMARLI for approval in the U.S. for the treatment of cholestatic pruritus in patients with PFIC three months of age and older, and in Europe for the treatment of PFIC in patients two months of age and older. 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 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 is 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 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 CHENODAL® (chenodiol) tablets CHENODAL® is a synthetic oral form of chenodeoxycholic acid (CDCA), a naturally occurring primary bile acid synthesized from cholesterol in the liver. The FDA approved CHENODAL for the treatment of people with radiolucent stones in the gallbladder. In 2010, CHENODAL was granted orphan drug designation for the treatment of cerebrotendinous xanthomatosis (CTX), a rare autosomal recessive lipid storage disease. While CHENODAL® is not currently approved for CTX, it received a medical necessity determination in the U.S. by the FDA and has been used as the standard of care for more than three decades. A Phase 3 clinical trial for this indication has recently been completed and based on the positive results, a New Drug Application (NDA) submission for CHENODAL in CTX planned in first half 2024. We believe the prevalent patient population in the United States with CTX exceeds 1,000. 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 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. Mirum has also submitted LIVMARLI for approval in the U.S. in cholestatic pruritus in PFIC patients three months of age and older and in Europe in PFIC for patients 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 2b VISTAS study for primary sclerosing cholangitis and Phase 2b VANTAGE study for primary biliary cholangitis. Lastly, CHENODAL, has been evaluated in a Phase 3 clinical study, RESTORE, to treat patients with CTX, with positive topline results reported in 2023. To learn more about Mirum, visit mirumpharma.com and follow Mirum on Facebook, LinkedIn, Instagram and Twitter. 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 growth in year over year net product sales, having sufficient cash and cash equivalent reserves, planned expansion into additional international markets, LIVMARLI label expansion into PFIC, the timing and results of LIVMARLI’s PDUFA, CHENODAL potential full indication in CTX, delivering life changes medicines and becoming a global leader in rare disease, the results, conduct and progress of Mirum’s ongoing and planned studies for its product candidates, the timing and results of interim analyses of our ongoing studies 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 “expected,” “forecasts,” “forward,” “planned,” “poised,”, “positioned” “potential”, “will” 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, 2023 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 Year ended December 31, December 31, 2023 2022 2023 2022 Revenue: Product sales, net $ 69,554 $ 27,906 $ 178,874 $ 75,062 License revenue - - 7,500 2,000 Total revenue 69,554 27,906 186,374 77,062 Operating expenses: Cost of sales (1) 22,510 4,494 44,529 12,374 Research and development 30,935 31,105 102,609 106,842 Selling, general and administrative 46,184 26,468 145,880 89,066 Total operating expenses (2) 99,629 62,067 293,018 208,282 Loss from operations (30,075 ) (34,161 ) (106,644 ) (131,220 ) Other income (expense): Interest income 3,775 2,143 13,735 3,857 Interest expense (3,563 ) (4,359 ) (15,105 ) (15,979 ) Change in fair value of derivative liability - 674 - 906 Loss from termination of revenue interest purchase agreement - - (49,076 ) - Other (expense) income, net (3,061 ) (588 ) (2,824 ) 365 Net loss before for income taxes (32,924 ) (36,291 ) (159,914 ) (142,071 ) Provision for (benefit from) income taxes 225 140 991 (6,406 ) Net loss $ (33,149 ) $ (36,431 ) $ (160,905 ) $ (135,665 ) Net loss per share: Basic $ (3.94 ) $ (4.01 ) Diluted $ (3.94 ) $ (4.02 ) Weighted-average shares of common stock outstanding: Basic 40,885,124 33,839,072 Diluted 40,885,124 33,982,493 (1) Amounts include intangible amortization expense as follows: Intangible amortization $ 5,305 $ 1,078 $ 10,404 $ 2,893 (2) Amounts include stock-based compensation expense as follows: Research and development $ 2,879 $ 2,531 $ 10,892 $ 10,050 Selling, general and administrative 6,841 4,365 24,131 16,957 Total stock-based compensation $ 9,720 $ 6,896 $ 35,023 $ 27,007 Mirum Pharmaceuticals, Inc. Condensed Consolidated Balance Sheet Data (Unaudited) December 31, 2023 December 31, 2022 Assets Current assets: Cash and cash equivalents $ 286,326 $ 28,003 Short-term investments - 123,716 Accounts receivable 67,968 23,994 Inventory 19,590 5,565 Prepaid expenses and other current assets 10,935 8,947 Total current assets 384,819 190,225 Restricted cash and cash equivalents - 100,000 Intangible assets, net 252,925 58,954 Other noncurrent assets 6,155 3,727 Total assets $ 643,899 $ 352,906 Liabilities and Stockholders’ Equity Current liabilities: Accounts payable $ 7,416 $ 8,690 Accrued expenses 77,161 54,018 Other current liabilities 1,104 2,021 Total current liabilities 85,681 64,729 Revenue interest liability, net - 140,351 Convertible notes, net 306,421 - Other noncurrent liabilities 617 5,789 Total liabilities 392,719 210,869 Commitments and contingencies Stockholders' equity: Preferred stock - - Common stock 5 4 Additional paid-in capital 803,260 535,074 Accumulated deficit (553,729 ) (392,824 ) Accumulated other comprehensive income (loss) 1,644 (217 ) Total stockholders' equity 251,180 142,037 Total liabilities and stockholders' equity $ 643,899 $ 352,906

- $186-188 million in total revenue and $178-180 million net product sales expected for 2023, preliminary and unaudited - LIVMARLI net products sales of $141-143 million expected for 2023, representing approximately 89% year-over-year growth, preliminary and unaudited FOSTER CITY, Calif.--(BUSINESS WIRE)--Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM) today provided its preliminary and unaudited estimates for full-year 2023 revenue and net product sales, corporate updates, and full-year 2024 outlook. “2023 was a transformative year for Mirum as we cemented our position as a leader in rare disease and dramatically advanced our operating and financial scale. We expanded our reach and impact through strong global adoption of LIVMARLI and the addition of CHOLBAM and CHENODAL,” said Chris Peetz, president and chief executive officer. “In the year ahead, we are excited about the growth prospects of all three commercial medicines, the potential label expansion opportunities for LIVMARLI and CHENODAL and key volixibat analyses in primary sclerosing cholangitis and primary biliary cholangitis.” 2023 Highlights Established a leading pediatric hepatology franchise with three commercial medicines 2023 estimated LIVMARLI net product sales of $141-143 million representing approximately 89% growth over 2022 LIVMARLI net product sales Total expected net product sales of $69-71 million in Q4 2023 including $41-43 million in LIVMARLI net sales and approximately $28 million in net sales from CHOLBAM and CHENODAL Acquired two therapies commercially available in the U.S.: CHOLBAM and CHENODAL Announced positive Phase 3 data from the RESTORE study evaluating CHENODAL in cerebrotendinous xanthomatosis (CTX) patients Expanded LIVMARLI’s US label in Alagille syndrome (ALGS) to include infants 3 months of age and older Grew international business to 18 countries with reimbursed access Company fully financed with strong balance sheet and financial performance Announced the appointment of Eric Bjerkholt as Chief Financial Officer The foregoing amounts relating to 2023 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, 2023. 2024 Expectations and Milestones Expect continued revenue growth across all three commercial medicines U.S. Food and Drug Administration (FDA) Prescription Drug User Free Act (PDUFA) date for LIVMARLI in progressive familial intrahepatic cholestasis (PFIC) is March 13, 2024. New Drug Application (NDA) submission for CHENODAL in CTX planned in first half 2024 Volixibat VISTAS study in primary sclerosing cholangitis blinded interim analysis expected first half 2024 Volixibat VANTAGE study for primary biliary cholangitis interim analysis expected in first half 2024 Mirum will present at the 42nd annual J.P. Morgan Healthcare Conference in San Francisco on Wednesday, January 10, 2024 at 10:30 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, once-daily, ileal bile acid transporter (IBAT) inhibitor and the only approved medication by the U.S. Food and Drug Administration for the treatment of cholestatic pruritus in patients with Alagille syndrome (ALGS) three months 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. For more information for U.S. residents, please visit LIVMARLI.com. Mirum has also submitted LIVMARLI for approval in the U.S. in cholestatic pruritus in PFIC patients three months of age and older, and in Europe, in PFIC for patients two months of age and older. LIVMARLI is currently being evaluated in late-stage clinical studies in other rare cholestatic liver diseases. 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 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 Volixibat Volixibat is an oral, minimally absorbed agent designed to selectively inhibit the apical sodium dependent bile acid transporter (ASBT). Volixibat may offer a novel approach in the treatment of adult cholestatic diseases by blocking the recycling of bile acids, through inhibition of ASBT, 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. 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 CHENODAL® (chenodiol) tablets CHENODAL® is a synthetic oral form of chenodeoxycholic acid (CDCA), a naturally occurring primary bile acid synthesized from cholesterol in the liver. The FDA approved CHENODAL for the treatment of people with radiolucent stones in the gallbladder. In 2010, CHENODAL was granted orphan drug designation for the treatment of cerebrotendinous xanthomatosis (CTX), a rare autosomal recessive lipid storage disease. While CHENODAL® is not currently approved for CTX, it received a medical necessity determination in the U.S. by the FDA and has been used as the standard of care for more than three decades. Efforts are being made to obtain FDA approval of CHENODAL for the treatment of CTX and a Phase 3 clinical trial for this indication was initiated in January 2020. 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 cholestatic pruritus in patients with Alagille syndrome in the U.S. (three months and older), in Europe (two months and older), and in Canada. Mirum has also submitted LIVMARLI for approval in the U.S. in cholestatic pruritus in PFIC patients three months of age and older and in Europe in PFIC for patients two months of age and older. CHOLBAM is FDA-approved for the treatment of bile acid synthesis disorders due to single enzyme defects 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 high-need rare diseases. Volixibat, also an IBAT inhibitor, is being evaluated in two potentially registrational studies including the Phase 2b VISTAS study for primary sclerosing cholangitis and Phase 2b VANTAGE study for primary biliary cholangitis. CHENODAL, has been evaluated in a Phase 3 clinical study, RESTORE, to treat patients with CTX. To learn more about Mirum, visit mirumpharma.com and follow Mirum on Facebook, LinkedIn, Instagram and Twitter. 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 and growth prospects for LIVMARLI, CHENODAL and CHOLBAM, including growth in LIVMARLI year-over-year net product sales, planned LIVMARLI launches in additional international markets and label expansion into PFIC, the timing and results of LIVMARLI’s PDUFA date, CHENODAL’s potential full indication in CTX, becoming a global leader in rare disease, 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 “forward,” “planned,” “poised,” “positioned,” “potential”, “will,” “prospects,” “opportunities” 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 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.

- Third quarter 2023 total revenue of $47.7 million - Completed acquisition of CHENODAL® and CHOLBAM® - Announced positive Phase 3 RESTORE study results evaluating CHENODAL (chenodiol) in patients with CTX; NDA filing expected in H1 2024 - Conference call to provide business updates today, November 2 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 third quarter 2023 and provided a business update. “We made significant progress in the third quarter with record LIVMARLI revenues in both the United States and Internationally, the closing of the acquisition of CHENODAL and CHOLBAM and the positive top line results from the unblinding of the RESTORE trial of CHENODAL in CTX,” said Chris Peetz, president and chief executive officer at Mirum. “The company is well positioned to maintain this momentum with continued strong revenue growth and we look forward to multiple exciting upcoming clinical and regulatory catalysts.” LIVMARLI®: Continued growth in Alagille syndrome worldwide net sales and progressive familial intrahepatic cholestasis (PFIC) near-term label expansion opportunity Third quarter 2023 global net sales of $38.7 million grew 106% as compared to third quarter 2022. International commercial expansion ongoing with continued strong demand. Presented 15 oral and poster presentations on clinical data and real-world evidence validating LIVMARLI in patients with Alagille syndrome and PFIC at the North American Society for Pediatric, Gastroenterology, Hepatology and Nutrition (NASPGHAN) Annual Meeting. Supplemental New Drug Application (sNDA) for LIVMARLI in PFIC assigned Prescription Drug User Fee Act (PDUFA) date of March 13, 2024. Completed acquisition of CHENODAL and CHOLBAM: establishes Mirum’s leading growth franchise in pediatric hepatology Acquired two therapies approved in the U.S.: CHOLBAM (cholic acid) for the treatment of bile acid synthesis disorders (BASD) and Zellweger spectrum disorders (ZSD), and CHENODAL, an approved medical necessity medicine for the treatment of cerebrotendinous xanthomatosis (CTX). Announced positive Phase 3 data from the landmark RESTORE study evaluating CHENODAL in patients with CTX. The Company expects to submit a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) in the first half of 2024. Third quarter 2023 net sales of $9 million recorded since acquisition close August 31st, 2023. Pipeline: Three upcoming late-stage data catalysts Phase 2b EMBARK study of LIVMARLI for pediatric patients with biliary atresia topline data expected by year end. Phase 2b interim analyses for volixibat in PSC (VANTAGE study) and in PBC (VISTAS study) expected in the first half of 2024. Corporate and financial: Strong balance sheet and experienced management team driving growth Total net revenue for the quarter ended September 30, 2023, was $47.7 million compared to $18.8 million for the quarter ended September 30, 2022. Net revenue for the nine months ended September 30, 2023, was $116.8 million compared to $49.2 million for the nine months ended September 30, 2022. Total operating expenses were $72.9 million for the quarter ended September 30, 2023, compared to $51.7 million for the quarter ended September 30, 2022. Total operating expenses were $193.4 million for the nine months ended September 30, 2023 compared to $146.2 million for the nine months ended September 30, 2022. As of September 30, 2023, Mirum had cash, cash equivalents, and short-term investments of $306.0 million and convertible debt of $316.3 million. Business Update Conference Call Mirum will host a conference call today, November 2, 2023, 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: 979561 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, 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 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 Volixibat Volixibat is an oral, minimally absorbed agent designed to selectively inhibit the apical sodium dependent bile acid transporter (ASBT). Volixibat may offer a novel approach in the treatment of adult cholestatic diseases by blocking the recycling of bile acids, through inhibition of ASBT, 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 CHENODAL® (chenodiol) tablets CHENODAL® is a synthetic oral form of chenodeoxycholic acid (CDCA), a naturally occurring primary bile acid synthesized from cholesterol in the liver. The FDA approved CHENODAL for the treatment of people with radiolucent stones in the gallbladder. In 2010, CHENODAL was granted orphan drug designation for the treatment of cerebrotendinous xanthomatosis (CTX), a rare autosomal recessive lipid storage disease. While CHENODAL® is not currently approved for CTX, it received a medical necessity determination in the U.S. by the FDA and has been used as the standard of care for more than three decades. Efforts are being made to obtain FDA approval of CHENODAL for the treatment of CTX and a Phase 3 clinical trial for this indication was initiated in January 2020. We believe the prevalent patient population in the United States with CTX exceeds 1,000. 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 cholestatic pruritus in patients with Alagille syndrome in the U.S. (three months and older), in Europe (two months and older), and in Canada. Mirum has also submitted LIVMARLI for approval in the U.S. in cholestatic pruritus in PFIC patients three months of age and older and in Europe in PFIC for patients two 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 three investigational treatments for debilitating liver diseases. The LIVMARLI development program includes the Phase 2b EMBARK study for biliary atresia. Mirum’s second investigational IBAT inhibitor is volixibat, which is being evaluated in two potentially registrational studies including the Phase 2b VISTAS study for primary sclerosing cholangitis and Phase 2b VANTAGE study for primary biliary cholangitis. Lastly, CHENODAL, has been evaluated in a Phase 3 clinical study, RESTORE, to treat patients with CTX. To learn more about Mirum, visit mirumpharma.com and follow Mirum on Facebook, LinkedIn, Instagram and Twitter. 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 LIVMARLI, CHENODAL and CHOLBAM including growth in year over year net product sales, planned LIVMARLI launches in additional international markets, label expansion into PFIC, CHENODAL potential full indication in CTX, becoming a global leader in rare disease, 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 “forward,” “planned,” “poised,”, “positioned” “potential”, “will” 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. Mirum Pharmaceuticals, Inc. Condensed Consolidated Statement of Operations Data (in thousands, except share and per share amounts) (Unaudited) Three Months Ended Nine Months Ended September 30, September 30, 2023 2022 2023 2022 Revenue: Product sales, net $ 47,725 $ 18,780 $ 109,320 $ 47,156 License revenue - - 7,500 2,000 Total revenue 47,725 18,780 116,820 49,156 Operating expenses: Cost of sales (1) 10,228 2,932 22,019 7,880 Research and development 26,117 26,217 71,674 75,737 Selling, general and administrative 36,528 22,513 99,696 62,598 Total operating expenses (2) 72,873 51,662 193,389 146,215 Loss from operations (25,148 ) (32,882 ) (76,569 ) (97,059 ) Other income (expense): Interest income 4,061 1,352 9,960 1,714 Interest expense (3,574 ) (3,971 ) (11,542 ) (11,620 ) Change in fair value of derivative liability - - - 232 Loss on extinguishment of RIPA - - (49,076 ) - Other income (expense), net 1,322 (192 ) 237 953 Net loss before for income taxes (23,339 ) (35,693 ) (126,990 ) (105,780 ) (Benefit) provision for income taxes 249 13 766 (6,546 ) Net loss $ (23,588 ) $ (35,706 ) $ (127,756 ) $ (99,234 ) Net loss per share, basic and diluted $ (0.57 ) $ (1.02 ) $ (3.28 ) $ (3.03 ) Weighted-average shares of common stock outstanding, basic 41,098,920 34,927,790 38,973,060 32,809,365 Weighted-average shares of common stock outstanding, diluted 41,098,920 34,927,790 38,973,060 32,825,314 (1) Amounts include intangible amortization expense as follows: Intangible amortization $ 2,582 $ 1,040 $ 5,099 $ 1,815 (2) Amounts include stock-based compensation expense as follows: Research and development $ 2,626 $ 2,517 $ 8,013 $ 7,519 Selling, general and administrative 5,759 4,391 17,290 12,592 Total stock-based compensation $ 8,385 $ 6,908 $ 25,303 $ 20,111 Mirum Pharmaceuticals, Inc. Condensed Consolidated Balance Sheet Data September 30, 2023 December 31, 2022 (unaudited) Assets Current assets: Cash and cash equivalents $ 303,059 $ 28,003 Short-term investments 2,971 123,716 Accounts receivable 47,834 23,994 Inventory 22,250 5,565 Prepaid expenses and other current assets 12,465 8,947 Total current assets 388,579 190,225 Restricted cash and cash equivalents - 100,000 Intangible assets, net 258,338 58,954 Other noncurrent assets 3,725 3,727 Total assets $ 650,642 $ 352,906 Liabilities and Stockholders’ Equity Current liabilities: Accounts payable $ 7,369 $ 8,690 Accrued expenses 66,213 54,018 Other current liabilities 1,082 2,021 Total current liabilities 74,664 64,729 Revenue interest liability, net - 140,351 Convertible notes, net 306,022 - Other noncurrent liabilities 875 5,789 Total liabilities 381,561 210,869 Commitments and contingencies Stockholders' equity: Preferred stock - - Common stock 5 4 Additional paid-in capital 791,114 535,074 Accumulated deficit (520,580 ) (392,824 ) Accumulated other comprehensive loss (1,458 ) (217 ) Total stockholders' equity 269,081 142,037 Total liabilities and stockholders' equity $ 650,642 $ 352,906