--- title: "Mirum widens beyond Livmarli with a new approval" url: "https://aibio.space/companies/mirum-pharmaceuticals/desk-view/" publisher: "aibio.space (Biotech Investor Relations News)" date: "2026-10-31" tickers: "NASDAQ:MIRM" summary: "Atebrioz, EXPAND and AZURE-1 landed within three weeks. Volixibat is the one program with a regulatory question." --- Opinion Desk view by the aibio.space Mirum desk. Updated October 22, 2026. Every figure links to its source. This is analysis, not a recommendation to trade. [How desk views are written](https://aibio.space/disclosures/). Mirum Pharmaceuticals ยท Opinion 2026-10-22 # Mirum widens beyond Livmarli with a new approval and two phase 3 wins Atebrioz, EXPAND and AZURE-1 landed within three weeks. Volixibat is the one program with a regulatory question. ## The technology Mirum is a rare disease company with a bile acid and liver focus. Livmarli (maralixibat) is an oral inhibitor of the ileal bile acid transporter, approved in the U.S. for cholestatic itch in [Alagille syndrome and progressive familial intrahepatic cholestasis](https://www.sec.gov/Archives/edgar/data/1759425/000175942526000044/mirm-20260805xexx991.htm). Cholbam and Ctexli (chenodiol) are bile acid medicines for rare disorders. Atebrioz (zilurgisertib), licensed from Incyte, is an oral ALK2 inhibitor that the FDA [approved on Sept. 25](https://www.sec.gov/Archives/edgar/data/1759425/000175942526000049/mirm-20260925.htm) for fibrodysplasia ossificans progressiva. The pipeline reuses the Livmarli mechanism and adds a hepatitis antibody. Volixibat is another bile acid transporter inhibitor, in studies for primary sclerosing cholangitis and primary biliary cholangitis. Brelovitug is a monoclonal antibody against the hepatitis B surface antigen that Mirum is testing in hepatitis delta. Livmarli itself is being extended in the [EXPAND study](https://www.sec.gov/Archives/edgar/data/1759425/000175942526000051/mirm-20261012.htm), and the company also lists a phase 2 Fragile X program, MRM-3379. ## The odds Mirum has strong recent data, with regulatory questions on timing. EXPAND met its primary and all five secondary endpoints, with a [0.98-point itch benefit over placebo](https://www.sec.gov/Archives/edgar/data/1759425/000175942526000051/mirm-20261012.htm) in children, and a supplemental filing is planned for the first half of 2027. For rare diseases, [93.6% of filed applications are approved](https://go.bio.org/rs/490-EHZ-999/images/ClinicalDevelopmentSuccessRates2011_2020.pdf) in BIO, Informa and QLS data for 2011 to 2020. Brelovitug cleared AZURE-1, where [56% of weekly-dose patients met the combined endpoint](https://www.sec.gov/Archives/edgar/data/1759425/000175942526000049/mirm-20260925.htm) against 0% on delayed treatment, and AZURE-4 is next. Mirum plans a biologics license application in the first half of 2027. Phase 3 programs reach a filing 57.8% of the time overall. Volixibat is the uncertain one: after the VISTAS study, the FDA said it [recommended a phase 3 study](https://www.sec.gov/Archives/edgar/data/1759425/000175942526000044/mirm-20260805xexx991.htm). ## The money Second-quarter net product sales were [$176.2 million](https://www.sec.gov/Archives/edgar/data/1759425/000175942526000044/mirm-20260805xexx991.htm), and 2026 guidance is $680 million to $700 million. Operating expenses were $218.8 million in the quarter, so the company is not yet profitable on that measure. Cash and investments were $561.3 million at June 30, up from $391.4 million at the end of 2025. The balance sheet changed in May. Mirum sold [$690.0 million of 0% convertible notes due 2032](https://www.sec.gov/Archives/edgar/data/1759425/000119312526228902/d113366d8k.htm) with a conversion price near $138.94, and it settled about 75% of its 4.00% notes due 2029 using cash and shares. That removes most of the older debt but adds potential dilution if the new notes convert. Livmarli sales grew 46% year over year in the second quarter. ## The risks Volixibat is the clearest risk. VISTAS met its primary endpoint, but the FDA's recommendation of a phase 3 study could add cost and time before any filing. Livmarli remains the core of sales, with [$128.7 million of the $176.2 million in the second quarter](https://www.sec.gov/Archives/edgar/data/1759425/000175942526000044/mirm-20260805xexx991.htm), so concentration is high until Atebrioz and brelovitug launch. Diarrhea is common with this class of drug: it occurred in [64.0% of patients on maralixibat in EXPAND](https://www.sec.gov/Archives/edgar/data/1759425/000175942526000051/mirm-20261012.htm) against 11.1% on placebo. Management also changed in medical development in September, when Rob Myers was [appointed chief medical officer](https://www.sec.gov/Archives/edgar/data/1759425/000175942526000047/mirm-20260902.htm) to succeed Joanne Quan. Atebrioz addresses a small population, about 300 diagnosed patients in the United States by the company's estimate. ## Our read Mirum has a growing commercial base and several late-stage programs, and the second half of 2026 has delivered three positive events: the EXPAND result, the AZURE-1 result and the Atebrioz approval. The FDA response on volixibat is the one disappointment. The next tests are dated and close. AZURE-4 reports in the fourth quarter, and Atebrioz becomes available in October. If AZURE-4 repeats AZURE-1, Mirum has a hepatitis delta filing for the first half of 2027. If not, the company leans harder on Livmarli growth and the cash raised in May. --- Source page: https://aibio.space/companies/mirum-pharmaceuticals/desk-view/. Facts in aibio.space stories are checked against company filings and releases; opinion is labelled. Cite as: aibio.space, "Mirum widens beyond Livmarli with a new approval", 2026-10-31, https://aibio.space/companies/mirum-pharmaceuticals/desk-view/