Zilurgisertib

iStock, nambitomo Regeneron’s Pasatru is the second fibrodysplasia ossificans progressiva drug approved in the U.S., following the 2023 approval of Ipsen’s Sohonos. Regeneron has won FDA approval for garetosmab in fibrodysplasia ossificans progressiva, giving the biotech a commercial product built on its scientific breakthrough in the ultrarare disease. It also sets up a showdown with Ipsen, which owns the only other FOP drug on the market. The Thursday approval covers the use of Pasatru—an antibody called garetosmab and REGN2477 during development—to reduce the formation of new heterotopic ossification (HO) lesions and clinician-assessed flare-ups in adults with FOP. HO is characterized by bone developing in soft tissues. Pasatru is the second FOP drug to secure U.S. approval. The first, Ipsen’s Sohonos, came to market in 2023 after a troubled development program marked by clinical and regulatory setbacks. Ipsen acquired the asset in 2019 from Clementia Pharmaceuticals. For the first half of 2026, Sohonos contributed to the €11.4 million ($13.4 million) in sales generated by Ipsen’s rare disease drugs apart from Iqirvo and Bylvay. Following Clinical Hold and Trial Setback, Ipsen Takes $728 Million Hit on FOP Drug Ipsen’s decision to pause dosing in its studies of palovarotene trials for patients with fibrodysplasia ossificans progressive (FOP) has hit the France-based company right in the pocketbook. February 13, 2020 · 2 min read · Alex Keown Read more Regeneron has now won approval based on Phase 3 trial data that showed two doses of Pasatru reduced the total number of new HO lesions compared to placebo. Investigators saw 19 new lesions in the 21 patients on placebo, compared to three new lesions in the 42 patients treated across two Pasatru dose cohorts. The recommended starting dosage is 10 mg/kg, the higher of the two doses given in the Phase 3 trial. Patients receive the antibody intravenously for one hour every month. If a patient doesn’t tolerate the dose, they can drop down to the lower Phase 3 dose, 3 mg/kg. Patients on the lower dose still receive a 60-minute infusion once monthly. Regeneron designed Pasatru to be given in a range of care settings, including at home when appropriate. The flexibility reflects the significant mobility challenges faced by many people with FOP, which can make walking difficult as bone builds up in muscles, tendons, ligaments and other connective tissues. Most patients are wheelchair-bound by age 30, Regeneron said. Regeneron’s efforts in the disease can be traced back to 2015, when researchers published a paper describing an unexpected discovery about the driver of HO in FOP. By looking at FOP in mice, Regeneron identified Activin A as the ligand responsible for HO. Regeneron started a Phase 1 trial of the anti-Activin A antibody—now known as Pasatru— in 2016. About 900 people are diagnosed with FOP. Rare disease–focused biopharma Mirum Pharmaceuticals has predicted that its rival FOP drug candidate, zilurgisertib, could generate peak sales of more than $200 million. Zilurgisertib, which Mirum licensed from Incyte, is under review at the FDA and has an approval decision date of Sept. 26. Mirum is seeking approval of zilurgisertib for the treatment of FOP in patients 12 years of age and older. Regeneron’s Phase 3 study only enrolled adults, although the company plans to start a trial in children and adolescents this year.

FOSTER CITY, Calif.--(BUSINESS WIRE)--Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM), a leading rare disease company, today announced that on August 10, 2026, the Compensation Committee of Mirum’s Board of Directors granted inducement awards consisting of non-qualified stock options to purchase 26,050 shares of common stock and 34,590 restricted stock units (“RSUs”) to 19 new employees under Mirum’s 2020 Inducement Plan. The Compensation Committee of Mirum’s Board of Directors approved the awards as an inducement material to the new employees’ employment in accordance with Nasdaq Listing Rule 5635(c)(4). Each stock option has an exercise price of $98.70 per share, which is equal to the closing price of Mirum’s common stock on August 10, 2026, and will vest over four years, with 25% of the underlying shares vesting on the one-year anniversary of the applicable vesting commencement date, and the balance of the underlying shares vesting monthly thereafter over 36 months, subject to the new employees’ continued service relationship with Mirum through the applicable vesting dates. The RSUs will vest over three years, with 33% of the underlying shares vesting on each anniversary of the applicable initial vesting date, subject to the new employees’ continued service relationship with Mirum through the applicable vesting dates. The awards are subject to the terms and conditions of Mirum’s 2020 Inducement Plan and the terms and conditions of an applicable award agreement covering the grant. About Mirum Pharmaceuticals Mirum Pharmaceuticals (NASDAQ: MIRM) is a leading rare disease company with a global footprint of approved products and a broad pipeline of investigational medicines. Purpose-built to bring forward breakthrough medicines for people with overlooked conditions, Mirum focuses on rare liver and rare genetic diseases, where it has built deep expertise and strong connections to patient communities. The company’s commercial portfolio includes LIVMARLI® (maralixibat) for Alagille syndrome (ALGS) and progressive familial intrahepatic cholestasis (PFIC), CHOLBAM® (cholic acid) for bile-acid synthesis disorders, and CTEXLI® (chenodiol) for cerebrotendinous xanthomatosis (CTX). ezstandalone.cmd.push(function () { ezstandalone.showAds(131); }); Mirum’s clinical-stage pipeline includes volixibat, an IBAT inhibitor in late-stage development for primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), brelovitug, a fully human monoclonal antibody in late-stage development for chronic hepatitis delta virus (HDV), zilurgisertib, an ALK2 inhibitor under regulatory review with the FDA for fibrodysplasia ossificans progressiva (FOP), and MRM-3379, a PDE4D inhibitor being evaluated for Fragile X syndrome (FXS). Mirum’s success is driven by a team dedicated to advancing high impact medicines through strategic development, disciplined execution and purposeful collaboration across the rare disease ecosystem. Learn more at and follow Mirum on Facebook , LinkedIn , Instagram and X . Mirum and the Mirum logo are trademarks of Mirum Pharmaceuticals, Inc. Contacts Investor Contact: Andrew McKibben ir@mirumpharma.com Media Contact: Meredith Kiernan media@mirumpharma.com