Mirum Pharmaceuticals reported back-to-back developments for its hepatitis delta virus (HDV) strategy: U.S. FDA approval of once-daily, oral ALK2 inhibitor Atebrioz (zilurgisertib) for fibrodysplasia ossificans progressiva (FOP), followed by positive Phase 3 results for brelovitug in chronic HDV. Together, the news strengthens both Mirum’s rare-disease commercial platform and its HDV pipeline push. For brelovitug, the company reported data hitting the primary virologic response and ALT normalization endpoint in one pivotal study, with an additional pivotal trial expected to read out later this year. Mirum reiterated guidance tied to potential HDV peak sales and indicated a future BLA filing timeline contingent on the second study.