Mirum Pharmaceuticals Reports Positive Phase 2 PROGRESS Study Results for ATEBRIOZ in Children with FOP

Mirum Pharmaceuticals reported positive 24-week results from the second cohort of its Phase 2 PROGRESS study of ATEBRIOZ (zilurgisertib) in children aged 6 to under 12 with fibrodysplasia ossificans progressiva. Bone lesion volume decreased by 8.09 cm³ among treated patients, compared with a 9.14 cm³ increase with placebo; treated patients also showed improved joint mobility, no new lesions, and no new safety signals. Mirum plans to submit a supplemental New Drug Application to the FDA in the first half of 2027 to seek approval for use in this younger age group.