Atebrioz (zilurgisertib) - (PROGRESS)

September 25, 2026: Mirum Pharmaceuticals (NASDAQ: MIRM) and Incyte (NASDAQ: INCY) said the FDA approved Atebrioz (zilurgisertib), a once-daily oral ALK2 inhibitor, to reduce total new heterotopic ossification in adults and pediatric patients aged 12 and older with fibrodysplasia ossificans progressiva (FOP).

The approval was based on Cohort 1 of the Phase 2 PROGRESS study in 63 patients aged 12 years and older. At Week 24, mean total new HO lesion volume decreased by 3.2 cm3 with zilurgisertib versus an increase of 24.6 cm3 with placebo; treatment effects were maintained through Week 48 in the open-label extension. The drug was generally well tolerated in the 24-week placebo-controlled period; the most common adverse reactions were headache, arthralgia, upper respiratory tract infection, epistaxis, and nausea, with no adverse events leading to discontinuation or dose reduction.

Atebrioz is expected to be available in the U.S. in October through Mirum Access Plus. The FDA also granted Incyte a Rare Pediatric Disease Priority Review Voucher. In Europe, the MAA for zilurgisertib is under EMA review. In the ongoing pediatric PROGRESS program, enrollment is complete in Cohort 2 (ages 6 to <12) and ongoing in Cohort 3 (ages 2 to <12).