Zilurgisertib (INCB000928) - (PROGRESS)

June 14, 2026: Mirum Pharmaceuticals (NASDAQ: MIRM) and Incyte (NASDAQ: INCY) reported pivotal Phase 2 Cohort 1 results from the PROGRESS study of zilurgisertib (investigational oral ALK2 inhibitor) in adolescents/adults (≥12) with fibrodysplasia ossificans progressiva (FOP), presented as a late-breaking rapid-fire at ENDO 2026. In the 24-week randomized, double-blind period (zilurgisertib 100 mg QD n=32 vs placebo n=31), fewer patients on zilurgisertib developed new heterotopic ossification (HO) lesions at Week 24 (3.1% vs 16.7%; 81% reduction; p=0.0986) and new lesion volume was reduced by 99.9% vs placebo (0.003 vs 6.57 cm³; nominal p<0.0001). Total lesion volume decreased on zilurgisertib vs increased on placebo (nominal p=0.004). Through Week 48 in the open-label extension/crossover (61 with CT data), no new HO lesions were observed and total HO lesion volume continued to decrease in both continued-treatment and crossover patients; flare activity remained low.

The FDA accepted the NDA for zilurgisertib for FOP (≥12 years) under Priority Review; PDUFA target action date is September 26, 2026.