JAK2V617F

Prelude Therapeutics disclosed preclinical data at ASH 2025 on two MPN programs: PRT12396, a JAK2V617F‑selective JH2 inhibitor that outperforms ruxolitinib, has completed GLP toxicology and is slated for IND filing and Phase 1 in Q1 2026 under an exclusive Incyte option; and mutant CALR‑directed degrader antibody conjugates delivering a CDK9 degrader, which achieve deep, mutant‑selective cell killing in vitro and in vivo while sparing normal hematopoietic cells. Both remain preclinical.