Lilly to present initial clinical data for first-in-class type II JAK2 inhibitor in patients with previously treated myelofibrosis at the 2026 EHA Annual Meeting

Lilly’s AJX-101 represents a first-in-class approach, targeting the type II conformation of JAK2 in patients with myelofibrosis who have failed type I inhibitors. In the Phase 1 AJX-101 study, 23 patients across five daily dose levels (25–125 mg) who had a median of two prior therapies and all previously received a type I JAK2 inhibitor were evaluated. Early efficacy showed 70% achieving a 35% or greater spleen volume reduction and 70% with at least a 50% improvement in symptoms by week 12; 21 of 23 showed reductions in driver mutation variant allele frequency, with week 24 data indicating 59% achieved at least 20% and 35% at least 50% reductions. Safety was generally manageable, with no dose-limiting toxicity described in the excerpt.