Models to Predict Response to JAK-inhibitor Therapy in Patients with Myelofibrosis

The use of JAK inhibitors in myelofibrosis (MF) has been noted to improve splenomegaly and constitutional symptoms, and possibly survival. Ruxolitinib, a JAK 1/2 inhibitor, has been approved for use in patients with intermediate- or high-risk MF, and newer agents such as the JAK2 inhibitor pacritinib are also under development. We hypothesized that DIPSS, a prognostic scoring system, does not accurately predict which patients may benefit most from treatment. We thus conducted a retrospective analysis to evaluate which clinical factors might best predict a patient's likelihood of achieving a response to therapy, measured as a > 50% reduction in splenic size by palpation.