Clinical outcomes of ruxolitinib treatment in 595 intermediate‐1 risk patients with myelofibrosis: The RUX‐MF Real‐World Study

Background Ruxolitinib (RUX) is a JAK1/2 inhibitor approved for the therapy of myelofibrosis (MF) based on clinical trials including only intermediate2‐high risk (INT2/HIGH) patients. However, RUX is commonly used in intermediate‐1 (INT1) patients, with scarce information on responses and outcome. Methods The authors investigated the benefit of RUX in 1055 MF patients, included in the “RUX‐MF” retrospective study. Results At baseline (BL), 595 (56.2%) patients were at INT1‐risk according to DIPSS (PMF) or MYSEC‐PM (SMF). The spleen was palpable at 10 cm below costal margin in 5.9%, 47.4%, and 39.7% of patients, respectively; 300 (54.1%) were highly symptomatic (total symptom score ≥20). High‐molecular‐risk (HMR) mutations (IDH1/2, ASXL‐1, SRSF2, EZH2, U2AF1Q157) were detected in 77/167 patients. A total of 101 (19.2%) patients had ≥1 cytopenia (Hb