Peripheral blasts are associated with responses to ruxolitinib and outcomes in patients with chronic-phase myelofibrosis

Results from a study of the impact of baseline peripheral blasts (PB) on treatment response and outcomes among 794 patients with chronic-phase myelofibrosis treated with ruxolitinib showed that, at 3 and 6 months, patients with PB 1%-4% (P = .001) and those with PB 5%-9% (P = .004) achieved spleen responses less frequently than patients with no baseline PB. Patients with PB 1%-4% and PB 5%-9% also experienced worse ruxolitinib discontinuation-free, leukemia-free, and overall survival (P = .001, P = .002, and P < .001, respectively).