Kaplan-Meier analysis of overall survival (in months) of patients enrolled at MDACC in study INCB18424-251 by degree of spleen length reduction. Patients were analyzed in 3 groups: patients who exhibited confirmed response of ≥ 50% reduction of palpable spleen length (n = 61), patients who exhibited confirmed response of > 25% but < 50% reduction in palpable spleen length (n = 13), and patients who exhibited confirmed < 25% reduction in palpable spleen length (n = 23). *Comparison of < 25% reduction to ≥ 50% reduction.