JAK2 allele burden in evaluable patients. (A) JAK2 allele burden at baseline in patients with or without splenomegaly. (B) Percentage change from baseline in JAK2 allele burden in patients with (responders) or without CHR (nonresponders) at C3D28, C5D28, and week 32. (C) Comparison of reduction in JAK2 allele burden between patients with hematocrit control (responders) or without hematocrit control (nonresponders). (D) Comparison of reduction in JAK2 allele burden between patients with CHR (responders) or without CHR (nonresponders). Black stars represent the mean.