JAK2p.V617F allele burden reductions and correlations with spleen volume reductions in patients with myelofibrosis. (A) Mean percent change (±SE) in allele burden from baseline. (B) Best molecular response in individual patients randomized to ruxolitinib and in patients receiving ruxolitinib after crossover from placebo. (Inset) Change from baseline at week 24 for individuals randomized to ruxolitinib and placebo. (C) Allele burden change over time for patients achieving CMR (<2% with confirmation). Solid green lines, patients randomized to ruxolitinib; dashed green line, patient initially randomized to placebo who crossed over to ruxolitinib, with time 0 marking the start of ruxolitinib treatment. (D) Mean percent change in spleen volume stratified by tertile of maximum allele burden reduction. SE, standard error. *Patients on placebo who did not cross over to ruxolitinib. ^†All patients randomized to placebo; shading of the line in this group represents crossover of patients from placebo to ruxolitinib.