PDGFRA and Chronic Eosinophilic Leukemia, Not Otherwise Specified: Given the historically poor prognosis of chronic eosinophilic leukemias and theexquisite sensitivity to imatinib in patients with rearrangedPDGFRA/B, consensus has emerged that these individuals betreated even in the absence of organ dysfunction.6 Several case reports and small case series of patients withchronic eosinophilic leukemia with PDGFRA/B rearrangement havedescribed the efficacy of imatinib at a dose of 100 to 400 mg per day to producedurable complete hematologic responses.7-11