[Chronic myeloid leukemia associated with sustained severe pancytopenia after imatinib mesylate therapy]

A 73-year-old woman with chronic myeloid leukemia was treated with interferon-alpha, hydroxyurea, and busulfan before imatinib mesylate treatment. The leukocyte count was 8,400/; hemoglobin concentration, 12.0 g/; and platelet count, 19.7 x 10(4)/. She received 400 mg of imatinib mesylate for 17 days before the agent was discontinued because of pancytopenia. A bone marrow biopsy on the 87th day after the last imatinib mesylate administration demonstrated severe hypocellularity. She needed many RBC and Plt transfusions and filgrastim administration. Grade 4 neutropenia continued for 35 days and Grade 3 thrombocytopenia continued for over 122 days. Imatinib mesylate, an agent targeting BCR-ABL, is expected to be useful as an effective therapeutic agent for chronic myeloid leukemia. However the present case suggests that its appropriate dose is individually variable and we should carefully consider the former treatment, and the clinical stage of the disease before initiating imatinib treatment.