Response to dasatinib in a patient with concomitant chronic myeloid leukemia and chronic lymphocytic leukemia.

While chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML) are common diseases in the elderly, they rarely occur simultaneously in the same patient. Here we present the case of a 77-year-old patient diagnosed with CML in the chronic phase who showed an optimal response to 400 mg/day of imatinib. This patient progressed to Binet B-CLL with an 11q22.3 deletion and CD38 positivity in the 4th month of treatment. During the follow-up, his lymphocyte number doubled in <6 months. Based on previous reports, dasatinib was chosen instead of imatinib. After 6 months of treatment with 100 mg/day of dasatinib, the patient demonstrated a partial response, characterized by the regression of lymph node enlargement, a hemoglobin level of 10.7 g/dl, neutrophils of 1.7 × 10(9)/l, a 82% reduction in the lymphocyte number and an increase in cytotoxic CD8+ and large granular lymphocytes. This partial response has persisted to the present time. While little data have been published regarding the in vitro effect of dasatinib monotherapy for CLL, this case report provides some evidence of the clinical activity of dasatinib in CLL.