Prolymphocytic leukemia. Response to asparaginase

A 69-year-old woman previously diagnosed as having chronic lymphocytic leukemia had a lymphocyte count of 1,500 X 10(9)/L develop. Bone marrow and peripheral blood lymphocyte morphology and lymphocyte surface markers were consistent with the diagnosis of prolymphocytic leukemia of the null cell type. The leukemia was resistant to management with alkylating agents, combination chemotherapy including doxorubicin hydrochloride, or leukapheresis. The addition of asparaginase to the previously ineffective prednisone and vincristine sulfate therapy produced a dramatic response during a two-week period with a decrease in the peripheral lymphocyte count from 980 X 10(9) to 20 X 10(9)/L and a return toward normal of the concentration of polymorphonuclear leukocytes. Previously, there has been only infrequent or transient benefit from treatment provided these patients from regimens including chemotherapy, splenectomy, irradiation, and leukopheresis. It is suggested that asparaginase be considered as initial induction therapy for this disease process.