Use of vinblastine in the terminal phase of chronic myelocytic leukemia

Vinblastine (6 mg/m2) was given to 15 patients in the terminal phase of Ph1 chromosome-positive chronic myelocytic leukemia and to one patient with chronic myelomonocytic leukemia. In each of these patients, there was prompt reduction in leukocyte counts (median, 80% decrease). Effects on platelet counts and hematocrit levels were inconsistent. Nine patients had decreases in the percentage of circulating blast cells. Reduction in splenomegaly and relief of bone pain were recorded in patients with these manifestations. Serious leukopenia was induced in only one patient, and was of brief duration. Additional doses of vinblastine at intervals of greater than or equal to 3 weeks were given to eight patients who had shown improvement in the differential cell count, as an adjunct to maintenance schedules of combination chemotherapy. Good results were obtained initially, but the quality and duration of responses decreased after two to six injections.