Prevention of blastic crisis in Ph1-positive chronic myeloid leukemia.

Fourteen untreated patients with Ph1-positive myeloid leukaemia received combination chemotherapy consisting of blocks of doxorubicin, vincristine, cytosine arabinoside and 6-thioguanine. Significant karyotypic conversion occurred in six patients, the percentage of Ph1-positive cells in the bone marrow falling by at least 50%. Maintenance therapy comprised vincristine, busulphan, hydroxyurea, 6-mercaptopurine and dibromannitol in rotation. Reinduction therapy was administered when Ph1 positivity reverted to 100%. Karyotypic reconversion was achieved in three of four patients. After induction, chromosome analysis of the bone marrow was performed every 3-6 months to detect the appearance of aneuploid clones, the intention being to intensify therapy at that stage.