Comparison of prednisolone, vincristine, methotrexate, and 6-mercaptopurine vs. vincristine and prednisone induction therapy in childhood acute leukemia.

This was designed to compare vincristine-prednisone (VP) vs. prednisolone, vincristine, methotrexate, and 6-mercaptopurine (POMP) with respect to response rates and toxicity for induction therapy in acute leukemia. Children with acute lymphoblastic, acute undifferentiated, or acute stem cell leukemia were stratified on the basis of initial leukocyte count and age, then randomly assigned to POMP or VP induction therapy. On the POMP regime, 19/34 (56%) achieved complete remission (CR), 7 achieved partial remission (PR), and 5 did not respond (NR). Three died prior to day 25 of the study. On the VP regime, 37/39 (95%) had CR, and 2 NR. On the VP regime neither sepsis nor toxicity were significant problems. The POMP regime had a higher incidence of sepsis and other toxicities frequently causing therapy interruption, but not enequivocally causing the poor response rate. Several other factors were evaluated as possible causes for the lack of response to POMP therapy.