Effective dose of L-asparaginase for induction of remission in previously treated children with acute lymphocytic leukemia: a report from Childrens Cancer Study Group.

L-Asparaginase, in the dose of greater than or equal to 6000 IU/sq m three times weekly, was demonstrated to be an effective agent in reinduction of remissions in childhood leukemia. Four hundred thirteen children with acute lymphocytic leukemia were treated with L-asparaginase. Doses i.m. ranged from 300 to 12,000 IU/sq m. None of the patients had received prior asparaginase therapy. 6-Mercaptopurine was given p.o. concurrently. All of the patients had experienced several previous relapses, and their disease was not responsive to 6-mercaptopurine. L-Asparaginase was found to be effective in reinducing remissions at the following rates: 9.5% for 300 IU/sq m; 35.1% for 3,000 IU/sq m; 53.5% for 6,000 IU/sq m; and 62.5% for 12,000 IU/sq m. The drug was given three times weekly for four weeks. Hypersensitivity reactions occurred in 6.5% of patients.