Prolonged second remissions in childhood acute lymphocytic leukemia: a report from the Childrens Cancer Study Group.

To date, median duration of second and subsequent remissions in childhood acute lymphocytic leukemia (ALL) has been short, with most studies reporting median remission duration less than 6 months. In May 1979, the Childrens Cancer Study Group (CCSG) undertook a pilot study to assess the efficacy of a vincristine, methotrexate, and L-asparaginase regimen (modified Capizzi) for maintenance in children with ALL in second or subsequent remission. Thirty patients were treated with this maintenance regimen. By life table analysis, predicted median duration of hematologic remission was 57 weeks. Ten patients (33%) were in continuous hematologic remission at 1 year and three (10%) continue in remission greater than 2 years from maintenance onset. Major toxicity included leukoencephalopathy in four patients, three of whom had experienced at least one central nervous system relapse prior to study entry. Allergic reactions to Escherichia coli L-asparaginase were common. Nine of 30 patients experienced at least one CNS relapse during therapy. We conclude that a modified Capizzi regimen is the most effective regimen reported to date for maintaining second and subsequent remission in childhood ALL. CCSG is currently utilizing this regimen in an ongoing open study.