Rubidazone in the treatment of recurrent acute leukemia in children. A Pediatric Oncology Group Study.

This study tested the efficacy of rubidazone in the treatment of recurrent acute leukemia in children. In the first phase of this study, rubidazone was administered in a dose of 450 mg/m2 to 26 children with acute lymphocyte leukemia (ALL) and to 8 children with acute nonlymphocytic leukemia (ANLL) in relapse. In children with ALL, 6 patients (23%) achieved a complete remission (CR) and an additional 4 patients (15%) achieved a partial remission (PR). Of 8 children with ANLL, 2, (25%) achieved a CR, and an additional patient achieved a PR. Because of the moderate to severe toxicity of rubidazone, the next phase of the study consisted of randomizing patients between a dose of 450mg/m2 and 300 mg/m2 of rubidazone. In children with ALL in their first relapse who were not resistant to Adriamycin (doxorubicin), 7 of 10 patients (70%) achieved a CR with 450 mg/m2 of rubidazone, whereas 2 of 12 patients (17%), achieved a CR with 300 mg/m2 (P less than 0.04). In children with ALL in their first relapse but resistant to Adriamycin, 3 of 17 patients (18%) achieved a CR with 450 mg/m2, and 2 of 17 patients (12%), acheived a CR with 300 mg/m2. This study suggests that rubidazone is capable of inducing remission in children with ALL in relapse. The main toxicity of rubidazone consisted of severe and prolonged myelosuppression resulting in fever and infection. This toxicity was not significantly decreased by reducing the dose of rubidazone from 450 mg/m2 to 300 mg/m2. Fatal cardiac toxicity was observed in 3 children.