5-(3,3-Dimethyl-1-triazeno)imidazole-4-carboxamide (NSC-45388) in the treatment of solid tumors in children.

5-(3,3-Dimethyl-1-triazeno)imidazole-4-carboxamide (NSC-45388) was administered to 46 children with various solid tumors which were resistant to conventional therapy. Two or more courses of NSC-45388 were administered to 13 of 18 children with neuroblastoma, seven of 11 children with rhabdomyosarcoma, three of four children with Wilms' tumor, one of three children with Ewing's tumor, and six of ten children with miscellaneous neoplastic disorders. Major toxic effects included nausea, vomiting, decreased hemoglobin level, thrombocytopenia, and leukopenia. A therapeutic regimen of 200-450 mg/m2/day for 5 consecutive days can be administered safely every 22 days. Objective responses were observed in three children with neuroblastoma and in one child with rhabdomyosarcoma. This drug has minimal but definite activity as a single agent in children with advanced neuroblastoma and rhabdomyosarcoma and should be evaluated further in combination therapy.