4'-demethylepipodophyllotoxin 9-(4,6-o-2-thenylidene-beta-D-glucopyranoside) (NSC-122819; VM-26) and 4'-demethylepipodophyllotoxin 9-(4.6-0-ethylidene-beta-D-glucopyranoside) (NSC-141540; VP-16-213) in childhood cancer: preliminary observations.

We evaluated the responses of 39 children with cancer who, after failure to respond to conventional chemotherapeutic agents, received either or both of two epipodophyllotoxins: 4'-demethylepipodophyllotoxin 9-(4,6-o-2-thenylidene-beta-D-glucopyranoside) (NSC-122819) and 4'-demethylepipodophyllotoxin 9-(4,6-o-ethylidene-beta-D-glucopyranoside) (NSC-141540). Seventeen patients has acute lymphocytic leukemia (ALL). 12 had acute nonlymphocytic leukemia (ANLL), and ten had solid tumors. Initially, the patients in each disease category were randomized to receive 50 mg/m2/dose of NSC-122819 intravenously (iv) twice weekly or 75 mg/m2/dose iv of NSC-141540 twice weekly for 4 weeks. Drug dosages and schedules of administration were adjusted during the course of the study. Although objective responses were not detected in the heterogeneous group of solid tumor patients, definite clinical responses were obtained in nine of the 29 patients with acute leukemia. The responses to the two epipodophyllotoxins were noted in patients with ALL as well as in patients with ANLL. Toxic side-effects included nausea, vomiting, diarrhea, fever, alopecia, leukopenia, and thrombocytopenia. These results, the first reported with both NSC-122819 and NSC-141540 in childhood cancer, indicate that the epipodophyllotoxins are well tolerated and may be effective against acute leukemia.