Phase II study of VM-26 in acute leukemia, neuroblastoma, and other refractory childhood malignancies: a report from the Children's Cancer Study Group.

VM-26, a semisynthetic podophyllotoxin, was tested for antitumor activity and clinical toxicity in 181 children. The drug was administered iv at weekly intervals, beginning at a dose of 130 mg/2/week. The dose was increased, as tolerated, after 3 and 6 weeks to 150 and 180 mg/m2/week, respectively. The only major toxicity was hematologic, with neutropenia predominating. Anaphylaxis occurred in one patient. The drug demonstrated significant activity in acute lymphocytic leukemia (four responses among 15 patients) and neuroblastoma (ten responses among 31 patients). Objective responses were also noted in one patient each with acute myelogenous leukemia, Hodgkin's disease, histiocytic lymphoma, Wilms' tumor, Ewing's sarcoma, undifferentiated carcinoma, and sacrococcygeal sarcoma. Further trials of VM-26 in these childhood malignancies are warranted.