Potent antitumor antibiotic complex: PD 114,759, PD 115,028, PD 119,707, and PD 119,193.

Four novel antitumor antibiotics (PD 114,759, PD 115,028, PD 119,707 and PD 119,193) are produced as a complex by a new species of Actinomadura. The proposed name for the culture is Actinomadura verrucosospora subsp. veractimyces ATCC 39363. The antibiotics are extremely bioactive, with MIC values of less than 0.006 ng/ml against several bacteria and ID50 values of 0.003 approximately 0.107 ng/ml against L1210 leukemia cells in vitro. Antitumor activities vs. P388 leukemia in vivo were observed at doses of 0.313, 0.40, and 0.5 micrograms/kg (daily X 5) for PD 119,707, PD 115,028, and PD 114,759, respectively.