Antitumor effect of a new antibiotic, neothramycin.

A new anthramycin-group antitumor antibiotic, neothramycin, isolated from a Streptomyces culture, showed activity against experimental tumors such as lymphocytic leukemia P388 ascites sarcoma-180, hepatoma AH130, Walker carcinosarcoma-256 and mouse mammary adenocarcinoma (CCMT). In particular, the tumor growth inhibition ratio was as high as 96% when neothramycin was injected intraperitoneally at a daily dose of 2 mg/kg into Wistar strain rats previously inoculated with Walker carcinosarcoma-256 by the subcutaneous route. Successive intraperitoneal injections of the compound were more effective than a single injection with the P388 system.