The effect of the 2-nitroimidazole Ro 03-8799 (8799) on the activity of 11 chemotherapeutic agents against the anaplastic MT tumour in mice has been determined by soft agar cloning. The 8799, whilst producing little cytotoxicity by itself, potentiated the cytotoxic actions of the alkylating agents melphalan and cyclophosphamide, and the nitrosoureas BCNU, CCNU and MeCCNU. This potentiation was influenced by the time interval between the administration of 8799 and the chemotherapeutic agents, and also by the site of tumour implantation. However, 8799 did not potentiate the cytotoxicities of the compounds CBDCA, cisplatin, adriamycin, vincristine, 5-fluorouracil and bleomycin. A review is included of the reported in vivo effects of nitroimidazoles on the chemotherapeutic agents investigated here
