Borato-1,2-diaminocyclohexane platinum (II) (BDP) was synthesized and compared to cisplatin (cisPt) as a potential anti-tumor drug. BDP and cisPt (0.2-20 microM) dose-dependently inhibited DNA synthesis in L1210 murine leukemia cells, DU-145 prostate cancer cells, A549 lung carcinoma cells, and MCF-7 breast cancer cells, as judged by measuring [(3)H]-thymidine incorporation. BDP and cisPt induced killing of L1210 murine cells by 97 and 78%, respectively. The LD(50) was 35 and 14 mg/kg for BDP and cisPt, respectively. Interestingly, while cisPt (at optimal dose) induced a 100% increase in life span (ILS) of BDF1 mice bearing L1210 tumor cells, BDP (at optimal dose) induced a 200% increase in ILS in the same tumor model. In conclusion, BDP is a novel platinum derivative compound that appears more effective in increasing the ILS than cisplatin against the leukemia tumor mouse model.