Evaluation of paclitaxel (taxol), cisplatin, and the combination paclitaxel-cisplatin in ovarian cancer in vitro with the ATP cell viability assay.

This study evaluates the in vitro sensitivities of 42 ovarian cancer specimens to the new anticancer agent Paclitaxel (taxol, Tx), cisplatin (DDP), and the combination Tx-DDP with the adenosine triphosphate cell viability assay (ATP-CVA). In vitro response is defined by > or = 50% ATP decrease compared to untreated controls 6-7 days after drug treatment with 20% of the peak plasma concentration (PPC). Response rates were 12% to Tx, 19% to DDP, and 27% to Tx + DDP. The mean IC50's of Tx, DDP, and the combination Tx-DDP were (2.6x, 1.0x, and 0.38x PPC, respectively). The mean inhibition of cell viability was significantly greater with drug combinations compared to single drugs. In 7/11 tumors synergistic effects and in 2/11 additive effects were found between Tx and DDP. We conclude that based on ATP-CVA in vitro results, Tx-DDP shows significantly better activity compared to each of the single drugs in ovarian cancer.