Vinorelbine (NVB) is a new anticancer drug belonging to the vinca alkaloid family that shows activity as a single-agent treatment in advanced non-small cell lung cancer (NSCLC). Preliminary results show a better response rate with a combination of cisplatin (CDDP) and NVB than with NVB alone. To assess whether this increased activity is secondary to a pharmacokinetic interaction, the authors compared the pharmacokinetic profiles of NVB alone and combined with CDDP in previously untreated inoperable NSCLC patients. Five patients received NVB (30 mg/m2) by short intravenous infusion, and four patients received CDDP (80 mg/m2) 1 hour after the NVB infusion (30 mg/m2). Serum NVB was assayed using a specific high-performance liquid chromatography method. The mean serum concentrations in both groups were similar. In addition, the areas under the curve calculated from 1 hour (beginning of CDDP administration) to 72 hours were 414 ng.hour/mL (standard deviation [SD]: 94) (group NVB alone) and 407.1 ng.hour/mL (SD: 32.9) (group NVB + CDDP). In conclusion, the increased activity observed with the combination NVB + CDDP is not the result of a pharmacokinetic interaction.