Phase I and pharmacokinetic study of paclitaxel and irinotecan for patients with advanced non-small cell lung cancer.

We conducted a phase I study of paclitaxel and irinotecan (CPT-11) in advanced non-small cell lung cancer (NSCLC). This study aimed to determine the maximum tolerated doses (MTD). The pharmacokinetics of CPT-11 and its major active metabolite, SN-38, were also analysed. Patients received paclitaxel (day 1) followed by CPT-11 (days 1, 8 and 15), in a 4-week cycle, and paclitaxel and CPT-11 were escalated from 120 and 40 mg/m(2), respectively. 28 patients were enrolled, who were evaluated for toxicity. 2 of 6 patients at 210 mg/m(2) paclitaxel and 50 mg/m(2) CPT-11, and 2 of 4 at 180 and 60 mg/m(2) developed dose-limiting toxicity (DLT) (neutropenia, fever, neurotoxicity and diarrhoea). The area under the plasma concentration-time curve (AUC) of CPT-11 on day 1 was significantly higher than that on days 8 or 15 at each dose level (P=0.002). The AUC of SN-38 on day 1 was significantly increased using paclitaxel doses >or=150 mg/m(2). A preceding paclitaxel administration changed the pharmacokinetics of CPT-11 and SN-38. However, the toxicity was tolerable. Paclitaxel 180 mg/m(2) and CPT-11 50 mg/m(2) were the recommended doses for further phase II study of this combination.