A phase I study of ifosfamide/carboplatin/etoposide/paclitaxel in advanced lung cancer

A phase I study was conducted to define the maximally tolerated dose and toxicity profile of the ifosfamide/carboplatin/etoposide/paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) (ICE-T) regimen in advanced lung cancer. This chemotherapy program uses paclitaxel given as a 24-hour continuous infusion in conjunction with full-dose ICE chemotherapy with growth factor support. The dosage of paclitaxel was escalated from 75 to 225 mg/m². Thirty-four patients have been accrued to date onto this study. Because hematologic dose-limiting toxicity was defined in terms of neutropenia and/or thrombocytopenia exceeding 7 days' duration, no patient demonstrated what was defined by the protocol as dose-limiting toxicity. Nonetheless, substantial hematologic toxicity was observed. Overall, 26% had fever and neutropenia, 56% had grade 4 neutropenia, and 26% had grade 4 thrombocytopenia. In all cases, hematologic toxicity was short term and reversible. While grade 3 and 4 myelosuppression was frequently observed, it was not dose related (in terms of paclitaxel dosage). Nonhematologic toxicity also was not dose related and, with only a few exceptions, was not clinically significant. Among 27 patients evaluable for response, 41% achieved an objective response, including 15% with a complete response. All of five patients with small cell lung cancer responded (including two with a complete response). Among 22 patients with non-small cell lung cancer, 27% achieved an objective response (also including two with a complete response). The results of this study suggest that with growth factor support, it is possible to safely administer full-dose, single-agent paclitaxel in conjunction with full-dose ICE chemotherapy. We will soon be initiating a phase II study of the ICE-T regimen using paclitaxel at 225 mg/m² as a 24-hour continuous infusion in advanced lung cancer. We will also conduct a phase I study of ICE-T, with paclitaxel administered as a 3-hour continuous infusion.