This dose-finding study was designed to determine the maximum tolerated dose (MTD), efficacy and toxicity of combined paclitaxel and carboplatin in 35 previously untreated patients with advanced non-small cell lung cancer (NSCLC). Paclitaxel was given as a 3-h infusion at escalating dose levels (100-250 mg/m(2)) immediately followed by carboplatin as a 30-min infusion (325 or 350 mg/ m(2)) every 3 weeks. The dose-limiting toxicity, paresthesia, occurred at the highest dose level, therefore the recommended dose was established one level below (paclitaxel 225 mg/m(2) with carboplatin 325 mg/m(2)). Neutropenia was the most common hematotoxicity; dose dependency was not apparent. Two patients, at different dose levels, had febrile neutropenia. Thrombocytopenia was rare. Non-hematological toxicities grade 3 or higher included infection, anorexia, alopecia and paresthesia. One patient had a hypersensitivity reaction (transient hypotension). The overall response rate was 23% and median survival time was 7.5 months. Promising activity and acceptable toxicity supports the development of this combination as a useful chemotherapeutic option in advanced NSCLC. [(C) 2000 Lippincott Williams & Wilkins].