Few cytotoxic agents tested in adequate phase II trials involving patients with non-small cell lung cancer have produced single-agent response rates greater than 15%. Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) is one of them, with reported response rates ranging from 21% to 36%. Platinum-based regimens have been key to the development of the most effective combination therapies for NSCLC. We are currently investigating the efficacy and toxicity of combining paclitaxel (175 mg/m2) given by 3-hour infusion, followed by cisplatin (75 mg/m2) via 1-hour infusion, on a 21-day schedule for the treatment of 75 chemotherapy-naive patients with stage IIIB (17.3%) or stage IV (82.6%) non-small cell lung cancer. Patient characteristics include a median age of 58 years (age range, 28 to 75 years) and a median Eastern Cooperative Oncology Group performance status of 2; 19 patients (25.3%) are women and 56 (74.7%) are men. All patients received standard prophylactic premedication as well as adequate hydration. To date, 75 subjects and 328 courses are evaluable for toxicity. Hematologic toxicities have been moderate; grade 3 or 4 neutropenia occurred in 37% of cycles (50% of patients), and grade 3 or 4 thrombocytopenia was observed in only 2% of cycles (2% of patients). Other notable toxicities were World Health Organization grade 2 or 3 alopecia and nausea/vomiting. Grade 1 or 2 peripheral neuropathy occurred in 26% and grade 3 or 4 in only 1% of all courses. Of 67 patients evaluable for response, complete remission was noted in three (5%) patients, partial remission in 25 (37%) patients, stable disease in 22 (33%) patients, and progressive disease in 17 (25%) patients. These results suggest that combination paclitaxel/cisplatin is active and well tolerated in the treatment of non-small cell lung cancer.