A phase II trial of combination paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) and carboplatin included 54 chemotherapy-naive patients with advanced non-small cell lung cancer. Eligibility mandated Eastern Cooperative Oncology Group performance status of 0 or 1 and adequate hematologic, renal, and hepatic function. Paclitaxel 135 mg/m2 over 24 hours preceded carboplatin dosed to an area under the concentration-time curve of 7.5. Six planned courses were given every 3 weeks. Granulocyte colony-stimulating factor was introduced during the second and subsequent cycles, and paclitaxel increased 40 mg/m2/cycle (maximum, 215 mg/m2) in patients with absolute neutrophil and platelet nadirs exceeding 500/microL and 50,000/microL, respectively. Grade 3 or 4 neutropenia, observed in 54% of patients during cycle 1, declined to 35% during cycle 2 and to 22% or less during cycles 3 through 6. Neuropathy, myalgias/arthralgias, and thrombocytopenia were mild but cumulative. In 53 evaluable patients, the objective response rate was 62%, with 9% complete remissions and a median response duration of 6 months (range, 1 to 19+ months). At median potential follow-up of 16 months, 9% of patients remain progression free (52+ to 80+ weeks). Median survival is 12.5 months; 1-year survival is 54%. Paclitaxel/carboplatin is highly active in advanced non-small cell lung cancer; granulocyte colony-stimulating factor abrogates neutropenia as the dose-limiting toxicity, but has no effect on the cumulative incidence of thrombocytopenia or treatment delays. One-hour paclitaxel infusion is minimally myelosuppressive, logistically easier, and less costly. A follow-up study combined paclitaxel (175 mg/m2) over 1 hour followed by carboplatin (area under the concentration-time curve, 7.5). In the absence of grade 4 myelosuppression, paclitaxel was increased 35 mg/m2/cycle (maximum, 280 mg/m2). Granulocyte colony-stimulating factor was implemented only after neutropenic fever or grade 4 neutropenia. Of 17 patients entered, 13 are evaluable for toxicity and seven for response. Four patients have sustained a partial response, two a minor response, and one stable disease. The incidence of grade 3 or 4 neutropenia, thrombocytopenia, and anemia in cycle 1 was 38%, 16%, and 0%, respectively, and 72%, 28%, and 28%, respectively, during cycle 2. Major nonhematologic toxicities include myalgias and arthralgias (54%) and fatigue and neuropathy (78%), the latter cumulative and progressive over successive cycles. Preliminary data suggest comparable activity for the 1- and 24 hour paclitaxel infusions in combination with carboplatin. The more severe neuropathy of the 1-hour paclitaxel/carboplatin combination may be related to the paclitaxel dosing schema (175 mg/m2 to as high as 280 mg/m2).(ABSTRACT TRUNCATED AT 400 WORDS)