Preliminary results of a phase I/II clinical trial of paclitaxel and carboplatin in non-small cell lung cancer.

A phase I/II study was carried out to determine the maximum tolerated dose of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in combination with a fixed dose of carboplatin (area under the concentration-time curve = 6 by Calvert method) given on an every-3-week schedule to patients with non-small cell lung cancer (NSCLC). Cohorts of patients were entered at increasing dose levels of paclitaxel: six at dose level I (paclitaxel 150 mg/m2), six at dose level 2 (paclitaxel 175 mg/m2), 11 at dose level 3 (paclitaxel 200 mg/ m2), 21 at dose level 4 (paclitaxel 225 mg/m2), and five at dose level 5 (paclitaxel 250 mg/m2). The patients comprised 31 men and 18 women with a median age of 62 years (age range, 46 to 81 years) and a median Southwest Oncology Group performance status of I (range, 0 to 2). Twenty-three patients had unresectable stage III NSCLC and 26 had stage IV NSCLC. Fortynine patients and 176 treatment courses are evaluable for toxicity. Grade 4 neutropenia or grade 3 arthralgias/ myalgias or sensory neuropathy were the most significant toxicities of therapy. In addition, two patients (dose levels 2 and 3) experienced acute chest pain, flushing, and hypotension, and had electrocardiogram changes during the paclitaxel infusion; one had mild creatine phosphokidnase MB elevation. Both recovered uneventfully, were not re-treated with paclitaxel, and account for two of only four hospitalizations for toxicity management in this trial. At this time, 42 patients with objectively measurable disease are evaluable for responses: two complete responses and 24 partial responses (62% objective response rate) have been observed. These data imply that the maximum tolerated dose of paclitaxel is 250 mg/m2 with dose-limiting toxicity consisting primarily of grade 3 osteo/arthralgias-myalgias or cumulative sensory neuropathy; paclitaxel at a dose of 225 mg/m2 given by 3-hour infusion combined with carboplatin at a calculated target area under the concentration-time curve of 6 is a well-tolerated outpatient treatment regimen and highly active in NSCLC; myelosuppression is mild and rarely dose limiting. Most notably, paclitaxel appears to decrease carboplatin's pharmacodynamic effects on thrombopoiesis.