Two phase II studies of paclitaxel involving patients with advanced non-small cell lung cancer (NSCLC) have been completed. The first study, conducted by the Eastern Cooperative Oncology Group (ECOG), involved 25 previously untreated patients who received intravenous (i.v.) paclitaxel 250 mg/m2 over 24 hours every 3 weeks. Among 24 evaluable patients with stage IV disease, 5 partial responses (21%) were observed, median survival was 24.1 weeks, and 1-year survival was approximately 45%. Common toxicities included leukopenia (66% grade 4), neurotoxicity (28% grade 3), and cardiotoxicity (12.5% grade 3). The second trial, conducted at the M.D. Anderson Cancer Center, yielded similar results. Twenty-seven previously untreated patients with stage IV disease received paclitaxel 200 to 250 mg/m2 i.v. over 24 hours every 3 weeks, yielding 1 complete response and 5 partial responses (24%) in 25 evaluable patients. The major toxicity was leukopenia. No cardiac toxicity was seen. For the past several years ECOG has tested several agents against previously untreated NSCLC, and none has demonstrated a response rate greater than 10%, other than paclitaxel. Given these results, the ECOG plans to conduct a three-arm phase III study involving patients with advanced NSCLC comparing 'standard' cisplatin/etoposide chemotherapy to two paclitaxel-containing arms: (1) paclitaxel 135 mg/m2 i.v. over 24 hours plus cisplatin 75 mg/m2 i.v.; (2) paclitaxel 250 mg/m2 i.v. over 24 hours plus cisplatin 75 mg/m2 i.v. plus recombinant human granulocyte colony-stimulating factor.(ABSTRACT TRUNCATED AT 250 WORDS)