A phase II study was performed to investigate the tolerance and efficacy of the combination of docetaxel (Taxotere; Rhône-Poulenc Rorer, Antony, France) and gemcitabine in chemotherapy-naive patients with advanced non-small cell lung cancer (NSCLC). To date, 24 patients (five with stage IIIB and 19 with stage IV NSCLC) have been treated according to the protocol: gemcitabine 900 mg/m2 was administered on days 1 and 8 as a 30-minute infusion and docetaxel 100 mg/m2 was administered on day 8 as a 1-hour infusion after appropriate premedication. Granulocyte colony-stimulating factor 150 microg/m2 subcutaneously was given on days 9 to 15. Treatment was repeated every 3 weeks. Grade 3/4 granulocytopenia occurred in seven (29%) patients, and one (4%) of these patients developed febrile neutropenia. Grade 3/4 thrombocytopenia and anemia were observed in three (13%) and one (4%) patient, respectively. Grade 2 neurotoxicity and fatigue occurred in one (4%) patient each. Other toxicities were mild. There were no treatment-related deaths. Eight patients experienced a partial response (53.3%; 95% confidence interval, 28.1% to 78.6%), and stable and progressive disease were documented in two (13%) and five (33%) patients, respectively. The median delivered dose was 600 mg/m2/wk and 33 mg/m2/wk for gemcitabine and docetaxel, respectively. These preliminary data suggest that the docetaxel/gemcitabine combination has significant antitumor activity and is well tolerated in chemotherapy-naive patients with NSCLC. The study is ongoing.