A Randomized Phase II Study of a Combination of Docetaxel and S-1 versus Docetaxel Monotherapy in Patients with Non-small Cell Lung Cancer Previously Treated with Platinum-Based Chemotherapy: Results of Okayama Lung Cancer Study Group (OLCSG) Trial 0503

Background The survival impact of single-agent treatment with docetaxel, the standard regimen for relapsed patients with non-small cell lung cancer (NSCLC), remains modest. We conducted a randomized phase II study to evaluate the efficacy and safety of the combination of docetaxel and S-1 in the second-line setting. Methods Patients with relapse of NSCLC after first-line platinum-based chemotherapy were randomly assigned to docetaxel alone (60 mg/m 2 , day 1, q3 weeks; arm A) or a combination of docetaxel (40 mg/m 2 , day 1, q3 weeks) and S-1 (80 mg/m 2 , days 1-15; arm B). The primary end point was response rate, whereas secondary endpoints included overall survival, progression-free survival, and toxicity. Results Between 2005 and 2008, a total of 60 patients were enrolled in the study. The objective response rates were 20.7% and 16.1% in arms A and B, respectively ( p = 0.81). Progression-free survival was comparable in the two arms (median: 3.7 versus 3.4 months, p = 0.27), whereas overall survival time was longer in arm A (22.9 versus 8.7 months, p = 0.02). The major toxicity was myelosuppression with grade ≥3 neutropenia in 89.7% of patients versus 64.5% in arms A and B, respectively. Conclusions This study suggests that docetaxel monotherapy should continue to be considered the standard for second-line chemotherapy against NSCLC.