A multi-institutional phase II study of combination chemotherapy with S-1 plus cisplatin in patients with advanced non-small cell lung cancer

S-1 is an oral anticancer fluoropyrimidine agent designed to elevate anticancer activity with a decrease in gastrointestinal toxicity. We conducted a phase II study to evaluate the efficacy and safety of combination chemotherapy with S-1 plus cisplatin in patients with advanced non-small cell lung cancer (NSCLC). Chemotherapy-naive patients were treated with S-1 administered orally at 40 mg/m2 twice a day for 21 consecutive days, and cisplatin (60 mg/m2) infused intravenously on day 8, repeated every 5 weeks. Of the 44 patients enrolled in the study, 40 were assessable for efficacy and safety. The median number of cycles administered was 3 (range 1–9 cycles). Among the 40 assessable patients, 7 partial responses were observed, with an overall response rate (RR) of 17.5% [95% confidence interval (CI), 5.2–29.8]. Patients with squamous cell carcinoma showed a significantly higher RR (55.5%) than those with adenocarcinoma (9.1%) or other types of NSCLC (0%). The median progression-free survival was 4.3 months (95% CI, 3.4–4.9), the median survival time was 17.9 months (95% CI, 15.0–20.8), and the 1- and 2-year survival rates were 63.3 and 27.3%, respectively. Major grade 3–4 hematologic toxicities were leukocytopenia (7.5%), neutropenia (5.0%), anemia (15.0%) and thrombocytopenia (2.5%). No grade 4 non-hematologic toxicity or treatment-related death occurred. These results suggest that combination chemotherapy with S-1 plus cisplatin is a promising therapeutic candidate for patients with advanced NSCLC, particularly squamous cell carcinoma.