A randomized phase 3 study of maintenance therapy with S-1 plus best supportive care versus best supportive care after induction therapy with carboplatin plus S-1 for advanced or relapsed squamous cell carcinoma of the lung (WJOG7512L)

Background: A randomized phase 3 study was performed to investigate the efficacy and safety of maintenance therapy with S-1 after induction therapy with carboplatin plus S-1 in patients with advanced squamous non–small cell lung cancer (NSCLC). Methods: Chemotherapy-naive patients with advanced or relapsed squamous NSCLC were treated with carboplatin (area under the curve of 5 on day 1 every 3 weeks) plus S-1 (40 mg/m² twice per day on days 1-14 every 3 weeks) as induction therapy. Patients who did not progress after 4 cycles of induction therapy were randomized to receive either S-1 plus best supportive care (BSC) or BSC alone. The primary objective of the study was to confirm the superiority of S-1 plus BSC in comparison with BSC alone with respect to progression-free survival. Results: Of the 365 patients enrolled in the study, 347 participated in the induction phase, and 131 of these individuals were randomized to receive S-1 plus BSC (n = 67) or BSC alone (n = 64). The risk of disease progression was significantly lower for patients in the S-1 plus BSC arm than those in the BSC-alone arm (hazard ratio, 0.548; 95% confidence interval, 0.374-0.802; P =.0019). The most common toxicities during maintenance therapy with S-1 included anorexia, anemia, and fatigue, but most cases were not severe. Conclusions: Continued maintenance with S-1 plus BSC is an effective and well-tolerated treatment option for patients with advanced squamous NSCLC previously treated with carboplatin plus S-1.