Phase II study of irinotecan plus S-1 combination for previously untreated advanced non-small cell lung cancer: Hokkaido Lung Cancer Clinical Study Group 0601

Abstract

e19012 Background: Platinum-containing therapy is a standard first-line treatment for advanced non-small cell lung cancer (NSCLC). Platinum-free regimens can be alternative if they can provide similar efficacy with better tolerability. This study evaluated the efficacy and safety for combination of irinotecan and S-1, a newly developed oral 5-fluorouracil derivative, for chemotherapy-naïve advanced NSCLC. Methods: In this multicenter phase II trial, we initially planned to enroll 40 patients. Chemotherapy consisted of 4-week cycles of irinotecan (100 mg/m2 IV, day 1 and 15) and S-1 (80 mg/m2 orally, day 1–14). Primary end point was response rate; secondary endpoints were overall survival (OS), progression-free survival (PFS), and safety. Association of UGT1A1 genotypes (*6 and *28) with frequency of severe toxicity was also examined. Results: A total of 112 cycles was administered into 40 patients (median, 3 cycles: range, 1–6). Median age was 64 years (range, 42–75); 29 patients (73%) had adenocarcinoma, and 8 patients (20%) had squamous cell carcinoma. Majority of the patients (32 cases, 80%) had stage IV disease. Twelve patients exhibited partial response (PR), and 17 patients exhibited stable disease (SD), resulting in response rate of 30% [95% confidence interval (95% CI), 16.6–46.5] and disease control rate of 72.5% (95% CI, 56.1–85.4). Median OS and PFS were 13.8 months (95% CI, 10.7–16.9) and 4.7 months (95% CI, 3.4–6.0), respectively. Hematological toxicities of grade 3 or 4 were neutropenia (32.5%) and anemia (5.0%). The most common non-hematologic toxicities of grade 3 or 4 included diarrhea (15.0%) and anorexia (17.5%). There were no treatment-related deaths. Among the 40 patients, there were 1 homozygous and 8 heterozygous for UGT1A1*6, whereas 7 heterozygous for UGT1A1*28; none of the patients had both genotypes. Patients with homozygous or heterozygous for UGT1A1*6 showed a trend for high incidence of grade 3 diarrhea (p = 0.055). No association of UGT1A1*28 with severe toxicity was observed in this study. Conclusions: Irinotecan and S-1 combination is an alternative treatment with tolerable toxicity for previously untreated advanced NSCLC. No significant financial relationships to disclose.