Interim analysis of a phase II trial evaluating the safety and efficacy of capecitabine plus oxaliplatin (XELOX) as adjuvant therapy in Japanese patients with operated stage III colon cancer.

PURPOSE: Adjuvant oxaliplatin plus oral capecitabine (XELOX) is recommended for patients with curatively resected colon cancer. However, its safety and tolerability in Asian patients is unclear; therefore, we evaluated the safety and efficacy of adjuvant XELOX in Japanese patients with curatively resected stage III colon cancer (MCSCO-1024) and present the interim safety data.

METHODS: This prospective, multi-center, open-label, single-arm phase II study recruited patients with curatively resected stage III colon cancer. The protocol was a 120-min intravenous infusion of oxaliplatin (130 mg/m2 ) on day 1 and oral capecitabine (2000 mg/m2 /day) in two divided doses for 14 days of a 3-week cycle, for a total of eight cycles (24 weeks). The primary endpoint was the 3-year disease-free survival, and secondary endpoints were the treatment completion rate, safety profile (rate and severity of adverse events), and correlation of adverse events, such as peripheral sensory neuropathy (PSN), with the administration period of oxaliplatin, etc.

RESULTS: From November 2011 to August 2014 (34 months), 196 patients were enrolled. Safety was analyzed in 190 patients. The median total doses of capecitabine and oxaliplatin were 215,586.9 and 777.2 mg/m2 , respectively, while the median relative dose intensities were 82.5 and 76.0%, respectively. The overall treatment completion rate was 73.7%. The most frequent treatment-related adverse event was PSN (88.4%), while the most frequent grade ≥3 treatment-related adverse events were neutropenia (12.6%), PSN (6.3%), diarrhea (4.2%), and thrombocytopenia (4.2%). There were no treatment-related deaths.

CONCLUSIONS: Adjuvant XELOX is tolerable for Japanese patients with Stage III colon cancer.