Biweekly Raltitrexed Combined With Irinotecan as Second-Line Therapy for Patients With Metastatic Colorectal Cancer: A Phase II Trial

Objective Irinotecan-based doublet chemotherapy strategy was standard second-line backbone for patients with oxaliplatin-refractory metastatic colorectal cancer. The aim of this study was to evaluate tolerability and efficacy of raltitrexed combined with irinotecan biweekly administered as the second-line therapy for mCRC patients. Methods The study was a prospective, single-center, non-randomized, open-label phase II clinical trial. Patients with mCRC after failure with oxaliplatin and fluoropyrimidine or its derivatives were enrolled. Irinotecan (180 mg/m2) and raltitrexed (2.5 mg/m2) were given intravenously on day 1. Cycles were repeated every 2 weeks. The primary endpoint was progression-free survival (PFS), and the secondary endpoints included overall response rate (ORR), disease control rate (DCR), overall survival (OS), and adverse events (AEs). Results Between December 2012 and October 2016, 33 and 35 patients enrolled were assessed for response and safety, respectively. The ORR was 8.6%, and the DCR was 71.4%. The median PFS was 4.5 months (95% CI 3.8-5.2). The median OS was 12.0 months (95% CI 8.5-15.5). Four patients received conversion therapy to no evidence of disease (NED), and 2 patients were still alive with beyond 24 months survival. The most common grade 3/4 AEs were anorexia (14.3%), vomiting (14.3%), nausea (11.4%), fatigue (8.6%), and leukopenia (8.6%). No one died from treatment-related events. The incidence and severity of toxicity were irrelevant to UGT1A1 status. Conclusions The combination of irinotecan with raltitrexed is an efficient, convenient, and acceptable toxic regimen for second-line treatment for mCRC patients.