A dose-escalation study of oxaliplatin/capecitabine/irinotecan (XELOXIRI) and bevacizumab as a first-line therapy for patients with metastatic colorectal cancer

Purpose The aim of this study was to determine the recommended dose (RD) of a triweekly capecitabine, oxaliplatin, irinotecan, and bevacizumab (XELOXIRI/bevacizumab) regimen that was easier to administer than FOLFOXIRI/bevacizumab, using capecitabine instead of 5-fuorouracil (5-FU), in patients with metastatic colorectal cancer (mCRC). Methods Patients received oxaliplatin (100 mg/m 2 , day 1), capecitabine (1,700 mg/m 2 per day from day 2 to 15), irinotecan (100, 120, 150 mg/m 2 for dose levels 1, 2, 3, day 1), and bevacizumab (7.5 mg/kg, day 1), repeated every 3 weeks. Dose-limiting toxicities (DLTs) were assessed in the first two cycles to determine the maximum tolerated dose (MTD). Results Twelve patients received a median of 6.5 cycles of therapy (range 2–12). The DLT was grade 4 neutropenia, observed in one of six patients at dose level 2. The MTD was not reached at dose level 3. Therefore, the RD of irinotecan was defined as 150 mg/m 2 . The most common grade ≥3 toxicities were neutropenia (41 %), anemia (17 %), diarrhea (8 %), and febrile neutropenia (8 %). The response rate and median progression-free survival were 83 % and 15 months, respectively. Conclusions XELOXIRI/bevacizumab is a feasible regimen for patients with mCRC, neutropenia was the DLT, and the RD of irinotecan is 150 mg/m 2 . The response rate observed is very promising and warrants further investigation.