The COMET Open-label Phase II Study of Neoadjuvant FOLFOX or XELOX Treatment Combined with Molecular Targeting Monoclonal Antibodies in Patients with Resectable Liver Metastasis of Colorectal Cancer

Background: Advantages of neoadjuvant chemotherapy combined with monoclonal antibodies for treating patients with resectable colorectal cancer liver metastasis (CLM) have not been established. The purpose of this study was to evaluate the efficacy and safety of oxaliplatin-based regimen (FOLFOX or XELOX) plus monoclonal antibodies (cetuximab or bevacizumab) treatment in patients with resectable CLM. Methods: A single-arm, open-label, multicenter, phase II trial was conducted for patients aged ≥ 20 years with resectable and untreated CLM. Patients received preoperative FOLFOX (6 cycles) or XELOX (4 cycles). Cetuximab or bevacizumab was administered to patients with wild-type or mutated KRAS codons 12 and 13, respectively. The primary endpoint was progression-free survival (PFS). Results: Between January 2010 and June 2012, 47 patients were enrolled from 12 institutions. Wild-type or mutant KRAS sequences were examined in 32 and 15 patients, respectively. Twenty-one (45 %) patients experienced Grades 3/4 adverse events, and 55 % of all patients responded to therapy. The sizes of tumors of patients in the wild-type KRAS group were significantly reduced compared with those of the mutant KRAS group. The overall rates of liver resection and postoperative morbidity were 83 and 14 %, respectively, and the median PFS was 15.6 months. The median PFS times of the KRAS wild-type and mutant groups were 22.5 months and 10.5 months, respectively. Conclusions: Neoadjuvant therapy using FOLFOX/XELOX combined with monoclonal antibodies did not improve PFS, although it was administered safely and had less adverse effects after liver resection.