The Clinical Efficacy Of Oxaliplatin And Fluorouracil/Xeloda With Or Without Cetuximab In The First Line Treatment Of Metastatic Colorectal Cancer.

Objective:Cetuximab is a chimeric IgG1 monoclonal antibody with high selectivity and affinity to the epidermal growth factor receptor (EGFR),which is over-expressed by25-80% of colorectal cancer and associated with advanced disease.After the initial pivotal randomized phase II study BOND which demonstrated the ability of cetuximab to reverse chemotherapy resistance,another phaseâ…¢study CRYSTAL showed the addition of cetuximab to first-line FOLFIRI improved response rate(RR)and progression free survival(PFS). The significant clinical benefit of cetuximab-based therapy concerning RR and PFSwas restricted to patients with wild-type K-ras. However,another first-line phaseâ…¢trial did not show statistically different response rate when cetuximab was added to FOLFOX.We retrospectively analyzed 28 cases of metastatic colorectal cancer as group A, who had been treated with FOLFOX/XELOX and cetuximab in our hospital from 2004 to 2010.Testing KRAS genomic status of its parattin embeded bloc sample to investigate the correlation between clinical efficacy of cetuximab to mCRC and the KRAS status.Method:Patients of group A received cetuximab (400 mg/m2 initial dose followed by 250 mg/m2/wk thereafter)no less than 2 doses plus chemotherapy(oxaliplatin 130 mg/m2 on day 1, plus leucovorin 200 mg/m2 and fluorouracil as a 400 mg/m2 bolus followed by a 600 mg/m2 infusion during 22 hours on days 1 and 2); while patients in group B just received chemotherapy alone. KRAS mutation status was assessed patients in group A with tumor samples.The content of analysis include PFS and toxicities.With help of software SPSS 17.0, we used Kaplan-Meier analysis to analyze survival rate of group A and B for comparison.Results:The Overal Response Rate and Disease Control Rate for cetuximab plus oxaliplatin and fluorouracil/Xeloda were higher than with that alone (42.86% vs21.74%,85.71% vs69.57%).The median PFS of group A is 6.3 months(1.5-17.Omonths),while it is 3.4months (1.8-13.0months) in group B.In patients with KRAS wild-type tumors, the addition of cetuximab to oxaliplatin, leucovorin and fluorouracil/Xeloda was associated with a clinically significant increased chance of response (ORR54.55% vs 21.74%, DCR90.91% vs69.57%) and a lower risk compared with chemotherapy alone. The median PFS of it is 7.0months(1.5-17.0months).Conclusion:The clinical efficacy of chemotherapy(oxaliplatin, leucovorin and fluorouracil/Xeloda) plus cetuximab is better than only chemotherapy. KRAS mutational status was shown to be a highly predictive selection criterion in relation to the treatment decision regarding the addition of cetuximab to oxaliplatin, leucovorin and fluorouracil/Xeloda for previously untreated patients with metastatic colorectal cancer.