Anti-EGFR and anti-VEGF agents:Important targeted therapies of colorectal liver metastases

Colorectal liver metastasis(CLM)is common worldwide.Targeted therapies with monoclonal antibodies have been proven effective in numerous clinical trials,and are now becoming standards for patients with CLM.Thedevelopment and application of anti-epidermal growth factor receptor(anti-EGFR)and anti-vascular endothelial growth factor(anti-VEGF)antibodies represents significant advances in the treatment of this disease.However,new findings continue to emerge casting doubt on the efficacy of this approach.The Kirsten ratsarcoma viral oncogene(KRAS)has been proven to be a crucial predictor of the success of anti-EGFR treatment in CLM.Whereas a recent study summarizedseveral randomized controlled trials,and showed thatpatients with the KRAS G13D mutation significantlybenefited from the addition of cetuximab in terms of progress-free survival(PFS,4.0 mo vs 1.9 mo,HR=0.51,P=0.004)and overall survival(OS,7.6 mo vs5.7 mo,HR=0.50,P=0.005).Some other studiesalso reported that the KRAS G13D mutation might notbe absolutely predictive of non-responsiveness to antiEGFR therapy.At the same time,"new"RAS mutations,including mutations in neuroblastoma RAS viral(vras)oncogene homolog(NRAS)and exons 3 and 4 of KRAS,have been suggested to be predictors of a poor treatment response.This finding was first reported by the update of the PRIME trial.The update showed that for patients with non-mutated KRAS exon 2 but other RAS mutations,panitumumab-fluorouracil,leucovorin,and oxaliplatin(FOLFOX)4 treatment led to inferior PFS(HR=1.28,95%CI:0.79-2.07)and OS(HR=1.29,95%CI:0.79-2.10),which was consistent with the findings in patients with KRAS mutations in exon 2.Then,the update of the PEAK trial and the FIRE-Ⅲtrial also supported this finding,which would reduce candidates for anti-EGFR therapy but enhance the efficacy.In firstline targeted combination therapy,the regimens of cetuximab plus FOLFOX was called into question because of the inferior prognosis in the COIN trial and the NORDIC-Ⅶtrial.Also,bevacizumab plus oxaliplatin-based chemotherapy was questioned because of the NO16966trial.By the update and further analysis of the COIN trial and the NORDIC-Ⅶtrial,cetuximab plus FOLFOX was reported to be reliable again.But bevacizumab plus oxaliplatin-based chemotherapy was still controversial.In addition,some trials have reported that bevacizumab is not suitable for conversion therapy.The results of the FIRE-Ⅲtrial showed that cetuximab led to a significant advantage over bevaci