A Comparision Study On One-week And Two-week Schedules Of Cetuximab For Metastatic Colorectal Cancer

Objective:Cetuximab(IMC-C225, Brand name:Erbitux) is an IgGl chimeric monoclonal antibodies that specifically targets the epidermal growth factor receptor (EGFR).Cetuximab can inhibits tumor cell from proliferating,invading or transferring by blocking ligand binding,It also can induce apoptosis of tumor cells and increase tumor sensitivity to chemotherapeutic agents.Many tumors including colorectal cancer can express the EGFR,so cetuximab can be used for the treatment of metastatic colorectal cancer(MCRC).In recent years,Many clinical researches have confirmed that Cetuximab alone or combining with chemotherapy is high effective and well tolerate for metastatic colorectal cancer.Cetuximab have been widely applied to clinical practice and was suggested given at an initial dose of 400mg/m2 followed by weekly doses of 250mg/m2.Because of long terminal half-life and demonstrates near non-linear pharmacokinetics, doubling the standard dose of cetuximab can result in a similar AUC(Area Under Curve) to that of the weekly dose.Some clinical research in abroad have start to using two-week schedule of cetuximab plus chemotherapy to treat metastatic colorectal cancer.Then the purpose of this research was to compare the short-term efficacy and main side effects between One-week and two-week schedule of cetuximab plus chemotherapy for metastatic colorectal cancer.Methods:56 patients with metastatic colorectal cancer were enrolled in the First Affiliated Hospital of Da Lian Medicial Universit and the Fourth Hospital of An Shan.All patients have been proved with pathology or cytology and these patients ever accepted adjuvant chemotherapy of FOLFOX4,XELOX or FOLFIRI.ECOG physical status 0-2,good liver and renal function,using the RECIST(Response Evaluation Criteria in Solid Tumors Group) published in 2000 to evaluate the measurable lesions.30 patients received One-week schedule of Cetuximab plus chemotherapy: Cetuximab combining with FOLFOX4 (L-OHP+5-FU+LV) is 21 patients, combining with XELOX(Xeloda+5-FU+LV) is 4 patients and combining with FOLFIRI(CPT-11+5-FU+LV) is 5 patients.Cetuximab was administered at an initial dose of 400mg/m2 followed by weekly doses of 250mg/m2;26 patients received two-week schedule of cetuximab plus FOLFOX4 chemotheraphy,cetuximab was administered at an initial dose of 500mg/m2 and the same dose was given every two weeks.The termination of the study was patients finishing 8 weeks treatment or disease progress.Observe healing effect and main side effects in the two groups.Efficacy were evaluated by CR(Complete Remission),PR(Partial Remission),SD(Stable Disease),PD(progress Disease).Side effects were evaluated according to NCI-CTC3.0 by 0～Ⅳdegree.Results:28 patients were evaluable in one-week schedule group:CR 1(3.6%),PR 7(25.0%),SD 11(39.3%),PD 9(32.14%),RR was 28.6%,DCR was 67.9%.26 patients were evaluable in two-week schedule:none of CR,PR 8(30.8%),SD 9(34.7%),PD 9(34.7%),RR was 28.6%,DCR was 67.9%,and no significant difference was found(P>0.05).The rate of Rash was similar (83.3%and 80.7%) in the two groups.Grade 3/4 toxicity observed in One-week schedule were acne-like rash, nausea,vomiting,neutropenia and reduction of leukemia.Although no 3/4 rash was observed in the two-week schedule,it was not siginificant difference of Grade 3/4 toxicity in the two groups(P>0.05).Conclusions:1.The similar efficacy was found in the two groups,both of the two groups have obtained obvious healing effect and safety in treating metastatic colorectal cancer.2.Cetuximab can reverse the drug resistance of the tumor cells and increase tumor sensitivity to chemo-therapeutic agents.3.Two-week schedule of cetuximab can reduce the times of patients being in the hospital,it is more convenient for patients to receive the treatment of two-week schedule of cetuximab,and the cost of medical care was cut down.