title: Cetuximab in the treatment of patients with colorectal cancer.
abstract: BACKGROUND
  Cetuximab is a chimeric mAb with avidity for the EGFR higher than that of the natural ligands of the receptor. Preclinical studies showed that cetuximab demonstrated synergy with topoisomerase I inhibitors in the treatment of human colorectal cancer (CRC) cell lines in vivo. Subsequent clinical trials have shown that cetuximab can reverse resistance to topoisomerase I inhibitors in addition to having modest monotherapy activity. These studies led to accelerated provisional FDA approval of the drug for the treatment of patients with irinotecan-refractory metastatic CRC. Its clinical utility has been improved with the discovery of negative predictive biomarkers; these have shown that there is a lack of cetuximab benefit for patients whose tumors generally harbor a KRAS mutation, thus sparing these patients the toxicity of the agent which would not be of treatment benefit.
  
  
  METHODS
  This review covers the last decade of clinical trials that have determined the toxicity and efficacy of cetuximab when given to patients with CRC, as well as some of the molecular subgroups tumors from patients with CRC who appear to not derive benefit from this mAb.
  
  
  CONCLUSIONS
  Cetuximab has modest single-agent efficacy in the treatment of patients with metastatic CRC whose tumors do not harbor a KRAS mutation. In combination with irinotecan, it is associated with an overall survival (OS) and progression-free survival (PFS) advantage in first-line therapy in patients with KRAS non mutant metastatic CRC; it can be combined with irinotecan to overcome resistance in patients with KRAS non mutant CRC who have previously progressed on prior irinotecan chemotherapy. Future studies of putative biomarkers are likely to give additional information to clearly define which patients with metastatic CRC receive therapeutic benefit from cetuximab and other monoclonal anti-EGFR therapies.
authors.affiliation: Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 4095, USA. cgarrett@mdanderson.org
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Garrett
authors.forename: Cathy
authors.initials: C
authors.lastname: Eng
mesh_terms: D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D061067:Antibodies, Monoclonal, Humanized; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002166:Camptothecin / Q000008:administration & dosage / Q000031:analogs & derivatives; D000068818:Cetuximab; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D019317:Evidence-Based Medicine; D006801:Humans; D000077146:Irinotecan; D009154:Mutation; D057285:Precision Medicine; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome; D018631:ras Proteins / Q000235:genetics
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D014408:Biomarkers, Tumor; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D000077146:Irinotecan; C512478:EGFR protein, human; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins; D000068818:Cetuximab; D002166:Camptothecin