EGFR and colorectal carcinoma: For example, when cetuximab, a monoclonal antibody directed against EGFR, is combination with irinotecan, response rates in irinotecan-refractory metastatic CRC patients has been improved with the mean survival time increased from 6.9 months (monotherapy with cetuximab alone) to 8.6 months (combined therapy with cetuximab and irinotecan) [27].