Current evidence and controversies in the incorporation of biologics for metastatic colorectal cancer.

With the advent of new drugs and therapeutic combinations for metastatic colorectal cancer, the prognosis for this often incurable disease is improving. In addition to traditional cytotoxic chemotherapeutics, targeted biologic therapies, such as cetuximab, panitumumab, bevacizumab, aflibercept and regorafenib, are significantly impacting the treatment of this disease. Recent investigations have focused on determination of the optimal usage of these biologic therapies, but many controversies still exist. Specifically, emerging data regarding appropriate combinations of cytotoxics and biologics in each metastatic colorectal cancer treatment setting, the superiority of particular biologics as single agents or in combination with chemotherapy, dual biologic therapy, use of biologics for conversion or maintenance therapies, and predictive biomarker discovery for biologics are addressed in this article, as these issues are rapidly changing our approach to the treatment of the patient with metastatic colorectal cancer.