Challenging chemoresistant metastatic colorectal cancer: therapeutic strategies from the clinic and from the laboratory.

As survival has improved for patients with metastatic colorectal cancer (mCRC), there is an increasing need for effective and well-tolerated third-line and subsequent-lines of treatment. Despite recent advances with the development of new-targeted therapies in this setting, there remains an unmet need to exploit oncogenic drivers of colorectal cancer and overcome acquired resistance. Potential treatment strategies include revisiting old targets such as human epidermal growth factor receptor 2, RAS, and BRAF and investigating new targets such as c-MET, the PI3 kinase, and Wnt pathways, and also the use of immune-checkpoint inhibitors. Here, we review recent phase III trials exploring approved agents, early trials investigating new drugs for chemorefractory mCRC, and the potential of capturing tumour dynamics during its evolution by liquid biopsy analysis.