5.2.3. Targeted Therapy

Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific types of cancer cell with less harm to healthy cells. Targeted therapy may have fewer side effects than other types of cancer treatment. Targeted therapies are either small molecule drugs or monoclonal antibodies [23]. The most investigated monoclonal antibodies are bevacizumab, cetuximab, and panitumumab [46,47].

Bevacizumab is a recombinant humanized monoclonal IgG antibody that selectively binds to vascular endothelial growth factor A (VEGF-A), and it demonstrates anti-tumor activity by blocking vascular endothelial growth factor receptor 2 (VEGFR2). Furthermore, patients treated with cetuximab and panitumumab showed a survival benefit in metastatic CRC [46]. Cetuximab is an anti-epithelial grow factor (EGFR) monoclonal antibody of the IgG1 class targeted against the extracellular domain of the EGFR. By binding to the EGFR, cetuximab blocks intracellular EGFR signaling and modulates tumor cell growth by inhibiting proliferation, angiogenesis, and di fferentiation; stimulating apoptosis; and preventing metastasis. Panitumumab is a fully human, monoclonal antibody targeting the EGFR with high a ffinity. Its mechanism of inhibiting the EGFR signaling pathway is similar to that of cetuximab, as described above [46]. Nevertheless, to improve the e fficacy of the treatment, the therapy should be complemented with cytotoxic chemotherapy using 5-FU [48,49].
