Bevacizumab is a monoclonal antibody to vascular endothelial growth factor (VEGF) that inhibits angiogenesis and extends survival in non-squamous non-small cell lung cancer (NSCLC) patients when given with carboplatin and paclitaxel. TRC105 is an antibody to endoglin, an essential angiogenic target expressed on proliferating endothelial cells that is distinct from the VEGFR and overexpressed in response to VEGF inhibition. TRC105 inhibits angiogenesis, tumor growth and metastases in preclinical models and complements the activity of antibodies and small molecules that target the VEGFR. In a phase 1b study, the combination of TRC105 and bevacizumab produced radiographic reductions in tumor volume in bevacizumab-refractory patients, and was well tolerated. TRC105 was also well tolerated with chemotherapy in a trial with capecitabine in breast cancer patients. The use of TRC105 with bevacizumab and paclitaxel/carboplatin may result in more effective angiogenesis inhibition and improved clinical efficacy over that seen with bevacizumab and paclitaxel/carboplatin alone.
