Question : Among patients with RAS wild-type, left-sided metastatic colorectal cancer, does adding panitumumab (an anti–epidermal growth factor receptor monoclonal antibody) vs bevacizumab (an anti–vascular endothelial growth factor monoclonal antibody) to standard first-line chemotherapy improve overall survival?
Findings : In this randomized clinical trial that included 802 patients with colorectal cancer (604 with left-sided tumors), adding panitumumab, compared with bevacizumab, to first-line chemotherapy significantly improved overall survival among patients with left-sided tumors (median overall survival, 37.9 months vs 34.3 months; hazard ratio for death, 0.82), and in the overall population (median overall survival, 36.2 months vs 31.3 months; hazard ratio for death, 0.84).
Meaning : Among patients with RAS wild-type metastatic colorectal cancer, adding panitumumab, compared with bevacizumab, to standard first-line chemotherapy significantly improved overall survival in patients with left-sided tumors and in the overall population.