Efficacy of Second-Line Bevacizumab-Containing Chemotherapy for Patients with Metastatic Colorectal Cancer following First-Line Treatment with an Anti-Epidermal Growth Factor Receptor Antibody

<b><i>Objective:</i></b> Anti-epidermal growth factor receptor (EGFR) antibodies and bevacizumab are commonly used, sequentially, as palliative chemotherapies for patients with metastatic colorectal cancer. However, little is known about the efficacy of second-line treatments containing bevacizumab after first-line treatment with an anti-EGFR antibody. <b><i>Methods:</i></b> We retrospectively reviewed 128 patients who received second-line bevacizumab-containing chemotherapy and evaluated the effect of prior use of anti-EGFR antibody on the efficacy of the second-line treatment. <b><i>Results:</i></b> As first-line treatments, 35 of these patients received only cytotoxic chemotherapy (cohort A), 58 received bevacizumab-containing chemotherapy (cohort B), and 35 received anti-EGFR-containing chemotherapy (cohort C). The median progression-free survival (PFS) with the second-line bevacizumab-containing therapy was 8.3 months in cohort C, 6.9 months in cohort A (hazard ratio [HR], 1.43; 95% confidence interval [CI], 0.83-2.51), and 5.6 months in cohort B (HR, 1.95; 95% CI, 1.18-3.22). Multivariate analysis showed that PFS in cohort C was the same as that in cohort A, but better than that in cohort B. The overall response rate in cohort C (25.7%) was also similar to that in cohort A (20.0%), but better than that in cohort B (10.3%). <b><i>Conclusions:</i></b> Prior use of anti-EGFR antibody did not adversely affect the efficacy of subsequent bevacizumab-containing chemotherapy.