Predictive biomarkers for bevacizumab: Are we there yet?

Therapy targeting VEGF has become the standard of care in several solid malignancies. Early investigations attempting to identify predictive markers for the efficacy of therapy failed to identify any predictive markers that could help oncologists decide who should - and, more importantly, who should not - receive VEGF-targeted therapies. However, interest has been renewed in predictive biomarkers for VEGF-targeted therapies, especially in light of the fact that the U.S. Food and Drug Administration withdrew approval for use of bevacizumab, an antibody to VEGF, in patients with metastatic breast cancer. In a recent publication in the Journal of Clinical Oncology, investigators identified circulating VEGF and tumor neuropilin-1 expression as potential predictive biomarkers for bevacizumab. From this perspective, we provide a critical evaluation of the use of these markers and the need for validation in prospective clinical trials.