Antiangiogenic therapies in epithelial ovarian cancer

Angiogenesis is a critical component of tumor development and proliferation, and increased angiogenesis has been associated with a worse clinical outcome in a number of solid tumors, including ovarian cancer. Therefore, agents that target the angiogenic process are of considerable interest in the treatment of ovarian cancer.

Studies evaluating the efficacy of antiangiogenic agents in ovarian cancer are reported. Antiangiogenic agents examined include vascular endothelial growth factor (VEGF) pathway inhibitors, including monoclonal antibodies, tyrosine kinase inhibitors (TKIs), and a soluble receptor decoy, as well as inhibitors of other angiogenic factors and vascular disrupting agents.

The VEGF inhibitor bevacizumab has been shown to have efficacy in ovarian cancer in phase II trials and a progression-free survival advantage in one phase III trial. TKIs block the VEGF receptors and secondary angiogenic pathways and have shown activity in phase I and II trials. Alternative angiogenesis inhibitors include EphA2 inhibitors and a selective angiopoietin 1/2-neutralizing peptibody. Another strategy is to destroy the existing tumor vasculature, and a number of vascular disrupting agents are being studied in preclinical and phase I trials. Antiangiogenic agents have a unique side effect profile, likely due to inhibition of normal physiologic angiogenesis.

Phase II and early phase III trials have demonstrated that antiangiogenic therapies have significant activity in ovarian cancer. The results of phase III trials in the front-line and recurrent settings will determine the extent of clinical benefit of antiangiogenic therapies in combination with chemotherapy. Antiangiogenic agents have a distinct side effect profile, and further studies are necessary to evaluate how to minimize the incidence of these events and to identify women most likely to benefit from these therapies.