Biomarkers in the development of anti-angiogenic therapies for ovarian cancer.

The treatment of ovarian cancer remains challenging as the majority of patients will relapse and die from their disease despite successful first-line treatment. New treatment strategies are needed and recently there has been an explosion of new agents being tested in ovarian cancer. Most of these are directed against molecularly defined pathways and a significant proportion target angiogenesis, an important process in the growth of ovarian cancer. We review the role of angiogenesis in the pathophysiology of ovarian cancer and discuss the development of the most promising anti-angiogenic drugs in this disease, including the first large phase III trials with bevacizumab which have demonstrated a disease-modifying role in ovarian cancer. Other studies with this drug and other inhibitors of the angiogenic pathways are underway in the first-line and recurrent disease settings. The financial cost of these agents, increased toxicity and requirement for prolonged therapy necessitates the urgent need to identify and validate biomarkers to guide the use of these drugs in the future. There are over 200 candidate biomarkers being studied in ovarian cancer. However, currently there are no validated biomarkers to predict response or progression of disease. In this review we present a selection of biomarkers that are under investigation and discuss their benefits and limitations.