Everolimus, an orally adminstered rapamycin analog, has recently been approved by the FDA for treatment of renal cell carcinoma (RCC) refractory to inhibitors of vascular endothelial growth factor receptor signaling. Everolimus significantly increased progression-free survival (median PFS for the everolimus treated group was 4.0 months versus 1.9 months for the placebo group), although tumor regressions were observed only infrequently. While the target for everolimus, (the serine/threonine kinase mTOR) is well established, the mechanism by which this agent retards tumor growth is not well defined. Further, biomarkers that predict tumor sensitivity are still elusive. The mechanism of action, preclinical antitumor activity, and clinical activity of everolimus against RCC are reviewed. 
Everolimus is a medication used as an immunosuppressant to prevent rejection of organ transplants and in the treatment of renal cell cancer and other tumours. Much research has also been conducted on everolimus and other mTOR inhibitors as targeted therapy for use in a number of cancers.