Systemic therapy for metastatic non-clear-cell renal cell carcinoma: recent progress and future directions.

Insights into the biology of clear-cell renal cell carcinoma (CCRCC) have identified multiple pathways associated with the pathogenesis and progression of this cancer. This progress has led to the development of multiple agents targeting these pathways, including the tyrosine kinase inhibitors sorafenib, sunitinib, and pazopanib, the monoclonal antibody bevacizumab, and the mTOR inhibitors temsirolimus and everolimus. With the exception of temsirolimus, phase 3 trials tested these agents in patients with clear-cell histology; therefore, their efficacy in non-CCRCC is unclear. To date, there is no established effective therapy for patients with advanced non-CCRCC. This article focuses on treatment options for metastatic non-CCRCC.