Critical appraisal of pazopanib as treatment for patients with advanced metastatic renal cell carcinoma

Abstract

The management of renal cell carcinoma (RCC) has undergone significant changes during the past 10 years, with the treatment of metastatic RCC undergoing the most radical changes. These developments reflect an enhanced understanding of this tumor's underlying biology, which was then translated into the development of a new treatment paradigm. Current therapeutic approaches for the management of patients with metastatic RCC utilize knowledge of histology, molecular abnormalities, clinical prognostic factors, the natural history of this malignancy, and the treatment efficacy and toxicity of available agents. The treatment options available for patients with metastatic RCC have changed dramatically over the past 6 years. Interferon-α and interleukin-2 were the previous mainstays of therapy, but since December 2005, six new agents have been approved in the US for the treatment of advanced RCC. Three are multi-targeted tyrosine kinase inhibitors (TKI) including sunitinib, sorafenib, and pazopanib, two target the mammalian target of rapamycin (temsirolimus and everolimus), and one is a humanized monoclonal antibody (bevacizumab in combination with interferon-α). The current review focuses on the newest TKI available to treat patients with metastatic RCC, pazopanib. The development of this agent both preclinically and clinically is reviewed. The efficacy and safety data from the pivotal clinical trials are discussed, and the potential role of pazopanib in the treatment of patients with metastatic RCC in comparison to other treatment alternatives is critically appraised. This agent has a favorable overall risk benefit, and the available data demonstrate efficacy in patients with metastatic RCC who are either treatment-naïve or cytokine refractory. It therefore represents another alternative for treatment of metastatic RCC patients.

Keywords: metastatic; pazopanib; renal cell carcinoma.

Figure 1

Flow diagram illustrating decision factors and therapeutic alternatives in patients with locally advanced and metastatic renal cell carcinoma.

Figure 2

Molecular structure and chemical name of pazopanib.

Figure 3

Comparison of progression free survival data from recent phase II and II randomized clinical trials utilizing a variety of targeted agents in treatment-naïve or cytokine refractory patients with metastatic renal cell carcinoma. Notes: ^apatient number; ^bhazard ratio (95% confidence interval).