Novel immunotherapeutic strategies in development for renal cell carcinoma

The purpose of this report is to review immunotherapies under investigation for patients with renal cell carcinoma (RCC), the most common form of kidney cancer, for which the incidence and mortality rate continue to increase.

To summarize and evaluate current data on immunotherapies for RCC and discuss issues to be resolved before integration into the RCC treatment paradigm.

A search of Medline, clinicaltrials.gov, and congress abstracts/treatment guidelines was performed in May 2012 using the following terms (and variations): metastatic renal cell carcinoma, practice guidelines, response/resistance to current treatments, immunotherapy, novel immunotherapeutic strategies, T-cell modulation, immune priming, innate immunity, and combination therapy.

Prior to the advent of novel agents targeting the vascular endothelial growth factor and mechanistic target of rapamycin pathways, interleukin-2 (IL-2) and interferon-α were the mainstays of RCC treatment. IL-2 remains one of the only treatments capable of curing advanced RCC, albeit in few patients. Despite recent advances, unmet need still exists for patients in the adjuvant setting, those with poor prognostic factors, and those who have progressed on prior targeted therapies. Improved understanding of host-tumor immune interactions has led to development of novel immunotherapeutic agents, including antibodies against immune checkpoint proteins (eg, programmed death-1 and cytotoxic T-lymphocyte antigen-4), and various vaccines. Because many of these compounds are in development, clinical experience with them is limited, although some have demonstrated activity in preliminary studies.

It is not yet clear where these new immunotherapies will fit into RCC treatment paradigms, but they may provide new options for patients whose current choices are limited. Furthermore, predictive biomarkers are needed to identify patients who will derive the greatest benefit from immunotherapy.