As described in the Focus on Angiogenesis section of this edition of TherapeuticAdvances, renal cell carcinoma is a niche cancer that accounts for 2-3% of all solid tumors in the major pharmaceutical markets. Approximately 30,000 patients are diagnosed with this disease each year in the US while RCC accounts for 12,000 deaths annually. The market is currently dominated by the cytokines and Indeed interleukin-2 (IL-2) is the only FDA-approved therapy used to treat renal cell carcinoma in the United States. Patients with RCC who fail the IL-2 therapy have a median survival of only six months and furthermore IL-2 produces a response in only 15-20% of patients. Treatment is also connected with serious side effects

The FDA's fast track program is designed to facilitate the development and expedite the review of new drugs or biologicals that are intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs of the patients. The treatments of RCC are therefore likely to gain fast-track status with the FDA.

Wyeth's Temsirolimus attaches to the immunophilin FKBP thus inhibiting mTOR kinase activity. This kinase regulates the protein translation machinery and is important to cell growth; consequently, CCI-779 leads to G1 phase cell cycle arrest effectively inhibiting cell proliferation. There is lot of evidence to suggest that mTOR plays a role in the etiology of RCC and this is reflected by data from a phase I study in which a patient with RCC exhibited a partial tumor response following dosing with CCI-779.