Researchers involved in a Phase II multicenter clinical trial have confirmed a response rate of 34% in patients with cytokine refractory metastatic renal cell carcinoma (RCC) treated with Sutent (SU 11248, sunitinib malate). The details of this study appeared in the June 7, 2006, issue of the Journal of the American Medical Association.

In January 2006 the U.S. Food and Drug Administration (FDA) approved the use of Sutent for the treatment of gastrointestinal stromal tumors (GIST) that had progressed after Gleevec® (imatinib mesylate) and for advanced RCC. A patient information sheet has been published on the FDA Web site (see related news).

Sutent is an oral kinase inhibitor of fms-like tyrosine kinase 3 (Flt3), Kit, VEGF, and PDGF receptors that is currently in clinical trials for treatment of a variety of malignancies. It produces anti-cancer effects through targeted mechanisms that include anti-angiogenesis, as well as direct killing of the cancer cell. In phase I-II studies, Sutent demonstrated antitumor and anti-angiogenic activity in RCC, as well as other solid tumors.

In the phase II study leading to FDA approval 63 patients with refractory RCC were treated with Sutent. The partial response (PR) rate was 40% with 27% having disease stabilization for 3 or more weeks. The median time to disease progression was 9 months. In the current study Sutent was administered to 106 patients with cytokine-refractory metastatic RCC. The PR rate was 34% and an additional 29% had disease stabilization. The median progression-free survival was 8.3 months. The most common complications were fatigue, diarrhea, neutropenia, anemia and elevated lipase.

Pooled analyses of the two phase II studies (n=168) showed an overall response rate of 42% and a progression-free survival of 8.3 months.

Comments:  These authors reported that a phase III randomized trial comparing Sutent to interferon alfa for first-line therapy of metastatic RCC has completed accrual of over 700 patients. This will define the role of Sutent in first-line therapy.

Reference: Motzer RJ, Rini BI, Bukowski RM, et al. Sunitinib in patients with metastatic renal cell carcinoma. Journal of the American Medical Association. 2006;295:2516-2524.

Related News

Sutent® Approved by FDA for Treatment of Renal Cell Carcinoma and Gastrointestinal Stromal Tumor  (4/4/2006)

Sunitinib Malate (SU11248) Promising for Metastatic Renal Cell Carcinoma  (11/17/2005)

SU11248 is Effective in Gastrointestinal Stromal Tumors (2/23/2005)