Sunitinib in advanced metastatic non-clear cell renal cell carcinoma: a single institution retrospective study

Sunitinib is an orally active multi-targeted tyrosine kinase inhibitor that exerts its antitumor effects primarily through the selective inhibition of VEGF. Novel targeted therapies such as sunitinib have transformed the treatment of advanced metastatic renal cell carcinomas, particularly those with clear cell histology. Here, our experience in patients with non-clear cell kidney cancer treated as part of the sunitinib Expanded Access Program is reported.

This was a retrospective assessment of 21 patients with non-clear cell renal cell carcinoma who were treated with oral sunitinib 50 mg/day in repeated 6 weekly cycles (4 weeks on and 2 weeks off). Disease assessment and physical examination were recorded at baseline and tumor assessments were performed every 3 months, according to Response Evaluation Criteria In Solid Tumors. The primary outcome measure was progression-free survival.

Patients received an average of 6.38 cycles of sunitinib; one patient was classified as a complete responder and two as partial responders. The overall response rate was 14.3% and clinical benefit was attained by 52.4%. The median progression-free survival was 4.1 months while median overall survival was 14.6 months. In general, sunitinib was well tolerated and only three patients experienced a grade 3 toxicity, which resolved with dosage reduction.

As expected, sunitinib exerted lower antitumor activity in patients with non-clear cell renal cell carcinoma than was achieved in the general population with metastatic kidney cancer. However, responses (one complete and two partial) were documented and clinical benefit was observed in more than half of all patients.