Tamaskar I et al. (2008) Antitumor effects of sunitinib or sorafenib in patients with metastatic renal cell carcinoma who received prior antiangiogenic therapy. J Urol 179: 81–86

Patients with metastatic renal cell carcinoma (RCC) that progresses after initial treatment with an antiangiogenic agent receive sorafenib or sunitinib as second-line antiangiogenic therapy; however, evidence for the clinical benefit of such second-line treatment is lacking. Tamaskar and colleagues, therefore, conducted a retrospective study to evaluate the efficacy and safety of sorafenib or sunitinib in 30 patients with metastatic RCC refractory to prior antiangiogenic therapy.

The patients (24 male) received sorafenib (n = 14) or sunitinib (n = 16) after therapy with at least one of thalidomide, lenalidomide, volociximab, bevacizumab, AG13736, sunitinib or sorafenib (no patient was re-treated with the same agent). Treatment efficacy was assessed by Response Evaluation Criteria for Solid Tumors (RECIST), total tumor burden change, objective response status and time to progression.

Tumor shrinkage occurred in 10 of the 14 patients who received sorafenib and 13 of the 16 patients who received sunitinib. Furthermore, a RECIST partial response was observed in one and nine patients in the sorafenib and sunitinib groups, respectively. For the entire cohort, median time to progression was 10.4 months. The toxicity profiles of the two agents were similar to those reported in other settings.

Tumor shrinkage after second-line therapy suggests that similar antiangiogenic agents have slightly different antitumor mechanisms; however, because of the small sample size and because not all first-line therapies assessed are currently in common use for RCC, the authors recommend prospective clinical trials be done to confirm their findings.