Combination Therapy of Interleukin-2 and Sorafenib Improves Survival Benefits and Prevents Spontaneous Pulmonary Metastasis in Murine Renal Cell Carcinoma Models

Objective: The objective of this study was to evaluate the benefits of combination therapy consisting of recombinant human interleukin-2 and sorafenib for survival efficacy and the suppression of metastasis in murine renal cell carcinoma models. Methods: Lung-metastasized renal cell carcinoma mice were treated with various combinations of recombinant human interleukin-2 and sorafenib. Tumor growth was observed using a bioluminescence imaging system. Next, the nephrectomized renal cell carcinoma mice were administered various combinations of recombinant human interleukin-2 and sorafenib, followed by a lung resection in order to examine lung metastasis by bioluminescence imaging. Results: The increased life-span ratio in mice receiving combination therapy was 1.45, whereas that in mice treated with sorafenib or recombinant human interleukin-2 alone therapy was 1.28 and 1.07, respectively. The concomitant administration of recombinant human interleukin-2 and sorafenib had a metastasis-inhibitory effect, whereas the other treatments failed. Conclusions: These findings indicate that combination therapy of recombinant human interleukin-2 and sorafenib may offer better outcomes than either monotherapy with recombinant human interleukin-2 or sorafenib with respect to survival benefits and the prevention of pulmonary metastasis in renal cell carcinoma patients.