Clinical outcome of combined immunotherapy with low-dose interleukin-2 and interferon-[alpha] for Japanese patients with metastatic renal cell carcinoma who had undergone radical nephrectomy: a preliminary report

Background The objective of this study was to evaluate the clinical outcome of combined immunotherapy with interferon-alpha (IFN-alpha) and low-dose interleukin-2 (IL-2) for Japanese patients with metastatic renal cell carcinoma (RCC) who had undergone radical nephrectomy. Methods This study included 13 patients who were diagnosed as having metastatic RCC following radical nephrectomy. These patients received a subcutaneous injection of IFN-alpha (6 times 106IU per day) three times per week and an intravenous injection of IL-2 (1.4 times 106IU per day) twice per week. Tumor response was evaluated every 16 weeks, and as a rule, this weekly regimen was repeated 50 times in patients with evidence of objective response or stable disease. Results One of the 13 patients dropped out because of severe toxicity; hence, 12 patients were evaluable, with a median follow-up period of 18 months after the start of this combined therapy. Six patients (50.0%) achieved objective responses, with 1 complete response (CR), while only 2 (16.7%) demonstrated progressive disease. The median duration of response in the 6 responders was 13.5 months. Toxicity associated with this combined immunotherapy was limited to WHO grade 1 or 2 in these 12 patients. All patients were alive at last follow-up, and 2 remain disease-free after 1 additional patient showed a CR following surgical resection of the remaining metastatic disease. Conclusion Our preliminary experience suggests that long-term, repeated treatment with IFN-alpha and low-dose IL-2 is feasible in Japanese patients with metastatic RCC who have undergone radical nephrectomy. Although it will be necessary to accumulate data from a larger number of patients with a longer follow-up period, the combined immunotherapy tested in this study may become the preferred therapy for Japanese patients with metastatic RCC. [PUBLICATION ABSTRACT]