Successful Outcomes Using Combination Therapy of Interleukin-2 and Interferon-α for Renal Cell Carcinoma Patients with Lung Metastasis

In our previous study, a combination therapy of interleukin-2 and interferon-alpha was found to be more effective than monotherapy, especially for lung metastasis. In order to determine the genetic markers of those who positively responded, a multi-institutional open study was conducted on the patients with lung metastasis. In this paper, the clinical response to our combination therapy is reported. Untreated patients with lung metastasis were enrolled in this study. Patients received interleukin-2 (0.7 x 10(6) U/day) and interferon-alpha (6 x 10(6) IU/day): interleukin-2, 5 days a week and interferon-alpha, 3 days a week for the first 8 weeks, and then both interleukin-2 and interferon-alpha, 2 or 3 days a week for 16 additional weeks. Forty-two patients were able to be evaluated for response. The overall positive response rate was 35.7% (15 of 42) including 2 patients with complete response. Progression-free patients were observed more frequently in patients with lung metastasis only (80.6%) than those with lung plus other organ metastasis (54.5%). Tumor shrinkage was observed in 81.0% (34 of 42) of patients. Progression-free survival rate at 200 days was 63.6%. Toxicities observed were primarily flu-like symptoms due to the cytokines and were typical of those observed with each single agent. Combination therapy of interleukin-2 and interferon-alpha was confirmed to be effective for renal cell carcinoma patients with lung metastasis. Identification of genetic markers is now ongoing with the tissue samples from this trial.