Intermittent Low-Dose IFN Gamma Treatment for Metastatic Renal Cell Carcinoma: Analysis of Factors Predicting Clinical Response and Long-Term Survival

Abstract

<i>Background</i>: Objective tumor remissions are induced by a variety of immunomodulating agents in a minority of patients suffering from metastasizing renal cell carcinoma. The results of different clinical studies, however, varied greatly for each of these treatment modalities. In order to elucidate potential causes for this variability and to further study the long-term results of intermittent low-dose IFN gamma therapy in patients with advanced renal cell cancer (RCC) we retrospectively analyzed factors predicting clinical response and long-term survival of 121 patients. <i>Material and Methods</i>: We retrospectively analyzed the clinical results of 5 phase II studies treating 121 patients with intermittent low-dose IFN gamma as first-line treatment for metastatic RCC. <i>Results</i>: 15% complete and partial responses were observed in these patients. Intermittent low-dose IFN gamma was well-tolerated and treatment was performed largely on an outpatient basis. Clinical presentation of the disease was the only factor predicting both clinical response and survival. Whereas a 23% response rate was observed in patients suffering from limited disease RCC (disease limited to one site including adjacent lymph nodes), the response rate in patients with widespread disease was less than 5%. When the results of the 5 studies were compared, a statistically highly significant correlation between the proportion of treated patients with limited disease and response rate was observed. <i>Conclusion</i>: We conclude that intermittent low-dose IFN gamma is effective and induced long-term complete remissions in a proportion of patients with limited disease metastatic RCC.