Complete response of metastatic renal cell carcinoma to low-dose interferon-gamma treatment.

The course of metastatic renal cell carcinoma may be positively influenced by immunotherapeutic agents. We report a case of renal cell carcinoma showing a complete response to once-weekly low-dose s. c. interferon-gamma (IFN gamma) treatment in multiple metastatic sites (lung, chest wall, abdomen, vertebral body), but concomitantly developing a solitary brain metastasis. High initial interleukin-6 (IL-6) levels returned to normal during IFN treatment suggesting that IFN gamma may have interrupted an autocrine IL-6/IL-6-receptor loop of the tumor cells. The duration of complete remission in the extracerebral sites is now 46+ months. IFN gamma may be less active beyond the blood/brain barrier.