Treatment of renal cell carcinoma with daily low-dose alpha-interferon

While alpha-interferon has yielded objective tumor regressions in patients with metastatic renal cell carcinoma, such therapy is usually associated with significant toxicity often requiring dose modifications and/or cessation of therapy. In the absence of a clearly defined optimal dose and schedule for alpha-interferon, it appears reasonable to seek a means for improving the therapeutic index for this drug. We report the results of a pilot trial in which patients with renal cell carcinoma were treated with a daily low dose of alpha-interferon. Seventeen patients were treated with alpha-interferon (Roferon-A) at a dose of 1 million U subcutaneously daily. There were no exclusionary criteria for this pilot trial. Sixteen patients were evaluable for response and toxicity. Therapy was well-tolerated with no interruption of therapy for toxicity. No patient experienced the "flu-like" syndrome that is associated with higher doses, and there was no episode of granulocytopenia or thrombocytopenia. Four patients achieved a partial response (PR), with one PR persisting at 20 months. Sites of response included lung (two patients), liver (one patient), and bone (one patient). These results indicate that this regimen is well tolerated and can be expected to render objective responses. Formal Phase II trials are warranted in order to define the response rate for this regimen.