The effectiveness of interferon-alpha subtypes alternation for metastasis from renal cell carcinoma

Interferon-alpha (IFN-alpha) has been used in systemic treatment for metastatic renal cell carcinoma (mRCC). IFN-alpha has at least 14 subtypes, each of which has different biological activity. There have been reports that mRCC resistant to an IFN-alpha treatment responded to another IFN-alpha subtype. This study was performed to evaluate the effectiveness of alternation of different IFN-alpha subtypes for mRCC that did not respond to initial IFN-alpha treatment. In our department and associated institutions, alternating therapy of IFN-alpha was provided for 15 initial IFN-alpha refractory mRCC cases from June 2005 to September 2008. Among the 15 patients, the effects of alternating IFN-alpha therapy were as follows: complete response (CR), 0 cases; partial response (PR), 1 case; stable disease (SD), 3 cases; progressive disease (PD), 11 cases. The response rate (CR+PR) was 7% and disease control rate (CR+PR+SD) was 27%. No severe side effects were observed in any of these cases. The PR case is still in PR 21 months after alternating IFN-alpha therapy. Among the three SD cases, one has continued SD for 14 months and the other for 12 months. Alternating IFN-alpha therapy for mRCC can be attempted even if other cytokines are not effective.