Introduction: Standard therapy for recurrent or metastatic renal carcinoma includes the biologic response modifiers interferon-alpha (IFN-alpha) and interleukin-2 (IL-2). The response rate for both agents is modest and toxicity is significant. New agents are needed. Interferon-gamma (IFN-gamma) is a type II interferon that demonstrated promising activity in renal carcinoma in early clinical trials. In vitro data suggested synergistic activity when IFN-gamma was combined with IFN-alpha. The Eastern Cooperative Oncology Group conducted a randomized phase II trial to confirm the efficacy of IFN-gamma as a single agent and to evaluate the efficacy and toxicity of IFN-gamma in combination with IFN-alpha in the treatment of patients with metastatic or recurrent renal carcinomas.
Materials and methods: Ninety-five patients with recurrent or metastatic renal carcinoma were entered on trial. Patients were stratified based on risk assessment using the Elson method. Patients were randomly assigned to receive either IFN-gamma 0.1 mg/m2 weekly (arm A) or IFN-gamma 0.3 mg/m2 iv daily x 5 every 3 wk plus IFN-alpha 10 MU/m2 daily (arm B). Treatment efficacy was evaluated every 6 weeks.
Results: Toxicity in the arm A was minimal. Significant toxicity was noted in arm B, with four cases of grade 4 neurotoxicity. No responses were seen with IFN-gamma alone. Five responses (two CR and three PR) were noted in the combination arm for an overall response rate of 10%. Four of five responders were classified as "good risk." Median survival for arm A was 7.0 mo vs 10.4 mo for arm B. Risk stratification was significant in arm B.
Conclusion: IFN-gamma at this dose and schedule failed to demonstrate activity in metastatic/recurrent renal carcinoma. The combination of IFN-gamma and IFN-alpha demonstrated a response rate similar to IFN-alpha alone. There was no evidence of synergy between IFN-gamma and IFN-alpha.