Stratification by risk factors predicts survival on the active treatment arm in a randomized phase II study of interferon-gamma plus/minus interferon-alpha in advanced renal cell carcinoma (E6890)

Abstract: Introduction: Standard therapy for recurrent or metastatic renal carcinoma includes the biologic response modifiers interferon-alpha (IFN-α) and interleukin-2 (IL-2). The response rate for both agents is modest and toxicity is significant. New agents are needed. Interferon-gamma (IFN-γ) is a type II interferon that demonstrated promising activity in renal carcinoma in early clinical trials. In vitro data suggested synergistic activity when IFN-γ was combined with IFN-α. The Eastern Cooperative Oncology Group conducted a randomized phase II trial to confirm the efficacy of IFN-γ as a single agent and to evaluate the efficacy and toxicity of IFN-γ in combination with IFN-α 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-γ 0.1 mg/m² weekly (arm A) or IFN-γ 0.3 mg/m² iv daily × 5 every 3 wk plus IFN-α 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-γ 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-γ at this dose and schedule failed to demonstrate activity in metastatic/recurrent renal carcinoma. The combination of IFN-γ and IFN-α demonstrated a response rate similar to IFN-α alone. There was no evidence of synergy between IFN-γ and IFN-α.