Role of recombinant interferon alfa-2a maintenance in patients with limited-stage small-cell lung cancer responding to concurrent chemoradiation: A Southwest Oncology Group study

Purpose: This study was designed to determine if recombinant interferon alfa-2a (rIFNα-2a) could prolong remission duration and/or survival in patients with limited-stage small-cell lung cancer (SCLC) who achieved an objective response to chemoradiotherapy. A secondary end point was to assess the toxicity of chronic IFN administration. Patients and Methods: One hundred seventy-one of 215 eligible patients achieved an objective response and were eligible to receive rIFNα-2a (3 million units [MU]/m² subcutaneously three times per week escalated to 9 MU/m² as tolerated) or observation for 2 years. Results: One hundred thirty-two of 140 registered patients were eligible. Sixty-four patients were randomized to receive IFN and 68 to observation alone. The median time from randomization to progression was 9 months on the IFN arm and 10 months on the observation arm (P = .72). The overall median survival time was 16 months an the observation arm versus 13 months on the IFN arm (P = .77). Significant toxicities occurred in the rIFNα-2a arm. Grade 3 or higher toxicities included malaise, fatigue, and/or lethargy (30%), leukopenia (14%), neutropenia (13%), dyspnea (13%), nausea (11%), and respiratory infection (6%). Forty-three patients discontinued treatment due to intolerable side effects. Conclusion: rIFNα-2a in the dose and schedule used in this study failed to prolong response duration or survival in patients with limited-stage SCLC who had previously responded to an induction chemoradiotherapy program. Failure may have been partly related to poor tolerance and inability to complete therapy.