Role of Recombinant Interferon-Gamma Maintenance in Responding Patients with Small Cell Lung Cancer. A Randomised Phase III Study of the EORTC Lung Cancer Cooperative Group.

This study was undertaken to determine if recombinant interferon-gamma (rIFN-γ) given every other day as maintenance therapy could prolong the survival of patients with small cell lung cancer (SCLC) who achieved a complete or nearly-complete response to induction therapy. A secondary endpoint was to assess the toxicity of alternate day doses of this treatment. One hundred and seventy seven patients in complete or nearly-complete response following chemotherapy with or without thoracic radiotherapy were studied. Patients were randomised to receive either rIFN-γ 4 million units (0.2 mg) subcutaneously every other day for 4 months or observation. One hundred and twenty of the 127 registered patients were eligible; 59 patients received IFN and 61 patients without maintenance therapy were followed. Alternate day IFN was reasonably well tolerated by the majority of patients, but in 12% substantial non-haematological toxicity (including flu-like syndrome) occurred. One of 3 patients with pneumonitis died after having received 3.6 mg IFN. The median survival time from the date of randomisation was 8.9 months for the IFN arm and 9.9 months for the observation arm. rIFN-γ at the dose and schedule used in this study failed to prolong response duration and survival in SCLC patients in complete or nearly-complete response. The toxicity seen with every other day doses of IFN was less than that reported with daily dosing. The hypothesis that this agent may increase the deleterious effects of radiation on normal lung tissue was supported by the development of pneumonitis in 3 cases of whom 1 had a fatal outcome. The results do not warrant further studies with rIFN-γ on maintaining response in SCLC.