Phase III trial of recombinant interferon gamma in complete responders with small-cell lung cancer.

PURPOSE: We evaluated the effect of recombinant interferon gamma (rIFN-gamma) on survival and toxicity in small-cell lung cancer (SCLC) patients in complete remission (CR). PATIENTS AND METHODS: One hundred patients in CR following treatment with six cycles of combination chemotherapy, thoracic radiotherapy (TRT), and prophylactic cranial irradiation (PCI) were studied. All patients had been enrolled onto a cooperative group trial (North Central Cancer Treatment Group NCCTG 86-20-51). Patients received observation only or rIFN-gamma at a dose of 4 x 10(6) U subcutaneously per day for 6 months. RESULTS: Six patients (12%) did not comply with rIFN-gamma treatment. Substantial nonhematologic toxicities consisting of chills, myalgia, lethargy, and alteration of mood-personality were observed. No patient experienced life-threatening or fatal toxicity. The median times to progression for rIFN-gamma treatment or observation were 6.9 and 8.1 months (P = .54). The median survival times were 13.3 and 18.8 months, respectively (P = .43). Approximately 70% of all patients relapsed within 2 years. CONCLUSION: Time to progression and survival were inferior in patients treated with rIFN-gamma compared with randomized control subjects, although this difference was not statistically significant. These data indicate that rIFN-gamma treatment is not associated with a 33% improvement in survival (P = .04). Because of the high rate of relapse, SCLC patients in CR are an ideal group in which to evaluate novel and minimally toxic agents.