Objective: To determine the efficacy of treatment using high-dose bolus interleukin 2 (IL-2) in patients with metastatic melanoma or renal cell cancer.
Design and setting: Consecutive series of all patients treated with high-dose IL-2 in the Surgery Branch of the National Cancer Institute from September 1985 through December 1992.
Patients: Two hundred eighty-three patients with metastatic melanoma or metastatic renal cell cancer who had failed standard treatment for their cancers.
Interventions: Patients received IL-2 at a dose of 720,000 IU/kg intravenously every 8 hours for a maximum of 15 doses per cycle. Two cycles constituted a treatment course, and patients with stable or responding disease received additional treatment courses. A total of 447 courses of treatment were administered.
Main outcome measures: Regression of measurable tumor, durability of response to treatment, and survival.
Results: Nine patients (7%) with metastatic melanoma achieved complete regression of all disease and 14 patients (10%) had partial regression. Ten patients (7%) with metastatic renal cell cancer experienced complete regression and 20 patients (13%) had partial regression. Of the 19 patients with complete regression, 15 have remained in complete remission from 7 to 91 months after treatment. Three treatment-related deaths (1.1%) occurred early in this series, but as experience with the administration of this IL-2 regimen increased, no treatment-related deaths occurred in 214 patients treated during the last 5 years of the study.
Conclusion: Biologic therapy with IL-2 can cause significant antitumor effects in patients with advanced metastatic melanoma or renal cell cancer. Because IL-2 does not have a direct effect on cancer cells but rather mediates its antitumor activity by altering host immune reactions, these data represent the best available evidence that immunologic therapy for cancer can be effective in selected patients.