Interleukin 2 maintains biologic stability and sterility over prolonged time

The FDA approved interleukin 2 (IL2) for clinical use in 1992 in a high-dose bolus intravenous infusion schedule. IL2 administered by continuous low- and intermediate-dose infusion can result in a variety of immunologic effects including the expansion of the Natural Killer (NK) cell pool and immune reconstitution in immune-deficient hosts. These immune modifications are essential for augmentation of both currently available and evolving immunotherapies. The manufacturer's data indicate stability of the IL2 for a period of 6 days. This time frame is not practical for prolonged infusional schemes necessitating frequent changes of drug depots. We tested the biologic stability and sterility of the commercially available recombinant IL2 preparation (aldesleukin; Proleukin, Chiron) under clinical conditions for up to 30 days. Our results confirm that IL2 retains its biologic activity and sterility under these conditions for prolonged periods. This information will simplify IL2 outpatient regimens, allowing for convenient intervals for drug depot renewal, leading to improved patient compliance and conserved health care expenditures.