What to do with targeted IL-2

A common strategy in immunotherapy of cancer is the induction of an increased immunogenicity of syngeneic malignancies. A novel approach to achieve this goal is the targeting of cytokines into the tumor microenvironment with antibody-cytokine fusion proteins, called immunocytokines. This report summarizes therapeutic efficacy and immune mechanisms involved in targeting IL-2 to syngeneic tumors and describes their extended use as a synergistic treatment modality for cancer vaccines and antiangiogenesis. Treatment of established melanoma and colon carcinoma metastases with IL-2 immunocytokines resulted in eradication of disease, followed by a vaccination effect protecting mice from lethal challenges with wild-type tumor cells. In a syngeneic neuroblastoma model, targeted IL-2 elicited effective antitumor responses mediated by NK cells in the absence of a T-cell memory. Interestingly, targeted IL-2 was effective in amplification of memory immune responses previously induced by cancer vaccines. Furthermore, a synergistic effect achieved by combining targeted IL-2- immunotherapy with an antiangiogenic inhibitor of integrin α(v)β₃ extends the potential of this immunotherapeutic strategy in combination with antiangiogenesis as demonstrated in three syngeneic tumor models. Based on these findings, targeted IL-2 may provide an effective tool for the adjuvant treatment of cancer either applied as a single strategy or in combination with cancer vaccines and antiangiogenic strategies. (C) 2000 Prous Science.