Background：cergutuzumab amunaleukin CEA-IL2v, RG7813, a novel monomeric CEA-targeted immunocytokine, that comprises a single IL-2 variant IL2v moiety with abolished CD25 binding, fused to the C-terminus of a high affinity, bivalent carcinoembryonic antigen CEA-specific antibody devoid of Fc-mediated effector functions. Its molecular design aims to i avoid preferential activation of regulatory T-cells vs. immune effector cells by removing CD25 binding; ii increase the therapeutic index of IL-2 therapy by a preferential retention at the tumor by having a lower dissociation rate from CEA-expressing cancer cells vs. IL-2R-expressing cells, b avoiding any FcγR-binding and Fc effector functions and c reduced binding to endothelial cells expressing CD25; and iii improve the pharmacokinetics, and thus convenience of administration, of IL-2.
