Definition

A fusion protein composed of MDK-1472, a structurally unrelated engineered mimetic peptide of endogenous human cytokine interleukin-7 (hIL-7), fused to an immunoglobulin G2 (IgG2) Fc-domain, with hematopoietic and immunopotentiating activities. Upon administration, Fc fusion IL-7 mimetic MDK-703 mimics endogenous cytokine IL-7 and binds to the IL-7 receptor (IL7R) on immune cells. The binding of IL-7 to IL7R activates IL7/IL7R-mediated signaling, which leads to the expansion of various subsets of T-lymphocytes, including memory T cells, especially CD8 and CD4 stem cell memory T cells (Tscm), central memory T cells (Tcm) and effector memory T cells (Tem). This may improve immune recovery and activation and may enhance T-cell-mediated anti-tumor immune responses. Fusion to the Fc domain enhances the half-life of the IL-7 mimetic. As MDK-703 is unrelated in sequence to the natural cytokine, it is unlikely to generate anti-drug antibodies (ADAs) that neutralize the endogenous IL-7 cytokine. IL-7 is a cytokine critical for the development, maintenance and survival of T-cell subpopulations.