Definition

A long-acting immunoglobulin (Ig) fusion protein composed of a recombinant form of the endogenous human protein interleukin-7 (rhIL-7) and fused to a hybrid Fc (hyFc) region of a human antibody, with hematopoietic and immunopotentiating activities. Upon administration of efineptakin alfa, IL-7 stimulates the proliferation, differentiation, trafficking and survival of a variety of T-cell subsets, including naive, central memory (CM), effector memory (EM), terminally differentiated effector memory (TEMRA) and natural killer (NK) T cells, and enhances T-cell-mediated anti-tumor immune responses. Compared to rhIL-7 alone, fusion to the hyFc region enhances the half-life of IL-7. The hyFc region is composed of the hinge and N-terminal portion of heavy chain constant (CH) region 2 (hinge-CH2) of human IgD, which is fused to the C-terminal region of CH2 and the entire CH3 region of human IgG4.