IMB071703

IMB071703 is a recombinant bifunctional antibody fusion protein designed as an immune activator for the tumor microenvironment. It selectively targets and binds to both 4-1BB (CD137) expressed on T cells and natural killer (NK) cells, and CD40 expressed on antigen-presenting cells (APCs), including dendritic cells, B cells, T cells, and NKs. The drug consists of a monovalent Fab fragment binding to 4-1BB fused with a trimeric split CD40 ligand (CD40L), which enables simultaneous activation of the CD137 signaling pathway in T/NK cells and the CD40 signaling pathway in APCs. This dual targeting promotes dendritic cell maturation, primes tumor-reactive T-cell responses, enhances antitumor immunity by increasing specific T-cell proliferation/activation, and inhibits tumor development. IMB071703 is engineered with an FcγR binding defect to reduce side effects while retaining high antitumor activity. It is being developed primarily for the treatment of recurrent or metastatic advanced solid tumors[1][2][3][4][7].

Other names

anti-4-1BB Fab/TriCD40L fusion protein XFab-α4-1BB/CD40L