NKB61

NKB61 is a first-in-class bispecific antibody designed for the treatment of autoimmune diseases, such as rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). Developed by PersonGen BioTherapeutics, the molecule combines a programmed cell death protein 1 (PD-1) agonist arm (derived from the PD-1-1F10 VHH) with a CD16A (FcγRIIIa) targeting arm (derived from CD16A VHHs), along with an Fc region that engages Fcγ receptors on innate immune cells. NKB61 selectively depletes pathogenic PD-1+ T cells (including CD4+PD-1+, CD8+PD-1+, T follicular helper [Tfh], and T peripheral helper [Tph] cells) via antibody-dependent cellular cytotoxicity (ADCC) while sparing regulatory T cells (Tregs). Additionally, it activates PD-1 signaling to suppress overactive effector T cells and cross-links Fcγ receptors on dendritic cells to suppress their activity, creating an immunosuppressive microenvironment.