Envafolimab (KN035) is a chimeric (human/camelid) anti-PD-L1 nanobody that acts as an immune checkpoint inhibitor, and which is being developed by Alphamab Co [1
]. Structurally it is a VH-Fc dimer, and does not contain variable light (VL) domains. It therefore has a reduced molecular size and offers more favourable physico-chemical properties than full-size monoclonal antibodies. X-ray crystal structures show that KN035 binds to the same surface on PD-L1 where the ligand interacts with its cognate receptor PD-1 (programmed death protein 1).
The peptide sequence of envafolimab's heavy chain returned no matches with patented peptide sequences in a Protein: BLAST search in September 2019.