Single-domain antibodies (sdAbs) are a class of heavy-chain only antibodies (HCAbs) initially identified in camelids and sharks, with the characteristics of small molecular size, good stability, high solubility, and high penetration in various tissues. Based on an in-depth understanding of the structure and function of sdAbs, we have established a comprehensive platform encompassing antibody screening, humanization, engineering and developability assessment.
Furthermore, by leveraging the unique properties of sdAbs, we have constructed bispecific and multifunctional biologics, with multiple candidates advancing through various stages of development. A notable example, Envafolimab (KN035)* , received market approval in 2021 as the world's first subcutaneous injected PD-L1 inhibitor.
* Fei Zhang, Hudie Wei, Xiaoxiao Wang, Ting Xu, et al. Structural basis of a novel PD-L1 nanobody for immune checkpoint blockade. Cell Discovery,(2017) 3, 17004; doi:10.1038/celldisc.2017.4.
