Antibody-drug conjugate (ADC) typically consists of an antibody linked to a cytotoxic drug using a linker. The targeting specificity of the antibody and the lethal effect of the drug make ADCs eliminate cancer cells efficiently and specifically. As such, ADCs have become a crucial area in the research and development of anticancer therapies. Recently, there has been development in techniques for site- specific drug conjugation in the production of ADCs to enhance homogeneity, stability, and efficacy. Here, we introduce a technology for site-selective drug conjugation by Fc-binding peptide-linker. The linker selectively forms a covalent bond with antibody through the affinity of a peptide for the Fc region. The linker contains trans-cyclooctene (TCO) that can conjugate with tetrazine-drug by inverse electron demand Diels-Alder (iEDDA), and during ligation, the peptide release from ADC based on click-to-release mechanism. This method mediates the iEDDA reaction, which is fast and bioorthogonal and by removing the peptide improve the stability and efficacy of the ADC. Moreover, unlike other techniques that use Fc- binding peptides, this method has the advantage of the peptide being released intact, allowing it to be recovered and recycled. we expect that this technology will be an innovative approach in the development of ADCs in the future. [Keywords: antibody-drug conjugate, site-selective drug conjugation, click-to- release]
