Harnessing Acylhydrazone-oxime Exchange Reaction to Achieve Diverse Synthesis of Glycosite-specific Antibody-Drug Conjugates

Abstract

Glycosite-specific antibody-drug conjugates (gsADCs), which carries cytotoxic payloads at the conserved N-glycosylation site, N297, of an IgG, has emerged as a promising ADC format with better therapeutic index. Conjugating the payloads via aldehyde-based chemistry is more friendly to IgGs which has been widely investigated. However, the efficiency to introduce aldehyde-tag at N297 site is poor due to the complicated procedures, such as multiple enzymes-catalyzed IgG glycoengineering process and the succussive step of oxidation, always resulting in heterogeneous products and poor stability. Herein, we report an efficient approach to assemble the aldehyde-based gsADCs, in which the aldehyde group is first protected by hydrazine and conjugates linker-payloads via acylhydrazone-oxime exchange reaction. This method exhibits remarkable coupling efficiency to various linker-payloads, and the corresponding gsADCs demonstrate good homogeneity, stability, and in vitro and in vivo efficacy.