Advances in the Development of Site-Specific Antibody-Drug Conjugation.
Antibody-drug conjugates (ADCs) showed strong anticancer efficacy in the clinic. However, the current conventional technologies generate conjugates with undefined attachment sites and heterogeneous profiles containing different sub-populations, leading to potential off-target toxicity. In order to reduce the variability and heterogeneity associated with the ADCs generated using conventional technologies, several site-specific antibody-drug conjugation strategies were developed for the next generation of ADCs. These strategies include cysteine-targeted conjugation by engineering a free cysteine into the antibody or by placing a thiol bridge on cysteines in hinge disulfides. Glutamine-targeted conjugation was also demonstrated by coupling the drug-linker to glutamine residues through an engineered glutamine tag or a native glutamine, as well as an additionally introduced glutamine residue in aglycosylated antibody mutant using microbial transglutaminase. The site-specific conjugation of drug-linker to antibody carbohydrates was developed either through metabolic engineering or a chemo-enzymatic approach. Other amino acids, such as unnatural amino acids or amino acid derivatives introduced through protein engineering, have also been shown to be efficient targets for site-specific conjugation. The sitespecific ADCs with homogeneous profiles and well-defined conjugation sites were obtained using these second generation ADC methods and showed potent in vitro cytotoxicity and strong in vivo antitumor activity. These results suggest that newly developed site-specific conjugation technologies can potentially be applied in producing the next generation ADC for cancer treatment in the clinic with high therapeutic index.
Protein Engineering, Global BioTherapeutics, Sanofi, Five Mountain Road, Framingham, Massachusetts 01701-9322 USA. qun.zhou@sanofi.com.
Qun
Q
Zhou
Jennifer
J
Kim
D000818:Animals; D000906:Antibodies / Q000737:chemistry*; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology / Q000627:therapeutic use; D002241:Carbohydrates / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry; D005973:Glutamine / Q000737:chemistry; D006801:Humans; D018796:Immunoconjugates / Q000737:chemistry* / Q000494:pharmacology / Q000627:therapeutic use
D000906:Antibodies; D000970:Antineoplastic Agents; D002241:Carbohydrates; D018796:Immunoconjugates; D005973:Glutamine; D003545:Cysteine