Straightforward Glycoengineering Approach to Site-Specific Antibody–Pyrrolobenzodiazepine Conjugates

• Published in: ACS medicinal chemistry letters Vol. 7; no. 11; pp. 1005 - 1008
• Main Authors: Thompson, Pamela, Ezeadi, Ebele, Hutchinson, Ian, Fleming, Ryan, Bezabeh, Binyam, Lin, Jia, Mao, Shenlan, Chen, Cui, Masterson, Luke, Zhong, Haihong, Toader, Dorin, Howard, Philip, Wu, Herren, Gao, Changshou, Dimasi, Nazzareno
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 10.11.2016; Amer Chemical Soc
• Subjects: Chemistry, Medicinal; Letter; Life Sciences & Biomedicine; Pharmacology & Pharmacy; Science & Technology; SG3364; click chemistry; site-specific conjugation; pyrrolobenzodiazepine; carbohydrate remodeling; Antibody−drug conjugates; THERAPEUTICS; EFFICACY; STABILITY; GLYCANS; GLYCOSYLATION; Antibody-drug conjugates; DRUG CONJUGATION; GLYCOSYLTRANSFERASES
• ISSN: 1948-5875; 1948-5875
• DOI: 10.1021/acsmedchemlett.6b00278

Antibody–drug conjugates (ADCs) have become a powerful platform to deliver cytotoxic agents selectively to cancer cells. ADCs have traditionally been prepared by stochastic conjugation of a cytotoxic drug using an antibody’s native cysteine or lysine residues. Through strategic selection of the mammalian expression host, we were able to introduce azide-functionalized glycans onto a homogeneously glycosylated anti-EphA2 monoclonal antibody in one step. Conjugation with an alkyne-bearing pyrrolobenzodiazepine dimer payload (SG3364) using copper-catalyzed click chemistry yielded a site-specific ADC with a drug-to-antibody ratio (DAR) of four. This ADC was compared with a glycoengineered DAR two site-specific ADC, and both were found to be highly potent against EphA2-positive human prostate cancer cells in both an in vitro cytotoxicity assay and a murine tumor xenograft model.