Evaluation Of Drug Conjugation Sites In An Anti-Egfr Centyrin

Centyrins are engineered alternative scaffold proteins that combine the affinity and specificity of antibodies with increased tissue penetration and simplified manufacturing. To identify optimal positions for chemical conjugation within the Centyrin scaffold, the crystal structure of an anti-EGFR Centyrin was solved and a library consisting of all possible single-cysteine variants was constructed and assessed for expression level in E. coli , efficiency of conjugation to maleimide derivatives, protein aggregation, thermostability, and EGFR binding. The best variants were conjugated to cytotoxic drugs and compared in a cell-killing assay. Three optimal positions were identified at which the Centyrin conjugated efficiently to maleimides; retained high expression, antigen binding, and biophysical properties; and showed increased cell-killing potency relative to the parent molecule. Citation Format: Rosa Cardoso, Shalom Goldberg, Tricia Lin, Tracy Spinka-Doms, Donna Klein, Steven Jacobs, Gary Gilliland, Karyn O’Neil. Evaluation of drug conjugation sites in an anti-EGFR Centyrin. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-062.