Site-Dependent Degradation of a Non-Cleavable Auristatin-Based Linker-Payload in Rodent Plasma and Its Effect on ADC Efficacy.

摘要: The efficacy of an antibody-drug conjugate (ADC) is dependent on the properties its linker-payload which must remain stable while in systemic circulation but undergo efficient processing upon internalization into target cells. Here, we examine stability a non-cleavable Amino-PEG6-based linker bearing monomethyl auristatin D (MMAD) payload site-specifically conjugated at multiple positions antibody. Enzymatic conjugation with transglutaminase allows us to create amide linkage that remains intact across all tested sites antibody, and provides opportunity itself. We report position-dependent degradation C terminus MMAD rodent plasma has detrimental effect potency. cleavage can be eliminated by either modifying toxin, or selection site. Both approaches result improved potency vitro vivo. Furthermore, show metabolism mouse likely mediated serine-based hydrolase, appears much less pronounced rat, was not detected cynomolgus monkey human plasma. Clarifying these species differences controlling toxin optimize ADC rodents essential make best from preclinical models. data presented here demonstrate site susceptibility are important considerations design ADCs, further highlight benefits site-specific methods.