Articles tagged ”Biotransformation”
Automated Biotransformation Analysis of ADCs using FabRICATOR
The development of antibody-drug conjugates (ADCs) has evolved from first generation formats prepared by random conjugation technologies to next generation ADCs generated by site-specific conjugation. While significant improvements in overall efficacy and safety is displayed by site-specific formats, bioanalysis remains challenging due to complex in vivo biotransformation events including deconjugation, linker-payload cleavage and payload metabolism.
In this work, scientists at Bristol-Myers Squibb describe the development of an automated and fast affinity capture method using a cartridge-based platform combined with LC-HRMS analysis for biotransformation assessment of site-specific ADCs.
ADC Biotransformation Analysis using FabRICATOR and LC-MS
Current strategies for analyzing in vivo biotransformation of antibody-drug conjugates (ADCs) are limited by the site of conjugation, extensive sample preparation and insufficient sensitivity. In this paper by Kotapati et al., the authors developed a universal affinity capture method for assessing the effects of biotransformation on any site-specific ADC using generic reagents and LC-HRMS analysis.
Antibody-Drug Conjugates (ADCs) can undergo in vivo biotransformation where the payload can be metabolized to an inactive species or be subjected to deconjugation releasing the payload into systemic circulation. Strategically selected conjugation sites can minimize proteolytic cleavage or steric hindrance of the surrounding mAb domains, ultimately improving the potency and stability in vivo. The process of screening for optimal conjugation sites is therefore an important part of ADC discovery and development.
ADCs prepared from various antibodies and payloads with site-specific conjugation sites at the LC, HC-Fab and HC-Fc were prepared and analyzed using a mono- or dual affinity capture method. Streptavidin magnetic beads coated with anti-human F(ab’)2 captured ADCs from mouse serum and were processed on a KingFisher Flex automated magnetic extraction instrument. The captured ADCs were then, according to conjugation site, either subjected to reduction, on-bead digestion with only the FabRICATOR enzyme or in combination with PNGaseF for complete Fc-deglycosylation. The samples were then either reduced or eluted directly for analysis using high resolution LC-TOF mass spectrometer.
With this method, the authors were able to successfully study biotransformation of site-specific ADCs independent of antibody type, conjugation type or linker-payload chemistry. Using the site-specific FabRICATOR enzyme, HC-Fab and HC-Fc ADCs were digested below the hinge into homogenous F(ab’)2 and Fc subunits for the generation of antibody fragments. Compared to intact ADC analysis, this middle-level approach increased the resolution and sensitivity for identification of the conjugated payload and its metabolites at exceptional sensitivity and resolution.
