SmartEnzymes™ in a new approach to characterize ADCs
Antibody drug conjugates (ADCs) consist of monoclonal antibodies chemically linked to a cytotoxic agent. The target specificity of the monoclonal antibody in combination with the potency of the cytotoxic drug make ADCs promising therapeutic agents. However, the molecules are often complex, making evaluation of the quality attributes for the ADC challenging.
In order to characterize the ADCs, the predominant analysis of choice is peptide mapping with reversed-phase liquid chromatography (RPLC) coupled to mass spectrometry. However, the sample preparation steps in a bottom-up approach are often time-consuming and a comprehensive view of ADCs with different sequence variants and post-translational modifications is lacking.
In this recently published article by Chen et al., a middle-down RPLC-MS strategy with electron transfer disscociation (ETD) was developed to analyze lysine and cysteine conjugated ADCs at the subunit level. FabRICATOR® (IdeS) and GingisKHAN® (KGB) were used to generate the subunits. FabRICATOR digests below the hinge, generating F(ab’)2 and Fc/2 fragments, and GingisKHAN digests above the hinge, generating intact Fab and Fc fragments. For the deglycosylation, the IgG-specific endoglycosidase GlycINATOR® (EndoS2) was used.
This middle-down approach enabled high-resolution evaluation of several ADC quality attributes at the subunit level, including drug to antibody ratio (DAR), conjugation sites and micro-variants. The approach shows great potential for investigating quality attributes during the development and characterization of novel ADCs.
Read more about FabRICATOR, GingisKHAN and GlycINATOR.