Charge heterogeneity is a widely monitored critical quality attribute (CQA) for monoclonal antibodies (mAbs), yet the charge profile alone rarely reveals which modifications drive the changes observed. In his talk, Julien Bourquin (Merck KGA) will describe how icIEF (imaged capillary isoelectric focusing) fractionation, combined with peptide mapping analysis by mass spectrometry, links individual charge variants to their underlying post-translational modifications at specific sites.
Using a set of stressed samples (thermal, low- and high-pH, mechanical, and light stress), his team demonstrated that critical quality attributes affect the charge profile non-proportionally: oxidation increased substantially with light stress while leaving the charge profile nearly unchanged, whereas deamidation produced a clear shift toward acidic variants and a corresponding loss of main peak. The resulting workflow provides a practical route to interpreting charge variant data with site-specific confidence, supporting better-informed decisions in biologics process and analytical development.
Dr. Laurence Talbot (Bio-Techne) will highlight the latest advancements in icIEF-fractionation using the MauriceFlex™ platform. She will give an overview of the different downstream characterization methods for charge variant characterization, including LC-MS (intact mass analysis), SPR and mass photometry and the important differences these methods uncover between a bispecific antibody (Mosunetuzumab-axgb) and a research-grade biosimilar. She will also discuss combining icIEF fractionation with LC-MS for the characterization of other modalities (ADCs and AAVs) as well as the advantages of implementing the FlexsonicIEF method to standard fractionation, which can provide up to a 40-minute faster method overall.
The webinar with cover the following topics:
- A streamlined workflow combining charge variant fractionation with peptide mapping (LC-MS) to determine underlying post-translational modifications at specific sites in mAbs
- A robust, scalable, and MS platform-independent analytical strategy for addressing charge heterogeneity challenges in complex biologics
- An improved understanding of critical quality attributes to accelerate development timelines and strengthen regulatory submissions
