Our team is presenting two posters during the scientific poster session.

Poster 1

Title: A Platform Approach for Enzymatic Remodelling of Antibodies and Conjugation to Branched Toxin Linkers

Presenter: Sebastian Braun, Senior Process Development Scientist.


The field of antibody-drug conjugation is moving rapidly with innovation and product breakthrough including complex multi-enzyme remodelling and conjugation strategies. Here, we evaluated a platform approach for one such technology, GlycoConnect™, that was applied to a variety of antibody isotypes and species with a range of branched toxin payloads based on MMAE, Maytansine, Exatecan, and DXd.

Two human IgG1 antibodies and one murine IgG2b antibody were trialled. A process was first developed for one antibody/toxin linker combination and then applied without further development to all combinations. Analysis of the resultant ADCs showed that the standard process achieved a high level of site-specific drug incorporation in all cases. Monomer levels and process yields were also consistently high across the combinations. PLRP worked well to determine drug to antibody ratios (DARs) while analysis by HIC depended on hydrophobicity of the toxin linker.

A single conjugate was selected for progressive scale up from milligram to multigram scale. We summarize our findings on the consistency of the ADC quality attributes across different scales and as purification methods change from lab to manufacturing-compatible unit operations.


Poster 2

Title: A standardised LC-MS workflow for rapid DAR determination of thiol-conjugated ADCs across a variety of toxin linkers

Presenter: Amy Hippard, Senior Process Development Scientist


Fast, reliable and generic methods are required for drug to antibody ratio (DAR) determination in an ADC development laboratory. In an effort to establish such a method, we have expanded on a previously developed “middle-up” workflow for determination of DAR by liquid chromatography-mass spectrometry (LC-MS). We demonstrate application of the workflow to a range of stochastically conjugated ADCs with DARs from 1 – 8, incorporating auristatin, α-amanitin, duocarmycin, PBD dimer and DX8951 payloads. DAR calculated by LC-MS is reported alongside DAR analysis through conventional chromatographic methods. The standardized LC-MS method provided DAR estimates in agreement with expected values for the auristatin, α-amanitin and DX8951 payloads. Optimisation of MS data analysis improved the DAR analysis for the duocarmycin ADC, however the protocol for PBD dimers has yet to achieve good agreement with expected DAR values. HPLC and LC-MS values for percent conjugated protein chain were consistent for peptidic payloads, independent of the degree of conjugation. However, the percent of conjugated protein chain is underestimated by LC-MS for more hydrophobic payloads, particularly with 2 or 3 payloads on the heavy chain. This work highlights the additional considerations that should be applied when analysing DAR of ADCs with hydrophobic payloads by LC-MS.