A Q&A with Dr. Ganesh Bala on LC–MS and Multi-Attribute Methods for Bioconjugate CQA Monitoring

BioPharm International® caught up with Ganesh Bala, PhD, product specialist—Mass Spec at Agilent Technologies, who presented at the American Association of Pharmaceutical Scientists (AAPS) National Biotechnology Conference (NBC) this past April, to discuss his talk about the analytical challenges posed by increasingly complex biotherapeutic molecules. Dr. Bala highlighted how multi-attribute methods (MAMs) are helping stakeholders address these challenges.

BioPharm: What is driving the industry-wide shift from traditional monoclonal antibodies toward more complex bioconjugates such as ADCs and AOCs?

Dr. Bala (Agilent): The key driver comes from unmet clinical need and the advancements in precision medicine that we see in the industry today. There is growing demand for bioconjugates that combine the target specificity of antibodies with highly potent payloads to achieve greater efficacy, differentiated mechanisms of action, and an improved therapeutic index.¹ This is particularly important in oncology and rare diseases, where conventional therapeutic approaches have shown limitations.

What are the primary challenges in monitoring critical quality attributes in these increasingly complex molecules?

These increasingly complex modalities are introducing more and more heterogeneity into the molecules we see. Variable conjugation sites, drug-to-antibody ratio, and new degradation pathways are emerging.² This makes the need for sensitive, site-specific, and quantitative analytics essential‚ while at the same time maintaining throughput and readiness for the manufacturing process.

How do MAMs allow researchers to monitor multiple quality traits simultaneously within a single workflow?

Multi-attribute methods are primarily an LC–MS [iquid chromatography–mass spectrometry]-based peptide mapping approach, but they quantify multiple critical quality attributes‚ such as post-translational modifications, sequence variations, and conjugation features, into a single, information-rich assay format.³ This enables end users to deliver results in a faster and more consistent and reliable manner compared with conventional approaches that rely on multiple separate analytical methods.

Why is robust peptide mapping essential for quantifying both standard protein modifications and specific conjugation features in bioconjugates?

Peptide mapping provides site-specific resolution, allowing accurate quantification of post-translational modifications alongside identification of conjugation sites, assessment of linker stability, and any modifications that may have occurred in the payload.⁴ These are critical for understanding the structure–function relationship of bioconjugates. [This is} information that supports both development decisions and regulatory submissions.

In what ways do these advanced analytical workflows improve the speed and accuracy of stability and comparability studies?

The ultimate goal is improving speed, sensitivity, and consistency through these consolidated assay formats. This enables earlier detection of subtle changes and generates highly comparable data sets across batches‚ which are critical when evaluating manufacturing changes.^3,4 By replacing multiple orthogonal assays with a single integrated workflow, these approaches also reduce analytical burden and cycle times throughout the product lifecycle.

What is the key take-home message for stakeholders in the bioconjugate analytical space from your presentation at AAPS NBC?

As modalities evolve, analytics must evolve along with them. Platforms like multi-attribute methods are no longer exploratory tools. They are foundational enablers of faster development, better decision-making, and regulatory-ready control strategies for the end user.³

References

1. Mansinho A, Albuquerque J, Barigazzi C, et al. Antibody-drug conjugates in cancer treatment: from molecular design to clinical implementation. The Lancet Regional Health – Europe 2026;64:101634. Accessed June 4, 2026. https://www.thelancet.com/journals/lanepe/article/PIIS2666-7762(26)00046-3/fulltext
2. Zhou X, Han Y, Fang Y, et al. Antibody-drug conjugates: Current challenges and innovative solutions for precision cancer therapy. Med 2025;6(10):100849. doi: 10.1016/j.medj.2025.100849
3. Millán-Martín S, Jakes C, Carillo S, Bones J. Multi-attribute method (MAM) analytical workflow for biotherapeutic protein characterization from process development to QC. Curr Protoc. 2023;3(11):e927. doi:10.1002/cpz1.927
4. Kristensen DB, Ørgaard M, Sloth TM, et al. Optimized multi-attribute method workflow addressing missed cleavages and chromatographic tailing/carry-over of hydrophobic peptides. Anal Chem. 2022;94(49):17195-17204. doi:10.1021/acs.analchem.2c03820