LC‑MS/MS Methods For ADC And Free Payload Analysis

Pharmaron poster on ADC and free payload analysis of Trastuzumab Deruxtecan using LC-MS/MS, with download button

Poster Authors:

Yunxi Zhong, Mandy Xu

Pharmaron (Ningbo) Bioscience Services Co., Ltd.

Presented at the 2026 Society of Toxicology (SOT) Annual Meeting & ToxExpo

San Diego, CA | March 22–25, 2026

Faster, Clearer ADC Pharmacokinetics and Free Payload Analysis:

Antibody–drug conjugates (ADCs) are transforming the field of oncology. Their complexity creates major analytical challenges. Understanding total antibody, conjugated payload, and free payload exposure is important for developing safer, more effective bioconjugates when traditional ligand‑binding approaches fall short.

Our recent SOT poster, “Method Development and Qualification for Determination of Total Antibody, ADC and Free Payload of Trastuzumab Deruxtecan Using LC‑MS/MS and its Application, introduces a simplified, LC‑MS/MS workflow that overcomes these challenges.

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Read the poster to learn how this method provides quicker results with enhanced understanding. You can gain data that provides better assistance for decision-making throughout the discovery and development phases.

What You Can Learn:

This poster walks you through a comprehensive LC-MS/MS workflow built for pharmacokinetic studies, stability assessments, and biotransformation analysis — using a hybrid immunoaffinity LC-MS/MS approach to simultaneously measure:

Total antibody (TAb)
Conjugated payload (ADC)
Unconjugated/free payload (DXd)

We present three complementary methods that work in unison to provide a complete overview of ADC:

TAb: Quantification of surrogate peptides following immunocapture and digestion
ADC: Measurement of enzymatically released payload using β-glucuronidase
DXd: High-sensitivity MRM detection following precipitation

Qualification of regulatory-ready results demonstrating:

Broad linear ranges
Outstanding sensitivity (e.g., free payload LLOQ of 0.02 ng/mL)
ICH M10 guideline compliance

Application to the pharmacokinetics of antibody-drug conjugates includes integrated exposure profiles in rats that monitor:

TAb levels
Concentrations of conjugated ADC
Release of unconjugated/free payload DXd
Decreases in drug-to-antibody ratio (DAR) over time, measuring in vivo deconjugation dynamics.

Why Does This Matter for ADC Developers?

This workflow enhances the efficiency of method development by reducing the dependence on ligand-binding reagents. It offers a comprehensive platform for assessing the pharmacokinetics of antibody-drug conjugates (ADCs). As a consequence, it leads to reduced timelines and more consistent data, facilitating more confident decision-making regarding the safety, efficacy, and design of molecules.

Download the poster to get the complete data package, including workflows, chromatograms, method parameters, validation metrics, and integrated PK results.