Characterization of critical reagents in ligand-binding assays: enabling robust bioanalytical methods and lifecycle management.

The effective management of validated ligand-binding assays used for PK, PD and immunogenicity assessments of biotherapeutics is vital to ensuring robust and consistent assay performance throughout the lifetime of the method. The structural integrity and functional quality of critical reagents is often linked to ligand-binding assay performance; therefore, physicochemical and biophysical characterization coupled with assessment of assay performance can enable the highest degree of reagent quality. The implementation of a systematic characterization process for monitoring critical reagent attributes, utilizing detailed analytical techniques such as LC-MS, can expedite assay troubleshooting and identify deleterious trends. In addition, this minimizes the potential for costly delays in drug development due to reagent instability or batch-to-batch variability. This article provides our perspectives on a proactive critical reagent QC process. Case studies highlight the analytical techniques used to identify chemical and molecular factors and the interdependencies that can contribute to protein heterogeneity and integrity.

Ligand binding assays in the 21st century laboratory: recommendations for characterization and supply of critical reagents.

Critical reagents are essential components of ligand binding assays (LBAs) and are utilized throughout the process of drug discovery, development, and post-marketing monitoring. Successful lifecycle management of LBA critical reagents minimizes assay performance problems caused by declining reagent activity and can mitigate the risk of delays during preclinical and clinical studies. Proactive reagent management assures adequate supply. It also assures that the quality of critical reagents is appropriate and consistent for the intended LBA use throughout all stages of the drug development process. This manuscript summarizes the key considerations for the generation, production, characterization, qualification, documentation, and management of critical reagents in LBAs, with recommendations for antibodies (monoclonal and polyclonal), engineered proteins, peptides, and their conjugates. Recommendations are given for each reagent type on basic and optional characterization profiles, expiration dates and storage temperatures, and investment in a knowledge database system. These recommendations represent a consensus among the authors and should be used to assist bioanalytical laboratories in the implementation of a best practices program for critical reagent life cycle management.