M.S. Lowenthal
National Institute of Standards and Technology,
United States
Keywords: glycans, glycosylation, monoclonal antibodies, quantification, SRM, reference material
Summary:
The quantitative and qualitative makeup of N-linked glycans associated with therapeutic monoclonal antibodies is considered a critical quality attribute of the antibody production process – an understanding of which helps ensure the desired product quality, safety, and efficacy. Typically, this analysis is completed using semi-quantitative approaches that rely on comparisons of chromatographic peak heights or peak areas of the major glycans, but this is achieved using a framework which is not calibrated to a known quantity (uncertain traceability chain) and which may not account for potential biases associated with enzymatic glycan release from the protein backbone, purification through multiple stages, chemical labeling with a fluorophore and/or variable ionization efficiency when detecting glycans by mass spectrometry. Glycan analysis of therapeutic mAbs is achieved in practice by comparing batch-to-batch data using in-house QC materials. NIST SRM 3655 – Glycans in Solution is intended to support these biomanufacturing efforts by providing an SI-traceable, homogeneous, stable material to calibrate the measurement of enzymatically released N-linked glycans. A common material will facilitate comparability between mAb products, batch releases, laboratories, analytical methods, or over time, and may be useful to value-assign in-house control materials.