Comparative Analysis of Glycan Composition in Therapeutic Antibodies via Glycan Profiling and Intact Mass Analysis

N-glycans represent the most common and abundant post-translational modification (PTM) in therapeutic antibodies, playing crucial roles in key functions such as antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Consequently, glycan profiling is regarded as a critical quality attribute (CQA) and is routinely performed to ensure antibody quality and consistency. The Rapi-Fluor method is a conventional standard for detailed glycan profiling, while intact mass analysis serves as a parallel CQA. However, the Rapi-Fluor method is a multi-step, time-consuming process that can limit high-throughput monitoring. In this study, we conducted a rigorous comparative validation of the Rapi-Fluor method and intact mass analysis for determining the glycan composition of ten therapeutic antibodies, comprising five original products and their biosimilars. Consistent with established findings, the biosimilars exhibited glycan compositions highly similar to their original counterparts. Furthermore, major glycans constituted over 85% of the total glycans across all samples. Crucially, the analytical comparison revealed highly congruent results between the Rapi-Fluor method and intact mass analysis, with quantitative differences in glycan composition being less than 10% across all ten therapeutic antibodies. This successfully demonstrates that intact mass analysis is a highly feasible, reliable, and significantly time-efficient alternative for rapidly and reliably assessing glycan composition, thereby accelerating quality control and process monitoring.