“…However, there have been limited studies involving the use of X-ray crystallography (XRC), a traditional technique for protein structural studies at the near-atomic level, as it works well only with proteins that can be crystallized, it requires expensive instrumentation, trained operators, and extensive time for analysis ( Lerch et al, 2020 ). If we look at the evolution of HOS assessment in biosimilarity studies ( Figure 4 ), the timeline is peppered with multiple orthogonal techniques such as single dimension NMR ( Visser et al, 2013 ; Sörgel et al, 2015 ; Montacir et al, 2017 ), multi-dimension NMR ( Shekhawat et al, 2019 ; Bor Tekdemir et al, 2020 ; Kovács et al, 2020 ), HDX-MS ( Cho et al, 2016 ; Brokx et al, 2017 ; Brown et al, 2019 ), IM-MS ( Fang et al, 2016 ; Montacir et al, 2017 , 2018 ), antibody conformational array ( Jung et al, 2014 ; Hong et al, 2017 ), aptamer-based enzyme linked apta-sorbent assay ( Wildner et al, 2019 ), and small angle X-ray scattering (SAXS) ( Narvekar et al, 2020 ) ( Supplementary Table S4 ). Of these, NMR has emerged as the new gold standard for HOS assessment with more than 10 published biosimilarity studies published with either 1D, or 1D and 2D as a part of the analytical platform ( Supplementary Table S4 ).…”