A Comparison of the Oligosaccharide Structures of Antithrombin Derived from Plasma and Recombinant Using POTELLIGENT® Technology

Abstract

Human antithrombin (AT) has two isoforms of which the predominant α-form is glycosylated on all four possible glycosylation sites and the lower abundant β-isoform lacks the oligosaccharide on Asn135. The main oligosaccharide structure of human AT consists of biantennary complex-type oligosaccharides lacking a core fucose. Generally, Chinese hamster ovary (CHO) cells produce recombinant human AT (rhAT) with core-fucosylated oligosaccharides. However, rhAT lacking core-fucose oligosaccharides can be produced by POTELLIGENT® technology, which uses FUT8 knockout CHO cells in production. The rhAT has more variable glycan structures, such as tetra-antennary complex type, high-mannose type, and mannose 6-phosphate species as minor components compared to plasma-derived human AT (phAT). In addition, the site-specific glycan profile was different between two ATs. We evaluated the effect of these properties on efficacy and safety based on a comparison of rhAT made by that technology with phAT in terms of their respective oligosaccharide structures, site-specific oligosaccharide profiles, and the ratio of α- and β-forms. Although some structural differences were found between the rhAT and phAT, we concluded that these differences have no significant effect on the efficacy and safety of rhAT.