Increased branching and sialylation of N-linked glycans correlate with an improved pharmacokinetic profile for BAY 81–8973 compared with other full-length rFVIII products

Abstract

Background

BAY 81–8973 (Kovaltry) is an unmodified full-length recombinant factor VIII (rFVIII) for treatment of hemophilia A. The BAY 81–8973 manufacturing process results in a product of enhanced purity with a consistently high degree of branching and sialylation of N-linked glycans. This study evaluated whether a relationship exists between N-linked glycosylation patterns of BAY 81–8973 and two other rFVIII (sucrose-formulated rFVIII [rFVIII-FS; Kogenate FS]) and antihemophilic factor (recombinant) plasma/albumin-free method (rAHF-PFM; Advate) and their pharmacokinetic (PK) characteristics.

Materials and methods

N-linked glycans or terminal carbohydrates were enzymatically removed from immobilized BAY 81–8973, rFVIII-FS, and rAHF-PFM proteins and analyzed using high-performance liquid chromatography to determine the percentage of individual N-linked glycan structures and degree of sialylation of each structure. PK data were available from two separate phase 1 crossover studies in which the PK profile of BAY 81–8973 was compared with that of rFVIII-FS (n=26) and rAHF-PFM (n=18) in patients with severe hemophilia A who received a single 50 IU/kg dose of each product.

Results

BAY 81–8973 and rFVIII-FS had increased N-linked glycan branching with higher levels of sialylation compared with rAHF-PFM. Levels of trisialylated glycans were 29.0% for BAY 81–8973 vs 11.5% for rFVIII-FS and 4.8%–5.5% for rAHF-PFM; tetrasialylated glycans were 12.0% vs 2.8% and 0.6%, respectively. Degree of sialylation was 96% for BAY 81–8973, 94% for rFVIII-FS, and 78%–81% for rAHF-PFM. Based on chromogenic assay results from the single-dose phase 1 PK studies, BAY 81–8973 half-life was 15% longer than that for rFVIII-FS and 16% longer than rAHF-PFM.

Conclusion

Increased N-glycan branching and sialylation were seen for BAY 81–8973 vs rFVIII-FS and rAHF-PFM. Improved PK for BAY 81–8973 relative to rFVIII-FS and rAHF-PFM as seen in single-dose crossover PK studies might be related to this greater level of branching and sialylation, which can prolong the time BAY 81–8973 remains in the circulation.

Keywords:

• clearance
• glycan structure
• glycosylation
• half-life

Acknowledgments

This study was funded by Bayer. Medical writing assistance was provided by Karen L Zimmermann from Complete Healthcare Communications, LLC (North Wales, PA, USA) and was fully funded by Bayer. The abstract of this paper was presented at the American Society for Hematology Conference “ASH 2018” as a poster presentation with interim findings. The poster’s abstract was published in 2018 in the journal Blood 132:1209; doi: https://doi.org/10.1182/blood-2018-99-113061.

Disclosure

John M Teare, David S Kates, Anita Shah, and Stephen Garger are employees of Bayer. The authors report no other conflicts of interest in this work.