Manuscript handled by: R. Camire
Glycoengineered factor IX variants with improved pharmacokinetics and subcutaneous efficacy
Article first published online: 12 SEP 2013
© 2013 International Society on Thrombosis and Haemostasis
Journal of Thrombosis and Haemostasis
Volume 11, Issue 9, pages 1699–1706, September 2013
How to Cite
Glycoengineered factor IX variants with improved pharmacokinetics and subcutaneous efficacy. J Thromb Haemost 2013; 11: 1699–706., , , , , , , , , , .
Final decision: P. H. Reitsma, 14 May 2013
- Issue published online: 12 SEP 2013
- Article first published online: 12 SEP 2013
- Accepted manuscript online: 21 MAY 2013 09:39AM EST
- Manuscript Accepted: 14 MAY 2013
- Manuscript Received: 5 APR 2013
- Bayer Healthcare
- coagulation factor IX;
- hemophilia B;
The rapid clearance of factor IX (FIX) necessitates frequent intravenous administration to achieve effective prophylaxis for patients with hemophilia B. Subcutaneous administration would be a preferred route of administration but is limited by bioavailability.
To improve the pharmacokinetics (PK) and bioavailability of FIX, a screen was performed to identify positions for the introduction of novel glycosylation sites with maximal effect on PK and maintenance of coagulation activity.
Two hundred fifty-one variants, each containing one additional N-linked glycosylation site, were screened in vitro, and the PK profiles of selected variants mapping to spatially distinct regions of FIX were evaluated in mice. Optimal variants were combined, and their PK and efficacy were determined in mice with hemophilia B.
Variants that mapped to spatially distinct regions of the FIX structure exhibited different degrees of improved PK and enabled selection of optimized sites while minimizing the loss of FIX activity. Combining the most effective N-glycan sites in the same FIX molecule resulted in further improvements in PK. An optimized variant containing three novel N-glycan sites (at amino acids 103, 151, and 228), and the activity enhancing 338A variant had double the specific activity of wild-type FIX, exhibited 4.5-fold reduced clearance and 2.4-fold increased subcutaneous bioavailability, and was efficacious at a fivefold lower mass dose than wild-type FIX after subcutaneous injection in a bleeding model in mice with hemophilia B.
Glycoengineering was used to significantly improve the subcutaneous PK and efficacy of FIX and may have advantages for subcutaneous dosing.