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Pegg CL, Zacchi LF, Recinos DR, Howard CB, Schulz BL. Identification of novel glycosylation events on human serum-derived factor IX. Glycoconj J 2020; 37:471-483. [PMID: 32378017 DOI: 10.1007/s10719-020-09922-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/06/2020] [Accepted: 03/24/2020] [Indexed: 12/12/2022]
Abstract
Human Factor IX is a highly post-translationally modified protein that is an important clotting factor in the blood coagulation cascade. Functional deficiencies in Factor IX result in the bleeding disorder haemophilia B, which is treated with plasma-derived or recombinant Factor IX concentrates. Here, we investigated the post-translational modifications of human serum-derived Factor IX and report previously undescribed O-linked monosaccharide compositions at serine 141 and a novel site of glycosylation. At serine 141 we observed two monosaccharide compositions, with HexNAc1Hex1NeuAc2 dominant and a low level of HexNAc1Hex1NeuAc1. This O-linked site lies N-terminal to the first cleavage site for the activation peptide, an important region of the protein that is removed to activate Factor IX. The novel site is an N-linked site in the serine protease domain with low occupancy in a non-canonical consensus motif at asparagine 258, observed with a HexNAc4Hex5NeuAc2 monosaccharide composition attached. This is the first reported instance of a site of modification in the serine protease domain. The description of these glycosylation events provides a basis for future functional studies and contributes to structural characterisation of native Factor IX for the production of effective therapeutic biosimilars and biobetters.
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Affiliation(s)
- Cassandra L Pegg
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Lucia F Zacchi
- Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Dinora Roche Recinos
- Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Christopher B Howard
- Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Benjamin L Schulz
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia. .,Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, 4072, Australia.
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2
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Jeanpierre E, Pouplard C, Lasne D, Le Cam Duchez V, Eschwege V, Flaujac C, Galinat H, Harzallah I, Proulle V, Smahi M, Sobas F, Stepina N, Toulon P, Voisin S, Ternisien C, Nougier C. Factor VIII and IX assays for post-infusion monitoring in hemophilia patients: Guidelines from the French BIMHO group (GFHT). Eur J Haematol 2020; 105:103-115. [PMID: 32277501 DOI: 10.1111/ejh.13423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 01/24/2023]
Abstract
Replacement therapy with plasma-derived or recombinant FVIII and FIX (pdFVIII/pdFIX or rFVIII/rFIX) concentrates is the standard of treatment in patients with haemophilia A and B, respectively. Measurement of factor VIII (FVIII:C) or factor IX (FIX:C) levels can be done by one-stage clotting assay (OSA) or chromogenic substrate assay (CSA). The French study group on the Biology of Hemorrhagic Diseases (a collaborative group of the GFHT and MHEMO network) presents a literature review and proposals for the monitoring of FVIII:C and FIX:C levels in treated haemophilia A and B patients, respectively. The use of CSA is recommended for the monitoring of patients treated with pdFVIII or rFVIII including extended half-life (EHL) rFVIII. Except for rFVIII-Fc, great caution is required when measuring FVIII:C levels by OSA in patients substituted by EHL-rFVIII. The OSA is recommended for the monitoring of patients treated with pdFIX or rFIX. Large discordances in the FIX:C levels measured for extended half-life rFIX (EHL-rFIX), depending on the method and reagents used, must lead to great attention when OSA is used for measuring FIX:C levels in patients substituted by EHL-rFIX. Data of most of recent studies, obtained with spiked plasmas, deserve to be confirmed in plasma samples of treated patients.
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Affiliation(s)
- Emmanuelle Jeanpierre
- CHU Lille, Institut d'Hématologie Transfusion, Institut Pasteur de Lille, UMR1011-EGID, Lille, 59000, France
| | - Claire Pouplard
- Service d'Hématologie Hémostase, Hôpital Trousseau, CHU de Tours, EA 7501, Université Francois Rabelais, Tours, France
| | - Dominique Lasne
- Laboratoire d'Hématologie Générale, Hôpital Necker AP-HP, Université Paris Sud Saclay, INSERM U1176, Paris, Le Kremlin-Bicêtre, France
| | | | | | - Claire Flaujac
- Laboratoire d'Hématologie, Centre Hospitalier de Versailles, Le Chesnay, France
| | - Hubert Galinat
- Labortaoire d'Hématologie, Hôpital La Cavale Blanche, CHU de Brest, France
| | - Ines Harzallah
- Service d'Hématologie Hémostase, Groupe Hospitalier Régional de Mulhouse et Sud Alsace, France
| | - Valérie Proulle
- Service d'Hématologie Biologique, CHU Bicètre, AP-HP, Université Paris Sud Saclay, INSERM U1176, Le Kremlin-Bicêtre, France
| | - Motalib Smahi
- Service d'Hématologie Hémostase, Hôpital Simone Veil, Eaubonne, France
| | - Frédéric Sobas
- Service d'Hématologie Hémostase, Hospices Civils de Lyon, Bron, France
| | | | - Pierre Toulon
- Service d'Hématologie Biologique, Hôpital Pasteur, CHU Nice, France
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Sommer JM, Sadeghi-Khomami A, Barnowski C, Wikén M, Willemze AJ. Real-world assay variability between laboratories in monitoring of recombinant factor IX Fc fusion protein activity in plasma samples. Int J Lab Hematol 2020; 42:350-358. [PMID: 32202380 PMCID: PMC7318191 DOI: 10.1111/ijlh.13189] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/25/2020] [Accepted: 02/28/2020] [Indexed: 02/06/2023]
Abstract
Introduction Monitoring of factor IX (FIX) replacement therapy in haemophilia B relies on accurate coagulation assays. However, considerable interlaboratory variability has been reported for one‐stage clotting (OSC) assays. This study aimed to evaluate the real‐world, interlaboratory variability of routine FIX activity assays used in clinical haemostasis laboratories for the measurement of recombinant FIX Fc fusion protein (rFIXFc) activity. Methods Human FIX‐depleted plasma was spiked with rFIXFc at 0.80, 0.20 or 0.05 IU/mL based on label potency. Participating laboratories tested samples using their own routine OSC or chromogenic substrate (CS) assay protocols, reagents and FIX plasma standards. Laboratories could perform more than one measurement and method, and were not fully blinded to nominal activity values. Results A total of 142 laboratories contributed OSC results from 175 sample kits using 11 different activated partial thromboplastin time (aPTT) reagents. The median recovered FIX activity for the 0.80, 0.20 and 0.05 IU/mL samples was 0.72 IU/mL, 0.21 IU/mL and 0.060 IU/mL, respectively. Across all OSC reagents, interlaboratory variability (% CV) per aPTT reagent ranged from 9.4% to 32.1%, 8.2% to 32.6% and 12.2% to 42.0% at the 0.80, 0.20 and 0.05 IU/mL levels, respectively. CS results showed excellent median recoveries at all nominal levels (87.5% to 115.0%; n = 11) with low interlaboratory variability (CV 3.6% to 15.4%). Conclusion This large, real‐world data set indicates that rFIXFc activity in plasma samples can be accurately measured with the majority of routine OSC and CS assay methods. Given the variation in FIX assay procedures between sites, it is important that individual laboratories qualify their in‐house methods for monitoring of rFIXFc activity.
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Yoo KY, Jung SY, Hwang SH, Lee SM, Park JH, Nam HJ. Global hemostatic assay of different target procoagulant activities of factor VIII and factor IX. Blood Res 2018; 53:41-48. [PMID: 29662861 PMCID: PMC5898993 DOI: 10.5045/br.2018.53.1.41] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/11/2017] [Accepted: 10/29/2017] [Indexed: 11/23/2022] Open
Abstract
Background Korean National Health Insurance reimburses factor VIII (FVIII) and factor IX (FIX) clotting factor concentrate (CFC) infusions to discrepant activity levels, allowing elevation of FVIII activity to 60 IU/dL and FIX to 40 IU/dL. We aimed to assess hemostatic response to these target levels using global hemostatic assays. Methods We enrolled 34 normal healthy men, 34 patients with hemophilia A, and 36 with hemophilia B, with residual factor activity of 3 IU/dL or less and without inhibitors. Patients with hemophilia A and B received injected CFCs according to reimbursement guidelines. Fifteen minutes after injection, we assessed hemostatic response with global hemostatic assays: thrombin generation assay (TGA), thromboelastography (TEG), and clot waveform analysis (CWA). Results Normal healthy men and patients with hemophilia A and B were 36.7, 37.2, and 35.1 years old, respectively. FVIII and recombinant FIX concentrate doses were 28.8 IU/kg and 43.6 IU/kg. Post-infusion FVIII activity rose from 0.5 IU/dL to 69.4 IU/dL, while FIX activity rose from 1.4 IU/dL to 46.8 IU/dL. Post-infusion peak thrombin concentrations in hemophilia A and B were 116.6 nM/L and 76.4 nM/L (P<0.001). Post-infusion endogenous thrombin potential (ETP) in hemophilia A and B was 1349.8 nM/min and 915.6 nM (P<0.001). TEG index of hemophilia A and B was 0.11 and −0.51 (P=0.006). Conclusion Current reimbursed doses for FIX concentrates are insufficient to achieve hemostatic responses comparable to those after reimbursed doses for FVIII concentrates in terms of peak thrombin concentration, ETP, and TEG index.
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Affiliation(s)
| | | | - Sung-Ho Hwang
- Mogam Institute for Biomedical Research, Yongin, Korea
| | - Su-Min Lee
- Mogam Institute for Biomedical Research, Yongin, Korea
| | - Jong-Ho Park
- Mogam Institute for Biomedical Research, Yongin, Korea
| | - Hyun-Ja Nam
- Mogam Institute for Biomedical Research, Yongin, Korea
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Iorio A, Fischer K, Blanchette V, Rangarajan S, Young G, Morfini M. Tailoring treatment of haemophilia B: accounting for the distribution and clearance of standard and extended half-life FIX concentrates. Thromb Haemost 2017; 117:1023-1030. [PMID: 28357444 DOI: 10.1160/th16-12-0942] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 03/08/2017] [Indexed: 01/23/2023]
Abstract
The prophylactic administration of factor IX (FIX) is considered the most effective treatment for haemophilia B. The inter-individual variability and complexity of the pharmacokinetics (PK) of FIX, and the rarity of the disease have hampered identification of an optimal treatment regimens. The recent introduction of extended half-life recombinant FIX molecules (EHL-rFIX), has prompted a thorough reassessment of the clinical efficacy, PK and pharmacodynamics of plasma-derived and recombinant FIX. First, using longer sampling times and multi-compartmental PK models has led to more precise (and favourable) PK for FIX than was appreciated in the past. Second, investigating the distribution of FIX in the body beyond the vascular space (which is implied by its complex kinetics) has opened a new research field on the role for extravascular FIX. Third, measuring plasma levels of EHL-rFIX has shown that different aPTT reagents have different accuracy in measuring different FIX molecules. How will this new knowledge reflect on clinical practice? Clinical decision making in haemophilia B requires some caution and expertise. First, comparisons between different FIX molecules must be assessed taking into consideration the comparability of the populations studied and the PK models used. Second, individual PK estimates must rely on multi-compartmental models, and would benefit from adopting a population PK approach. Optimal sampling times need to be adapted to the prolonged half-life of the new EHL FIX products. Finally, costs considerations may apply, which is beyond the scope of this manuscript but might be deeply connected with the PK considerations discussed in this communication.
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Affiliation(s)
- Alfonso Iorio
- Alfonso Iorio, McMaster University, 1280 Main St West, Hamilton, ON L8S 4K1, Canada, Tel.: +1 905 525 9140 ext 22421, Fax: +1 905 526 8447, E-mail:
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