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Population pharmacokinetic modeling of factor concentrates in hemophilia: an overview and evaluation of best practice. Blood Adv 2021; 5:4314-4325. [PMID: 34496017 PMCID: PMC8945640 DOI: 10.1182/bloodadvances.2021005096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/10/2021] [Indexed: 12/30/2022] Open
Abstract
The accuracy of pharmacokinetic (PK)-guided dosing depends on the clinical and laboratory data used to construct a population PK model, as well as the patient’s individual PK profile. This review provides a detailed overview of data used for published population PK models for factor VIII (FVIII) and factor IX (FIX) concentrates, to support physicians in their choices of which model best suits each patient. Furthermore, to enhance detailed data collection and documentation, we do suggestions for best practice. A literature search was performed; publications describing prophylactic population PK models for FVIII and FIX concentrates based on original patient data and constructed using nonlinear mixed-effect modeling were included. The following data were collected: detailed demographics, type of product, assessed and included covariates, laboratory specifications, and validation of models. Included models were scored according to our recommendations for best practice, specifically scoring the quality of data documentation as reported. Respectively, 20 models for FVIII and 7 for FIX concentrates were retrieved. Although most models (22/27) included pediatric patients, only 4 reported detailed demographics. The wide range of body weights suggested that overweight and obese adults were represented. Twenty-six models reported the assay applied to measure factor levels, whereas only 16 models named reagents used. Eight models were internally validated using a data subset. This overview presents detailed information on clinical and laboratory data used for published population PK models. We provide recommendations on data collection and documentation to increase the reliability of PK-guided prophylactic dosing of factor concentrates in hemophilia A and B.
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2
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Kitchen S, Jennings I, Makris M, Kitchen DP, Woods TAL, Walker ID. Clotting and chromogenic factor VIII assay variability in post‐infusion and spiked samples containing full‐length recombinant FVIII or recombinant factor VIII Fc fusion protein (
rFVIIIF
c). Int J Lab Hematol 2018; 41:176-183. [DOI: 10.1111/ijlh.12940] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 10/01/2018] [Accepted: 10/05/2018] [Indexed: 12/30/2022]
Affiliation(s)
- Steve Kitchen
- UK NEQAS Blood Coagulation Sheffield UK
- Sheffield Haemophilia and Thrombosis Centre Sheffield UK
| | | | - Mike Makris
- Sheffield Haemophilia and Thrombosis Centre Sheffield UK
- Department of Cardiovascular ScienceUniversity of Sheffield Sheffield UK
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3
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Iorio A, Edginton AN, Blanchette V, Blatny J, Boban A, Cnossen M, Collins P, Croteau SE, Fischer K, Hart DP, Ito S, Korth‐Bradley J, Lethagen S, Lillicrap D, Makris M, Mathôt R, Morfini M, Neufeld EJ, Spears J. Performing and interpreting individual pharmacokinetic profiles in patients with Hemophilia A or B: Rationale and general considerations. Res Pract Thromb Haemost 2018; 2:535-548. [PMID: 30046759 PMCID: PMC6046594 DOI: 10.1002/rth2.12106] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 04/09/2018] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVES In a separate document, we have provided specific guidance on performing individual pharmacokinetic (PK) studies using limited samples in persons with hemophilia with the goal to optimize prophylaxis with clotting factor concentrates. This paper, intended for clinicians, aims to describe how to interpret and apply PK properties obtained in persons with hemophilia. METHODS The members of the Working Party on population PK (PopPK) of the ISTH SSC Subcommittee on Factor VIII and IX and rare bleeding disorders, together with additional hemophilia and PK experts, completed a survey and ranking exercise whereby key areas of interest in the field were identified. The group had regular web conferences to refine the manuscript's scope and structure, taking into account comments from the external feedback to the earlier document. RESULTS Many clinical decisions in hemophilia are based on some form of explicit or implicit PK assessment. Individual patient PK profiles can be analyzed through traditional or PopPK methods, with the latter providing the advantage of fewer samples needing to be collected on any prophylaxis regimen, and without the need the for a washout period. The most useful presentation of PK results for clinical decision making are a curve of the factor activity level over time, the time to achieve a certain activity level, or related parameters like half-life or exposure (AUC). Software platforms have been developed to deliver this information to clinicians at the point of care. Key characteristics of studies measuring average PK parameters were reviewed, outlining what makes a credible head-to-head comparison among different concentrates. Large data collections of PK and treatment outcomes currently ongoing will advance care in the future. CONCLUSIONS Traditionally used to compare different concentrates, PK can support tailoring of hemophilia treatment by individual profiling, which is greatly simplified by adopting a PopPK/Bayesian method and limited sampling protocol.
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Affiliation(s)
- Alfonso Iorio
- Department of Health Research, Methods, Evidence and ImpactMcMaster UniversityHamiltonONCanada
- Department of MedicineMcMaster UniversityHamiltonONCanada
| | | | - Victor Blanchette
- Division of Hematology/OncologyHospital for Sick Children and Department of PediatricsUniversity of TorontoTorontoONCanada
| | - Jan Blatny
- Department of Paediatric HaematologyUniversity Hospital BrnoBrnoCzech Republic
| | - Ana Boban
- Department of Internal MedicineUniversity Hospital CenterZagrebCroatia
| | - Marjon Cnossen
- Department of Pediatric HematologyErasmus University Medical CenterSophia Children’s HospitalRotterdamThe Netherlands
| | - Peter Collins
- Arthur Bloom Haemophilia CentreSchool of MedicineUniversity Hospital of WalesCardiff UniversityCardiffUK
| | | | - Katheljin Fischer
- Van CreveldkliniekUniversity Medical CenterUtrecht UniversityUtrechtThe Netherlands
| | - Daniel P. Hart
- The Royal London Hospital Haemophilia Centre, Barts and The London School of Medicine and DentistryLondonUK
| | | | | | | | - David Lillicrap
- Department of Pathology & Molecular MedicineQueen’s UniversityKingstonONCanada
| | - Mike Makris
- Department of Infection, Immunity& Cardiovascular DiseaseUniversity of SheffieldSheffieldUK
| | - Ron Mathôt
- Hospital Pharmacy–Clinical PharmacologyAcademic Medical CentreAmsterdamThe Netherlands
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4
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Jacquemin M, Vodolazkaia A, Toelen J, Schoeters J, Van Horenbeeck I, Vanlinthout I, Debasse M, Peerlinck K. Measurement of B-domain-deleted ReFacto AF activity with a product-specific standard is affected by choice of reagent and patient-specific factors. Haemophilia 2017; 24:675-682. [DOI: 10.1111/hae.13123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2016] [Indexed: 12/01/2022]
Affiliation(s)
- M. Jacquemin
- Center for Molecular and Vascular Biology; University of Leuven; Leuven Belgium
- Laboratorium Geneeskunde; UZ Leuven; Leuven Belgium
| | | | - J. Toelen
- Laboratorium Geneeskunde; UZ Leuven; Leuven Belgium
| | - J. Schoeters
- Laboratorium Geneeskunde; UZ Leuven; Leuven Belgium
| | | | | | - M. Debasse
- Laboratorium Geneeskunde; UZ Leuven; Leuven Belgium
| | - K. Peerlinck
- Center for Molecular and Vascular Biology; University of Leuven; Leuven Belgium
- Vascular Medicine and Haemostasis; UZ Leuven; Leuven Belgium
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5
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McEneny-King A, Iorio A, Foster G, Edginton AN. The use of pharmacokinetics in dose individualization of factor VIII in the treatment of hemophilia A. Expert Opin Drug Metab Toxicol 2016; 12:1313-1321. [PMID: 27539370 DOI: 10.1080/17425255.2016.1214711] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
INTRODUCTION Hemophilia A is a bleeding disorder resulting from a lack of clotting factor VIII (FVIII), and treatment typically consists of prophylactic replacement of the deficient factor. However, high between subject variability precludes the development of a 'one size fits all' dosing strategy and necessitates an individualized approach. We sought to summarize the data on the pharmacokinetics of FVIII available as a basis for the development of population pharmacokinetic models to be used in dose tailoring. Areas covered: We reviewed the pharmacokinetics of FVIII as used for the treatment of hemophilia A, with a focus on the variability observed between patients and the application of pharmacokinetic methods to dose individualization. We also explored the covariates affecting pharmacokinetic parameters, the differences between plasma-derived and recombinant FVIII and the development of extended half-life products. Expert opinion: The pharmacokinetics of factor VIII in patients with hemophilia shows a high interpatient variability, and is affected by age, weight, level of von Willebrand factor, and blood group. A population approach to estimating individual pharmacokinetics is likely to provide the most successful strategy to tailor factor concentrate dosing to the individual needs and to ensure optimal patient outcomes, while also improving the cost-effectiveness of prophylactic replacement therapy.
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Affiliation(s)
- Alanna McEneny-King
- a School of Pharmacy, Health Sciences Campus , University of Waterloo , Waterloo , ON , Canada
| | - Alfonso Iorio
- b Health Information Research Unit , McMaster University , Hamilton , ON , Canada
| | - Gary Foster
- c Clinical Epidemiology and Biostatistics , McMaster University , Hamilton , ON , Canada
| | - Andrea N Edginton
- a School of Pharmacy, Health Sciences Campus , University of Waterloo , Waterloo , ON , Canada
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6
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Turecek PL, Romeder‐Finger S, Apostol C, Bauer A, Crocker‐Buqué A, Burger DA, Schall R, Gritsch H. A world‐wide survey and field study in clinical haemostasis laboratories to evaluate
FVIII
:C activity assay variability of
ADYNOVATE
and
OBIZUR
in comparison with
ADVATE. Haemophilia 2016; 22:957-965. [DOI: 10.1111/hae.13001] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2016] [Indexed: 01/27/2023]
Affiliation(s)
| | | | | | | | | | - D. A. Burger
- Quintiles Biostatistics Bloemfontein South Africa
| | - R. Schall
- Quintiles Biostatistics Bloemfontein South Africa
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7
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Kitchen S, Katterle Y, Beckmann H, Maas Enriquez M. Chromogenic assay for BAY 81-8973 potency assignment has no impact on clinical outcome or monitoring in patient samples. J Thromb Haemost 2016; 14:1192-9. [PMID: 27002680 DOI: 10.1111/jth.13322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 03/03/2016] [Indexed: 11/29/2022]
Abstract
UNLABELLED Essentials Discrepancies can exist in factor VIII activity measured by the one-stage or chromogenic assays. LEOPOLD trial data were used to assess clinical impact of BAY 81-8973 potency assignment assay. Efficacy was not affected by the assay used for potency assignment and dosing of BAY 81-8973. Either assay may be used to measure factor VIII activity after BAY 81-8973 infusion. SUMMARY Background Product-specific discrepancies have been reported for factor VIII (FVIII) activity determined with one-stage or chromogenic assays. Objective To assess the clinical impact of potency assignment of BAY 81-8973, a full-length, unmodified, recombinant human FVIII, by use of the chromogenic assay or chromogenic assay adjusted to mimic results obtained with the one-stage assay Patients/methods Patients aged 12-65 years with severe hemophilia A received BAY 81-8973 in LEOPOLD I (20-50 IU kg(-1) two or three times weekly [investigator decision]) and LEOPOLD II (randomized to 20-30 IU kg(-1) twice weekly, 30-40 IU kg(-1) three times weekly, or on-demand treatment). Both trials included two 6-month crossover periods in which potency labeling was determined with the chromogenic substrate assay as per the European Pharmacopoeia (CS/EP) or the chromogenic substrate assay adjusted to mimic results obtained with the one-stage assay (CS/ADJ). The annualized bleeding rate (ABR) and FVIII incremental recovery were assessed by the use of pooled data. Results The analysis was perfomed on 121 patients. Median (quartile [Q] 1; Q3) ABRs during the CS/EP and CS/ADJ periods were 1.98 (0; 5.92) and 1.98 (0; 7.34), respectively. The mean incremental recovery was > 2 IU dL(-1) per IU kg(-1) in both periods with the use of either assay for postinfusion FVIII measurements. The median (Q1; Q3) chromogenic/one-stage assay recovery ratio was 1.054 (0.892; 1.150) for the CS/EP period when a plasma standard was used for calibration. Conclusions No impact on the ABR was observed with chromogenic-based as compared with one-stage assay-based potency and dosing. Either assay may be used to determine FVIII plasma activity after infusion of BAY 81-8973 without the need for a product-specific standard.
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Affiliation(s)
- S Kitchen
- Sheffield Haemophilia and Thrombosis Centre, Sheffield Teaching Hospitals NHS Trust, Sheffield, UK
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8
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Kitchen S, Jennings I, Makris M, Kitchen DP, Woods TAL, Walker ID. Factor VIII assay variability in postinfusion samples containing full length and B-domain deleted FVIII. Haemophilia 2016; 22:806-12. [PMID: 27217329 DOI: 10.1111/hae.12962] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2016] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Although the variability in factor VIII (FVIII):C measurement is well recognized, this has not been widely reported for post-FVIII infusion samples. AIM/METHODS Three samples from haemophilia A patients were distributed in a UK National External Quality Assessment Scheme survey, each after treatment with either ReFacto AF, Kogenate FS or Advate. Fifty-two UK haemophilia centres performed FVIII assays using one-stage (n = 46) and chromogenic (n = 10) assays. Centres calibrated assays with the local plasma standard and with ReFacto AF laboratory standard for the ReFacto AF sample. RESULTS/CONCLUSIONS Chromogenic assays gave significantly higher results than one-stage assays (P < 0.0001, 32% difference) in the post-Kogenate sample but not in the post-ReFacto AF (11% higher by chromogenic assay, ns) or post-Advate samples (3% lower by chromogenic, ns) when assays were calibrated with plasma standards. Twenty centres used all Instrumentation Laboratory (IL)-activated partial thromboplastin time reagents (Synthasil)/IL deficient plasma/reference plasma) in the one-stage assay and 15 used all Siemens reagents (Actin FS/Siemens deficient plasma/reference plasma); this made a significant difference to results post-ReFacto AF (41% higher by IL reagents, P < 0.0001) and Advate (39% higher by IL reagents, P < 0.0001), but not Kogenate (7% higher by IL, ns) when calibrated with plasma standards. Differences between results obtained with different one-stage assay reagents for monitoring Advate have implications for dosing patients. Furthermore, there was considerable inter-laboratory variation as indicated by CVs in the range 15-26% for chromogenic assay and 12-19% for one-stage assay results. This study suggests that external quality assessment schemes should offer participation in post-FVIII infusion schemes where haemophilic patients are monitored.
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Affiliation(s)
- S Kitchen
- UK NEQAS Blood Coagulation, Sheffield, UK. .,Sheffield Haemophilia and Thrombosis Centre, Sheffield, UK.
| | - I Jennings
- UK NEQAS Blood Coagulation, Sheffield, UK
| | - M Makris
- UK NEQAS Blood Coagulation, Sheffield, UK.,Department of Cardiovascular Science, University of Sheffield, Sheffield, UK
| | | | | | - I D Walker
- UK NEQAS Blood Coagulation, Sheffield, UK
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9
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Kusch M, Grundmann C, Keitel S, König H. Factor VIII assay mimicking in vivo coagulation conditions. Haemophilia 2013; 20:e164-70. [PMID: 24286249 DOI: 10.1111/hae.12333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2013] [Indexed: 11/30/2022]
Abstract
Under certain circumstances, the determination of coagulation factor VIII (FVIII) is hampered by assay discrepancies between clotting and chromogenic approaches. These are observed in certain patients' plasma as well as in certain concentrates. We intended to develop a novel assay for the quantification of coagulation FVIII which reflects the physiological situation better than the established assays. It is based on plasma without chelation of divalent cations and simultaneously minimizes the generation of activated factors which could function as uncontrolled triggers of coagulation. FVIII deficient plasma is prepared with the aid of biotinylated antibodies against FVIII from normal plasma in presence of inhibitors of contact activation. To start the assay only tiny amounts of activated FIX serve as trigger. The FVIII determination is performed in a kinetic experiment and is based on the cleavage of a fluorogenic substrate for activated FX. FVIII concentrations between 0.01 and 1 IU mL(-1) are easily determined. Plasma-derived and recombinant FVIII concentrates were compared. All plasma-derived concentrates were found to contain FVIII activities within the specification of the manufacturer. Recombinant concentrates yielded only 35-50% of the claimed potency. The novel in vivo-like assay avoids the undue advantage or disadvantage of certain product characteristics by eliminating unphysiological assay conditions. Its usefulness could turn out in future experiments with plasma from haemophilia A patients.
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Affiliation(s)
- M Kusch
- Department of Haematology and Transfusion Medicine, Paul Ehrlich Institute, Langen, Germany
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10
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Sommer JM, Moore N, McGuffie-Valentine B, Bardan S, Buyue Y, Kamphaus GD, Konkle BA, Pierce GF. Comparative field study evaluating the activity of recombinant factor VIII Fc fusion protein in plasma samples at clinical haemostasis laboratories. Haemophilia 2013; 20:294-300. [PMID: 24261554 PMCID: PMC4216409 DOI: 10.1111/hae.12296] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2013] [Indexed: 11/29/2022]
Abstract
Discrepancies exist for some of the modified coagulation factors when assayed with different one-stage clotting and chromogenic substrate assay reagents. The aim of this study was to evaluate the performance of a recombinant factor VIII Fc fusion protein (rFVIIIFc), currently in clinical development for the treatment of severe haemophilia A, in a variety of one-stage clotting and chromogenic substrate assays in clinical haemostasis laboratories. Haemophilic plasma samples spiked with rFVIIIFc or Advate® at 0.05, 0.20 or 0.80 IU mL−1 were tested by 30 laboratories using their routine procedures and plasma standards. Data were evaluated for intra- and inter-laboratory variation, accuracy and possible rFVIIIFc-specific assay discrepancies. For the one-stage assay, mean recovery was 95% to 100% of expected for both Advate® and rFVIIIFc at 0.8 IU mL−1. Intra-laboratory percent coefficient of variance (CV) ranged from 6.3% to 7.8% for Advate®, and 6.0% to 10.3% for rFVIIIFc. Inter-laboratory CV ranged from 10% for Advate® and 16% for rFVIIIFc at 0.8 IU mL−1, to over 30% at 0.05 IU mL−1 for both products. For the chromogenic substrate assay, the average FVIII recovery was 107% ± 5% and 124% ± 8% of label potency across the three concentrations of Advate® and rFVIIIFc, respectively. Plasma rFVIIIFc levels can be monitored by either the one-stage or the chromogenic substrate assay routinely performed in clinical laboratories without the need for a product-specific rFVIIIFc laboratory standard. Accuracy by the one-stage assay was comparable to that of Advate®, while marginally higher results may be observed for rFVIIIFc when using the chromogenic assay.
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Affiliation(s)
- J M Sommer
- Biogen Idec Hemophilia, Cambridge, MA, USA
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11
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Kosloski MP, Pisal DS, Mager DE, Balu-Iyer SV. Allometry of factor VIII and informed scaling of next-generation therapeutic proteins. J Pharm Sci 2013; 102:2380-94. [PMID: 23620343 DOI: 10.1002/jps.23566] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 03/31/2013] [Accepted: 04/02/2013] [Indexed: 02/04/2023]
Abstract
Allometric scaling has been applied to the pharmacokinetics (PK) of factor VIII (FVIII), but published relationships are based on relatively small subsets of available data. Numerous next-generation forms of FVIII are being developed (e.g., Fc fusion, PEGylated, and liposomal formulations) and traditional PK scaling of these products would not incorporate the wealth of existing knowledge for current FVIII therapy in humans. We conducted a meta-analysis and developed allometric relationships of FVIII from over 100 PK studies collected from literature. Normalized Wajima curves were used to relate mean FVIII profiles between species. An "informed scaling" approach was derived for predicting first-in-human PK parameters and demonstrated with a case study for an Fc fusion FVIII. NCA values for FVIII PK were well described by the allometric equations CL = 6.59 W(0.85) and V(ss) = 65.0 W(0.97). A subset of studies characterized by two-compartment modeling showed strong linearity in scaling of total clearance (CL) and central volume, but more variability in distributional CL and peripheral volume. Wajima curves for FVIII superimposed across species and the disposition of Fc fusion FVIII in humans was well predicted by "informed scaling." This approach might be generally applicable for predicting human PK of next-generational therapeutics.
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Affiliation(s)
- Matthew P Kosloski
- Department of Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, New York 14214, USA
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12
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Cauchie M, Toelen J, Peerlinck K, Jacquemin M. Practical and cost-effective measurement of B-domain deleted and full-length recombinant FVIII in the routine haemostasis laboratory. Haemophilia 2013; 19:e133-8. [DOI: 10.1111/hae.12093] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2012] [Indexed: 11/30/2022]
Affiliation(s)
- M. Cauchie
- Center for Molecular and Vascular Biology; University of Leuven; Leuven; Belgium
| | - J. Toelen
- Center for Molecular and Vascular Biology; University of Leuven; Leuven; Belgium
| | - K. Peerlinck
- Center for Molecular and Vascular Biology; University of Leuven; Leuven; Belgium
| | - M. Jacquemin
- Center for Molecular and Vascular Biology; University of Leuven; Leuven; Belgium
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13
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Henrard S, Speybroeck N, Hermans C. Body weight and fat mass index as strong predictors of factor VIII in vivo recovery in adults with hemophilia A. J Thromb Haemost 2011; 9:1784-90. [PMID: 21729239 DOI: 10.1111/j.1538-7836.2011.04431.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The treatment of hemophilia A requires infusions of factor VIII (FVIII) concentrates. The number of units to be given in order to obtain the target level is calculated using the formula: [body weight (BW) × desired FVIII increase]/2, which assumes that each unit infused per kg of BW increases the FVIII level by 2%. OBJECTIVES The present observational study evaluated the dependence of FVIII recovery on different morphometrical variables: BW, fat mass index (FMI), body mass index, and the difference between actual and ideal BW. PATIENTS AND METHODS FVIII recovery was measured in 46 non-actively bleeding hemophilia A patients, being treated with a recombinant FVIII concentrate. Regression trees were used to identify morphometrical predictors of recovery. RESULTS The median recovery was 2.08 for all patients, 2.63 for those with a BW ≥ 81.0 kg and 1.87 for others (P < 0.001). The recovery was significantly higher when FMI was ≥ 20% compared with FMI < 15% (median recovery: 2.35 vs. 1.74; P = 0.007). Using regression trees, three groups were created: BW < 80.5 kg and FMI < 22.3%, BW < 80.5 kg and FMI ≥ 22.3% and BW ≥ 80.5 kg. Median recovery in these groups was 1.80, 2.16 and 2.63, respectively (P < 0.001). CONCLUSIONS The dose calculation of FVIII should take into account both BW and FMI, and be adapted to underweight or overweight patients. Comparison of the average recovery after different FVIII concentrates should keep in mind morphometrical patient characteristics.
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Affiliation(s)
- S Henrard
- Institute of Health and Society, Université catholique de Louvain, Brussels, Belgium
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14
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Epstein J, Xiong Y, Woo P, Li-McLeod J, Spotts G. Retrospective analysis of differences in annual factor VIII utilization among haemophilia A patients. Haemophilia 2011; 18:187-92. [DOI: 10.1111/j.1365-2516.2011.02636.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J Epstein
- Baxter Healthcare, One Baxter Way, Westlake Village, CA 91362, USA.
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15
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POUPLARD C, CARON C, AILLAUD MF, TERNISIEN C, DESCONCLOIS C, DUBANCHET A, SOBAS F. The use of the new ReFacto AF Laboratory Standard allows reliable measurement of FVIII:C levels in ReFacto AF mock plasma samples by a one-stage clotting assay. Haemophilia 2011; 17:e958-62. [DOI: 10.1111/j.1365-2516.2011.02523.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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VIUFF D, BARROWCLIFFE TW, SAUGSTRUP T, EZBAN M, LILLICRAP D. International comparative field study of N8 evaluating factor VIII assay performance. Haemophilia 2011; 17:695-702. [DOI: 10.1111/j.1365-2516.2010.02481.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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