Factor VIII: C (FVIII: C) Recovery and Half-Life After Infusion of Steam-Treated High Purity Factor VIII Concentrate in Severe Hemophilia A - Comparison of One-Stage Assay, Two-Stage Assay and a Chromogenic Substrate Assay

1986 ◽  
Vol 56 (03) ◽  
pp. 353-359 ◽  
Author(s):  
Peter Hellstern ◽  
Ralf Kiehl ◽  
Chieko Miyashita ◽  
Holger Schwerdt ◽  
Gerhard von Blohn ◽  
...  
Keyword(s):  
Factor Viii ◽  
High Purity ◽  
Plasma Levels ◽  
Half Life ◽  
Hemophilia A ◽  
Least Square ◽  
Chromogenic Substrate ◽  
Two Stage ◽  
One Stage ◽  
The One

SummaryFactor VIII :C recovery and half-life was measured in 16 hemophilia A patients under comprehensively standardized conditions. Each patient received the same lot of a steam-treated high purity FVIII concentrate at a dose of 19-33 U/kg body weight. A comparison was made between the one-stage assay, the two-stage assay and a chromogenic substrate test for FVIII :C determination using a FXa-sensitive chromogenic substrate. Factor VIII :C potency of the administered FVIII concentrate was measured using calibration curves derived from a concentrate standard and FVIII: C plasma levels were read from calibration curves derived from a plasma standard. The chromogenic assay showed a good reproducibility at FVIII: C levels between 0.015 and 0.50 U/ml. The FVIII :C recoveries calculated from the results of the one-stage assay, the two-stage assay and the chromogenic substrate test were 109 ± 20, 92 ± 14 and 81 ± 11% (x ± SD), respectively. The elimination half-lives of FVIII :C were calculated by non-linear least square analysis using a modified computerized Gauss-Newton algorithm. The half-lives calculated from the FVIII: C plasma levels measured by the one-stage assay, the two-stage assay and the chromogenic test were 23.8 ± 6.4, 22.2 ± 5.7 and 17.1 ± 4.8 h (x ± SD), respectively. No previous study has reported such long half-life values. Our findings indicate that measurements of recoveries and half-lives by the chromogenic FVIII :C assay and by computerized nonlinear least square analysis allow the possibility of individualized FVIII replacement therapy.

Standardization of Factor VIII – IV. Establishment of the 3rd International Standard for Factor VIII: C Concentrate

1983 ◽  
Vol 50 (03) ◽  
pp. 697-702 ◽  
Author(s):  
T W Barrowcliffe ◽  
A D Curtis ◽  
D P Thomas
Keyword(s):  
Factor Viii ◽  
High Purity ◽  
Collaborative Study ◽  
World Health ◽  
Current Standard ◽  
Two Stage ◽  
International Standard ◽  
One Stage ◽  
The One ◽  
Health Organization

SummaryAn international collaborative study was carried out to establish a replacement for the current (2nd) international standard for Factor VIII: C, concentrate. Twenty-six laboratories took part, of which 17 performed one-stage assays, three performed two-stage assays and six used both methods. The proposed new standard, an intermediate purity concentrate, was assayed against the current standard, against a high-purity concentrate and against an International Reference Plasma, coded 80/511, previously calibrated against fresh normal plasma.Assays of the proposed new standard against the current standard gave a mean potency of 3.89 iu/ampoule, with good agreement between laboratories and between one-stage and two- stage assays. There was also no difference between assay methods in the comparison of high-purity and intermediate purity concentrates. In the comparison of the proposed standard with the plasma reference preparation, the overall mean potency was 4.03 iu/ampoule, but there were substantial differences between laboratories, and the two-stage method gave significantly higher results than the one stage method. Of the technical variables in the one-stage method, only the activation time with one reagent appeared to have any influence on the results of this comparison of concentrate against plasma.Accelerated degradation studies showed that the proposed standard is very stable. With the agreement of the participants, the material, in ampoules coded 80/556, has been established by the World Health Organization as the 3rd International Standard for Factor VIII :C, Concentrate, with an assigned potency of 3.9 iu/ampoule.

scholarly journals Assessing the Performance of Extended Half-Life Coagulation Factor VIII, FC Fusion Protein by Using Chromogenic and One-Stage Assays in Saudi Hemophilia A Patients

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Tarek M. Owaidah ◽  
Hazzaa A. Alzahrani ◽  
Nouf S. Al-Numair ◽  
Abdulmjeed O. Alnosair ◽  
Amelita M. Aguilos ◽  
...  
Keyword(s):  
Factor Viii ◽  
Half Life ◽  
Hemophilia A ◽  
Coagulation Factor ◽  
Time Interval ◽  
One Stage ◽  
Chromogenic Assay ◽  
Significant Difference ◽  
Mean Differences ◽  
The One

Background. The one-stage assay is the most common method to measure factor VIII activity (FVIII : C) in hemophilia A patients. The chromogenic assay is another two-stage test involving purified coagulation factors followed by factor Xa-specific chromogenic substrate. Aim. This study aimed to assess the discrepancy and correlation between the chromogenic and one-stage assays in measuring FVIII : C levels in hemophilia patients receiving Extended Half-Life Elocta® as a recombinant extended half-life coagulation factor. Methods. We performed a study comparing the measurements of FVIII : C levels by the chromogenic versus the one-stage assays at different drug levels. Data of FVIII : C levels, dosage, and the time interval from administration to measurement were retrieved from the hospital records. The correlation, mean differences, and discrepancy between the two assays were calculated. The linear regression analysis was used to predict the time interval till reaching 1% FVIII : C. Results. Fourteen patients with 56 samples were included in the study. Of them, 13 patients were receiving Elocta® as a prophylactic, while one was receiving Elocta® on demand. One-third of these samples showed a discrepancy between the chromogenic and one-stage assays. The two assays were well correlated. Mean differences were significant at the individual and the time interval level. The time since the last Elocta® injection could significantly predict FVIII : C levels (β = 0.366, P<0.001). Conclusion. Our findings suggested a significant difference between both methods; the FVIII : C levels measured by the one-stage assay were less than those estimated by the chromogenic assay. However, the measurements of FVIII levels by the two assays were well correlated but discrepant in one-third of the samples. The levels of FVIII : C reach 1% after 5.4 days since the last Elocta® administration.

In Vivo Recovery of Factor VIII: A Comparison of One-Stage and Two-Stage Assay Methods

1979 ◽  
Vol 42 (04) ◽  
pp. 1230-1239 ◽  
Author(s):  
I M Nilsson ◽  
T B L Kirkwood ◽  
T W Barrowcliffe
Keyword(s):  
Factor Viii ◽  
Half Life ◽  
In Vitro Assays ◽  
Two Stage ◽  
One Stage ◽  
Significant Difference ◽  
Assay Methods ◽  
The One ◽  
Fraction I

SummaryThe recovery and half-life of VIII: C in the plasma of severely haemophilic patients was measured by one-stage and two-stage assays after injection of two Factor VIII concentrates (Hemofil, Hyland and Fraction I-O, Kabi). Plasma volumes were measured with an Evans� Blue technique, and both concentrates and post-infusion samples were measured against the same plasma standard.There was a highly significant difference in recoveries estimated by the two assay methods. The one-stage assays gave the most consistent results, in that the average recovery was 100%, whereas the two-stage assays gave only about 80% of the value expected from in vitro assays. There was no difference in recoveries between the two concentrates.The two-stage assays gave a slightly shorter half-life than the one-stage assays, and the half-life of Hemofil was also shorter than that of Fraction I-O.

Clinical Application of a Chromogenic Substrate Method for Determination of Factor VIII Activity

1985 ◽  
Vol 54 (04) ◽  
pp. 818-823 ◽  
Author(s):  
S Rosén ◽  
M Andersson ◽  
M Blombäck ◽  
U Hégglund ◽  
M J Larrieu ◽  
...  
Keyword(s):  
Factor Viii ◽  
Clinical Application ◽  
Healthy Subjects ◽  
Hemophilia A ◽  
Chromogenic Substrate ◽  
Factor Viii Activity ◽  
One Stage ◽  
The One ◽  
Good Agreement

SummaryA chromogenic substrate kit for the determination of factor VIII activity (COATEST® Factor VIII) has been evaluated in five different laboratories, one of them using a semi-automated procedure. This chromogenic method was compared to one-stage clotting assays for factor VIII determination in plasmas from healthy subjects, carriers of hemophilia A, severe, mild and moderate hemophilia A as well as von Willebrand’s patients. In all these cases, a high correlation between these two methods was obtained (r = 0.96-0.99, n = 385) with a good agreement of the assigned potencies at all levels of factor VIII. A good correlation (r = 0.94) was also obtained for the levels of factor VIII after infusion of concentrates in six severe hemophiliacs or after administration of DDAVP to von Willebrand’s patients.The chromogenic method is insensitive to preactivation of factor VIII by thrombin, thus yielding valid potency assignments also in these situations.The precision was higher with the chromogenic method than with the one-stage clotting assays (C.V. = 2-5% vs 4-15%). Altogether, the new chromogenic substrate method has proven itself suitable for determination of factor VIII in plasma and concentrates.

Characterization of PEGylated Factor VIII Molecules.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4024-4024
Author(s):  
Joanne Severs ◽  
Nicole Samuels ◽  
John Teare ◽  
Amy Tollner ◽  
Lisa Regan
Keyword(s):  
Mass Spectrometry ◽  
Factor Viii ◽  
Half Life ◽  
Hemophilia A ◽  
Maldi Mass Spectrometry ◽  
Potency Assay ◽  
One Stage ◽  
Thrombin Activation ◽  
The One

Abstract Patients with hemophilia A typically require frequent treatment with replacement Factor VIII (FVIII) products due to the relatively short circulating half-life of FVIII. Increasing the half-life of FVIII would profound impact the lives of patients with hemophilia A, especially children, by reducing the frequency of infusions. The addition of polyethylene glutamate (PEG) to therapeutic molecules or their carriers has been demonstrated to increase the survival of such molecules in the circulation. To create a longer circulating product, we have developed novel FVIII molecules using site specific PEGylation techniques. We present a characterization of these PEGylated FVIII molecules in terms of the site of PEGylation, the binding of von Willebrand Factor (vWF), and the effect of PEGylation on thrombin digestion, and we compare the one-stage and chromogenic potency test results. The site of PEGylation was determined using MALDI-mass spectrometry. A vWF binding assay was developed using surface plasmon resonance technology (Biacore). The effect of PEGylation on thrombin digestion of the novel constructs was evaluated using MALDI-mass spectrometry, thrombin activation, and potency decay curves following thrombin activation. All novel constructs were PEGylated on the expected target site based on the site of introduced mutation. PEGylation of FVIII appeared to have a slight reduction on vWF-binding capability. The site of PEGylation reduced the ability of thrombin to digest FVIII, as assayed by MALDI-mass spectrometry analysis and by thrombin digestion and decay curves. The size and position of the PEG molecule influenced the extent of FVIII thrombin sensitivity. The one-stage potency assay was more sensitive to the size and position of the attached PEG molecule than the chromogenic potency assay. We report that some PEGylated FVIII molecules are less sensitive to thrombin activation than unmodified FVIII, and that the size and position of the PEG molecule can significantly affect the potency of FVIII. The findings of this study suggest that site-directed PEGylation of FVIII may be a useful technique for the development of FVIII molecules with extended activity in circulation and that careful choice of size and position of the PEG molecule is critical.

scholarly journals Identification of Sources of Inter-Laboratory Variation in Factor VIII Assay

1977 ◽  
Author(s):  
T.B.L. Kirkwood ◽  
C.R. Rizza ◽  
T.J. Snape ◽  
I. Rhymes ◽  
D.E.G. Austen
Keyword(s):  
Factor Viii ◽  
Systematic Difference ◽  
Normal System ◽  
Two Stage ◽  
Initial Dilution ◽  
One Stage ◽  
Collaborative Studies ◽  
Freeze Dried ◽  
Sources Of Variation ◽  
The One

A repeated finding of national and international collaborative studies of standard Factor VIII preparations has been that systematic differences exist between laboratories in their measurement of the relative activities of the same pairs of Factor VIII preparations.A workshop meeting was held at the Oxford Haemophilia Centre (England) during 23rd-26th November 1976 to investigate which of the possible sources of variation between laboratories were responsible. Participants from 16 British laboratories (9 one-stage, 7 two-stage) performed a total of 273 assays using three freeze-dried preparations of differing purity (a plasma, an intermediate and a high purity concentrate). The results of assays with each participant using their normal system established that, if the participants were a representative cross-section, approximately one-third of one-stage laboratories would show a systematic difference from the overall mean of at least 16%, with a similar figure for the two-stage laboratories of 9%. Various features of the assay systems were then modified in a controlled series of experiments. The results showed conclusively that i) differences between reagents accounted for most of the variation between laboratories and, ii) the two-stage assays were, on average, detecting relatively more activity in the more purified preparations than the one-stage assays. The results also suggested that the use of buffer as opposed to haemophilic plasma for the initial dilution of concentrates did not affect the assay results.

Comparative Investigations on Factor VIII Assays

1975 ◽  
Author(s):  
R. Pflugshaupt ◽  
S. Moser ◽  
K. Züger ◽  
R. Bütler
Keyword(s):  
Factor Viii ◽  
High Activity ◽  
Hemophilia A ◽  
Statistical Evaluation ◽  
Two Stage ◽  
One Stage ◽  
Normal Plasma ◽  
Calibration Curves ◽  
Factor Viii Concentrates

Six one stage methods and one two stage method were tested for precision and reproducibility. With each method twenty calibration curves of normal plasma and two lots of Factor VIII concentrates were established. Statistical evaluation revealed only minor differences. Neither one of the methods was optimal for both the physiological-pathological region and the region of high activity preparations.Three selected methods were tested in vivo for accuracy: nine patients with hemophilia A were treated with equal amounts of Factor VIII concentrates or kryoprecipitates respectively. The methods showed different activities for preparations as well as for patient’s plasma. The discrepancy between measured and expected recovery differed for each method.

Mild Hemophilia A Caused by Increased Rate of Factor VIII A2 Subunit Dissociation: Evidence for Nonproteolytic Inactivation of Factor VIIIa In Vivo

Blood ◽  
1999 ◽  
Vol 93 (1) ◽  
pp. 176-183 ◽  
Author(s):  
S.W. Pipe ◽  
A.N. Eickhorst ◽  
S.H. McKinley ◽  
E.L. Saenko ◽  
R.J. Kaufman
Keyword(s):  
Factor Viii ◽  
Missense Mutation ◽  
Time Course ◽  
Hemophilia A ◽  
Specific Activity ◽  
Metabolic Labeling ◽  
Two Stage ◽  
One Stage ◽  
Thrombin Cleavage

Abstract Approximately 5% of hemophilia A patients have normal amounts of a dysfunctional factor VIII (FVIII) protein and are termed cross-reacting material (CRM)-positive. FVIII is a heterodimer (domain structure A1-A2-B/A3-C1-C2) that requires thrombin cleavage to elicit procoagulant activity. Thrombin-activated FVIII is a heterotrimer with the A2 subunit (amino acid residues 373 to 740) in a weak ionic interaction with the A1 and A3-C1-C2 subunits. Dissociation of the A2 subunit correlates with inactivation of FVIII. Recently, a phenotype of CRM-positive hemophilia A patients has been characterized whose plasma displays a discrepancy between their FVIII activities, where the one-stage clotting assay displays greater activity than the two-stage clotting assay. One example is a missense mutation whereARG531 has been substituted by HIS531. An FVIII cDNA construct was prepared containing theARG531HIS mutation and the protein was expressed in COS-1 monkey cells by transient DNA transfection. Metabolic labeling with [35S]-methionine demonstrated that ARG531HIS was synthesized at an equal rate compared with FVIII wild-type (WT) but had slightly reduced antigen in the conditioned medium, suggesting a modest secretion defect. A time course of structural cleavage of ARG531HISdemonstrated identical thrombin cleavage sites and rates of proteolysis as FVIII WT. Similar to the patient phenotypes,ARG531HIS had discrepant activity as measured by a one-stage activated partial thromboplastin time (aPTT) clotting assay (36% ± 9.6% of FVIII WT) and a variation of the two-stage assay using a chromogenic substrate (COAMATIC; 19% ± 6.9% of FVIII WT). Partially purified FVIII WT and ARG531HISproteins were subjected to functional activation by incubation with thrombin. ARG531HIS demonstrated significantly reduced peak activity and was completely inactivated after 30 seconds, whereas FVIII WT retained activity until 2.5 minutes after activation. Because the ARG531HIS missense mutation predicts a charge change to the A2 subunit, we hypothesized that theARG531HIS A2 subunit could be subject to more rapid dissociation from the heterotrimer. The rate of A2 dissociation, using an optical biosensor, was determined to be fourfold faster forARG531HIS compared with FVIII WT. Because the two-stage assay involves a preincubation phase before assay measurement, an increased rate of A2 dissociation would result in an increased rate of inactivation and reduced specific activity.

The Pharmacokinetics Of Turoctocog Alfa Are Consistent Over Different Concentrations and Production Lots

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4783-4783 ◽  
Author(s):  
Víctor Jiménez-Yuste ◽  
Sandra Lejniece ◽  
Robert Klamroth ◽  
Trine Saugstrup ◽  
Judi Moss
Keyword(s):  
Half Life ◽  
Research Funding ◽  
Fixed Effects ◽  
Hemophilia A ◽  
Severe Hemophilia ◽  
Pooled Data ◽  
One Stage ◽  
Chromogenic Assay ◽  
The One ◽  
Pharmacokinetic Difference

Introduction Turoctocog alfa is a B domain truncated human recombinant FVIII for treatment of patients with hemophilia A. The production yields a highly homogenous product with the same tyrosine sulphation as human FVIII. In order to confirm the consistency of turoctocog alfa pharmacokinetics (PK) over different production lots and vial strengths, a clinical trial was performed in 15 patients with severe hemophilia A. Aim To compare the PK of 3 lots of 2000 IU/vial and 1 lot of 3000 IU/vial of turoctocog alfa after i.v. administration of 50 IU/kg in patients with severe haemophilia A. Methods This was a multi-centre, open-label trial investigating the PK of 4 lots of turoctocog alfa (3 lots of 2000 IU/vial; Lots A, B and C, and 1 lot of 3000 IU/vial; Lot D) in patients with severe hemophilia A (FVIII<1%). The trial was performed as a two-period, incomplete block, cross-over trial, in which each patient was allocated at random to a predefined sequence of 2 different lots of turoctocog alfa. The FVIII activity was assessed using both the one-stage clot and chromogenic assays. Both the primary endpoint, normalized AUC (AUC*(planned dose/actual dose)), and the secondary PK endpoints were analyzed by ANCOVA on the log transformed values, with lot, visit and patient as fixed effects. Each of the three 2000 IU/vial lots was compared and tested against the 2 other 2000 IU/vial lots. If not significantly different on a 5% level, the 3 lots were pooled together and tested against the 3000 IU/vial lot. Results Fifteen patients with a mean age of 38.6 years (ranging from 21 to 60 years) were included from 3 hemophilia centres in 3 different countries. Three adverse events (AEs) were reported in the trial by 2 separate patients; all AEs were judged to be unlikely related to the trial product. There was no development of inhibitors. There was no pharmacokinetic difference observed between Lots A, B, C (2000 IU/vials) and there was no pharmacokinetic difference observed between the pooled data from lot A, B and C (2000 IU/vial) and lot D (3000 IU/vial) based on normalized AUC, half-life, incremental recovery and clearance. The estimated mean values (with 90% CI) for the PK parameters based on the chromogenic assay are presented in Table 1. The results were similar for the one-stage clot assay and the chromogenic assay. Conclusions No pharmacokinetic differences were observed between the three 2000 IU/vial lots (Lot A, Lot B and Lot C), nor were there pharmacokinetic differences between Lot D (3000 IU/vial) and pooled data from Lots A, B and C, based on normalized AUC, half-life, incremental recovery and clearance. There were no safety concerns and no inhibitor development in the trial. Disclosures: Jiménez-Yuste: Novo Nordisk: Consultancy, Research Funding, Speakers Bureau. Klamroth:Novo Nordisk, CSL Behring, Bayer, Baxter, Pfizer: Honoraria, Research Funding. Saugstrup:Novo Nordisk: Employment. Moss:Novo Nordisk: Employment.

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