| 1. |
|
|
| 2. |
|
|
| 3. |
- Borel-Derlon, A., et al.
(author)
-
Treatment of severe von Willebrand disease with a high-purity von Willebrand factor concentrate (Wilfactin (R)): a prospective study of 50 patients
- 2007
-
In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 5:6, s. 1115-1124
-
Journal article (peer-reviewed)abstract
- Background and objectives: A plasma-derived von Willebrand factor (VWF) concentrate with low factor VIII (FVIII) content was specifically developed to treat von Willebrand disease (VWD). Efficacy and safety were investigated by merging the results of two comparable protocols conducted prospectively in 5 European and 12 French centers. Methods and results: Fifty patients with clinically severe VWD (72% had VWF ristocetin cofactor activity less than 10 IU dL(-1) and 46% had FVIII < 20 IU dL(-1)) were treated with the concentrate as the only therapy, except for clinical situations requiring a priming dose of FVIII to rapidly correct an intrinsic coagulation defect. A total of 139 spontaneous bleeding episodes were treated; only 53 (38%) needed a concomitant FVIII dose. Outcome was excellent or good in 89% of the episodes. Forty-four patients underwent 108 surgical or invasive procedures. Outcome was excellent or good in 95 scheduled procedures (only VWF was infused) and 13 emergency procedures (a priming FVIII dose was co-administered with the first VWF infusion). There were no thrombotic complications and none of the 18 patients with type 3 VWD developed anti-VWF or anti-FVIII antibodies. Conclusions. This concentrate safely and effectively provides hemostasis in patients with clinically severe VWD.
|
|
| 4. |
- Goudemand, J, et al.
(author)
-
Pharmacokinetic studies on Wilfactin((R)), a von Willebrand factor concentrate with a low factor VIII content treated with three virus-inactivation/removal methods
- 2005
-
In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 3:10, s. 2219-2227
-
Journal article (peer-reviewed)abstract
- Objective: In order to correct the primary von Willebrand factor (VWF) defect and avoid supra-physiologic plasma levels of factor VIII, a pure VWF concentrate almost devoid of FVIII was developed and used in France since 1989. Methods: The pharmacokinetic (PK) profile of the most recent version of this concentrate (Wilfactin (R); LFB, Les Ulis, France), treated with three virus-inactivation/removal methods (solvent/detergent, 35 nm filtration, dry heat treatment), was investigated in 25 patients. Seventeen patients with various types of clinically severe von Willebrand disease (VWD) were included in a crossover, randomized trial carried out in five European centers and comparing Wilfactin (R) with concentrates containing both FVIII and VWF (FVIII/VWF). Eight type 3 VWD patients were included in another trial carried out in six French centers comparing Wilfactin (R) with its previous version (Facteur Willebrand-LFB (R); LFB) that adopted one virus-inactivation method only. Results: For both the measurements evaluated in this study (VWF antigen, VWF:Ag; and VWF ristocetin co-factor activity, VWF:RCo), Wilfactin (R) had a PK profile similar to that of the FVIII/VWF concentrates and of Facteur Willebrand-LFB (R). VWF:RCo and VWF:Ag recoveries were 2.1 +/- 0.3 and 1.8 +/- 0.3 per IU kg(-1) respectively, and the half-lives were 12.4 +/- 1.8 and 15.9 +/- 1.5 h. The FVIII synthesis rate was 5.8 +/- 1.0 IU dL(-1) h(-1), with a half-life of 15.8 +/- 2.4 h. Conclusion: The PK of VWF and FVIII have not been altered by the three virus-inactivation/removal steps during the manufacturing of Wilfactin (R).
|
|
| 5. |
- Tiede, A, et al.
(author)
-
Safety and pharmacokinetics of subcutaneously administered recombinant activated factor VII (rFVIIa).
- 2011
-
In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 9, s. 1191-1199
-
Journal article (peer-reviewed)abstract
- Background: Recombinant factor VIIa (rFVIIa) is used to treat bleeds in hemophilia patients with inhibitors. A subcutaneous formulation could potentially improve its half-life and make it suitable for prophylactic treatment. Objectives: A study was conducted to determine the safety of subcutaneously administered rFVIIa in patients with hemophilia and the pharmacokinetic profile (including bioavailability). Patients/Methods: This was a multi-center, open-label, cross-over comparison of single doses of intravenous rFVIIa 90 μg/kg and a new formulation of rFVIIa for subcutaneous injection at dose levels of 45, 90, 180, 270 and 360 μg/kg. Sixty subjects (12 per dose cohort) with hemophilia A or B were enrolled. Results: Subcutaneously administered rFVIIa showed lower mean peak plasma concentrations and prolonged FVII activity (C(max) :0.44-5.16 IU/mL [across doses], t(1/2) :12.4 hours, t(max) :5.6 hours) compared with intravenously administered rFVIIa (C(max) :51.7 IU/mL, t(1/2) :2.7 hours, t(max) :<10 minutes). The absolute bioavailability of subcutaneous rFVIIa ranged from 21.1%-30.1% across dose levels. Dose proportionality was observed within a 2-fold dose increase but not across the full dose range. No thromboembolic events, drug-related serious adverse events, severe injection-site reactions or neutralizing antibodies were reported (primary endpoint). Mild and moderate injection-site reactions were more frequent with subcutaneous than with intravenous injections. Conclusion: This phase I clinical trial did not identify safety concerns of prolonged exposure to rFVIIa administered subcutaneously in single doses to hemophilia patients.
|
|
| 6. |
- Varadi, K, et al.
(author)
-
Monitoring the bioavailability of FEIBA with a thrombin generation assay
- 2003
-
In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 1:11, s. 2374-2380
-
Journal article (peer-reviewed)abstract
- Background: Hemophilia A patients with inhibitors are generally treated with preparations containing activated coagulation factors to achieve hemostasis by bypassing factor (F)VIII. Objectives: We developed an assay for monitoring the kinetic of thrombin generation in human FVIII inhibitor plasma reconstituted in vitro with activated prothrombin complex concentrate, FEIBA, and in plasma samples from hemophilia A patients taken after FEIBA treatment. Patients and methods: For pharmacokinetic studies three patients with severe hemophilia A and with a high-titer inhibitor received a single dose of FEIBA. Repeated FEIBA treatment was monitored in one patient with acquired hemophilia A. Coagulation was triggered in citrated plasma by adding a low concentration of tissue factor/phospholipid complex and CaCl2 in the presence of a fluorogenic thrombin substrate. The intensity of the fluorescence signal (FU) was continuously monitored, and the rate of increase in the fluorescence signal for every time point, which reflects the actual thrombin concentrations, was calculated. Results: The maximum rate of substrate conversion, which indicates the highest thrombin concentration, was approximately 1900 FU min(-1) in a normal plasma pool. Practically no thrombin generation was observed in the FVIII inhibitor plasma, but when it was spiked with FEIBA, the rate and the peak of thrombin generation increased dose-dependently to close to normal. Plasma samples from FVIII inhibitor patients treated with a single dose of FEIBA had an improved thrombin maximum within an hour after treatment, which gradually returned to baseline values with a half-life of 4-7 h. Changes in the characteristic parameters of thrombin generation coincided with the repeated administration of FEIBA in a patient with acquired hemophilia A. Conclusions: This assay enables the pharmacodynamic and pharmacokinetic properties of bypassing therapies to be monitored, thus helping to optimize treatment.
|
|
| 7. |
- Abshire, T, et al.
(author)
-
Prophylaxis Escalation in Severe von Willebrand Disease: A Prospective Study from the von Willebrand Disease Prophylaxis Network.
- 2015
-
In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 13:9, s. 1585-1589
-
Journal article (peer-reviewed)abstract
- Treatment of mucosal bleeding (epistaxis, gastrointestinal and menorrhagia) and joint bleeding remains problematic in clinically severe von Willebrand Disease (VWD). Patients are often unresponsive to treatment (e.g. desmopressin or antifibrinolytic therapy) and may require von Willebrand (VW) factor replacement therapy. There are little data on the use of prophylaxis in VWD and none applied in a prospective, treatment escalation design.
|
|
| 8. |
- Brekkan, Ari, et al.
(author)
-
Population Pharmacokinetics of Plasma-Derived Factor IX : Procedures for Dose Individualization
- 2016
-
In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 14:4, s. 724-732
-
Journal article (peer-reviewed)abstract
- Background: Population pharmacokinetic (POPPK) models describing factor IX (FIX) activity levels in plasma, in combination with individual FIX measurements, may be used to individualize dosing in the treatment of hemophilia B. Objectives: The aim was to reevaluate a previously developed POPPK model for FIX activity and to explore the number and timing of FIX samples required in pharmacokinetic (PK) dose individualization. Methods: The POPPK model was reevaluated using an extended data set. Several sampling schedules, varying with respect to the timing and number of samples, were evaluated in a simulation study with relative dose errors compared between schedules. The performance of individually calculated doses was compared with commonly prescribed FIX doses with respect to the number of patients with a trough FIX activity > 0.01 U mL(-1). Results and conclusions: A three-compartment PK model best described the FIX activity levels. The number and timing of samples greatly influenced imprecision in dose prediction. Schedules with single samples taken on both day 2 and day 3 were identified as being convenient schedules with an acceptable performance level. Individually calculated doses performed better with respect to patient target attainment than a fixed 40 U kg(-1) dose regardless of how many samples were available to calculate individual doses. The results of this study suggest that PK dose tailoring with limited sampling may be applicable for plasma-derived FIX products.
|
|
| 9. |
|
|
