Population pharmacokinetics of the von Willebrand factor-factor VIII interaction in patients with von Willebrand disease

Replacement therapy in pregnant women with von Willebrand disease during delivery: Factor levels and pharmacokinetics

Limited data are available on VWF activity (VWF:Act) and factor VIII (FVIII:C) levels during delivery after VWF/FVIII concentrate administration in women with von Willebrand disease (VWD). We aimed to evaluate treatment with a specific VWF/FVIII concentrate on factor levels in women with VWD during delivery and the postpartum period. A retrospective single-center study was conducted between January 1, 2008, and August 1, 2022. Pregnant women treated with Haemate®P during delivery were included if they had ≥2 consecutive VWF:Act and FVIII:C measurements post-infusion. VWF:Act/FVIII:C levels were compared to predefined target levels. A population pharmacokinetic (PopPK) model was developed, estimating VWF and FVIII pharmacokinetics after Haemate®P administration. Nineteen women were included. Targeted VWF:Act/FVIII:C peak levels were achieved after the first infusion (≥1.00 IU/mL, n = 12; ≥1.50 IU/mL, n = 5), and all VWF:Act/FVIII:C trough levels remained ≥0.50 IU/mL during first 72 h of treatment. All women had pretreatment FVIII:C levels ≥1.00 IU/mL, except one woman with type 2N, which was significantly higher than FVIII:C levels during the third trimester (median increase: 0.42 IU/mL, interquartile range: [0.12-0.92]). FVIII:C trough levels increased during treatment, median 2.05 IU/mL [1.65-2.71]. Nine women (47%) experienced postpartum hemorrhage and no thrombosis occurred. A one-compartment PopPK model adequately described VWF:Act/FVIII:C levels. Targeted VWF:Act/FVIII:C peak levels were achieved with the prescribed dosing regimens. VWF clearance was similar to that in nonpregnant individuals. Both pretreatment and FVIIIC trough levels during treatment were high with reduced FVIII clearance. Monitoring VWF:Act/FVIII:C levels is recommended for optimizing target levels and enriching the current PopPK model, improving VWF:Act/FVIII:C level predictions, and achieving more effective dosing.

Prophylaxis in von Willebrand disease with von Willebrand factor concentrate and nonfactor therapies

This manuscript summarizes the current status of prophylaxis and novel potential therapies to prevent bleeding in patients with von Willebrand disease (VWD). VWD is the most common inherited bleeding disorder, which is associated mainly with mucocutaneous bleeding and bleeding during surgical and dental interventions. More severely affected VWD patients, mostly those with type 2 and type 3, can also suffer from joint, muscle, and gastrointestinal bleeds. Most patients with mild and moderate VWD are treated with desmopressin. The majority of patients with type 2 and 3 are treated with von Willebrand factor concentrates, with or without factor VIII. These patients suffer from severe and frequent bleeds and may require regular infusions of von Willebrand factor concentrate to prevent bleeding, so-called prophylaxis, 1 to 3 times per week. In this article, we review the current status of prophylaxis in VWD. We will also discuss emerging treatments that may be used as long-term prophylaxis in patients with severe VWD. We include relevant new data on this topic that were presented during the 2024 International Society on Thrombosis and Haemostasis (ISTH) Congress.

Kinetic Modeling for BT200 to Predict the Level of Plasma-Derived Coagulation Factor VIII in Humans

Lack of Factor VIII (FVIII) concentrates is one of limiting factors for Hemophilia A prophylaxis in resource-limited countries. Rondaptivon pegol (BT200) is a pegylated aptamer and has been shown to elevate the level of von Willebrand Factor (VWF) and FVIII in previous studies. A population pharmacokinetic model for BT200 was built and linked to the kinetic models of VWF and FVIII based on reasonable assumptions. The developed PK/PD model for BT200 described the observed kinetic of BT200, VWF, and FVIII in healthy volunteers and patients with mild-to-moderate hemophilia A from two clinical trials. The developed model was evaluated using an external dataset in patients with severe hemophilia A taking recombinant FVIII products. The developed and evaluated PK/PD model was able to describe and predict concentration-time profiles of BT200, VWF, and FVIII in healthy volunteers and patients with hemophilia A. Concentration-time profiles of FVIII were then predicted following coadministration of plasma-derived FVIII concentrate and BT200 under various dosing scenarios in virtual patients with severe hemophilia A. Plasma-derived products, that contain VWF, are more accessible in low-resource countries as compared to their recombinant counterparts. The predicted time above 1 and 3 IU/dL FVIII in one week was compared between scenarios in the absence and presence of BT200. A combination dose of 6 mg BT200 once weekly plus 10 IU/kg plasma-derived FVIII twice weekly maintained similar coverage to a 30 IU/kg FVIII thrice weekly dose in absence of BT200, representing only 22% of the FVIII dose per week.

Diagnosis and treatment of von Willebrand disease in 2024 and beyond

MANUSCRIPT BACKGROUND AND AIM

The diagnosis and clinical care of patients with von Willebrand disease (VWD) has continued to evolve since the characterization of the von Willebrand factor (VWF) gene in 1985. This condition is almost certainly the most common inherited bleeding disorder, and the major symptomatic burden of the disease is experienced by females during their reproductive years. Diagnosis relies on the identification of a personal and family history of excessive mucocutaneous bleeding, and laboratory features consistent with quantitative and/or qualitative abnormalities of VWF. This review focuses on three aspects of VWD management, with current updates and a look into the future.

MANUSCRIPT THEMES

First, we will address the role of genetics in the diagnosis and possible therapies for VWD. With current technologies, VWD genetic diagnosis is usually confined to the confirmation of type 2 subtypes of the disease and type 3 VWD analysis for family planning. While type 3 VWD is a potential candidate for the application of gene therapy, no treatments are currently close to entering the clinic. Second, the peri-procedural management of patients with VWD remains an important element of care. The choice of product, its dose and schedule all require careful consideration depending upon the type and disruptive nature of the planned procedure. Lastly, in addition to gene therapy, several other novel therapeutic interventions are also being developed for bleeding and prophylaxis in VWD. These include a VWF aptamer interfering with VWF clearance and bioengineered forms of VWF.

The road to implementation of pharmacokinetic-guided dosing of factor replacement therapy in hemophilia and allied bleeding disorders. Identifying knowledge gaps by mapping barriers and facilitators

Clinical guidelines and expert groups recommend the use of pharmacokinetic (PK)-guided dosing of factor replacement therapy for the treatment of bleeding disorders, especially for patients with hemophilia. Although PK-guided dosing is increasingly applied, it is generally not considered standard clinical practice. The aim of this scoping review is to map barriers and facilitators for the implementation of PK-guided dosing in clinical practice and to identify knowledge gaps. A literature search was performed and 110 articles were included that describe PK-guided dosing in patients with bleeding disorders, mostly hemophilia A. We defined two overarching themes, efficacy and feasibility, and discuss five topics within each theme. For each topic, barriers, facilitators and knowledge gaps were described. Although consensus was found with regard to some topics, contradicting reports were found for others, especially with respect to the efficacy of PK-guided dosing. These contradictions highlight the need for future research to elucidate current ambiguities.

Von Willebrand Factor Multimer Analysis and Classification: A Comprehensive Review and Updates

Von Willebrand factor (VWF) is a multimeric glycoprotein with essential roles in primary hemostasis. Patients with von Willebrand disease (VWD), due to quantitative and/or qualitative defects of VWF usually experience mucocutaneous bleeding. Based on the laboratory results of VWF antigen, various VWF activities, factor VIII activity, and VWF multimer patterns, VWD can be categorized as type 1, 2, and 3 VWD. VWF multimer analysis by either manual or semi-automated electrophoresis and immunoblotting is a critical part of the laboratory testing to differentiate type 1, type 2 VWD, and subtypes of type 1 or 2 VWD. The multimer distribution patterns can also help to understand the underlying molecular mechanism of VWF synthesis, multimerization, and clearance defects in VWD. This review will cover VWF synthesis, multimerization, secretion, VWF multimer analysis, and VWF multimer interpretation of various types and subtypes of VWD.

Pharmacokinetic-Pharmacodynamic Comparison of Recombinant and Plasma-Derived von Willebrand Factor in Patients with von Willebrand Disease Type 3

Background

Recombinant von Willebrand factor (rVWF, vonicog alfa, Vonvendi/Veyvondi, Takeda Pharmaceuticals USA, Lexington, MA) and several plasma-derived VWF/factor VIII (pdVWF/FVIII) concentrates are available for treating bleeding episodes in patients with von Willebrand disease (VWD).

Purpose

To develop population pharmacokinetic (PK)/pharmacodynamic (PD) models that describe VWF:ristocetin cofactor (VWF:RCo) activity and its relationship with FVIII activity (FVIII:C) over time following intravenous administration of either rVWF or a pdVWF/FVIII concentrate (VWF:RCo/FVIII:C 2.4:1) in patients with VWD; to use the final PK/PD models for an in silico comparison of rVWF and pdVWF/FVIII.

Methods

The population PK model for rVWF was based on data from four clinical studies in which rVWF was administered to adult patients with VWD type 1, 2 or 3 (phase 1: NCT00816660; phase 3: NCT01410227 and NCT02283268) or severe hemophilia A (phase 1: EudraCT 2011-004314-42). The PK and PK/PD models for pdVWF/FVIII were based on data from the phase 1 study (NCT00816660) in patients with type 3 VWD who received either rVWF plus recombinant FVIII (rFVIII, octocog alfa, ADVATE^®, Takeda Pharmaceuticals USA, Lexington, MA, USA) or pdVWF/FVIII.

Results

There was a marked difference in clearance following rVWF administration compared with pdVWF/FVIII in type 3 VWD, leading to a ~1.75 longer mean residence time (ie, persistence of VWF:RCo activity in the body) and half-life for rVWF versus pdVWF/FVIII. Simulations showed that following repeated administration of rVWF (50 IU/kg), a FVIII:C activity of >40 IU/dL can be maintained for the full 72 h dosing interval.

Conclusion

The slower elimination of VWF:RCo following rVWF administration results in a prolonged effect on FVIII turnover compared with pdVWF/FVIII administration.

SYMPHONY consortium: Orchestrating personalized treatment for patients with bleeding disorders

BACKGROUND

Treatment choices for individual patients with an inborn bleeding disorder are increasingly challenging due to increasing options and rising costs for society. We have initiated an integrated interdisciplinary national research programme.

OBJECTIVES

The SYMPHONY consortium strives to orchestrate personalized treatment in patients with an inborn bleeding disorder, by unravelling the mechanisms behind inter-individual variations of bleeding phenotype.

PATIENTS

The SYMPHONY consortium will investigate patients with an inborn bleeding disorder, both diagnosed and not yet diagnosed.

RESULTS

Research questions are categorized under the themes: 1) Diagnosis; 2) Treatment; and 3) Fundamental research and consist of workpackages addressing specific domains. Importantly, collaborations between patients and talented researchers from different areas of expertise promise to augment the impact of the SYMPHONY consortium, leading to unique interactions and intellectual property.

CONCLUSIONS

SYMPHONY will perform research on all aspects of care, treatment individualization in patients with inborn bleeding disorders as well as diagnostic innovations and results of molecular genetics and cellular model technology with regard to the hemostatic process. We believe that these research investments will lead to health care innovations with long-term clinical and societal impact. This consortium has been made possible by a governmental, competitive grant from the Netherlands Organization for Scientific Research (NWO) within the framework of the NWA-ORC Call grant agreement NWA.1160.18.038.