Analysis of current perioperative management with Haemate® P/Humate P® in von Willebrand disease: Identifying the need for personalized treatment

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.

Perioperative hemostasis management in patients with von Willebrand disease: an institutional experience

OBJECTIVES

Patients with von Willebrand disease (vWD) undergoing surgery are routinely treated with von Willebrand factor (vWF)/factor VIII (FVIII) concentrate to control bleeding risk, but consensus is lacking on optimal dosing. This study aimed to evaluate the efficacy and safety of tailored doses of vWF/FVIII concentrate according to intervention-associated bleeding risk in vWD patients undergoing surgery.

METHODS

This was a retrospective analysis of vWD patients who underwent surgical procedures at a haemophilia centre. Patients received vWF/FVIII concentrate with dosage and duration of treatment dependent on intervention type (dental, gynaecological, abdominal or orthopaedic/traumatic) and bleeding risk (moderate/high).

RESULTS

Eighty-three surgical procedures (42 patients) were included. Median preoperative loading doses of vWF/FVIII concentrate were 29.9 IU/kg and 35.7 IU/kg for interventions with moderate ( n  = 16) or high ( n  = 67) bleeding risk, respectively. The median perioperative dose was highest in orthopaedic or trauma-related surgery (140 IU/kg) and lowest in dental or gynaecological interventions (76.4 IU/kg and 80.0 IU/kg, respectively). During follow-up, no bleeding or other complications were observed in 95% of patients.

CONCLUSIONS

Individually tailored doses of vWF/FVIII concentrate according to intervention-associated bleeding risk were effective in preventing postoperative bleeding, with few complications observed. These doses may be used as guidance in routine clinical care.

Key Drivers of Coagulation Factor Use in Von Willebrand Disease During Hospitalization: An Overview of the French BERHLINGO Cohort

BACKGROUND

Von Willebrand disease (VWD) is the most common inherited bleeding disorder. However, studies of hospitalisation patterns with replacement treatment are scarce.

OBJECTIVES

The aim of this study was to investigate the current therapeutic management of VWD and determine the key drivers of coagulation factor uses in patients during hospitalisation.

METHODS

Hopscotch-WILL was a multi-centric retrospective study conducted over a 48-month period in any patients with VWD. The data were collected from the BERHLINGO Research Database and the French Hospital database.

RESULTS

A total of 988 patients were included; 153 patients (15%) were hospitalised during 293 stays requiring treatment with von Willebrand factor (VWF) concentrates-pure or in association with Factor VIII (FVIII). Their median basal concentrations of VWF and FVIII were significantly lower than in untreated patients: VWF antigen < 30 IU/dL, VWF activity < 20 IU/dL and FVIII:C < 40 IU/dL. The median (interquartile range) concentrate consumption was similar between highly purified VWF or VWF combined with FVIII (72 [110] vs 57 [89] IU/kg/stay, p = 0.154). The use of VWF was highly heterogeneous by VWD type; type 3 had a particularly high impact on VWF consumption in non-surgical situations. The main admissions were for ear/nose/throat, hepato-gastroenterology, and trauma/orthopaedic conditions, besides gynaecological-obstetric causes in women.

CONCLUSIONS

The use of VWF concentrates is mostly influenced by low basal levels of VWF and FVIII, but also by VWD type or the cause for hospitalisation. These results could inform future studies of newly released recombinant VWF.

Neurological Complications Associated with Hereditary Bleeding Disorders

PURPOSE OF REVIEW

Hereditary bleeding disorders may have a wide variety of clinical presentations ranging from mild mucosal and joint bleeding to severe central nervous system (CNS) bleeding, of which intracranial hemorrhage (ICH) is the most dreaded complication. In this review, we will discuss the pathophysiology of specific hereditary bleeding disorders, namely, hemophilia A, hemophilia B, and von Willebrand disease (vWD); their clinical manifestations with a particular emphasis on neurological complications; a brief overview of management strategies pertaining to neurological complications; and a review of literature guiding treatment strategies.

RECENT FINDINGS

ICH is the most significant cause of morbidity and mortality in patients with hemophilia. Adequate control of bleeding with the administration of specific factors or blood products, identification of risk factors for bleeding, and maintaining optimal coagulant activity are essential for appropriately managing CNS bleeding complications in these patients. The administration of specific recombinant factors is tailored to a patient's pharmacokinetics and steady-state levels. During acute bleeding episodes, initial factor activity should be maintained between 80 and 100%. Availability of monoclonal antibody Emicizumab has revolutionized prophylactic therapies in patients with hemophilia. Management of ICH in patients with vWD involves using plasma-derived factor concentrates, recombinant von Willebrand factor, and supportive antifibrinolytic agents individualized to the type and severity of vWD. Hemophilia and vWD are the most common hereditary bleeding disorders that can predispose patients to life-threatening CNS complications-intracranial bleeds, intraspinal bleeding, and peripheral nerve syndromes. Early care coordination with a hematologist can help develop an effective prophylactic regimen to avoid life-threatening bleeding complications in these patients. Further research is needed to evaluate using emicizumab as an on-demand treatment option for acute bleeding episodes in patients with hemophilia.

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.

Perioperative Outcomes of Patients with Bleeding Disorders Undergoing Major Surgery at an Academic Hemophilia Treatment Center

Persons with bleeding disorders (PwBD) are at high risk for bleeding with invasive procedures. However, the risk of bleeding in PwBD undergoing major surgery and outcomes of patients managed perioperatively at a hemophilia treatment center (HTC) are not well described. We performed a retrospective review of surgical outcomes among PwBD undergoing major surgery between January 1st, 2017 and December 31st, 2019 at the Cardeza Foundation Hemophilia and Thrombosis Center in Philadelphia, PA. The primary outcome was postoperative bleeding, assessed according to the ISTH-SSC's 2010 definition. Secondary outcomes included use of unplanned postoperative hemostatic therapy, LOS, and 30-day readmission rate. Results were compared to non-PwBD population from a surgical database, matched for surgery, age, and sex. During the study period, 50 PwBD underwent 63 major surgeries. The most common diagnoses were VWD (64%) and hemophilia A (20.0%). The most common surgical procedure category was orthopedic (33.3%), predominantly arthroplasties. Postoperatively,4.8% of procedures were complicated by major bleeding and 1.6% by non-major bleeding. The mean LOS was 1.65 days, and 30-day readmission rate was 1.6%. In comparison to matched, non-PwBD patients in a national surgical database undergoing the same procedures, study patients had a similar rate of bleeding complications per procedure (5.0% vs 1.04% P = .071, Fisher's exact test). PwBD undergoing major surgeries have low rates of major bleeding when receiving comprehensive care at an HTC. Bleeding and hospital readmission rates were similar to non-PwBD baseline in a large database.

Effectiveness of long-term prophylaxis using pdFVIII/VWF concentrate in patients with inherited von Willebrand disease

Background

Patients with symptomatic von Willebrand disease (VWD) should be offered long‐term prophylaxis (LTP) to prevent recurrent bleedings. Our objective was to evaluate the effectiveness and safety of Voncento®, a plasma‐derived FVIII/VWF concentrate (ratio 1:2.4), administrated in LTP.

Methods

We included patients from the OPALE study (May 2016 to April 2021), a French multicenter observational study following patients with inherited VWD, who received a Voncento® LTP during the study period.

Results

Among the 130 OPALE‐study patients, 23 patients (12 women) received a LTP and were therefore included. The median (range) age was 16 (1–85) years; 16 patients were type 3, 1 was type 2A, 6 were type 2B. Before inclusion, 19 (83%) were under LTP and 4 (17%) received on‐demand (OD) treatment. The indications for initiating prophylaxis in the overall population were joint bleeding (43%), ear, nose, and throat (ENT) bleeding including epistaxis or oral bleeding (39%), and recurrent muscle hematoma (22%). The medians (ranges) dose of Voncento® per infusion, frequency, and weekly dose were 45 (33–109) IU/kg, 2 infusions per week, and 96 (44–222) IU/kg/week, respectively. The median (range) annualized bleeding rate (ABR) was 0.8, 0.7 (0–3.5), and 0 (0–2.3) for type 2A, 2B, 3 patients, respectively. There was no difference regarding to the dose, frequency of infusion, or in terms of ABR in 9/19 patients who replaced previous concentrates with Voncento®. During the study period, no adverse event was reported.

Conclusion

These results suggest that Voncento® is effective to prevent recurrent bleedings in patients symptomatic VWD.

Sixth Åland Island Conference on von Willebrand disease

Introduction

The sixth Åland Islands Conference on von Willebrand disease (VWD) on the Åland Islands, Finland, was held from 20 to 22 September 2018.

Aim

The meeting brought together experts in the field of VWD from around the world to share the latest advances and knowledge in VWD.

Results and discussion

The topics covered both clinical aspects of disease management, and biochemical and laboratory insights into the disease. The clinical topics discussed included epidemiology, diagnosis and treatment of VWD in different countries, management of children with VWD, bleeding control during surgery, specific considerations for the management of type 3 VWD and bleeding control in women with VWD. Current approaches to the management of acquired von Willebrand syndrome were also discussed. Despite significant advances in the understanding and therapeutic options for VWD, there remain many challenges to be overcome in order to optimise patient care. In comparison with haemophilia A, there are very few registries of VWD patients, which would be a valuable source of data on the condition and its management. VWD is still underdiagnosed, and many patients suffer recurrent or severe bleeding that could be prevented. Awareness of VWD among healthcare practitioners, including non‐haematologists, should be improved to allow timely diagnosis and intervention. Diagnosis remains challenging, and the development of fast, simple assays may help to facilitate accurate and rapid diagnosis of VWD.

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.

Use of the von Willebrand factor concentrate with low factor VIII content to manage patients with inherited von Willebrand disease requiring surgical or secondary long-term prophylaxis: An expert opinion paper from an Italian panel

OBJECTIVES

The present review aims to summarize the state-of-the-art von Willebrand disease (VWD) treatment focusing on specific clinical settings (obstetrics, surgery, long-term prophylaxis and comorbidities) as well as on the use of a Von Willebrand factor (VWF) concentrate with low FVIII content.

METHODS

Literature research and case reports.

RESULTS AND CONCLUSIONS

Considering that patients affected by VWD have an intact ability to synthesize FVIII, in order to avoid excessive levels of FVIII, a highly purified plasma VWF concentrate with low FVIII content could be particularly useful in those patients and clinical circumstances at high thrombotic risk as well as for long-term prophylaxis. When deciding the optimal therapeutic strategy, physicians should take into account both the patient's history and the differences among available concentrates according to the clinical situations requiring treatment.

Is pharmacokinetic-guided dosing of desmopressin and von Willebrand factor-containing concentrates in individuals with von Willebrand disease or low von Willebrand factor reliable and feasible? A protocol for a multicentre, non-randomised, open label cohort trial, the OPTI-CLOT: to WiN study

INTRODUCTION

Von Willebrand disease (VWD) is a bleeding disorder, caused by a deficiency or defect of von Willebrand factor (VWF). In case of medical procedures or bleeding, patients are treated with desmopressin and/or VWF-containing concentrates to increase plasma VWF and factor VIII (FVIII). However, in many cases these factor levels are outside the targeted range. Therefore, population pharmacokinetic (PK) models have been developed, which aim to quantify and explain intraindividual and interindividual differences in treatment response. These models enable calculation of individual PK parameters by Bayesian analysis, based on an individual desmopressin test or PK profile with a VWF-containing concentrate. Subsequently, the dose necessary for an individual to achieve coagulation factor target levels can be calculated.

METHODS AND ANALYSIS

Primary aim of this study is to assess the predictive performance (the difference between predicted and measured von VWF activity and FVIII levels) of Bayesian forecasting using the developed population PK models in four different situations: (A) desmopressin testing (n≥30); (B) medical procedures (n=70; 30 receiving desmopressin, 30 receiving VWF-containing concentrate and 10 receiving a combination of both); (C) bleeding episodes (n=20; 10 receiving desmopressin and 10 receiving VWF-containing concentrate) and (D) prophylaxis with a VWF-containing concentrate (n=3 to 5). Individuals with all types of VWD and individuals with low VWF (VWF 0.30-0.60 IU/mL) will be included. Reliability and feasibility of PK-guided dosing will be tested by assessing predictive performance, treatment duration, haemostasis, patient satisfaction and physician satisfaction.

ETHICS AND DISSEMINATION

The OPTI-CLOT:to WiN study was approved by the medical ethics committee of the Erasmus MC, University Medical Centre Rotterdam, the Netherlands. Results of the study will be communicated through publication in international scientific journals and presentation at (inter)national conferences.

TRIAL REGISTRATION NUMBER

NL7212 (NTR7411); Pre-results, EudraCT 2018-001631-46.

Surgical management of patients with von Willebrand disease: summary of 2 systematic reviews of the literature

von Willebrand disease (VWD) is the most common inherited bleeding disorder. The management of patients with VWD who are undergoing surgeries is crucial to prevent bleeding complications. We systematically summarized the evidence on the management of patients with VWD who are undergoing major and minor surgeries to support the development of practice guidelines. We searched Medline and EMBASE from inception through October 2019 for randomized clinical trials (RCTs), comparative observational studies, and case series that compared maintaining factor VIII (FVIII) levels or von Willebrand factor (VWF) levels at >0.50 IU/mL for at least 3 days in patients undergoing major surgery, and those with options for perioperative management of patients undergoing minor surgery. Two authors screened and abstracted data and assessed the risk of bias. We conducted meta-analyses when possible. We evaluated the certainty of the evidence using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. We included 7 case series for major surgeries and 2 RCTs and 12 case series for minor surgeries. Very-low-certainty evidence showed that maintaining FVIII levels or VWF levels of >0.50 IU/mL for at least 3 consecutive days showed excellent hemostatic efficacy (as labeled by the researchers) after 74% to 100% of major surgeries. Low- to very-low-certainty evidence showed that prescribing tranexamic acid and increasing VWF levels to 0.50 IU/mL resulted in fewer bleeding complications after minor procedures compared with increasing VWF levels to 0.50 IU/mL alone. Given the low-quality evidence for guiding management decisions, a shared-decision model leading to individualized therapy plans will be important in patients with VWD who are undergoing surgical and invasive procedures.

Prophylactic management of patients with von Willebrand disease

Von Willebrand disease, the most common inherited bleeding disorder that affects both males and females, is due to quantitative or qualitative defects of the multimeric glycoprotein von Willebrand factor, which cause mucous membrane bleeding but also soft tissue bleeding owing to the secondary deficiency of factor VIII. The aim of treatment is to correct this dual defect of hemostasis. In addition to the episodic management of bleeding episodes, therapy includes their short- or long-term prevention. Short-term prophylaxis is mainly warranted in order to provide effective hemostatic coverage to patients undergoing surgery or invasive procedures and to affected women at the time of delivery or during menstruations associated with excessive bleeding. The aim of long-term prophylaxis is to prevent bleeding in particular categories of patients at increased risk of frequent and spontaneous bleeding in the joints, nose, and gastrointestinal tract.

Economic Burden Associated with Major Surgery in Patients with von Willebrand Disease: A United States Retrospective Administrative Database Analysis

Purpose

To estimate the incremental economic burden of major surgeries in patients with von Willebrand disease (VWD).

Patients and Methods

This was a retrospective analysis of the IBM Health MarketScan^® database (2008–2018). Patients with at least two healthcare visits for VWD in the database who had undergone at least one major surgery unrelated to VWD (identified via International Classification of Diseases, Ninth and Tenth Revisions procedure codes) were included. Patients without VWD with major surgeries were selected from a 1% random database sample. All patients had ≥12 months of continuous healthcare plan enrollment before and following their first major surgery. Patients with VWD were matched (1:1) with patients without VWD using propensity score matching. Regression models compared healthcare resource utilization and costs between the matched cohorts over a 12-month period after patients’ index major surgery.

Results

After propensity score matching, 2972 pairs were selected. Musculoskeletal and digestive surgeries were the two most common major surgeries (patients with VWD, 39.6% and 25.0%; without VWD, 37.1% and 23.4%, respectively). Patients with VWD were significantly more likely (p<0.0001) to have an inpatient admission (odds ratio = 1.71; 95% confidence interval [CI] 1.52–1.92) or emergency room visit (odds ratio = 1.41; 95% CI 1.25–1.59) than patients without VWD. The numbers of inpatient admissions (incidence rate ratio [IRR] = 1.47; 95% CI 1.35–1.60), emergency room visits (IRR = 1.44; 95% CI 1.31–1.59), and outpatient visits (IRR = 1.16; 95% CI 1.11–1.21) per patient were also significantly greater for patients with VWD than for those without VWD (p<0.0001). Patients with VWD incurred significantly higher (p<0.0001) total healthcare costs (medical and pharmacy) per patient than patients without VWD ($50,733.89 versus $30,154.84, respectively).

Conclusion

Healthcare resource utilization and associated costs among patients undergoing major surgeries were significantly higher for those with VWD than for patients without VWD.

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

Recent studies have reported that patients with von Willebrand disease treated perioperatively with a von Willebrand factor (VWF)/factor VIII (FVIII) concentrate with a ratio of 2.4:1 (Humate P/Haemate P) often present with VWF and/or FVIII levels outside of prespecified target levels necessary to prevent bleeding. Pharmacokinetic (PK)-guided dosing may resolve this problem. As clinical guidelines increasingly recommend aiming for certain target levels of both VWF and FVIII, application of an integrated population PK model describing both VWF activity (VWF:Act) and FVIII levels may improve dosing and quality of care. In total, 695 VWF:Act and 894 FVIII level measurements from 118 patients (174 surgeries) who were treated perioperatively with the VWF/FVIII concentrate were used to develop this population PK model using nonlinear mixed-effects modeling. VWF:Act and FVIII levels were analyzed simultaneously using a turnover model. The protective effect of VWF:Act on FVIII clearance was described with an inhibitory maximum effect function. An average perioperative VWF:Act level of 1.23 IU/mL decreased FVIII clearance from 460 mL/h to 264 mL/h, and increased FVIII half-life from 6.6 to 11.4 hours. Clearly, in the presence of VWF, FVIII clearance decreased with a concomitant increase of FVIII half-life, clarifying the higher FVIII levels observed after repetitive dosing with this concentrate. VWF:Act and FVIII levels during perioperative treatment were described adequately by this newly developed integrated population PK model. Clinical application of this model may facilitate more accurate targeting of VWF:Act and FVIII levels during perioperative treatment with this specific VWF/FVIII concentrate (Humate P/Haemate P).

von Willebrand disease: what does the future hold?

von Willebrand disease (VWD) is characterized by its heterogeneous clinical manifestation, which complicates its diagnosis and management. The clinical management of VWD has remained essentially unchanged over the last 30 years or so, using von Willebrand factor (VWF) concentrates, desmopressin, and anti-fibrinolytic agents as main tools to control bleeding. This is in contrast to hemophilia A, for which a continuous innovative path has led to novel treatment modalities. Despite current VWD management being considered effective, quality-of-life studies consistently reveal a higher than anticipated burden of VWD on patients, which is particularly true for women. Apparently, despite our perceived notion of current therapeutic efficiency, there is space for innovation with the goal of reaching superior efficacy. Developing innovative treatments for VWD is complex, especially given the heterogeneity of the disease and the multifunctional nature of VWF. In this perspective article, we describe several potential strategies that could provide the basis for future VWD treatments. These include genetic approaches, such as gene therapy using dual-vector adenoassociated virus and transcriptional silencing of mutant alleles. Furthermore, protein-based approaches to increase factor FVIII levels in VWD-type 3 or 2N patients are discussed. Finally, antibody-based options to interfere with VWF degradation (for congenital VWD-type 2A or acquired von Willebrand syndrome-type 2A) or increase endogenous VWF levels (for VWD-type 1) are presented. By highlighting these potential strategies, we hope to initiate an innovative path, which ultimately would allow us to better serve VWD patients and their specific needs.

Toward Personalized Treatment for Patients with Low von Willebrand Factor and Quantitative von Willebrand Disease

The biological mechanisms involved in the pathogenesis of type 2 and type 3 von Willebrand disease (VWD) have been studied extensively. In contrast, although accounting for the majority of VWD cases, the pathobiology underlying partial quantitative VWD has remained somewhat elusive. However, important insights have been attained following several recent cohort studies that have investigated mechanisms in patients with type 1 VWD and low von Willebrand factor (VWF), respectively. These studies have demonstrated that reduced plasma VWF levels may result from either (1) decreased VWF biosynthesis and/or secretion in endothelial cells and (2) pathological increased VWF clearance. In addition, it has become clear that some patients with only mild to moderate reductions in plasma VWF levels in the 30 to 50 IU/dL range may have significant bleeding phenotypes. Importantly in these low VWF patients, bleeding risk fails to correlate with plasma VWF levels and inheritance is typically independent of the VWF gene. Although plasma VWF levels may increase to > 50 IU/dL with progressive aging or pregnancy in these subjects, emerging data suggest that this apparent normalization in VWF levels does not necessarily equate to a complete correction in bleeding phenotype in patients with partial quantitative VWD. In this review, these recent advances in our understanding of quantitative VWD pathogenesis are discussed. Furthermore, the translational implications of these emerging findings are considered, particularly with respect to designing personalized treatment plans for VWD patients undergoing elective procedures.

ASH ISTH NHF WFH 2021 guidelines on the management of von Willebrand disease

BACKGROUND

von Willebrand disease (VWD) is a common inherited bleeding disorder. Significant variability exists in management options offered to patients.

OBJECTIVE

These evidence-based guidelines from the American Society of Hematology (ASH), the International Society on Thrombosis and Haemostasis (ISTH), the National Hemophilia Foundation (NHF), and the World Federation of Hemophilia (WFH) are intended to support patients, clinicians, and health care professionals in their decisions about management of VWD.

METHODS

ASH, ISTH, NHF, and WFH formed a multidisciplinary guideline panel. Three patient representatives were included. The panel was balanced to minimize potential bias from conflicts of interest. The University of Kansas Outcomes and Implementation Research Unit and the McMaster Grading of Recommendations Assessment, Development and Evaluation (GRADE) Centre supported the guideline development process, including performing and updating systematic evidence reviews (through November 2019). The panel prioritized clinical questions and outcomes according to their importance to clinicians and patients. The panel used the GRADE approach, including GRADE Evidence-to-Decision frameworks, to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 12 recommendations and outlined future research priorities.

CONCLUSIONS

These guidelines make key recommendations regarding prophylaxis for frequent recurrent bleeding, desmopressin trials to determine therapy, use of antiplatelet agents and anticoagulant therapy, target VWF and factor VIII activity levels for major surgery, strategies to reduce bleeding during minor surgery or invasive procedures, management options for heavy menstrual bleeding, management of VWD in the context of neuraxial anesthesia during labor and delivery, and management in the postpartum setting.

New therapies for von Willebrand disease

The management of von Willebrand disease (VWD) is based upon the dual correction of the primary hemostasis defect, due to the inherited deficiency of von Willebrand factor (VWF), and of the secondary defect of factor VIII coagulant activity (FVIII:C), due to the loss of binding and stabilization by VWF of this intrinsic coagulation factor in flowing blood. The traditional therapeutic weapons (the synthetic derivative of the antidiuretic hormone desmopressin and plasma-derived VWF/FVIII concentrates) are able to transiently correct both the defects. With the goal of tackling the primary deficiency in the disease, that is, VWF, but at the same time exploiting the normal capacity of patients to produce FVIII, the novel approach of replacing only VWF was implemented in the last 10 years. Following the manufacturing of a concentrate fractionated from human plasma and of one obtained by recombinant DNA technology, clinical studies have shown that VWF-only products correct not only the primary VWF deficiency but also the secondary FVIII:C deficiency. The demonstrated efficacy of these products in various clinical situations and, ultimately, in such a hemostasis-challenging context as surgery testifies to the effectiveness and safety of this approach. It remains to be seen whether VWF-only products are efficacious and safe in still-unexplored situations, such as use in children; the long-term use for prophylaxis; and in recurrent gastrointestinal (GI) bleeding due to angiodysplasia, a major therapeutic problem in VWD.

One piece of the puzzle: Population pharmacokinetics of FVIII during perioperative Haemate P® /Humate P® treatment in von Willebrand disease patients

INTRODUCTION

Many patients with von Willebrand disease (VWD) are treated on demand with von Willebrand factor and factor VIII (FVIII) containing concentrates present with VWF and/or FVIII plasma levels outside set target levels. This carries a risk for bleeding and potentially for thrombosis. Development of a population pharmacokinetic (PK) model based on FVIII levels is a first step to more accurate on-demand perioperative dosing of this concentrate.

METHODS

Patients with VWD undergoing surgery in Academic Haemophilia Treatment Centers in the Netherlands between 2000 and 2018 treated with a FVIII/VWF plasma-derived concentrate (Haemate® P/Humate P®) were included in this study. Population PK modeling was based on measured FVIII levels using nonlinear mixed-effects modeling (NONMEM).

RESULTS

The population PK model was developed using 684 plasma FVIII measurements of 97 VWD patients undergoing 141 surgeries. Subsequently, the model was externally validated and reestimated with independent clinical data from 20 additional patients undergoing 31 surgeries and 208 plasma measurements of FVIII. The observed PK profiles were best described using a one-compartment model. Typical values for volume of distribution and clearance were 3.28 L/70 kg and 0.037 L/h/70 kg. Increased VWF activity, decreased physical status according to American Society of Anesthesiologists (ASA) classification (ASA class >2), and increased duration of surgery were associated with decreased FVIII clearance.

CONCLUSION

This population PK model derived from real world data adequately describes FVIII levels following perioperative administration of the FVIII/VWF plasma-derived concentrate (Haemate® P/Humate P® ) and will help to facilitate future dosing in VWD patients.

Perioperative management of patients with von Willebrand disease

Surgical procedures represent a serious hemostatic challenge for patients with von Willebrand disease (VWD), and careful perioperative management is required to minimize bleeding risk. Risk stratification includes not only the nature of the surgery to be performed but the baseline plasma von Willebrand factor (VWF) levels, bleeding history, and responses to previous challenges. Baseline bleeding scores (BSs) may assist in identification of patients with a higher risk of postsurgical bleeding. There remains a lack of consensus between best practice guidelines as to the therapeutic target and assays to be monitored in the postoperative period. Hemostatic levels are maintained until bleeding risk abates: usually 3 to 5 days for minor procedures and 7 to 14 days for major surgery. Hemostatic supplementation is more complex in VWD than in other bleeding disorders owing to the combined but variable deficiency of both plasma VWF and factor VIII (FVIII) levels. For emergency surgery, coadministration of VWF and FVIII is required to ensure hemostasis; however, for elective procedures, early infusion of VWF replacement therapy will stabilize endogenous FVIII. Because endogenous FVIII production is unaffected in patients with VWD, repeated VWF supplementation (particularly with plasma-derived FVIII-containing products) may lead to accumulation of FVIII. Frequent monitoring of plasma levels and access to hemostatic testing are, therefore, essential for patients undergoing major surgery, particularly with more severe forms of VWD.

New therapies for von Willebrand disease

The management of von Willebrand disease (VWD) is based upon the dual correction of the primary hemostasis defect, due to the inherited deficiency of von Willebrand factor (VWF), and of the secondary defect of factor VIII coagulant activity (FVIII:C), due to the loss of binding and stabilization by VWF of this intrinsic coagulation factor in flowing blood. The traditional therapeutic weapons (the synthetic derivative of the antidiuretic hormone desmopressin and plasma-derived VWF/FVIII concentrates) are able to transiently correct both the defects. With the goal of tackling the primary deficiency in the disease, that is, VWF, but at the same time exploiting the normal capacity of patients to produce FVIII, the novel approach of replacing only VWF was implemented in the last 10 years. Following the manufacturing of a concentrate fractionated from human plasma and of one obtained by recombinant DNA technology, clinical studies have shown that VWF-only products correct not only the primary VWF deficiency but also the secondary FVIII:C deficiency. The demonstrated efficacy of these products in various clinical situations and, ultimately, in such a hemostasis-challenging context as surgery testifies to the effectiveness and safety of this approach. It remains to be seen whether VWF-only products are efficacious and safe in still-unexplored situations, such as use in children; the long-term use for prophylaxis; and in recurrent gastrointestinal (GI) bleeding due to angiodysplasia, a major therapeutic problem in VWD.

How I manage severe von Willebrand disease

Von Willebrand disease (VWD) is the most common inherited bleeding disorder. Most patients with mild and moderate VWD can be treated effectively with desmopressin. The management of severe VWD patients, mostly affected by type 2 and type 3 disease, can be challenging. In this article we review the current diagnosis and treatment of severe VWD patients. We will also discuss the management of severe VWD patients in specific situations, such as pregnancy, delivery, patients developing alloantibodies against von Willebrand factor and VWD patients with recurrent gastrointestinal bleeding. Moreover, we review emerging treatments that may be applied in future management of patients with severe VWD.

Blood, blood components, plasma, and plasma products

This review of 2018 publications identifies side effects of blood, blood components, and plasma products. In addition, albumin, blood transfusion (erythrocytes, granulocytes, and platelets), blood substitutes (hemoglobin-based oxygen carriers), plasma products (alpha1-antitrypsin, C1 esterase inhibitor concentrate, cryoprecipitate, and fresh frozen plasma), plasma substitutes (etherified starches, and gelatin), globulins (intravenous immunoglobulin, subcutaneous immunoglobulin, and anti-D immunoglobulin), coagulation proteins (factor I, factor II, factor VIIa, factor VIII, factor IX, prothrombin complex concentrate, antithrombin III, and von Willebrand factor/factor VIII concentrates), erythropoietin and derivatives, thrombopoietin and receptor agonists, transmission of infectious agents through blood donation, and stem cells are reviewed. This chapter informs the reader about newly recognized and published data in the blood product domain.