Inherited Von Willebrand Disease Research Articles

Optimal design of infusion tests for the identification of physiological models of acquired von Willebrand syndrome

Acquired von Willebrand syndrome (AVWS) is a bleeding disorder resembling inherited Von Willebrand disease (VWD) characterised by a qualitative and/or quantitative deficiency of von Willebrand factor (VWF) that occurs in patients with no personal or family history of bleeding as a result of underlying pathological conditions. To treat AVWS patients, desmopressin (DDAVP) and plasma-derived VWF concentrates are the primary therapies for spontaneous acute bleeding episodes and for preventing bleeding during invasive or surgical procedures. Pharmacokinetic (PK) models have been recently developed and applied to characterize VWD and AVWS, but these models cannot be calibrated from infusion tests data, and their calibration requires stressful 24-hours long tests to be carried out on subjects to achieve a satisfactory estimation of the individual haemostatic parameters. The objectives of this paper are: i) to present a new physiological model of VWD including exogenous infusion of plasma-derived VWF concentrates, suitable to describe AVWS; ii) to validate the newly proposed model from clinical data; iii) to quantify the information that can be obtained from clinical tests using different VWF concentrates by applying model-based design of experiments (MBDoE) techniques. Results show that the newly developed model calibrated from infusion data allows to estimate precisely the full set of haemostatic parameters for a subject affected by AVWS preserving the same level of information obtained from conventional tests. Most importantly, results demonstrate that the overall duration of infusion tests for the identification of key haemostatic parameters can significantly be reduced from 24 h to 2.5 h.

Acquired von Willebrand syndrome: Five cases report and literature review

Acquired von Willebrand syndrome is a rare bleeding disorder with laboratory findings similar to those of inherited von Willebrand disease. Principal factors distinguishing acquired von Willebrand syndrome from the latter condition include lack of prior bleeding disorders, diagnosis at older age, negative family history and association with underlying conditions. MethodsRetrospective, monocentric descriptive case series of acquired von Willebrand syndrome diagnosed between 2010 and 2020. Diagnostic criteria included a recent history of bleeding, a negative family history and a presence of underlying disorders. ResultsFive men were diagnosed with acquired von Willebrand syndrome. All of them presented with recent mucocutaneous bleeding. The biological phenotype was a type 2 von Willebrand disease in all cases, with decreased VWF:RCo/VWF:Ag and VWF:CB/VWF:Ag ratios (<0.7). Lymphoproliferative, autoimmune and cardiovascular diseases were the main underlying conditions identified. Screening for an anti-von Willebrand factor inhibitor was positive in two patients. Four patients received treatment for the underlying disorder. High-dose intravenous immunoglobulins were the most frequent treatment administrated. Improvement of plasma von Willebrand factor levels was observed in four cases. ConclusionAcquired von Willebrand syndrome is a rare but potentially serious disease. The diagnostic should be suspected in adults with unusual mucocutaneous bleeding associated with lymphoproliferative, myeloproliferative, autoimmune and cardiovascular disorders.

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.

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. Literature research and case reports. 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.

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

BackgroundPatients 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.MethodsWe 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.ResultsAmong 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.ConclusionThese results suggest that Voncento® is effective to prevent recurrent bleedings in patients symptomatic VWD.

Acquired von Willebrand syndrome in patients with monoclonal gammopathy of undetermined significance investigated using a mechanistic approach.

Acquired von Willebrand syndrome (AVWS) has been reported to occur in association with monoclonal gammopathy, usually of undetermined significance (MGUS). It may present as a type 1 or type 2 von Willebrand factor (VWF) defect depending on the patient's representation of large VWF multimers. The mathematical model by Galvanin et al., already employed for studying inherited von Willebrand disease (VWD), was used to explore the pathogenic mechanisms behind MGUS-associated AVWS. The patients studied showed significantly reduced VWF levels and function; an increased VWF propeptide to VWF antigen ratio; and all VWF multimers present but in reduced quantities, with the low-molecular-weight VWF forms being significantly more represented than those of higher molecular weight. Our mathematical model revealed a significantly increased VWF elimination rate constant, with values similar to those of type Vicenza VWD. An even more increased VWF proteolysis rate constant was observed, with values one order of magnitude higher than in type 2A VWD but, in contrast, no loss of large multimers. The model predicted the same elimination rate for high- and low-molecular-weight VWF multimers, but proteolysis of the high-molecular-weight forms also contributes to the pool of low-molecular-weight oligomers, which explains why they were relatively over-represented. In MGUS-associated AVWS the increase of both clearance and proteolysis contributes to the circulating levels and multimer pattern of VWF, with a phenotype that appears to be a combination of type Vicenza and type 2A VWD. Hence, the mechanisms behind the onset of AVWS seem to differ from those of inherited VWD.

Effectiveness and safety of hFVIII/VWF concentrate (Voncento®) in patients with inherited von Willebrand disease requiring surgical procedures: the OPALE multicentre observational study.

In patients with moderate to severe qualitative and quantitative von Willebrand disease (VWD), even minor surgical procedures can be associated with a risk of life-threatening bleeding. Treatment strategies vary according to the levels of von Willebrand factor (VWF) and Factor VIII (FVIII). The aim of this study was to evaluate the effectiveness and the safety of Voncento® (CSL Behring, Marburg, Germany), a plasma-derived FVIII/VWF concentrate (ratio 1:2.4), during surgeries performed in patients with inherited VWD. The OPALE study, a French multicentre observational study, was carried out from May 2016 to May 2019. It evaluated and analysed patients with inherited VWD (any type) requiring treatment with Voncento® who underwent surgery. In total, 92 patients were enrolled, and 66 patients underwent 100 surgical procedures: 69 minor and 31 major surgeries conducted in 30 patients with type 1, 50 patients with type 2, and 20 patients with type 3 VWD. During minor surgeries, the median number of infusions was one (range: 1-9), the pre-operative loading dose was 41 IU VWF:RCo kg-1 (range: 18-147), and the total dose was 63 (range: 18-594). During major surgeries, the number of infusions was 4 (range: 1-23), the pre-operative loading dose was 43 (range: 25-66) IU VWF: RCo kg-1, and the total dose was 155 (range: 40-575). The median FVIII:C levels ranged from 78 to 165 IU dL-1 during 5 days after minor surgeries and from 86 and 167 IU dL-1 during 11 days after major surgeries. VW:RCo levels ranged between 35 and 65 IU dL-1 and between 34 and 76 IU dL-1 after minor and major surgeries, respectively. The overall clinical effectiveness was qualified as "excellent" or "good" in 99% of patients. No thrombotic events related to Voncento® were recorded. The present study suggests that Voncento® is an effective and well-tolerated therapy for the peri-operative management of patients with all VWD types.

Obstacles to Early Diagnosis and Treatment of Inherited von Willebrand Disease: Current Perspectives.

Von Willebrand disease (VWD), the most common inherited bleeding disorder, is highly heterogeneous, and its early diagnosis may be difficult, especially for mild cases and in qualitative von Willebrand factor (VWF) defects. Appropriate VWD diagnosis requires the combination of personal and/or family history of bleeding and abnormal VWF laboratory testing. The use of bleeding assessment tools has been helpful in standardizing bleeding history collection and quantification of bleeding symptoms to select patients who may benefit of further hemostatic testing. Type 1 and 3 VWD which represent quantitative VWD variants are relatively easy to diagnose. The diagnosis of type 2 VWD requires multiple assessments to evaluate the effects induced by the responsible abnormality on the heterogeneous functions of VWF. Sensitive and reproducible tests are needed to evaluate different VWF activities, starting from measuring VWF-platelet interaction. In the recent years, several increasingly sensitive, rapid and automated assays have been developed, but they are not widely available so far. Genetic testing for VWD diagnosis is not a common practice because VWF gene is very large and highly polymorphic and therefore it is used only in specific cases. It is evident that the early and correct VWD diagnosis allows optimal management of bleeding and situations at risk. Tranexamic acid, desmopressin, replacement therapy with plasma-derived concentrates with a variable content of VWF and FVIII, or the new recombinant VWF are the different therapeutic options available. Careful VWD classification guides treatment because desmopressin is widely used in type 1 while replacement therapy is the cornerstone of treatment for type 2 and 3 variants.

Efficacy and safety of a recombinant Von Willebrand Factor treatment in patients with inherited Von Willebrand Disease requiring surgical procedures.

Von Willebrand Disease is a common inherited haemorrhagic disorder due to a deficiency of Von Willebrand Factor (VWF). In case of surgical procedures in patients who are not responsive or have contraindications to desmopressin, replacement therapy with VWF concentrates is indicated. Until recently, only plasma-derived VWF concentrates were available. A new recombinant VWF (rVWF) concentrate that contains no Factor VIII (FVIII) but a high amount of high molecular weight VWF multimers has been available in France since 2018. Describe real-world experience of using rVWF in surgical procedures. Sixty-three surgeries for 55 patients were retrospectively analysed in 7 French haemostasis centres. During minor surgeries, the median (range) number of infusions was 1 (1-8) with a preoperative loading dose of 35 (19-56) rVWF IU/kg and a total median dose of 37.5IU (12-288). During major surgeries, the median (range) number of infusions was only 3 (1-14) with a median preoperative loading dose of 36IU (12-51) rVWF IU/kg, and a total median dose of 108IU (22-340) rVWF IU/kg. The overall clinical efficacy was qualified as excellent/good in 61 of the procedures (97%), moderate in 1 (1.5%) and poor in 1 (1.5%). There was no accumulation of VWF or FVIII during postoperative monitoring. No thromboembolic events, anti-VWF antibodies or adverse events were reported. This French 'real-world' experience shows that a few infusions and low doses of rVWF provided effective prevention of bleeding in major and minor surgeries in inherited VWD, with no clinically significant safety concerns.

Cost-Effectiveness of Long-Term Prophylaxis Versus on-Demand Treatment with Von Willebrand Factor Concentrate in Severe Inherited Von Willebrand Disease

Introduction: von Willebrand Disease (VWD) is the most common inherited bleeding disorder with significant variability in clinical phenotype. Patients with the most severe forms of VWD suffer from frequent bleeding complications including mucosal bleeding, gastrointestinal hemorrhage, hemarthrosis, and muscle hematomas. Long-term prophylaxis with von Willebrand factor (VWF) concentrate has been shown to reduce the frequency of bleeding episodes, but higher costs associated with regular VWF concentrate administration remains a barrier to access. Methods: We constructed a Markov state transition model to compare the cost-effectiveness of on-demand treatment (ODT) with long-term prophylaxis (PRO) from a United States (US) societal perspective with costs inflated to 2020 US dollars using the Consumer Price Index. Cycle-length was one month with a one-year time horizon and during each cycle, patients could experience either major (hemarthrosis, gastrointestinal bleeding, muscle hematoma), minor (epistaxis, other mucosal bleeding), or no bleeding. Model inputs for event probabilities, costs, and utility were obtained from previously published literature; while there are no specific utility data for these treatment strategies in VWD patients, we assumed they would be similar to published age-specific utilities used in hemophilia analyses and performed sensitivity analyses to assess these assumptions. The base case scenario was modeled on a 70 kg patient with severe VWD receiving plasma-derived VWF concentrate. In the PRO strategy, patients received 60 units/kg every 3 days. ODT patients were only treated for specific bleeding events (minor bleeding: 60 units/kg every 12 hours for 3 days in the outpatient setting; major bleeding: VWF concentrate 60 units/kg every 12 hours for 5 days in the hospital). Microsimulation of 1000 trials was performed using to calculate mean quality-adjusted life-years (QALYs) and costs associated with the two treatment strategies. TreeAge Pro 2017 (TreeAge Software, Williamstown, MA) was used to construct the model and perform analyses. Results: In the base-case scenario using plasma-derived VWF concentrate, on-demand treatment resulted in a mean cost of US$1,140,586 (± $65,215) generating 0.52 QALYs (±0.01) while the prophylaxis strategy resulted in a mean cost of US$918,329 (± $94,983) generating 0.8 QALYs (±0.04). The microsimulation was repeated to reflect the cost of recombinant VWF concentrate for prophylaxis and a single dose of recombinant factor VIII. Using recombinant VWF, on-demand treatment resulted in a mean cost of US$1,568,005 (± $94206) and generated 0.52 QALYs (±0.01) while the prophylaxis strategy resulted in a mean cost of US$1,343,715 (± $124,974) and generated 0.8 QALYs (±0.04). One-way sensitivity analysis of model inputs showed this result to be robust, as prophylaxis remained the preferred strategy at a willingness to pay (WTP) threshold of US$150,000/QALY for both plasma-derived and recombinant therapies (Figure). Conclusions: With greater effectiveness and lower total societal health care costs, the prophylaxis strategy dominated the on-demand treatment strategy. While the cost of long-term prophylaxis is primarily due to the high cost of VWF concentrate every 3 days, this strategy results in significantly fewer bleeding episodes per year resulting in more QALYs. Our findings suggest that when compared to on-demand treatment, long-term prophylaxis with VWF concentrate is a cost-effective strategy in patients with severe forms of VWD, which helps to avoid expensive hospitalizations and decreased quality of life due to bleeding episodes and their complications. Figure 1 Disclosures No relevant conflicts of interest to declare.

Acquired von Willebrand Syndrome Hiding Inherited von Willebrand Disease Can Explain Severe Bleeding in Patients With Aortic Stenosis.

Aortic stenosis may be complicated by an acquired von Willebrand syndrome that rarely causes significant bleeding, raising the question of why it does so in a few cases. To seek an explanation, we studied 5 severe bleeder aortic stenosis patients in a cohort of 49 patients, using the flowchart for inherited von Willebrand disease. Approach and Results: All 5 patients were lacking in large and intermediate VWF (von Willebrand factor) multimers, 3 had reduced plasma and platelet VWF levels, and none showed PFA100 closure. Two patients (those with most multimers missing) also had a short VWF half-life. Genetic analyses on the 3 patients with reduced platelet VWF levels revealed that one carried both the c.1164C>G and the c.7880G>A mutations, and another carried the c.3390C>T mutation, while the third had one of the 2 VWF alleles relatively less expressed than the other (25% versus 75%). No genetic alterations emerged in the other 2 patients. Successful replacement of the stenotic aortic valve, performed in the 2 patients with VWF mutations, did not correct their abnormal VWF multimer picture-unlike what happened in the aortic stenosis patients without bleeding symptoms. Our findings suggest that acquired von Willebrand syndrome can develop in patients with hitherto-undiagnosed inherited von Willebrand disease. Since von Willebrand disease is the most common bleeding disorder, this possibility should be considered in aortic stenosis patients-especially those with a more severe bleeding history and more disrupted VWF laboratory patterns-because they risk hemorrhage during aortic valve replacement.

Acquired von Willebrand syndrome: focused for hematologists.

The acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder with laboratory findings similar to those of inherited von Willebrand disease. However, unlike the inherited disease, AvWS occurs in persons with no personal and family history of bleeding and is often associated with a variety of underlying diseases, most frequently lymphoproliferative, myeloproliferative and cardiovascular disorders. After the presentation of a typical case, in this narrative review we discuss the more recent data on the pathophysiology, clinical, laboratory and therapeutic aspects of this acquired bleeding syndrome. We chose to focus particularly on those aspects of greater interest for the hematologist.

Von Willebrand factor propeptide (VWFpp) — potential biomarker in inherited von Willebrand disease and acquired von Willebrand syndrome

Von Willebrand factor propeptide (VWFpp) is a fragment of a new synthesized VWF molecule that plays an important part in the biosynthesis of this protein. After completion of multimerisation of von Willebrand factor (VWF) dimers in the Golgi apparatus, as result of furin proteolysis VWFpp is truncated/disconnected from the mature VWF molecule to form a non-covalent complex with VWF. The VWFpp-VWF complex is stored in endothelial and platelet storage granules and released into the bloodstream where it dissociates into VWFpp and VWF. Plasma VWFpp level and ratio of plasma VWF propeptide (VWFpp) to VWF antigen (VWF:Ag) i.e VWFpp /VWF:Ag ratio are important biomarkers of VWF synthesis/release/clearance. These biomarkers have distinct therapeutic utility as they help to identify patients with von Willebrand disease (VWD) in whom DDAVP (desmopressin 1-desamino-8-D-arginine vasopressin) is ineffective due to rapid VWF clearance. They also have significant diagnostic value because they help to differentiate between congenital VWD subtypes as well as between congenital VWD and acquired von Willebrand Syndrome (AVWS). The purpose of the study was to determine the VWFpp level and the VWFpp/VWF: Ag ratio in patients with VWD and AVWS and to assess the significance of these biomarkers for diagnosis and management of congenital and acquired von Willebrand disease. Our study involved 120 VWD patients; 21 with AVWS and 111 healthy controls. Study results confirm that VWFpp level and the VWFpp/VWF: Ag ratio have significant value fordiscrimination between severe type 1 VWD and type 3 VWD as well as between acquired and congenital VWD which has serious implications for therapy. The biomarkers are also useful for identification of patients in whom DDAVP treatment may prove ineffective. In type 1 VWD (< 30 IU/ml) the VWFpp/VWF: Ag ratio was elevated in 57% of patients while in the group of patients with threshold VWF values (‘Low VWF’, 30–50 IU/dL) the ratio was within normal, which may be suggestive of other underlying causes of VWF deficiency. Assays in patients with non-neutralizing anti-VWF antibodies (AVWS) have shown that the VWFpp/VWF: Ag ratio can have significant impact on monitoring therapy and assessment of remission in patients with anti VWF antibodies.

Clinical Study to Investigate the Efficacy and Safety of Wilate during Prophylaxis in Previously Treated Patients with Von Willebrand Disease (VWD)

Background: Inherited von Willebrand disease (VWD) is the most common inherited hemorrhagic disorder, with an estimated prevalence of 1 in every 100 individuals. Type 1 and type 3 (the most severe form) are characterized by a quantitative deficiency of von Willebrand factor (VWF) and type 2 arises from a qualitative deficiency of VWF. Treatment of VWD depends on the type and severity of the disease. Severe bleeding is reported in patients with all subtypes, leading to progressive joint disease as well as diminished quality of life (QoL). VWF/factor VIII (FVIII) concentrates have become the mainstay of VWD treatment for these patients with severe disease or for those patients in whom other treatments (e.g., desmopressin) are ineffective or contraindicated but this is broadly applicable only for on demand treatment. Aims: The primary objective of this study is to determine the efficacy of VWF/FVIIII concentrate in the prophylactic treatment of previously treated patients with type 3, type 2 (except 2N), or severe type 1 VWD. Secondary objectives of this study will be to collect data to 1) Assess the VWF:Ac and VWF:Ag incremental IVR of VWF/FVIIII concentrate over time and, 2) Assess the safety and tolerability of VWF/FVIIII concentrate in this indication. The study will also examine, the efficacy of VWF/FVIIII concentratein the treatment of breakthrough bleeding episodes (BEs), and in surgical prophylaxis, as well as the QoL during prophylaxis with VWF/FVIIII concentrate. Methods: The study is planned to enroll 28 patients aged ≥6 years and with VWD type 1, 2A, 2B, 2M, or 3. Eligible patients must be receiving on-demand treatment with a VWF-containing product, with at least 1, and an average of ≥2, documented spontaneous BEs per month in the preceding 6 months requiring treatment with a VWF-containing product. This will be assessed as part of a run-in observational study to collect the bleeding profile prior to the start of prophylaxis. From the beginning of the study, patients will receive prophylactic treatment with VWF/FVIIII concentrate for 12 months and record all BEs in a patient diary. Based on these data, the frequency of BEs and the annualized bleeding rate (ABR) under prophylactic treatment will be calculated. Treatment efficacy of BEs will be assessed by the patient (together with the investigator in case of on-site treatment) using a 4-point scale (excellent, good, moderate, none) In patients that undergo surgeries, efficacy of VWF/FVIIII concentratewill be assessed at the end of surgery by the surgeon and at the end of the postoperative period by the haematologist. In both cases, predefined assessment criteria will be used. In addition, an overall assessment of efficacy will be made at the end of the postoperative period by the investigator. Results: Data will be monitored on an ongoing basis and the study is expected to end Q2 2021. Conclusions: Prophylactic treatment in other congenital bleeding disorders is widely accepted as the standard of care to prevent bleeding and preserve QoL in patients but to date, this form of treatment in VWD is not well characterized. This study will provide data on the efficacy of prophylactic treatment in reducing the rate of bleeding and on the impact of prophylaxis on the QoL in VWD patients. Disclosures Sidonio: Genetech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda-Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding; Biomarin: Membership on an entity's Board of Directors or advisory committees; Octapharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bioverativ: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Grifols: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kedrion: Research Funding; Uniqure: Membership on an entity's Board of Directors or advisory committees. Schwartz:Octapharma: Employment.

Characterization of Von Willebrand Factor Multimer Structure in Patients With Severe Aortic Stenosis.

Acquired von Willebrand syndrome (AVWS) associated with severe aortic stenosis (AS) has been frequently subclassified into a subtype 2A based on the deficiency of high-molecular-weight (HMW) multimers as it is seen in inherited von Willebrand disease (VWD) type 2A. However, the multimeric phenotype of VWD type 2A does not only include an HMW deficiency but also a decrease in intermediate-molecular-weight (IMW) multimers and an abnormal inner triplet band pattern. These additional characteristics have not been evaluated in AVWS associated with severe AS. Therefore, we recruited N = 31 consecutive patients with severe AS and performed a high-resolution Western blot with densitometrical band quantification to characterize the von Willebrand factor (VWF) multimeric structure and reevaluate the AVWS subtype classification. Study patients showed an isolated HMW VWF multimer deficiency without additional abnormalities of the IMW portions and the inner triplet structure in 65%. In conclusion, the multimeric pattern of AVWS associated with severe AS does neither resemble that seen in AVWS type 2A nor that seen in inherited VWD type 2A. Therefore, a subclassification into a type 2A should not be used.

Current and Emerging Options for the Management of Inherited von Willebrand Disease.

Von Willebrand disease (VWD) is the most common inherited bleeding disorder with an estimated prevalence of ~1% and clinically relevant bleeding symptoms in approximately 1:10,000 individuals. VWD is caused by a deficiency and/or defect of von Willebrand factor (VWF). The most common symptoms are mucocutaneous bleeding, hematomas, and bleeding after trauma or surgery. For decades, treatment to prevent or treat bleeding has consisted of desmopressin in milder cases and of replacement therapy with plasma-derived concentrates containing VWF and Factor VIII (FVIII) in more severe cases. Both are usually combined with supportive therapy, e.g. antifibrinolytic agents, and maximal hemostatic measures. Several developments such as the first recombinant VWF concentrate, which has been recently licensed for VWD, will make a more “personalized” approach to VWD management possible. As research on new treatment strategies for established therapies, such as population pharmacokinetic-guided dosing of clotting factor concentrates, and novel treatment modalities such as aptamers and gene therapy are ongoing, it is likely that the horizon to tailor therapy to the individual patients’ needs will be extended, thus, further improving the already high standard of care in VWD in most high-resource countries.

Efficacy and safety of a VWF/FVIII concentrate (wilate®) in inherited von Willebrand disease patients undergoing surgical procedures

Surgical procedures in von Willebrand disease (VWD) patients may require prophylactic treatment with exogenous von Willebrand factor (VWF) and coagulation factor VIII (FVIII) to prevent excessive bleeding. Wilate® is a plasma-derived, double virus-inactivated, highly purified, freeze-dried VWF/FVIII concentrate, containing both factors in a physiological activity ratio of 1:1. To investigate the efficacy and safety of wilate® in maintaining haemostasis in VWD patients undergoing surgical procedures. This prospective, open-label multinational clinical study documents 28 individuals who underwent 30 surgical procedures managed with wilate® . Twenty-one patients had VWD Type 3, and 21 surgeries were major. Efficacy was assessed intra- and postoperatively by the surgeon and investigator, respectively, and adjudicated by an Independent Data Monitoring Committee, using an objective scale based on blood loss, transfusion requirements and postoperative bleeding and oozing. Treatment success (primary endpoint) was determined using a composite assessment algorithm and was formally assessed. Surgical prophylaxis with wilate® was successful in 29 of 30 procedures. The overall rate of success was 96.7% (98.75% CI: 0.784, 1.000). All 21 surgeries in patients with VWD Type 3 were managed successfully. There was no accumulation of VWF or FVIII after multiple dosing, and no thromboembolic events or inhibitors to VWF or FVIII were observed. Wilate® demonstrated effective prevention and treatment of bleeding in inherited VWD patients undergoing surgery, with no clinically significant safety concerns.

Safety and Effectiveness of Desmopressin for the Management of Delivery and Major Surgery in Patients with Mild-Moderate Von Willebrand Disease: Final Analysis of the Prodeswil Study

Introduction. Despite the fact that desmopressin (DDAVP) is considered the treatment of choice in the majority of patients with inherited von Willebrand disease (VWD), there are still open questions about the efficacy and safety of the use of DDAVP to manage recurrent bleeding episodes, delivery and major surgery. In fact, to avoid tachyphylaxis and possible side effects with repeated DDAVP injections, VWF concentrates are usually preferred to manage delivery and major surgery also in VWD patients proven to be DDAVP-responsive. No prospective data have been reported so far to correlate biological response with DDAVP clinical efficacy in VWD and guide clinical practice.Design, aims and methods. ProDesWilis an investigator-driven Pro spective study on D esmopressin e fficacy and s afety of patients with inherited von Wil lebrand disease assessed at enrolment for DDAVP biological response during a test-infusion. Inclusion criteria: VWD diagnosis without any age restriction according to bleeding score >4, VWF activity levels <45U/dL, and at least another affected member in the family. DDAVP Biological Response: VWD were classified as complete, partial or no-responders as previously reported (Blood 2008;111:3531). Treatment regimens: DDAVP given intravenously or subcutaneously (0.3 ug/Kg) or by nasal spray (4 ug/Kg) according to preparations available in different countries with or without standard doses of anti-fibrinolytic agents (Epsilon-amino-caproic acid, EACA or tranexamic acid, TA). In case of major surgery, DDAVP was used together with TA using a 3dayOn-4dayOff-3dayOn schedule. DDAVP efficacy-safety evaluated with criteria currently used for VWF concentrates, with poor efficacy defined when VWF concentrates were needed. Patients were prospectively followed up for 24 months by ProDesWil Investigators who reported detailed information about DDAVP therapy used for bleeds, deliveries, oral and minor/major surgeriesResults. 268 patients were enrolled in this 24-month prospective study. DDAVP-biological response: 225/268 (85%) patients met inclusion criteria as VWD1(n=184), VWD1C (n=14), VWD2A(n=15), VWD2M(n=12). The 14 VWD1C with accelerated clearance carried C1130F and R1205H mutations. DDAVP biological response was complete, partial and absent in 89%, 10% and 1% of all VWD. DDAVP clinical efficacy and safety: during the 24-month follow-up 84/225 (37.3%) received DDAVP for bleeding episodes (n=104), oral surgeries (n=33), deliveries (n=12), other minor/major surgeries (n=25). Total DDAVP injections were 652 with median, range/episode during bleeds (2,1-12), oral surgeries (1,1-10), deliveries (3,1-13), minor/major surgeries (3.6,1-16). Clinical efficacy was excellent/good in bleeds (93.3%), oral surgery (100%), deliveries (91.7%), minor/major surgeries (92.3%). All VWD treated for oral surgery with (75%) and without (25%) EACA/TA had excelled/good outcomes. Efficacy was rated excellent/good in 96/104 bleeds, with 8 episodes rated poor during menorrhagia (n=4) in 2 VWD1 and 2 VWD2A, during nose (n=2) and gastrointestinal (n=2) bleeds in 3 VWD2A and 1 VWD1C. 11/12 deliveries had excellent/good outcome with poor response in only one VWD1C who required VWF concentrates after caesarean section. All the 11/25 cases with minor surgeries had excellent outcomes. Among the 14/25 major surgeries [abdominal (n=5), hysterectomy (n=3), tonsillectomy (n=3), orthopaedic and others (n=3)] 2 episodes (partial resection of kidney in VWD2A and tonsillectomy in VWD1) were rated poor. Side effects (16 cases) were mainly minor (flushing, headache, tachycardia) with water retention reported only in 2 patients who received >12 doses of DDAVP for delivery or major surgery.Conclusions: DDAVP is an effective, safe and cheap treatment for managing patients with mild-moderate VWD who showed complete biological response to this drug. Therefore, DDAVP must be always recommended as first line therapy in responsive VWD not only in bleeds and oral surgery but also in deliveries and major surgeries. On the other hands, DDAVP should be used with caution in VWD2A and VWD1 with partial response. The additional use of EACA/TA should be considered especially when DDAVP is required for more than 4 days. DisclosuresNo relevant conflicts of interest to declare.

Von Willebrand factor in patients on mechanical circulatory support - a double-edged sword between bleeding and thrombosis.

Mechanical circulatory support (MCS) is an umbrella term describing the various technologies used in both short- and long-term management of patients with either end-stage chronic heart failure (HF) or acute HF. Most often, MCS has emerged as a bridge to transplantation, but more recently it is also used as a destination therapy. Mechanical circulatory support includes left ventricular assist device (LVAD) or bi-ventricular assist device (Bi-VAD). Currently, 2- to 3-year survival in carefully selected patients is much better than with medical therapy. However, MCS therapy is hampered by sometimes life-threatening complications including bleeding and device thrombosis. Von Willebrand factor (vWF) has two major functions in haemostasis. First, it plays a crucial role in platelet-subendothelium adhesion and platelet-platelet interactions (aggregation). Second, it is the carrier of factor VIII (FVIII) in plasma. Von Willebrand factor prolongs FVIII half-time by protecting it from proteolytic degradation. It delivers FVIII to the site of vascular injury thus enhancing haemostatic process. On one hand, high plasma levels of vWF have been associated with an increased risk of thrombosis. On the other, defects or deficiencies of vWF underlie the inherited von Willebrand disease or acquired von Willebrand syndrome. Here we review the pathophysiology of thrombosis and bleeding associated with vWF.

The Acquired Von Willebrand Syndrome in Patients with Monoclonal IgA Proteins Is Rare but May be Clinically Severe

During the last 10 years our laboratory diagnosed and typed 5585 different patients with inherited von Willebrand disease (VWS) and acquired von Willebrand syndrome (aVWS). Out of these 21% (1217) suffered from aVWS. With 252 patients lymphoproliferative disorders were number three in frequency (21%) after cardiovascular (43%) and myeloproliferative (27%) disorders. Out of the patients with lymphoproliferative disorders patients with a monoclonal IgA protein comprised only 3.6% (9 patients). Much more abundant were monoclonal IgG´s (71%) and IgM´s (26%).According to our data only one patient was classified as MGUS and the others suffered from myeloma. The most impressive property was the heterogeneity of their laboratory and clinical data with the exception that all patients suffered from severe bleeding complications whenever their hemostatic system was challenged by accidents or invasive procedures (even iliac crest biopsy).The VWF:Ag ranged from 0.06 – 5.60 IU/ml and only one patient had a VWF:Ag <0.5 IU/dl. The functional test (VWF:CB) ranged from 0.06 and 5.48 IU/ml again with only one patient <0.5 IU/dl. The ratio VWF:CB / VWF:Ag was below 0.8 in three patients. Thus more than 50% of the patients would remain undetected if the VWF multimers were not included in thediagnostic panel. Two patients displayed the whole set of multimers, while the others showed a mild (5) or severe (2) absence of the large multimers. The hallmark of the multimic pattern from patients with an IgA monoclonal protein was the presence of a lot of smeary material within the electrophoretic lanes diplayed in all patients.In summary aVWS in the course of lymphoproliferative disorders and monoclonal IgA proteins is clinically severe, although probably not life threatening. It remains undetected with standard VWF tests and might be therefore not as rare as detected in our large patient panel. DisclosuresNo relevant conflicts of interest to declare.

The bleeding score predicts clinical outcomes and replacement therapy in adults with von Willebrand disease

AbstractAnalyses of the bleeding tendency by means of the bleeding score (BS) have been proposed until now to confirm diagnosis but not to predict clinical outcomes in patients with inherited von Willebrand disease (VWD). We prospectively followed up, for 1 year, 796 Italian patients with different types of VWD to determine whether the previous BS of European VWD1 is useful to predict the occurrence of spontaneous bleeds severe enough to require replacement therapy with desmopressin (DDAVP) and/or von Willebrand factor (VWF)/factor VIII concentrates. Among the 796 patients included, 75 (9.4%) needed treatment of 232 spontaneous bleeding events. BS >10 and VWF:ristocetin cofactor activity <10 U/dL were associated with the risk of bleeding, but only a BS >10 remained highly associated in a multivariable Cox proportional hazard model (adjusted hazard ratio: 7.27 [95% confidence interval, 3.83-13.83]). Although the bleeding event-free survival was different in VWD types, only a BS >10 could predict for each type which patient had bleeding events severe enough to require treatment with DDAVP and/or concentrates. Therefore, BS can be considered a simple predictor of clinical outcomes of VWD and may identify patients needing intensive therapeutic regimens.