Von Willebrand factor propeptide and pathophysiological mechanisms in European and Iranian patients with type 3 von Willebrand disease enrolled in the 3WINTERS-IPS study

BACKGROUND

Type 3 von Willebrand disease (VWD) is a severe bleeding disorder caused by the virtually complete absence of von Willebrand factor (VWF). Pathophysiological mechanisms of VWD like defective synthesis, secretion, and clearance of VWF have previously been evaluated using ratios of VWF propeptide (VWFpp) over VWF antigen (VWF:Ag) and factor (F)VIII coagulant activity (FVIII:C) over VWF:Ag.

OBJECTIVE

To investigate whether the VWFpp/VWF:Ag and FVIII:C/VWF:Ag ratios may also be applied to understand the pathophysiological mechanism underlying type 3 VWD and whether VWFpp is associated with bleeding severity.

METHODS

European and Iranian type 3 patients were enrolled in the 3WINTERS-IPS study. Plasma samples and buffy coats were collected and a bleeding assessment tool was administered at enrolment. VWF:Ag, VWFpp, FVIII:C, and genetic analyses were performed centrally, to confirm patients' diagnoses. VWFpp/VWF:Ag and FVIII:C/VWF:Ag ratios were compared among different variant classes using the Mann-Whitney test. Median differences with 95% confidence intervals (CI) were estimated using the Hodges-Lehmann method. VWFpp association with bleeding symptoms was assessed using Spearman's rank correlation.

RESULTS

Homozygosity/compound heterozygosity for missense variants showed higher VWFpp level and VWFpp/VWF:Ag ratio than homozygosity/compound heterozygosity for null variants ([VWFpp median difference, 1.4 IU/dl; 95% CI, 0.2-2.7; P = .016]; [VWFpp/VWF:Ag median difference, 1.4; 95% CI, 0-4.2; P = .054]).

FVIII

C/VWF:Ag ratio was similarly increased in both. VWFpp level did not correlate with the bleeding symptoms (r = .024; P = .778).

CONCLUSIONS

An increased VWFpp/VWF:Ag ratio is indicative of missense variants, whereas FVIII:C/VWF:Ag ratio does not discriminate missense from null alleles. The VWFpp level was not associated with the severity of bleeding phenotype.

Joint status of patients with nonsevere hemophilia A

BACKGROUND

Joint bleeding in hemophilia may eventually lead to joint damage. In nonsevere hemophilia, joint bleeds occur infrequently. Currently, knowledge on the joint status of patients with nonsevere hemophilia using objective imaging is limited.

OBJECTIVE

To investigate the joint status in patients with nonsevere hemophilia A.

METHODS

This cross-sectional study included patients with nonsevere hemophilia A aged 24-55 years. Joint status was assessed by magnetic resonance imaging (MRI) of the elbows, knees, and ankles and International Prophylaxis Study Group (IPSG) scores were calculated. Lifetime joint bleeding history was collected from medical files. The contribution of factors to joint outcome was explored using multivariable linear regression analysis.

RESULTS

In total, 51 patients were included, of whom 19 (37%) had moderate and 32 (63%) had mild hemophilia. Patients had a median age of 43 years (interquartile range [IQR] 32-50), a median factor VIII activity of 10 IU/dl (IQR 4-16) and a median annual joint bleeding rate (AJBR) of 0.0 (IQR 0.0-0.2). Soft-tissue changes (IPSG subscore > 0) in the elbows, knees, and ankles were present in 19%, 71%, and 71% of patients, respectively. Osteochondral changes (IPSG subscore > 0) in the elbows, knees, and ankles were present in 0%, 20%, and 35% of patients, respectively. In 14% of bleed-free joints, hemosiderin depositions were observed. Age and AJBRs were most strongly associated with the IPSG score.

CONCLUSION

This study demonstrates that a substantial proportion of adults with nonsevere hemophilia has joint changes on MRI despite low joint bleeding rates.

Rosuvastatin treatment decreases plasma procoagulant phospholipid activity after a VTE: A randomized controlled trial

BACKGROUND

Venous thromboembolism (VTE) is a frequent cardiovascular disease with severe complications, including recurrence and death. There is a great need for alternative prophylactic treatment options as anticoagulation is accompanied by increased bleeding risk. Statins are reported to reduce the risk of incident and recurrent VTE, but the mechanisms are elusive. Procoagulant phospholipids (PPL), and phosphatidylserine in particular, are crucial for efficient coagulation activation, but no studies have investigated the effect of statin treatment on plasma PPL activity.

OBJECTIVES

To investigate the impact of rosuvastatin treatment on plasma PPL activity and levels of extracellular vesicles (EVs).

PATIENTS/METHODS

Patients with a history of VTE (≥18 years) allowed to stop anticoagulant treatment were randomized to either 20 mg/day of rosuvastatin treatment or no treatment for 28 days in the Statins Reduce Thrombophilia (NCT01613794) trial. Plasma samples were collected at baseline and study end. PPL activity was measured in samples from 245 participants using a factor Xa-dependent clotting assay and EV levels by flow cytometry.

RESULTS

Rosuvastatin treatment yielded an overall 22% (95% confidence interval [CI] -38.2 to -5.8) reduction in PPL activity, and 37% (95% CI -62.9 to -11.2) reduction in PPL activity in participants with a history of pulmonary embolism. The effect of rosuvastatin on plasma PPL activity was not explained by changes in total cholesterol nor change in levels of total- or platelet-derived EVs.

CONCLUSIONS

Rosuvastatin treatment caused a substantial decrease in plasma PPL activity, suggesting that a PPL-dependent attenuation of coagulation activation may contribute to a reduced VTE risk following statin treatment.

Outcomes of long-term von Willebrand factor prophylaxis use in von Willebrand disease: A systematic literature review

BACKGROUND

Von Willebrand Disease (VWD) is a common inherited bleeding disorder. Patients with VWD suffering from severe bleeding may benefit from the use of secondary long-term prophylaxis.

AIM

Systematically summarize the evidence on the clinical outcomes of secondary long-term prophylaxis in patients with VWD and severe recurrent bleedings.

METHODS

We searched Medline and EMBASE through October 2019 for relevant randomized clinical trials (RCTs) and comparative observational studies (OS) assessing the effects of secondary long-term prophylaxis in patients with VWD. We used Cochrane Risk of Bias (RoB) tool and the RoB for Non-Randomized Studies of interventions (ROBINS-I) tool to assess the quality of the included studies. We conducted random-effects meta-analyses and assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

We included 12 studies. Evidence from one placebo controlled RCT suggested that VWD prophylaxis as compared to no prophylaxis reduced the rate of bleeding episodes (Rate ratio [RR], .24; 95% confidence interval [CI], .17-.35; low certainty evidence), and of epistaxis (RR, .38; 95%CI, .21-.67; moderate certainty evidence), and may increase serious adverse events RR 2.73 (95%CI .12-59.57; low certainty). Evidence from four before-and-after studies in which researchers reported comparative data suggested that VWD prophylaxis reduced the rate of bleeding (RR .34; 95%CI, .25-.46; very low certainty evidence).

CONCLUSION

VWD prophylaxis treatment seems to reduce the risk of spontaneous bleeding, epistaxis, and hospitalizations. More RCTs should be conducted to increase the certainty in these benefits.

Platelet degranulation and bleeding phenotype in a large cohort of Von Willebrand disease patients

Von Willebrand disease (VWD) is a bleeding disorder caused by quantitative (type 1 or 3) or qualitative (type 2A/2B/2M/2N) defects of circulating von Willebrand factor (VWF). Circulating VWF levels not always fully explain bleeding phenotypes, suggesting a role for alternative factors, like platelets. Here, we investigated platelet factor 4 (PF4) in a large cohort of patients with VWD. PF4 levels were lower in type 2B and current bleeding phenotype was significantly associated with higher PF4 levels, particularly in type 1 VWD. Based on our findings we speculate that platelet degranulation and cargo release may play a role across VWD subtypes.

Design of a Prospective Study on Pharmacokinetic-Guided Dosing of Prophylactic Factor Replacement in Hemophilia A and B (OPTI-CLOT TARGET Study)

In resource-rich countries, almost all severe hemophilia patients receive prophylactic replacement therapy with factor concentrates to prevent spontaneous bleeding in joints and muscles to decrease the development of arthropathy and risk of long-term disability. Pharmacokinetic (PK)-guided dosing can be applied to individualize factor replacement therapy, as interindividual differences in PK parameters influence factor VIII (FVIII) and FIX activity levels. PK-guided dosing may therefore lead to more optimal safeguarding of FVIII/FIX levels during prophylaxis and on demand treatment. The OPTI-CLOT TARGET study is a multicenter, nonrandomized, prospective cohort study that aims to investigate the reliability and feasibility of PK-guided prophylactic dosing of factor concentrates in hemophilia-A and -B patients in daily clinical practice. At least 50 patients of all ages on prophylactic treatment using standard half-life (SHL) and extended half-life (EHL) factor concentrates will be included during 9 months and will receive PK-guided treatment. As primary endpoint, a minimum of four FVIII/FIX levels will be compared with FVIII/FIX levels as predicted by Bayesian forecasting. Secondary endpoints are the association of FVIII and FIX levels with bleeding episodes and physical activity, expectations and experiences, economic analyses, and optimization of population PK models. This study will lead to more insight in the reliability and feasibility of PK-guided dosing in hemophilia patients. Moreover, it will contribute to personalization of treatment by greater knowledge of dosing regimens needed to prevent and treat bleeding in the individual patient and provide evidence to more clearly associate factor activity levels with bleeding risk.

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.

Patient-reported outcomes in autosomal inherited bleeding disorders: A systematic literature review

Aim

Currently, it is unknown which patient‐reported outcomes are important for patients with autosomal inherited bleeding disorders. Therefore, the purpose of this study is to systematically review the available literature assessing patient‐reported outcomes and their measurement methods in autosomal inherited bleeding disorders.

Methods

The Embase, Medline ALL, Web of Science Core Collection, Cochrane Central Register of Controlled Trails and Google Scholar databases were searched from inception until 14 August 2020. Studies on patient‐reported outcomes in patients with von Willebrand disease, inherited platelet function disorders and coagulation factor deficiencies were included.

Results

Twenty‐one articles met the inclusion criteria. Three studies were assessed as having poor quality, and therefore a high risk of bias. Nineteen studies had fair quality rating. Different measurements methods were used, ranging from predefined to self‐developed questionnaires. The majority of included studies focused on von Willebrand disease. Patients with von Willebrand disease reported lower health‐related quality of life compared to the general population. Overall, this trend was especially visible in the following domains: vitality, physical and social functioning and pain. Women with inherited bleeding disorders scored lower on health‐related quality of life compared to men, especially women with heavy menstrual bleeding. Patients with joint bleeds or heavy menstrual bleeding reported an increased level of pain.

Conclusion

Patients with autosomal inherited bleeding disorders report lower health related quality of life, especially those with joint bleeds or heavy menstrual bleeding. Numerous measurement methods are used in patients with autosomal inherited bleeding disorders, highlighting the need for studies using established, standardized measurement methods.

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.

Social participation is reduced in type 3 Von Willebrand disease patients and in patients with a severe bleeding phenotype

INTRODUCTION

The negative impact of haemophilia on social participation is well established in previous studies, however, the impact of Von Willebrand disease (VWD) on social participation has not been studied.

AIM

To compare the social participation of a large cohort of VWD patients in the Netherlands with the general Dutch population. In addition, to identify factors associated with social participation in VWD.

METHODS

Patients participating in the "Willebrand in the Netherlands" study completed an extensive questionnaire on educational level, absenteeism from school or work, and occupational disabilities.

RESULTS

Seven-hundred and eighty-eight VWD patients were included (mean age 38.9 years, 59.5% females), of whom 136 children < 16 years. Adult patients with type 3 VWD more often had a low educational level (52.9%) compared to type 1 (40.2%), type 2 VWD (36.8%) and the general population (36.4%) (p = .005). Moreover, in patients aged ≥16 years the days lost from school and/or work in the year prior to study inclusion differed significantly between the VWD types (p = .011). Using negative binomial regression analysis, the occurrence of bleeding episodes requiring treatment in the year preceding study inclusion was significantly associated with the number of days lost from school and/or work among patients aged ≥16 years. Multivariable logistic regression analysis showed that a higher total bleeding score, older age and presence of at least one comorbidity were significantly associated with occupational disability in patients aged ≥16 years.

CONCLUSION

Our study shows that social participation was lower in type 3 VWD and VWD patients with a more severe bleeding phenotype.

Indication and outcome of lupus anticoagulant and antiphospholipid antibodies testing in routine clinical practice

Objectives

Lupus anticoagulans (LACs) and aPLs, both further summarized as aPL, are frequently assessed in routine daily clinical practice in diagnostic workups for suspected autoimmune diseases or to test for underlying risk factors in patients with thrombosis or obstetric complications. The aim of this study was to determine the prevalence of aPL positivity in patients with an indication for aPL testing in routine clinical practice.

Methods

In this retrospective single-centre study, indication for aPL testing, aPL test results and clinical data were collected for patients tested between June 2015 and April 2018.

Results

During the study period, 16 847 single aPL tests were performed in 2139 patients. In 212 patients one or more positive aPL test was found, confirmed in 43.9% with a second positive test. Indications for aPL testing were diagnostic workup/follow-up of autoimmune diseases (33.6%), thrombosis (21.4%) and obstetric complications (28%). Seventy-four patients (3.5% of all patients) fulfilled the criteria of APS, of whom 51% were newly diagnosed. Second positive aPL titres and titres of APS patients were significantly higher compared with positive aPL titres at the first measurement (P < 0.05). Patients with indications of arterial thrombosis and diagnostic workup/follow-up of autoimmune diseases had significantly higher levels of aCL IgG and anti-β2 glycoprotein I (β2GPI) IgG compared with patients with other indications.

Conclusion

The prevalence of one or more positive aPL test was 9.9% and APS was diagnosed in 3.5% of the patients. Patients with arterial thrombosis had significantly higher anti-β2GPI IgG and aCL IgG, which should be confirmed in future studies.

Hepatitis C virus in hemophilia: Health-related quality of life after successful treatment in the sixth Hemophilia in the Netherlands study

INTRODUCTION

Persons with hemophilia and hepatitis C virus (HCV) infection have a lower health-related quality of life (HRQoL) than those never HCV infected. However, it is unknown whether HRQoL after HCV eradication is comparable to individuals never HCV infected. We aimed to compare HRQoL between HCV-cured and never chronically HCV-infected persons with hemophilia.

METHODS

All persons with hemophilia in the Netherlands were invited for a nationwide study conducted in 2018-2019. For the current analysis, participants born before 1992 with data on HRQoL and HCV status were included. HCV status was collected from medical records. HRQoL was measured by RAND-36 questionnaire, with a minimally important difference set at 4.0 points. Multivariable linear regression was used to adjust for age, hemophilia severity, HIV status, and self-reported joint impairment.

RESULTS

In total, 486 persons were eligible; 180 were HCV cured and 306 never chronically HCV infected. Compared with those never HCV infected, HCV-cured individuals were older (57 vs. 53 years), more often had severe hemophilia (67% vs. 21%), and reported more impaired joints (median 3 vs. 0). Compared with those never HCV infected, adjusted RAND-36 domain scores of HCV-cured individuals cured were lower on all RAND-36 domains except Pain, ranging from a difference of 4.5 (95% CI, -8.8 to -0.3) for Physical functioning to 11.3 (95% CI, -19.4 to -3.1) for Role limitations due to physical problems.

CONCLUSION

Despite effective HCV treatment, HRQoL of HCV-cured persons with hemophilia is still lower than HRQoL of those never chronically HCV-infected on all RAND-36 domains. This implies that careful psychosocial follow-up and support are indicated.

Validation of PROMIS Profile-29 in adults with hemophilia in the Netherlands

BACKGROUND

The Patient-Reported Outcomes Measurement Information System (PROMIS) Profile-29 questionnaire is widely used worldwide, but it has not yet been validated in the Netherlands, nor in persons with hemophilia.

OBJECTIVE

To validate the Dutch-Flemish version of the PROMIS-29 Profile v2.01 in adults with hemophilia.

METHODS

Dutch males with hemophilia (all severities) completed questionnaires that contained sociodemographic and clinical characteristics, the PROMIS-29, RAND-36, and the Hemophilia Activities List (HAL). Structural validity of each subscale was assessed with confirmatory factor analysis (CFA). Internal consistency was calculated for each subscale with sufficient model fit in CFA. Construct validity was assessed by testing hypotheses about (1) correlations of each PROMIS-29 subscale with corresponding scales of RAND-36 and domains of HAL, and (2) mean differences in T-scores between subgroups with different hemophilia severities, self-reported joint impairment, and HIV infection status. We considered ≥75% of data in accordance with the hypotheses evidence for construct validity.

RESULTS

In total, 770 persons with hemophilia participated in this cross-sectional study. CFA revealed sufficient structural validity for five subscales: Physical Function, Depression, Sleep Disturbance, Ability to Participate in Social Roles and Activities, and Pain Interference. Internal consistency was high and Cronbach's alpha ranged from 0.79 for Sleep Disturbance to 0.96 for Pain Interference. Differences between clinical subgroups were in the expected direction. Construct validity was confirmed for Physical Function, Anxiety, Depression, Fatigue, Sleep Disturbance, and Pain Intensity.

CONCLUSION

This study revealed sufficient evidence for structural validity, internal consistency, and construct validity for most PROMIS Profile-29 subscales among people with hemophilia in the Netherlands.

In silico evaluation of limited sampling strategies for individualized dosing of extended half-life factor IX concentrates in hemophilia B patients

PURPOSE

Hemophilia B is a bleeding disorder, caused by a factor IX (FIX) deficiency. Recently, FIX concentrates with extended half-life (EHL) have become available. Prophylactic dosing of EHL-FIX concentrates can be optimized by assessment of individual pharmacokinetic (PK) parameters. To determine these parameters, limited sampling strategies (LSSs) may be applied. The study aims to establish adequate LSSs for estimating individual PK parameters of EHL-FIX concentrates using in silico evaluation.

METHODS

Monte Carlo simulations were performed to obtain FIX activity versus time profiles using published population PK models for N9-GP (Refixia), rFIXFc (Alprolix), and rIX-FP (Idelvion). Fourteen LSSs, containing three or four samples taken within 8 days after administration, were formulated. Bayesian analysis was applied to obtain estimates for clearance (CL), half-life (t_1/2), time to 1% (Time_1%), and calculated weekly dose (Dose_1%). Bias and precision of these estimates were assessed to determine which LSS was adequate.

RESULTS

For all PK parameters of N9-GP, rFIXFc and rIX-FP bias was generally acceptable (range: -5% to 5%). For N9-GP, precision of all parameters for all LSSs was acceptable (< 25%). For rFIXFc, precision was acceptable for CL and Time_1%, except for t_1/2 (range: 27.1% to 44.7%) and Dose_1% (range: 12% to 29.4%). For rIX-FP, all LSSs showed acceptable bias and precision, except for Dose_1% using LSS with the last sample taken on day 3 (LSS 6 and 10).

CONCLUSION

Best performing LSSs were LSS with samples taken at days 1, 5, 7, and 8 (N9-GP and rFIXFc) and at days 1, 4, 6, and 8 (rIX-FP), respectively.

Health and treatment outcomes of patients with hemophilia in the Netherlands, 1972-2019

INTRODUCTION

We conducted six cross-sectional nationwide questionnaire studies among all patients with hemophilia in the Netherlands from 1972 until 2019 to assess how health outcomes have changed, with a special focus on patients >50 years of age.

METHODS

Data were collected on patient characteristics, treatment, (joint) bleeding, joint impairment, hospitalizations, human immunodeficiency virus and hepatitis C infections, and general health status (RAND-36).

RESULTS

In 2019, 1009 patients participated, of whom 48% had mild, 15% moderate, and 37% severe hemophilia. From 1972 to 2019, the use of prophylaxis among patients with severe hemophilia increased from 30% to 89%. Their median annual bleeding rate decreased from 25 to 2 bleeds. Patients with severe hemophilia aged <16 years reported joint impairment less often over time, but in those aged >40 years joint status did not improve. In 2019, 5% of all 1009 patients were positive for the human immunodeficiency virus. The proportion of patients with an active hepatitis C infection drastically decreased from 45% in 2001 to 2% in 2019 due to new anti-hepatitis C treatment options. Twenty-five percent had significant liver fibrosis even after successful therapy. Compared to the general male population, patients aged >50 years reported much lower scores on the RAND-36, especially on physical functioning.

DISCUSSION/CONCLUSION

Our study shows that increased use of prophylactic treatment and effective hepatitis C treatment have improved joint health and nearly eradicated hepatitis C infection in patients with hemophilia in the Netherlands. However, patients still suffer from hemophilia-related complications, especially patients aged >50 years.

Treatment-related risk factors for inhibitor development in non-severe hemophilia A after 50 cumulative exposure days: A case-control study

BACKGROUND

Non-severe hemophilia A patients have a life-long inhibitor risk. Yet, no studies have analyzed risk factors for inhibitor development after 50 factor VIII (FVIII) exposure days (EDs).

OBJECTIVES

This case-control study investigated treatment-related risk factors for inhibitor development in non-severe hemophilia A and assessed whether these risk factors were different for early versus late inhibitor development.

PATIENTS/METHODS

Non-severe hemophilia A patients (FVIII:C 2%-40%) were selected from the INSIGHT study. Inhibitor-positive patients were defined as early (<50 EDs) or late (>50EDs) cases and matched to 1-4 inhibitor-negative controls by year of birth, cumulative number of EDs, and center/country. We investigated treatment intensity during the last 10 EDs prior to inhibitor development. Intensive treatment was defined as: surgery, peak treatment (10 consecutive EDs), and high mean FVIII dose (>45 IU/kg/ED). Odds ratios (OR) were calculated by logistic regression.

RESULTS

Of 2709 patients, we analyzed 63 early and 26 late cases and 195 and 71 respectively matched controls. Peak treatment was associated with early and late inhibitor risk (crude OR 1.8, 95% confidence interval [CI] 1.0-3.4; 4.0, 95%CI 1.1-14.3). This association was slightly less pronounced after adjustment for mean FVIII dose. High mean FVIII dose was also associated with early and late inhibitor risk (crude OR 2.8, 95%CI 1.5-5.1; 4.5, 95%CI 1.2-16.6). Surgery increased inhibitor risk for early cases. This was less pronounced for late cases.

CONCLUSIONS

Our findings suggest that intensive FVIII treatment remains a risk factor for inhibitor development in non-severe hemophilia A after more than 50 EDs. Therefore, persistent caution is required throughout the life-time treatment course.

Quantitative 3D microscopy highlights altered von Willebrand factor α-granule storage in patients with von Willebrand disease with distinct pathogenic mechanisms

BACKGROUND

Platelets play a key role in hemostasis through plug formation and secretion of their granule contents at sites of endothelial injury. Defects in von Willebrand factor (VWF), a platelet α-granule protein, are implicated in von Willebrand disease (VWD), and may lead to defective platelet adhesion and/or aggregation. Studying VWF quantity and subcellular localization may help us better understand the pathophysiology of VWD.

OBJECTIVE

Quantitative analysis of the platelet α-granule compartment and VWF storage in healthy individuals and VWD patients.

PATIENTS/METHODS

Structured illumination microscopy (SIM) was used to study VWF content and organization in platelets of healthy individuals and patients with VWD in combination with established techniques.

RESULTS

SIM capably quantified clear morphological and granular changes in platelets stimulated with proteinase-activated receptor 1 (PAR-1) activating peptide and revealed a large intra- and interdonor variability in VWF-positive object numbers within healthy resting platelets, similar to variation in secreted protein acidic and rich in cysteine (SPARC). We subsequently characterized VWD platelets to identify changes in the α-granule compartment of patients with different VWF defects, and were able to stratify two patients with type 3 VWD rising from different pathological mechanisms. We further analyzed VWF storage in α-granules of a patient with homozygous p.C1190R using electron microscopy and found discrepant VWF levels and different degrees of multimerization in platelets of patients with heterozygous p.C1190 in comparison to VWF in plasma.

CONCLUSIONS

Our findings highlight the utility of quantitative imaging approaches in assessing platelet granule content, which may help to better understand VWF storage in α-granules and to gain new insights in the etiology of VWD.

Perioperative pharmacokinetic-guided factor VIII concentrate dosing in haemophilia (OPTI-CLOT trial): an open-label, multicentre, randomised, controlled trial

BACKGROUND

Dosing of replacement therapy with factor VIII concentrate in patients with haemophilia A in the perioperative setting is challenging. Underdosing and overdosing of factor VIII concentrate should be avoided to minimise risk of perioperative bleeding and treatment costs. We hypothesised that dosing of factor VIII concentrate on the basis of a patient's pharmacokinetic profile instead of bodyweight, which is standard treatment, would reduce factor VIII consumption and improve the accuracy of attained factor VIII levels.

METHODS

In this open-label, multicentre, randomised, controlled trial (OPTI-CLOT), patients were recruited from nine centres in Rotterdam, Groningen, Utrecht, Nijmegen, The Hague, Leiden, Amsterdam, Eindhoven, and Maastricht in The Netherlands. Eligible patients were aged 12 years or older with severe or moderate haemophilia A (severe haemophilia was defined as factor VIII concentrations of <0·01 IU/mL, and moderate haemophilia as 0·01-0·05 IU/mL), without factor VIII inhibitors, and planned for elective low or medium risk surgery as defined by surgical risk score. Patients were randomly assigned (1:1) using a web-based randomisation system and treatment minimisation, stratified by method of administration of factor VIII concentrate (continuous infusion vs bolus administration) and risk level of surgery (low and medium risk surgery), to the pharmacokinetic-guided or standard treatment group. The primary endpoint was total amount of infused factor VIII concentrate (IU per kg bodyweight) during perioperative period (from day of surgery up to 14 days after surgery). Analysis was by intention to treat and the safety analysis population comprised all participants who underwent surgery with factor VIII concentrate. This study is registered with the Netherlands Trial Registry, NL3955, and is now closed to accrual.

FINDINGS

Between May 1, 2014, and March 1, 2020, 98 patients were assessed for eligibility and 66 were enrolled in the trial and randomly assigned to the pharmacokinetic-guided treatment group (34 [52%]) or the standard treatment group (32 [48%]). Median age was 49·1 years (IQR 35·0 to 62·1) and all participants were male. No difference was seen in consumption of factor VIII concentrate during the perioperative period between groups (mean consumption of 365 IU/kg [SD 202] in pharmacokinetic-guided treatment group vs 379 IU/kg [202] in standard treatment group; adjusted difference -6 IU/kg [95% CI -88 to 100]). Postoperative bleeding occurred in six (18%) of 34 patients in the pharmacokinetic-guided treatment group and three (9%) of 32 in the standard treatment group. One grade 4 postoperative bleeding event occurred, which was in one (3%) patient in the standard treatment group. No treatment-related deaths occurred.

INTERPRETATION

Although perioperative pharmacokinetic-guided dosing is safe, it leads to similar perioperative factor VIII consumption when compared with standard treatment. However, pharmacokinetic-guided dosing showed an improvement in obtaining factor VIII concentrations within the desired perioperative factor VIII range. These findings provide support to further investigation of pharmacokinetic-guided dosing in perioperative haemophilia care.

FUNDING

Dutch Research Council (NWO)-ZonMw and Takeda.

Adherence to prophylaxis and its association with activation of self-management and treatment satisfaction

INTRODUCTION

Prophylactic replacement therapy (prophylaxis) in patients with haemophilia (PWH) requires lifelong, frequent (self)infusions. Prophylaxis effectiveness depends on adherence, and the drivers of treatment adherence among PWH are unclear.

AIM

To quantify prophylaxis adherence and associations between adherence and patients' treatment attitudes and satisfaction in a large cohort of children and adults with haemophilia.

METHODS

In a nationwide, cross-sectional, questionnaire-based study, PWH with complete information currently using prophylaxis were selected. Validated Hemophilia Regimen Treatment Adherence Scale-Prophylaxis (VERITAS-Pro; normalised score range: 0-100, optimum 0) measured treatment adherence; the Patient Activation Measure (PAM-13; total score range 0-100, optimum 100) measured activation of self-management; Hemophilia Patient Satisfaction Scale (Hemo-Sat; range 0-100, optimum 0) measured treatment satisfaction. Groups were compared according to age (children: <12 years; adolescents: 12-18 years; adults >18 years) and adherence levels using non-parametric tests, and correlations were assessed using Spearman's rho.

RESULTS

Among 321 participants (median age 33 years, interquartile range [IQR]:15-54 years), adherence was high (median VERITAS-Pro total score 17, 89% adherent) but worsened with age, with median scores of 5, 14 and 20 in children, adolescents, adults, respectively (p < .001). Attitudes towards treatment (median 66 vs. 68) participants and treatment satisfaction (12 vs. 10) were similar between adherent and non-adherent patients. The VERITAS-Pro total score was moderately correlated with PAM-13 (r = .41) but not with Hemo-Sat (r = -.11).

DISCUSSION

Prophylaxis adherence was high (89%) but decreased significantly with age and was not correlated with treatment attitude or treatment satisfaction.

Illustrated State-of-the-Art Capsules of the ISTH 2020 Congress

This year's Congress of the International Society of Thrombosis and Haemostasis (ISTH) was hosted virtually from Philadelphia July 17-21, 2021. The conference, now held annually, highlighted cutting-edge advances in basic, population and clinical sciences of relevance to the Society. Despite being held virtually, the 2021 congress was of the same scope and quality as an annual meeting held in person. An added feature of the program is that talks streamed at the designated times will then be available on-line for asynchronous viewing. The program included 77 State of the Art (SOA) talks, thematically grouped in 28 sessions, given by internationally recognized leaders in the field. The SOA speakers were invited to prepare brief illustrated reviews of their talks that were peer reviewed and are included in this article. The topics, across the main scientific themes of the congress, include Arterial Thromboembolism, Coagulation and Natural Anticoagulants, COVID-19 and Coagulation, Diagnostics and Omics, Fibrinogen, Fibrinolysis and Proteolysis, Hemophilia and Rare Bleeding Disorders, Hemostasis in Cancer, Inflammation and Immunity, Pediatrics, Platelet Disorders, von Willebrand Disease and Thrombotic Angiopathies, Platelets and Megakaryocytes, Vascular Biology, Venous Thromboembolism and Women's Health. These illustrated capsules highlight the major scientific advances with potential to impact clinical practice. Readers are invited to take advantage of the excellent educational resource provided by these illustrated capsules. They are also encouraged to use the image in social media to draw attention to the high quality and impact of the science presented at the congress.

Similar sports participation as the general population in Dutch persons with haemophilia; results from a nationwide study

Introduction

Although sports participation is advocated in people with haemophilia (PWH), detailed data concerning sports participation in Dutch PWH is lacking.

Aim

to assess sports participation in Dutch PWH (6‐65 years) compared to the Dutch general population (GP).

Methods

Data from a nationwide, cross‐sectional study in PWH were analysed. Sports participation (type, duration, frequency) was assessed by the Modifiable Activities Questionnaire (MAQ), limitations in activities using the (Paediatric) Haemophilia Activities List ((Ped)HAL). Sports in the two highest categories according to the National Hemophilia Foundation classification were considered high‐risk sports. Groups were compared using Chi‐square testing.

Results

A total of 524 Adult PWH (median age: 45 (IQR: 30–55); 37% severe) and 126 paediatric PWH (median age: 11 (IQR: 8–14); 52% severe) were included. Sports participation was higher in adults (70%) than the GP (58%) and similar to the GP in children (PWH: 68%, GP: 72%). High‐risk sports participation decreased with age in PWH: from 65% (6‐12 years) to 17% (50‐65 years), which was also observed in the GP. Sports participation in children was independent of severity (non‐severe: 67% vs. severe: 65%; P = 0.97), but not in adults (non‐severe: 75%, severe: 62%; P < 0.01). Non‐severe PWH played more high‐risk sports than severe PWH: children at 65% vs. 48% (P = 0.05), adults at 25% vs. 15% (P = 0.07).

Discussion

These results suggest that sports participation in PWH was comparable to the GP. Sports participation was dependent of haemophilia severity in adults. Children were more involved in high‐risk sports than adults. More studies on sports‐related injury‐risk are needed for adequate counselling.

Therapeutic plasma exchange for anticoagulant-refractory antiphospholipid syndrome with severe ischemic and necrotic skin lesions: A case series

Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by clinical findings including thrombosis and/or obstetric complication and laboratory findings, e.g. ≥1 positive antiphospholipid antibodies (aPL) (lupus anticoagulant, anticardiolipin IgG/IgM and/or anti-β2-glycoprotein IgG/IgM). A rare APS clinical entity is severe necrosis which is difficult to treat and often does not respond to anticoagulant therapy. Three consecutive patients with primary or secondary APS who presented with necrotic skin lesions secondary to APS were treated with therapeutic plasma exchange (TPE), glucocorticoids and low-molecular-weight heparin. All patients had a rapid-onset, either full or significant recovery of their APS-related necrotic lesions. Upon treatment, one patients showed resolution of lupus anticoagulant. Two patients had a decrease of at least 88 % in aPL titers after the initial treatment, and were kept on TPE maintenance every 5-6 weeks. None of the patients experienced significant side effects of the TPE. This is the first case series showing the clinical benefits of TPE in patients with ischemic and necrotic skin lesions due to severe anticoagulant-refractory vascular APS.

Endothelial Dysfunction, Atherosclerosis, and Increase of von Willebrand Factor and Factor VIII: A Randomized Controlled Trial in Swine

It is well known that high von Willebrand factor (VWF) and factor VIII (FVIII) levels are associated with an increased risk of cardiovascular disease. It is still debated whether VWF and FVIII are biomarkers of endothelial dysfunction and atherosclerosis or whether they have a direct causative role. Therefore, we aimed to unravel the pathophysiological pathways of increased VWF and FVIII levels associated with cardiovascular risk factors. First, we performed a randomized controlled trial in 34 Göttingen miniswine. Diabetes mellitus (DM) was induced with streptozotocin and hypercholesterolemia (HC) via a high-fat diet in 18 swine (DM + HC), while 16 healthy swine served as controls. After 5 months of follow-up, FVIII activity (FVIII:C) was significantly higher in DM + HC swine (5.85 IU/mL [5.00-6.81]) compared with controls (4.57 [3.76-5.40], p = 0.010), whereas VWF antigen (VWF:Ag) was similar (respectively 0.34 IU/mL [0.28-0.39] vs. 0.34 [0.31-0.38], p = 0.644). DM + HC swine had no endothelial dysfunction or atherosclerosis during this short-term follow-up. Subsequently, we performed a long-term (15 months) longitudinal cohort study in 10 Landrace-Yorkshire swine, in five of which HC and in five combined DM + HC were induced. VWF:Ag was higher at 15 months compared with 9 months in HC (0.37 [0.32-0.42] vs. 0.27 [0.23-0.40], p = 0.042) and DM + HC (0.33 [0.32-0.37] vs. 0.25 [0.24-0.33], p = 0.042). Both long-term groups had endothelial dysfunction compared with controls and atherosclerosis after 15 months. In conclusion, short-term hyperglycemia and dyslipidemia increase FVIII, independent of VWF. Long-term DM and HC increase VWF via endothelial dysfunction and atherosclerosis. Therefore, VWF seems to be a biomarker for advanced cardiovascular disease.

Validation of a perioperative population factor VIII pharmacokinetic model with a large cohort of pediatric hemophilia a patients

AIMS

Population pharmacokinetic (PK) models are increasingly applied to perform individualized dosing of factor VIII (FVIII) concentrates in haemophilia A patients. To guarantee accurate performance of a population PK model in dose individualization, validation studies are of importance. However, external validation of population PK models requires independent data sets and is, therefore, seldomly performed. Therefore, this study aimed to validate a previously published population PK model for FVIII concentrates administrated perioperatively.

METHODS

A previously published population PK model for FVIII concentrate during surgery was validated using independent data from 87 children with severe haemophilia A with a median (range) age of 2.6 years (0.03-15.2) and body weight of 14 kg (4-57). First, the predictive performance of the previous model was evaluated with MAP Bayesian analysis using NONMEM v7.4. Subsequently, the model parameters were (re)estimated using a combined dataset consisting of the previous modelling data and the data available for the external validation.

RESULTS

The previous model underpredicted the measured FVIII levels with a median of 0.17 IU mL^-1 . Combining the new, independent and original data, a dataset comprising 206 patients with a mean age of 7.8 years (0.03-77.6) and body weight of 30 kg (4-111) was obtained. Population PK modelling provided estimates for CL, V1, V2, and Q: 171 mL h^-1  68 kg^-1 , 2930 mL 68 kg^-1 , 1810 mL 68 kg^-1 , and 172 mL h^-1  68 kg^-1 , respectively. This model adequately described all collected FVIII levels, with a slight median overprediction of 0.02 IU mL^-1 .

CONCLUSIONS

This study emphasizes the importance of external validation of population PK models using real-life data.