Type 1 VWD classification revisited: novel insights from combined analysis of the LoVIC and WiN studies

ABSTRACT

There is significant ongoing debate regarding type 1 von Willebrand disease (VWD) defintion. Previous guidelines recommended patients with von Willebrand factor (VWF) levels <30 IU/dL be diagnosed type 1 VWD, whereas patients with significant bleeding and VWF levels from 30 to 50 IU/dL be diagnosed with low VWF. To elucidate the relationship between type 1 VWD and low VWF in the context of age-induced increases in VWF levels, we combined data sets from 2 national cohort studies: 162 patients with low VWF from the Low VWF in Ireland Cohort (LoVIC) and 403 patients with type 1 VWD from the Willebrand in The Netherlands (WiN) studies. In 47% of type 1 VWD participants, VWF levels remained <30 IU/dL despite increasing age. Conversely, VWF levels increased to the low VWF range (30-50 IU/dL) in 30% and normalized (>50 IU/dL) in 23% of type 1 VWD cases. Crucially, absolute VWF antigen (VWF:Ag) levels and increase of VWF:Ag per year overlapped between low VWF and normalized type 1 VWD participants. Moreover, multiple regression analysis demonstrated that VWF:Ag levels in low VWF and normalized type 1 VWD patients would not have been different had they been diagnosed at the same age (β = 0.00; 95% confidence interval, -0.03 to 0.04). Consistently, no difference was found in the prevalence of VWF sequence variants; factor VIII activity/VWF:Ag or VWF propeptide/VWF:Ag ratios; or desmopressin responses between low VWF and normalized type 1 VWD patients. In conclusion, our findings demonstrate that low VWF does not constitute a discrete clinical or pathological entity. Rather, it is part of an age-dependent type 1 VWD evolving phenotype. Collectively, these data have important implications for future VWD classification criteria.

Etranacogene dezaparvovec gene therapy for haemophilia B (HOPE-B): 24-month post-hoc efficacy and safety data from a single-arm, multicentre, phase 3 trial

BACKGROUND

Etranacogene dezaparvovec, the first gene therapy approved for haemophilia B treatment, was shown to be superior to treatment with continuous prophylactic factor IX in terms of bleeding protection 18 months after gene therapy in a phase 3 trial. We report post-hoc 24-month efficacy and safety data from this trial to evaluate the longer-term effects of etranacogene dezaparvovec in individuals with haemophilia B.

METHODS

The phase 3 HOPE-B trial enrolled males aged 18 years or older with inherited haemophilia B, classified as severe (plasma factor IX activity level <1%) or moderately severe (plasma factor IX activity level ≥1% and ≤2%), with a severe bleeding phenotype and who were on stable continuous factor IX prophylaxis. Participants were treated with a single infusion of etranacogene dezaparvovec (2 × 1013 genome copies per kg of bodyweight). The primary endpoint, reported previously, was non-inferiority of the annualised bleeding rate (ABR) during the 52 weeks following stable factor IX expression (defined as months 7-18 after treatment) versus an at least 6-month lead-in period in which participants received their usual continuous factor IX prophylaxis, and is updated here up to month 24. Additional, post-hoc efficacy analyses, including adjusted ABR, factor IX activity, participants within factor IX ranges, and factor IX use, and safety analyses were performed at 24 months after gene therapy. Data were analysed in the full analysis set, which comprised the 54 patients who received at least a partial dose of gene therapy. The trial is ongoing and is registered with ClinicalTrials.gov, number NCT03569891.

FINDINGS

The study began on June 27, 2018, and participants were treated between January, 2019, and March, 2020; the date of data cutoff was April 21, 2022. 54 adult males (40 White, two Asian, one Black or African American, 11 other or missing) received a single intravenous infusion of etranacogene dezaparvovec and were followed for a median of 26·51 months (IQR 24·54-27·99), after a lead-in period of 7·13 months (6·51-7·82). In the updated analysis comparing months 7-24 after gene therapy to the lead-in period, mean adjusted ABR significantly reduced from 4·18 to 1·51 (p=0·0002) for all bleeds and from 3·65 to 0·99 (p=0·0001) for factor IX-treated bleeds. During each 6-month period after gene therapy, at least 67% of participants experienced no bleeding (36 of 54 during months 0-6 and stable thereafter), compared with 14 (26%) of 54 during the lead-in period. 24 months after gene therapy, 1 (2%) participant had one-stage factor IX activity less than 5%, whereas 18 (33%) had factor IX activity more than 40% (non-haemophilia range), with mean factor IX activity stable and sustained at 36·7% (SD 19·0%). 52 (96%) of 54 participants expressed endogenous factor IX, remaining free of factor IX prophylaxis at month 24. No new safety concerns were identified and no treatment-related serious adverse events or treatment-related deaths occurred. The most common treatment-related adverse events were an increase in alanine aminotransferase (nine [17%] of 54 patients), headache (eight [15%]), influenza-like illness (seven [13%]), and an increase in aspartate aminotransferase (five [9%]).

INTERPRETATION

By providing durable disease correction throughout the 24 months after gene therapy, etranacogene dezaparvovec provides a safe and effective therapeutic option for patients with severe or moderately severe haemophilia B.

FUNDING

uniQure and CSL Behring.

Effect of etranacogene dezaparvovec on quality of life for severe and moderately severe haemophilia B participants: Results from the phase III HOPE-B trial 2 years after gene therapy

INTRODUCTION

For people with haemophilia B (PwHB), bleeding may occur despite prophylaxis, negatively affecting health-related quality of life (HRQoL). The pivotal phase 3 HOPE-B trial investigating the adeno-associated virus gene transfer product, etranacogene dezaparvovec (EDZ), demonstrated sustained factor IX (FIX) activity and bleed protection in PwHB with baseline FIX levels ≤2%.

AIM

Assess how EDZ affects HRQoL in HOPE-B trial participants.

METHODS

HRQoL was evaluated using generic and disease-specific patient reported outcomes (PROs) including the EQ-5D-5L and the Hem-A-QoL questionnaires. Mean domain and total scores were compared 6 months pre- and the first 2 years post-EDZ administration using repeated measures linear mixed models. The percentage of participants with minimal clinically important improvements in HRQoL was also evaluated.

RESULTS

Two years post-EDZ, there were nominally significant increases in the least squares (LS) mean score for the EQ-5D-5L Index Value (.04; p = .0129), reflecting better HRQoL. Nominally significant decreases in the LS mean scores, reflecting better HRQoL, were also found for the Hem-A-QoL total score (-6.0; p < .0001) and the Treatment (-13.94; p < .0001), Feelings (-9.01; p < .0001), Future (-6.45; p = .0004) and Work/School (-5.21; p = .0098) domains. The percentage of participants with ≥15-point improvement ranged from 45.83% (95% CI: 31.37%, 60.83%) for Treatment to 13.89% (95% CI: 4.67%, 29.50%) for Family Planning. Results were similar for Year 1.

CONCLUSION

In conclusion, gene therapy with EDZ improved HRQoL in the first and second years in several Hem-A-QoL domains, including Treatment, Feelings, Work/School and Future domains, whereas improvement in other aspects of HRQoL were not demonstrated.

Peri-operative desmopressin combined with pharmacokinetic-guided factor VIII concentrate in non-severe haemophilia A patients

INTRODUCTION

Non-severe haemophilia A patient can be treated with desmopressin or factor VIII (FVIII) concentrate. Combining both may reduce factor consumption, but its feasibility and safety has never been investigated.

AIM

We assessed the feasibility and safety of combination treatment in nonsevere haemophilia A patients.

METHODS

Non-severe, desmopressin responsive, haemophilia A patients were included in one of two studies investigating peri-operative combination treatment. In the single-arm DAVID study intravenous desmopressin (0.3 μg/kg) once-a-day was, after sampling, immediately followed by PK-guided FVIII concentrate, for maximally three consecutive days. The Little DAVID study was a randomized trial in patients undergoing a minor medical procedure, whom received either PK-guided combination treatment (intervention arm) or PK-guided FVIII concentrate only (standard arm) up to 2 days. Dose predictions were considered accurate if the absolute difference between predicted and measured FVIII:C was ≤0.2 IU/mL.

RESULTS

In total 32 patients (33 procedures) were included. In the DAVID study (n = 21), of the FVIII:C trough levels 73.7% (14/19) were predicted accurately on day 1 (D1), 76.5% (13/17) on D2. On D0, 61.9% (13/21) of peak FVIII:C levels predictions were accurate. In the Little DAVID study (n = 12), on D0 83.3% (5/6) FVIII:C peak levels for both study arms were predicted accurately. Combination treatment reduced preoperative FVIII concentrate use by 47% versus FVIII monotherapy. Desmopressin side effects were mild and transient. Two bleeds occurred, both despite FVIII:C > 1.00 IU/mL.

CONCLUSION

Peri-operative combination treatment with desmopressin and PK-guided FVIII concentrate dosing in nonsevere haemophilia A is feasible, safe and reduces FVIII consumption.

The spectrum of neutralizing and non-neutralizing anti-FVIII antibodies in a nationwide cohort of 788 persons with hemophilia A

Objectives

Anti-factor VIII (FVIII) antibodies have been reported to exhibit both neutralizing and non-neutralizing characteristics. This is the first study investigating the full spectrum of FVIII-specific antibodies, including non-neutralizing antibodies, very-low titer inhibitors, and inhibitors, in a large nationwide population of persons with hemophilia A of all severities.

Methods

All persons with hemophilia A (mild (FVIII > 5-40 IU/dL)/moderate [FVIII 1-5 IU/dL)/severe (FVIII < 1 IU/dL)] with an available plasma sample who participated in the sixth Hemophilia in the Netherlands study between 2018 and 2019 were included. The presence of anti-FVIII antibodies of the immunoglobulin A, M, and G isotypes and IgG subclasses, along with antibody titer levels, were assessed using direct-binding ELISAs. FVIII specificity was assessed using a competition-based ELISA approach. The inhibitor status was determined using the Nijmegen ultra-sensitive Bethesda assay (NusBA) and the Nijmegen Bethesda assay (NBA).

Results

In total, 788 persons with hemophilia A (336 (42.6%) mild, 123 (15.6%) moderate, 329 (41.8%) severe hemophilia) were included. The median age was 45 years (IQR 24-60), and the majority (50.9%) had over 150 exposure days to FVIII concentrates. Within our population, 144 (18.3%) individuals had non-neutralizing FVIII-specific antibodies, 10 (1.3%) had very low-titer inhibitors (NusBA positive; NBA negative), and 13 (1.6%) had inhibitors (both NusBA and NBA positive). IgG1 was the most abundant FVIII-specific antibody subclass, and the highest titer levels were found for IgG4. In individuals without a reported history of inhibitor development, no clear differences were observed in antibody patterns between those who were minimally or highly exposed to FVIII concentrates. IgG4 subclass antibodies were only observed in persons with a reported history of FVIII inhibitor or in those with a currently detected (very low-titer) inhibitor.

Conclusion

In this cross-sectional study, we identified non-neutralizing antibodies in a relatively large proportion of persons with hemophilia A. In contrast, in our population, consisting of persons highly exposed to FVIII concentrates, (very low-titer) inhibitors were detected only in a small proportion of persons, reflecting a well-tolerized population. Hence, our findings suggest that only a small subpopulation of non-neutralizing FVIII-specific antibodies is associated with clinically relevant inhibitors.

A new population pharmacokinetic model for recombinant factor IX-Fc fusion concentrate including young children with haemophilia B

AIMS

Recombinant factor IX Fc fusion protein (rFIX-Fc) is an extended half-life factor concentrate administered to haemophilia B patients. So far, a population pharmacokinetic (PK) model has only been published for patients aged ≥12 years. The aim was to externally evaluate the predictive performance of the published rFIX-Fc population PK model for patients of all ages and develop a model that describes rFIX-Fc PK using real-world data.

METHODS

We collected prospective and retrospective data from patients with haemophilia B treated with rFIX-Fc and included in the OPTI-CLOT TARGET study (NTR7523) or United Kindom (UK)-EHL Outcomes Registry (NCT02938156). Predictive performance was assessed by comparing predicted with observed FIX activity levels. A new population PK model was constructed using nonlinear mixed-effects modelling.

RESULTS

Real-world data were obtained from 37 patients (median age: 16 years, range 2-71) of whom 14 were aged <12 years. Observed FIX activity levels were significantly higher than levels predicted using the published model, with a median prediction error of -48.8%. The new model showed a lower median prediction error (3.4%) and better described rFIX-Fc PK, especially for children aged <12 years. In the new model, an increase in age was correlated with a decrease in clearance (P < .01).

CONCLUSIONS

The published population PK model significantly underpredicted FIX activity levels. The new model better describes rFIX-Fc PK, especially for children aged <12 years. This study underlines the necessity to strive for representative population PK models, thereby avoiding extrapolation outside the studied population.

Patients with moderate hemophilia A and B with a severe bleeding phenotype have an increased burden of disease

BACKGROUND

Patients with moderate hemophilia express varying bleeding phenotypes.

OBJECTIVES

To assess the burden of disease in patients with moderate hemophilia and a mild or severe phenotype incorporating the thrombin generation profile.

METHODS

This sub-study of the 6th Hemophilia in the Netherlands study, analyzed data of adults with moderate hemophilia A or B. Patient characteristics and information on bleeding tendency, joint status, and quality of life were obtained from electronic patient files and self-reported questionnaires. A severe bleeding phenotype was defined as an annual bleeding rate ≥5, an annual joint bleeding rate ≥3, and/or the use of secondary/tertiary prophylaxis, and a mild phenotype vice versa. TG was measured with the Nijmegen Hemostasis Assay.

RESULTS

This study included 116 patients: 21% had a severe phenotype of whom 46% used prophylaxis. Patients with a severe phenotype treated on demand reported a higher median annual bleeding rate (7), annual joint bleeding rate (3), and more frequently an impaired joint (77%) than patients with a severe phenotype on prophylaxis (2; 0; 70%) or patients with a mild phenotype (0; 0; 47%). Furthermore, patients with a severe phenotype treated on demand experienced a more decreased quality of life. Despite similar factor activity levels, patients with a severe phenotype had a lower thrombin peak height and thrombin potential (0.7%; 0.06%) than patients with a mild phenotype (21.3%; 46.8%).

CONCLUSION

Patients with moderate hemophilia and a severe phenotype treated on demand displayed a high burden of disease as well as a low thrombin generation profile advocating them toward more intensive prophylactic treatment.

Desmopressin to prevent and treat bleeding in pregnant women with an inherited bleeding disorder: a systematic literature review

BACKGROUND

Although desmopressin (DDAVP) is an accessible and inexpensive hemostatic drug, its use in pregnancy is still debated due to safety uncertainties.

OBJECTIVES

We aimed to review the safety and effectiveness of DDAVP in women with an inherited bleeding disorder during pregnancy and delivery.

METHODS

Databases were searched for articles up to July 25, 2022, reporting maternal and/or neonatal outcomes. PRISMA methodology for systematic reviews and meta-analyses was followed (PROSPERO CRD42022316490).

RESULTS

Fifty-three studies were included, comprising 273 pregnancies. Regarding maternal outcomes, DDAVP was administered in 73 women during pregnancy and in 232 during delivery. Safety outcome was reported in 245 pregnancies, with severe adverse events reported in 2 (1%, hyponatremia with neurologic symptoms). Overall, DDAVP was used as monotherapy in 234 pregnancies, with effectiveness reported in 153 pregnancies (82% effective; 18% ineffective). Regarding neonatal outcomes, out of 60 pregnancies with reported neonatal outcomes after DDAVP use during pregnancy, 2 children (3%) had a severe adverse event (preterm delivery n = 1; fetal growth restriction n = 1). Of the 232 deliveries, 169 neonates were exposed to DDAVP during delivery, and in 114 neonates, safety outcome was reported. Two children (2%) experienced a moderate adverse event (low Apgar score n = 1; transient hyperbilirubinemia not associated with DDAVP n = 1).

CONCLUSION

DDAVP use during pregnancy and delivery seems safe for the mother, with special attention to the occurrence of hyponatremia and for the child, especially during delivery. However, due to poor study designs and limited documentation of outcomes, a well-designed prospective study is warranted.

Stable and durable factor IX levels in patients with hemophilia B over 3 years after etranacogene dezaparvovec gene therapy

Etranacogene dezaparvovec (AMT-061) is a recombinant adeno-associated virus serotype 5 (AAV5) vector containing a codon-optimized Padua variant human factor IX (FIX) transgene with a liver-specific promoter. Here, we report 3-year outcomes from a phase 2b, open-label, single-dose, single-arm, multicenter trial conducted among adults with severe or moderately severe hemophilia B (FIX ≤2%). All participants (n = 3) received a single intravenous dose (2 × 1013 gene copies per kg) and will be followed up for 5 years. The primary end point of FIX activity ≥5% at 6 weeks was met. Secondary end points included bleed frequency, FIX concentrate use, joint health, and adverse events (AEs). All participants required routine FIX prophylaxis and had neutralizing antibodies to AAV5 before etranacogene dezaparvovec treatment. After administration, FIX activity rose to a mean of 40.8% in year 1 and was sustained in year 3 at 36.9%. All participants discontinued FIX prophylaxis. Bleeding was completely eliminated in 2 out of 3 participants. One participant required on-demand FIX replacement therapy per protocol because of elective surgical procedures, for 2 reported bleeding episodes, and twice for a single self-administered infusion because of an unreported reason. One participant experienced 2 mild, self-limiting AEs shortly after dosing. During the 3-year study period, there were no clinically significant elevations in liver enzymes, no requirement for steroids, no FIX inhibitor development, and no late-emergent safety events in any participant. Etranacogene dezaparvovec was safe and effective in adults with hemophilia B over 3 years after administration. This trial was registered at www.clinicaltrials.gov as #NCT03489291.

Transition readiness among adolescents and young adults with haemophilia in the Netherlands: Nationwide questionnaire study

INTRODUCTION

Care for adolescents with haemophilia is transferred from paediatric to adult care around the age of 18 years. Transition programs help to prepare adolescents for this transfer and prevent declining treatment adherence. Evaluating transition readiness may identify areas for improvement.

OBJECTIVE

Assess transition readiness among Dutch adolescents and young adults with haemophilia, determine factors associated with transition readiness, and identify areas of improvement in transition programs.

METHODS

All Dutch adolescents and young adults aged 12-25 years with haemophilia were invited to participate in a nationwide questionnaire study. Transition readiness was assessed using multiple-choice questions and was defined as being ready or almost ready for transition. Potential factors associated with transition readiness were investigated, including: socio-demographic and disease-related factors, treatment adherence, health-related quality of life, and self-efficacy.

RESULTS

Data of 45 adolescents and 84 young adults with haemophilia (47% with severe haemophilia) were analyzed. Transition readiness increased with age, from 39% in 12-14 year-olds to 63% in 15-17 year-olds. Nearly all post-transition young adults (92%, 77/84) reported they were ready for transition. Transition readiness was associated with treatment adherence, as median VERITAS-Pro treatment adherence scores were worse in patients who were not ready (17, IQR 9-29), compared to those ready for transition (11, IQR 9-16). Potential improvements were identified: getting better acquainted with the adult treatment team prior to transition and information on managing healthcare costs.

CONCLUSIONS

Nearly all post-transition young adults reported they were ready for transition. Improvements were identified regarding team acquaintance and preparation for managing healthcare costs.

Quantitative super-resolution imaging of platelet degranulation reveals differential release of von Willebrand factor and von Willebrand factor propeptide from alpha-granules

BACKGROUND

Von Willebrand factor (VWF) and VWF propeptide (VWFpp) are stored in eccentric nanodomains within platelet alpha-granules. VWF and VWFpp can undergo differential secretion following Weibel-Palade body exocytosis in endothelial cells; however, it is unclear if the same process occurs during platelet alpha-granule exocytosis. Using a high-throughput 3-dimensional super-resolution imaging workflow for quantification of individual platelet alpha-granule cargo, we studied alpha-granule cargo release in response to different physiological stimuli.

OBJECTIVES

To investigate how VWF and VWFpp are released from alpha-granules in response to physiological stimuli.

METHODS

Platelets were activated with protease-activated receptor 1 (PAR-1) activating peptide (PAR-1 ap) or collagen-related peptide (CRP-XL). Alpha-tubulin, VWF, VWFpp, secreted protein acidic and cysteine rich (SPARC), and fibrinogen were imaged using 3-dimensional structured illumination microscopy, followed by semiautomated analysis in FIJI. Uptake of anti-VWF nanobody during degranulation was used to identify alpha-granules that partially released content.

RESULTS

VWFpp overlapped with VWF in eccentric alpha-granule subdomains in resting platelets and showed a higher degree of overlap with VWF than SPARC or fibrinogen. Activation of PAR-1 (0.6-20 μM PAR-1 ap) or glycoprotein VI (GPVI) (0.25-1 μg/mL CRP-XL) signaling pathways caused a dose-dependent increase in alpha-granule exocytosis. More than 80% of alpha-granules remained positive for VWF, even at the highest agonist concentrations. In contrast, the residual fraction of alpha-granules containing VWFpp decreased in a dose-dependent manner to 23%, whereas SPARC and fibrinogen were detected in 60% to 70% of alpha-granules when stimulated with 20 μM PAR-1 ap. Similar results were obtained using CRP-XL. Using an extracellular anti-VWF nanobody, we identified VWF in postexocytotic alpha-granules.

CONCLUSION

We provide evidence for differential secretion of VWF and VWFpp from individual alpha-granules.

Poor correlation between biomarkers and MRI-detected joint damage in a cross-sectional study of persons with nonsevere hemophilia A (DYNAMO study)

BACKGROUND

Persons with nonsevere hemophilia A (NSHA) experience less frequent joint bleeding than persons with severe hemophilia A, but may still develop joint damage. Biomarkers of cartilage and synovial remodeling can reflect ongoing pathologic processes that may precede or coincide with damage on joint imaging. If so, biomarkers may be an important diagnostic tool for joint damage in NSHA.

OBJECTIVE

To assess the correlation between biomarkers and MRI-detected joint damage in persons with NSHA.

METHODS

In a cross-sectional study, men with NSHA (factor VIII [FVIII], 2-35 IU/dL) were included. Participants underwent magnetic resonance imaging of elbows, knees, and ankles and blood and urine sampling for biomarker analysis on a single visit. The following biomarker(s) were analyzed in urine: CTX-II or serum: cartilage oligomeric matrix protein, chondroitin sulfate 846, vascular cell adhesion molecule 1, osteopontin (OPN), neo-epitope of MMP -mediated degradation of type II collagen, N-terminal propeptide of type II collagen, collagen type IV M, and propetide of type IV collagen. Spearman's rank correlations were calculated between these biomarkers and the total International Prophylaxis Study group (IPSG) score, soft-tissue subscore, and osteochondral subscore.

RESULTS

In total, 48 persons with NSHA were included. Median age was 43 years (range, 24-55 years) and median FVIII was 10 IU/dL (IQR, 4-16 IU/dL). The median IPSG score was 4 (IQR, 2-9). Median IPSG soft-tissue subscores were 3 (IQR, 2-4) and osteochondral subscores were 0 (IQR, 0-4). No strong correlations were found between the studied biomarkers, total IPSG score, subsequent soft-tissue, and osteochondral subscores.

CONCLUSIONS

In this study, selected biomarkers indicative of different aspects of hemophilic arthropathy showed no consistent correlation with IPSG scores. This suggests that systemically measured biomarkers are currently not suitable for identifying milder joint damage in NSHA, as observed on magnetic resonance imaging.

von Willebrand factor neutralizing and non-neutralizing alloantibodies in 213 subjects with type 3 von Willebrand disease enrolled in 3WINTERS-IPS

BACKGROUND

Type 3 von Willebrand disease (VWD) is the most severe form of this disease owing to the almost complete deficiency of von Willebrand factor (VWF). Replacement therapy with plasma-derived products containing VWF or recombinant VWF rarely cause the development of alloantibodies against VWF that may be accompanied by anaphylactic reactions.

OBJECTIVE

The objective of this study was to assess the prevalence of anti-VWF alloantibodies in subjects with type 3 VWD enrolled in the 3WINTERS-IPS.

METHODS

An indirect in-house enzyme-linked immunosorbent assay has been used to test all the alloantibodies against VWF. Neutralizing antibodies (inhibitors) have been tested with a Bethesda-based method by using a VWF collagen binding (VWF:CB) assay. Samples positive for anti-VWF antibodies were further tested with Bethesda-based methods by using the semiautomated gain-of-function glycoprotein-Ib binding (VWF:GPIbM) and a VWF antigen (VWF:Ag) enzyme-linked immunosorbent assay.

RESULTS

In total, 18 of the 213 (8.4%) subjects tested positive for anti-VWF antibodies and 13 of 213 (6%) had VWF:CB inhibitors. These 13 were among the 18 with anti-VWF antibodies. Of the 5 without VWF:CB inhibitors, 3 had non-neutralizing antibodies, 1 only inhibitor against VWF:GPIbM, and one could not be tested further. Ten of the 13 subjects with VWF:CB inhibitors also had VWF:GPIbM inhibitors, 6 of whom also had VWF:Ag inhibitors. Subjects with inhibitors were homozygous for VWF null alleles (11/14), homozygous for a missense variant (1/14), or partially characterized (2/14).

CONCLUSIONS

Anti-VWF antibodies were found in 8.4% of subjects with type 3 VWD, whereas neutralizing VWF inhibitors were found in 6%, mainly in subjects homozygous for VWF null alleles. Because inhibitors may be directed toward different VWF epitopes, their detection is dependent on the assay used.

A factor IX variant that functions independently of factor VIII mitigates the hemophilia A phenotype in patient plasma

BACKGROUND

Recombinant factor (F)IX-FIAV has previously been shown to function independently of activated FVIII (FVIIIa) and ameliorate the hemophilia A (HA) phenotype in vitro and in vivo.

OBJECTIVES

To assess the efficacy of FIX-FIAV in HA patient plasma using thrombin generation (TG) and intrinsic clotting activity (APTT) analyses.

PATIENTS/METHODS

Plasma obtained from 21 HA patients (>18yrs; 7 mild, 7 moderate, and 7 severe) was spiked with FIX-FIAV. The FXIa-triggered TG lag time and APTT were quantified in terms of FVIII-equivalent activity using FVIII calibration for each patient plasma.

RESULTS

The linear, dose-dependent improvement of the TG lag time and APTT reached its maximum with ∼400-600% FIX-FIAV in severe HA plasma and with ∼200-250% FIX-FIAV in non-severe HA plasma. The cofactor-independent contribution of FIX-FIAV was therefore suggested and confirmed by addition of inhibitory anti-FVIII antibodies to non-severe HA plasma, resulting in a FIX-FIAV response similar to severe HA plasma. Addition of 100% (5 μg/mL) FIX-FIAV mitigated the HA phenotype from severe to moderate (from <0.01% to 2.9% [IQR 2.3-3.9%] FVIII-equivalent activity), from moderate to mild (3.9% [IQR 3.3-4.9] to 16.1% [IQR 13.7-18.1%] FVIII-equivalent activity), and from mild to normal (19.8% [IQR 9.2-24.0%] to 48.0% [IQR 34.0-67.5%] FVIII-equivalent activity). No substantial effects were observed when combining FIX-FIAV with current HA therapies.

CONCLUSION

FIX-FIAV is capable of increasing the FVIII-equivalent activity and coagulation activity in HA patient plasma, thereby mitigating the HA phenotype. Hence, FIX-FIAV could serve as a potential treatment for HA with or without inhibitors.

Gene Therapy with Etranacogene Dezaparvovec for Hemophilia B

BACKGROUND

Moderate-to-severe hemophilia B is treated with lifelong, continuous coagulation factor IX replacement to prevent bleeding. Gene therapy for hemophilia B aims to establish sustained factor IX activity, thereby protecting against bleeding without burdensome factor IX replacement.

METHODS

In this open-label, phase 3 study, after a lead-in period (≥6 months) of factor IX prophylaxis, we administered one infusion of adeno-associated virus 5 (AAV5) vector expressing the Padua factor IX variant (etranacogene dezaparvovec; 2×10¹³ genome copies per kilogram of body weight) to 54 men with hemophilia B (factor IX activity ≤2% of the normal value) regardless of preexisting AAV5 neutralizing antibodies. The primary end point was the annualized bleeding rate, evaluated in a noninferiority analysis comparing the rate during months 7 through 18 after etranacogene dezaparvovec treatment with the rate during the lead-in period. Noninferiority of etranacogene dezaparvovec was defined as an upper limit of the two-sided 95% Wald confidence interval of the annualized bleeding rate ratio that was less than the noninferiority margin of 1.8. Superiority, additional efficacy measures, and safety were also assessed.

RESULTS

The annualized bleeding rate decreased from 4.19 (95% confidence interval [CI], 3.22 to 5.45) during the lead-in period to 1.51 (95% CI, 0.81 to 2.82) during months 7 through 18 after treatment, for a rate ratio of 0.36 (95% Wald CI, 0.20 to 0.64; P<0.001), demonstrating noninferiority and superiority of etranacogene dezaparvovec as compared with factor IX prophylaxis. Factor IX activity had increased from baseline by a least-squares mean of 36.2 percentage points (95% CI, 31.4 to 41.0) at 6 months and 34.3 percentage points (95% CI, 29.5 to 39.1) at 18 months after treatment, and usage of factor IX concentrate decreased by a mean of 248,825 IU per year per participant in the post-treatment period (P<0.001 for all three comparisons). Benefits and safety were observed in participants with predose AAV5 neutralizing antibody titers of less than 700. No treatment-related serious adverse events occurred.

CONCLUSIONS

Etranacogene dezaparvovec gene therapy was superior to prophylactic factor IX with respect to the annualized bleeding rate, and it had a favorable safety profile. (Funded by uniQure and CSL Behring; HOPE-B ClinicalTrials.gov number, NCT03569891.).

Prophylaxis with recombinant von Willebrand factor (rVWF) in patients with type 3 von Willebrand disease (VWD): results of a post hoc analysis from a phase 3 trial

OBJECTIVES

To describe efficacy/safety of recombinant von Willebrand factor (rVWF) prophylaxis in patients with type 3 von Willebrand disease (VWD).

METHODS

This post hoc analysis of a phase 3 open-label trial provides a more detailed analysis of adults with type 3 VWD, categorized based on prior treatment at screening: "Prior On-Demand (OD)" (OD VWF; ≥3 documented spontaneous bleeding events [BEs] requiring VWF in previous 12 months) or "Switch" (plasma-derived [pd] VWF prophylaxis for ≥12 months). Annualized bleeding rates (ABRs) were evaluated during 12 months of rVWF prophylaxis versus historical data from medical records.

RESULTS

In the Prior OD group (n=10), mean spontaneous ABR (sABR) for treated BEs was reduced by 91.6% (ratio, 0.08; 95% CI, 0.02-0.45) versus mean historical sABR. In the Switch group (n=8), mean sABR for treated BEs was reduced by 47% (ratio, 0.53; 95% CI, 0.08-3.62). One non-serious adverse event (AE) was considered possibly related to rVWF. No treatment-related, fatal, or life-threatening serious AEs were reported, and no patient developed VWF inhibitors.

CONCLUSIONS

rVWF prophylaxis reduced sABR in type 3 VWD patients previously treated with OD VWF therapy, and maintained a similar level of hemostatic control in those switching from pdVWF prophylaxis to rVWF prophylaxis. This article is protected by copyright. All rights reserved.

Colorectal cancer screening in patients with inherited bleeding disorders: high cancer detection rate in hemophilia patients

BACKGROUND

The population-based colorectal cancer (CRC) screening program in individuals aged 55 to 75 years in the Netherlands uses fecal immunochemical testing (FIT), to detect hemoglobin in feces, followed by colonoscopy in individuals with a positive FIT.

OBJECTIVES

The objectives of this study are to assess the false-positive rate, detection rate, and positive predictive value of FIT for CRC and advanced adenoma (AA) in patients with Von Willebrand disease (VWD) or hemophilia.

METHODS

We performed a multicenter, nationwide cross-sectional study embedded in 2 nationwide studies on VWD and hemophilia in the Netherlands.

RESULTS

In total, 493 patients with hemophilia (n = 329) or VWD (n = 164) were included, of whom 351 patients participated in the CRC screening program (71.2%). FIT positivity and false-positive rate in patients with hemophilia and VWD were significantly higher than those in the general population (14.8% vs. 4.3%, p < .001 and 10.3% vs. 2.3%, p <.001, respectively). In patients with hemophilia, the detection rate of CRC/AA was significantly higher than that in the general male population (4.5% vs. 1.8%, p = .02), and the positive predictive value of FIT for CRC/AA was comparable (32.3% vs. 39.7%, n.s.). In patients with VWD, the detection rate was similar to that of the general population (0.8% vs. 1.4%, n.s.), whereas the positive predictive value was significantly lower than that in the general population (6.3% vs. 36.8%, p = .02).

CONCLUSION

This study indicates that despite a high false-positive rate of FIT in patients with inherited bleeding disorders, the detection rate of CRC and/or AA in hemophilia patients is high. FIT performs different in patients with hemophilia or VWD compared with the general population.

Desmopressin testing in von Willebrand disease: Lowering the burden

Background

Individuals with von Willebrand disease (VWD) require desmopressin testing because of interindividual response differences. However, testing is burdensome, while not all patients may need extensive testing.

Objectives

To provide von Willebrand factor (VWF) cutoffs that predict desmopressin nonresponse and thereby identify individuals who do not need extensive testing in a retrospective cohort. We validated these cutoffs in a prospective cohort.

Patients and Methods

We included 376 patients (Type 1 VWD with VWF activity [VWF:Act] <0.30 IU/ml: n = 112; with VWF:Act 0.30–0.50 IU/ml: n = 206; Type 2 VWD: n = 58; ages, 5–76 years) from January 2000 to July 2020. We collected VWF:Act and factor VIII activity (FVIII:C) at baseline and several time points after desmopressin (T1–T6). We defined response as VWF:Act and FVIII:C 0.50 IU/ml or greater at T1 and T4. We compared VWF:Act and FVIII:C distribution (historically lowest level, baseline, and T1) between responders and nonresponders and determined cutoffs discriminating between these groups. Results were validated in a group of 30 individuals.

Results

All individuals with Type 1 VWD and Type 2 VWD, respectively, with baseline VWF:Act 0.34 IU/ml or greater or 0.28 IU/ml or greater were responders. In individuals with T1 VWF:Act ≥0.89 IU/ml (Type 1 VWD) or T1 VWF:Act 1.10 IU/ml or greater (Type 2 VWD), response remained at T4.

Conclusion

Desmopressin testing is not needed when lowest historical VWF:Act is 0.30 IU/ml or greater. In patients with Type 1 VWD who require testing, measurements after T1 are often not needed. In patients with Type 2 VWD who require testing, we advise performing T1 and T4 measurements.

Socioeconomic participation of persons with hemophilia: Results from the sixth hemophilia in the Netherlands study

Background and objectives

Treatment availability and comprehensive care have resulted in improved clinical outcomes for persons with hemophilia. Recent data on socioeconomic participation in the Netherlands are lacking. This study assessed participation in education, in the labor market, and social participation for persons with hemophilia compared with the general male population.

Methods

Dutch adults and children (5–75 years) of all hemophilia severities (n = 1009) participated in a questionnaire study that included sociodemographic, occupational, and educational variables. Clinical characteristics were extracted from electronic medical records. General population data were extracted from Statistics Netherlands. Social participation was assessed with the PROMIS Ability to Participate in Social Roles and Activities short form, with a minimal important difference set at 1.0.

Results

Data from 906 adults and children were analyzed. Participation in education of 20 to 24 year olds was 68% (general male population: 53%). Educational attainment was higher compared with Dutch males, especially for severe hemophilia. Absenteeism from school was more common than in the general population. The employment‐to‐population ratio and occupational disability were worse for severe hemophilia than in the general population (64.3% vs. 73.2% and 14.7% vs. 4.8%, respectively), but similar for nonsevere hemophilia. Unemployment was 5.4% (general male population: 3.4%). Absenteeism from work was less common (38% vs. 45.2%). Mean PROMIS score was similar to or higher than in the general population (54.2; SD 8.9 vs. 50; SD 10).

Conclusion

Socioeconomic participation of persons with nonsevere hemophilia was similar to the general male population. Some participation outcomes for persons with severe hemophilia were reduced.

Desmopressin for bleeding in non‐severe hemophilia A: Suboptimal use in a real‐world setting

Background

Desmopressin is an important treatment option in nonsevere hemophilia A because it has several benefits compared with factor (F) concentrates, including no inhibitor risk and much lower costs. Despite these advantages, data are limited on the real‐world use of desmopressin in the treatment of bleeds.

Objective

To describe the clinical use of desmopressin in relation to other therapeutic modalities in the treatment of bleeding episodes in patients with nonsevere hemophilia A.

Methods

Patients with nonsevere hemophilia A aged 12–55 years were included from the DYNAMO cohort study. Data on the desmopressin test response and treated bleeding events in the period January 2009 to July 2020 were retrospectively collected from medical files. An adequate desmopressin test response was defined based on a peak FVIII level of ≥30 IU/dl.

Results

A total of 248 patients with a median age of 38 years (interquartile range 25–49) were included. An adequate desmopressin test response was documented in 25% and 73% of patients with moderate and mild hemophilia, respectively. In adequate responders, 51% of bleeds were exclusively treated with FVIII concentrates, 24% exclusively with desmopressin, 21% with a combination of both and 4% with other treatments. In 54% of bleeds treated with a single dose of factor concentrates, the expected FVIII level after desmopressin exceeded the level targeted.

Conclusion

Most bleeds in patients with an adequate response to desmopressin are treated with factor concentrates. These findings may indicate a suboptimal use of desmopressin and that barriers to the use of desmopressin should be explored.

The bleeding phenotype in people with nonsevere hemophilia

Detailed information on the onset, frequency, and severity of bleeding in nonsevere hemophilia is limited. We aimed to assess the bleeding phenotype of persons with nonsevere hemophilia and to analyze the association between baseline factor VIII/IX (FVIII/IX) levels and the joint bleeding rate. In the DYNAMO (Dynamic Interplay Between Bleeding Phenotype and Baseline Factor Level in Moderate and Mild Hemophilia A and B) study, an international multicenter cohort, we included males with nonsevere hemophilia (FVIII/IX, 0.02-0.35 IU/mL) aged 12 to 55 years. Information on age at first treated (joint) bleed, annual bleeding rates (ABRs), and annual joint bleeding rates (AJBRs) was collected from the medical files. The association between baseline FVIII/IX levels and the joint bleeding rate was assessed by using a frailty model for recurrent events. In total, 304 persons (70 with moderate hemophilia and 234 with mild hemophilia) were included. The median age was 38 years (interquartile range [IQR], 25-49 years), and the median baseline FVIII/IX level was 0.12 IU/mL (IQR, 0.05-0.21 IU/mL). In total, 245 (81%) persons had experienced at least 1 bleed, and 156 (51%) had experienced at least 1 joint bleed. The median age at first bleed and first joint bleed was 8 and 10 years, respectively. The median ABR and AJBR was 0.2 (IQR, 0.1-0.5) and 0.0 (IQR, 0.0-0.2). From baseline FVIII/IX levels 0.02 to 0.05 IU/mL to >0.25 IU/mL, the median ABR decreased from 0.6 (IQR, 0.2-1.4) to 0.1 (IQR, 0.0-0.2) and the AJBR from 0.2 (IQR, 0.0-0.4) to 0.0 (IQR, 0.0-0.0). Baseline FVIII/IX was inversely associated with the joint bleeding rate (P < .001). Low bleeding rates were observed in persons with nonsevere hemophilia. However, one-half of all adolescents and adults had experienced a joint bleed.

Deep compartment models: A deep learning approach for the reliable prediction of time-series data in pharmacokinetic modeling

Nonlinear mixed effect (NLME) models are the gold standard for the analysis of patient response following drug exposure. However, these types of models are complex and time-consuming to develop. There is great interest in the adoption of machine-learning methods, but most implementations cannot be reliably extrapolated to treatment strategies outside of the training data. In order to solve this problem, we propose the deep compartment model (DCM), a combination of neural networks and ordinary differential equations. Using simulated datasets of different sizes, we show that our model remains accurate when training on small data sets. Furthermore, using a real-world data set of patients with hemophilia A receiving factor VIII concentrate while undergoing surgery, we show that our model more accurately predicts a priori drug concentrations compared to a previous NLME model. In addition, we show that our model correctly describes the changing drug concentration over time. By adopting pharmacokinetic principles, the DCM allows for simulation of different treatment strategies and enables therapeutic drug monitoring.

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.

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.

Outcome of Surgical Interventions and Deliveries in Patients with Bleeding of Unknown Cause: An Observational Study

BACKGROUND

 The most optimal management for patients with bleeding of unknown cause (BUC) is unknown, as limited data are available.

OBJECTIVE

 Evaluate management and outcome of surgical procedures and deliveries in patients with BUC.

MATERIALS AND METHODS

 All patients ≥12 years of age, referred to a tertiary center for a bleeding tendency, were included. Bleeding phenotype was assessed and hemostatic laboratory work-up was performed. Patients were diagnosed with BUC or an established bleeding disorder (BD). Data on bleeding and treatment during surgical procedures and delivery following diagnosis were collected.

RESULTS

 Of 380 included patients, 228 (60%) were diagnosed with BUC and 152 (40%) with an established BD. In 14/72 (19%) surgical procedures major bleeding occurred and 14/41 (34%) deliveries were complicated by major postpartum hemorrhage (PPH). More specifically, 29/53 (55%) of the BUC patients who underwent surgery received prophylactic treatment to support hemostasis. Despite these precautions, 4/29 (14%) experienced major bleeding. Of BUC patients not treated prophylactically, bleeding occurred in 6/24 (25%). Of pregnant women with BUC, 2/26 (8%) received prophylactic treatment during delivery, one women with and 11 (46%) women without treatment developed major PPH.

CONCLUSION

 Bleeding complications are frequent in BUC patients, irrespective of pre- or perioperative hemostatic treatment. We recommend a low-threshold approach toward administration of hemostatic treatment in BUC patients, especially during delivery.