Multiyear Factor VIII Expression after AAV Gene Transfer for Hemophilia A.

BACKGROUND: The goal of gene therapy for patients with hemophilia A is to safely impart long-term stable factor VIII expression that predictably ameliorates bleeding with the use of the lowest possible vector dose. METHODS: In this phase 1-2 trial, we infused an investigational adeno-associated viral (AAV) vector (SPK-8011) for hepatocyte expression of factor VIII in 18 men with hemophilia A. Four dose cohorts were enrolled; the lowest-dose cohort received a dose of 5 × 1011 vector genomes (vg) per kilogram of body weight, and the highest-dose cohort received 2 × 1012 vg per kilogram. Some participants received glucocorticoids within 52 weeks after vector administration either to prevent or to treat a presumed AAV capsid immune response. Trial objectives included evaluation of the safety and preliminary efficacy of SPK-8011 and of the expression and durability of factor VIII. RESULTS: The median safety observation period was 36.6 months (range, 5.5 to 50.3). A total of 33 treatment-related adverse events occurred in 8 participants; 17 events were vector-related, including 1 serious adverse event, and 16 were glucocorticoid-related. Two participants lost all factor VIII expression because of an anti-AAV capsid cellular immune response that was not sensitive to immune suppression. In the remaining 16 participants, factor VIII expression was maintained; 12 of these participants were followed for more than 2 years, and a one-stage factor VIII assay showed no apparent decrease in factor VIII activity over time (mean [±SD] factor VIII activity, 12.9±6.9% of the normal value at 26 to 52 weeks when the participants were not receiving glucocorticoids vs. 12.0±7.1% of the normal value at >52 weeks after vector administration; 95% confidence interval [CI], -2.4 to 0.6 for the difference between matched pairs). The participants had a 91.5% reduction (95% CI, 88.8 to 94.1) in the annualized bleeding rate (median rate, 8.5 events per year [range, 0 to 43.0] before vector administration vs. 0.3 events per year [range, 0 to 6.5] after vector administration). CONCLUSIONS: Sustained factor VIII expression in 16 of 18 participants who received SPK-8011 permitted discontinuation of prophylaxis and a reduction in bleeding episodes. No major safety concerns were reported. (Funded by Spark Therapeutics and the National Heart, Lung, and Blood Institute; ClinicalTrials.gov numbers, NCT03003533 and NCT03432520.).

The eTHINK Study: Cognitive and Behavioral Outcomes in Children with Hemophilia.

OBJECTIVE: To assess cognitive, behavioral, and adaptive functions in children and young adults with hemophilia treated according to contemporary standards of care. STUDY DESIGN: Evolving Treatment of Hemophilia's Impact on Neurodevelopment, Intelligence, and Other Cognitive Functions (eTHINK) is a US-based, prospective, cross-sectional, observational study (September 2018 through October 2019). Males (aged 1-21 years) with hemophilia A or B of any severity, with or without inhibitors, were eligible. Participants underwent neurologic examinations and age-appropriate neuropsychological assessments, including standardized tests/ratings scales of early development, cognition, emotional/behavioral adjustment, and adaptive skills. RESULTS: Five hundred and fifty-one males with hemophilia A (n = 433) or B (n = 101) were enrolled. Performance on cognitive tests was largely comparable with that of age-matched US population norms, although participants in certain age groups (4-5 and 10-21 years) performed worse on measures of attention and processing speed. Furthermore, adolescents and young adults and those with comorbid attention-deficit/hyperactivity disorder (ADHD; n = 64) reported more adaptive and executive function problems in daily life. Incidence of ADHD in adolescents (21%) was higher than expected in the general population. CONCLUSIONS: In general, males with hemophilia demonstrated age-appropriate intellectual, behavioral, and adaptive development. However, specific patient/age groups showed poorer attention performance and concerns for executive and adaptive development. This study established a normative data set for monitoring neurodevelopment in individuals with hemophilia and highlight the importance of screening and intervention for challenges with cognitive and adaptive skills in this population. CLINICAL TRIAL REGISTRATION: Evolving Treatment of Hemophilia's Impact on Neurodevelopment, Intelligence, and Other Cognitive Functions (eTHINK); NCT03660774; https://clinicaltrials.gov/ct2/show/NCT03660774.

Benefits and risks of non-factor therapies: Redefining haemophilia treatment goals in the era of new technologies.

INTRODUCTION: Over the last decades progress in haemophilia treatment has been remarkable and prophylaxis with clotting factor concentrates in haemophilia A and B has been established as the standard of care in individuals with haemophilia and a severe bleeding phenotype. Besides clotting factor products with prolonged half-life non-factor therapies were developed which enable prophylaxis via subcutaneous administration. Factor VIIIa mimetics like emicizumab facilitate the coagulation pathway and are used in routine clinical practice for indivdiduals with haemophilia A. Rebalancing therapeutic agents like fitusiran, concizumab, marstacimab and serpin PC block the anticoagulant pathway and clinical trials using these products in individuals with haemophilia A and B are ongoing. AIM AND METHODS: A narrative review to asess the benefits and risks of non-factor therapies taking in to account re-defined haemophilia treatment goals. RESULTS: Prophylaxis for prevention of bleeds using non-factor products by subcutaneous administration is effective and results in reductions of bleeding episodes in individuals with haemophilia A or B with and without inhibitors. The treatment with emicizumab showed tolerable safety both in clinical trials and long-term real-world observations with few thrombotic events. In some clinical trials with rebalancing therapies (fitusiran and concizumab) thrombotic events occurred. Monitoring of the haemostatic function of novel therapies especially with concomitant haemostatic treatment is not yet established. CONCLUSION: With the advent of novel therapeutic agents including factor concentrates with ultra-long half-life and improved FVIIIa mimetics aimed at raising the bar of protection into the non-hemophilic range redefinition of haemophilia treatment goals is eagerly needed.

Quality of life in a large multinational haemophilia B cohort (The B-Natural study) - Unmet needs remain.

INTRODUCTION: The B-Natural study is a multicentre, multinational, observational study of haemophilia B (HB) designed to increase understanding of clinical manifestations, treatment and quality of life (QoL). AIM: To characterise and compare QoL in HB across disease severity groups and individuals with inhibitors to identify gaps in treatment. METHODS: A total of 224 individuals from 107 families were enrolled from a total of 24 centres in North America (n = 16), Europe (n = 7) and Asia (n = 1). Of these, 68 (30.4%) subjects had severe (<1 IU/dL), median age 15.6 years, 114 (50.9%) moderate (1-5 IU/dL), age 13.3 years, and 42 (18.8%) mild (>5-< 40 IU/dL), age 12.1 years, disease. Twenty-nine participants had inhibitors or a history of inhibitors. Three versions of the EQ-5D instrument were used as a measure of QoL: proxy (ages 4-7), youth (ages 8-15) and self (age 16+). Each instrument included a visual analogue scale ranging from 100 (best health) to 0 (worst health) to assess current day's health (EQ VAS). Range-of-motion (ROM) for elbows, knees and ankles was assessed using a four-point scale, from which a composite score was calculated. RESULTS: In all severity groups, a proportion of subjects showed less than optimal QoL. The majority of the mild and moderate severe participants reported a normal EQ-5D health profile (79% and 72%, respectively), whereas about half (47%) of the severe participants and only 13% of the inhibitor participants reported this profile. CONCLUSION: The B-Natural study reveals impacted QoL in all disease severities of HB including those with inhibitors. Unmet needs remain and include nonsevere HB.

A New Risk Assessment Model for Hospital-Acquired Venous Thromboembolism in Critically Ill Children: A Report From the Children's Hospital-Acquired Thrombosis Consortium.

OBJECTIVES: To create a risk model for hospital-acquired venous thromboembolism in critically ill children upon admission to an ICU. DESIGN: Case-control study. SETTING: ICUs from eight children's hospitals throughout the United States. SUBJECTS: Critically ill children with hospital-acquired venous thromboembolism (cases) 0-21 years old and similar children without hospital-acquired venous thromboembolism (controls) from January 2012 to December 2016. Children with a recent cardiac surgery, asymptomatic venous thromboembolism, or a venous thromboembolism diagnosed before ICU admission were excluded. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The multi-institutional Children's Hospital-Acquired Thrombosis registry was used to identify cases and controls. Multivariable logistic regression was used to determine the association between hospital-acquired venous thromboembolism and putative risk factors present at or within 24 hours of ICU admission to develop the final model. A total of 548 hospital-acquired venous thromboembolism cases (median age, 0.8 yr; interquartile range, 0.1-10.2) and 187 controls (median age, 2.4 yr; interquartile range, 0.2-8.3) were analyzed. In the multivariable model, recent central venous catheter placement (odds ratio, 4.4; 95% CI, 2.7-7.1), immobility (odds ratio 3.6, 95% CI, 2.1-6.2), congenital heart disease (odds ratio 2.9, 95% CI, 1.7-4.7), length of hospital stay prior to ICU admission greater than or equal to 3 days (odds ratio, 2.5; 95% CI, 1.1-5.6), and history of autoimmune/inflammatory condition or current infection (odds ratio, 2.1; 95% CI, 1.2-3.4) were each independently associated with hospital-acquired venous thromboembolism. The risk model had an area under the receiver operating characteristic curve of 0.79 (95% CI, 0.73-0.84). CONCLUSIONS: Using the multicenter Children's Hospital-Acquired Thrombosis registry, we identified five independent risk factors for hospital-acquired venous thromboembolism in critically ill children, deriving a new hospital-acquired venous thromboembolism risk assessment model. A prospective validation study is underway to define a high-risk group for risk-stratified interventional trials investigating the efficacy and safety of prophylactic anticoagulation in critically ill children.

Development of a Risk Model for Pediatric Hospital-Acquired Thrombosis: A Report from the Children's Hospital-Acquired Thrombosis Consortium.

OBJECTIVE: To identify pertinent clinical variables discernible on the day of hospital admission that can be used to assess risk for hospital-acquired venous thromboembolism (HA-VTE) in children. STUDY DESIGN: The Children's Hospital-Acquired Thrombosis Registry is a multi-institutional registry for all hospitalized participants aged 0-21 years diagnosed with a HA-VTE and non-VTE controls. A risk assessment model (RAM) for the development of HA-VTE using demographic and clinical VTE risk factors present at hospital admission was derived using weighted logistic regression and the least absolute shrinkage and selection (Lasso) procedure. The models were internally validated using 5-fold cross-validation. Discrimination and calibration were assessed using area under the receiver operating characteristic curve and Hosmer-Lemeshow goodness of fit, respectively. RESULTS: Clinical data from 728 cases with HA-VTE and 839 non-VTE controls, admitted between January 2012 and December 2016, were abstracted. Statistically significant RAM elements included age <1 year and 10-22 years, cancer, congenital heart disease, other high-risk conditions (inflammatory/autoimmune disease, blood-related disorder, protein-losing state, total parental nutrition dependence, thrombophilia/personal history of VTE), recent hospitalization, immobility, platelet count >350 K/µL, central venous catheter, recent surgery, steroids, and mechanical ventilation. The area under the receiver operating characteristic curve was 0.78 (95% CI 0.76-0.80). CONCLUSIONS: Once externally validated, this RAM will identify those who are at low-risk as well as the greatest-risk groups of hospitalized children for investigation of prophylactic strategies in future clinical trials.

The B-Natural study-The outcome of immune tolerance induction therapy in patients with severe haemophilia B.

INTRODUCTION: Inhibitors develop less frequently in haemophilia B (HB) than haemophilia A (HA). However, when present, the success of tolerization by immune tolerance induction (ITI) therapy is lower and the risk of complications higher. AIM: To evaluate the use and outcome of ITI in patients with HB and inhibitors. METHODS: Subjects include singletons or siblings with a current/history of inhibitors enrolled in B-Natural-an observational study designed to increase understanding of clinical management of patients with HB. Patients were followed for 6 months and information on demographics, medical and social history, and treatment were recorded. RESULTS: Twenty-nine patients with severe HB and inhibitors were enrolled in 24 centres. Twenty-two underwent one or more courses of ITI with or without immune suppression. Eight patients (36.4%) were successfully tolerized after the first course of ITI. One of these successes (12.5%) experienced allergic manifestations, whereas the corresponding number for the 10 treatment failures was five (50%). One of seven (14.2%) patients with large deletions and three of eight (37.5%) with nonsense mutations were tolerized at the first attempt, and all patients experiencing nephrosis either failed or were on-going. At study end, 11 (50%) were considered successfully tolerized after one or more ITI courses, three were unsuccessful, and eight were still undergoing treatment. CONCLUSION: Our data underscore the possibilities and difficulties of achieving tolerization in patients with HB with inhibitors. The type of mutation and complications appear to correlate with ITI outcome, but more accurate definitions of successful ITI are warranted.

Outcomes for studies assessing the efficacy of hemostatic therapies in persons with congenital bleeding disorders.

INTRODUCTION: Management strategies and hemostatic treatments to achieve control of bleeding are relevant across many disease areas. Identification of primary outcomes for studies assessing hemostatic intervention was the objective of a National Heart, Lung and Blood Institute (NHLBI) sponsored multidisciplinary initiative. The aim of this report is to summarize the evidence reviewed, and the outcomes identified by the subgroup tasked to assess outcomes for inherited bleeding disorders. METHODS: The subgroup decided to focus on haemophilia, the prototypal congenital bleeding disorder and the one with the largest available body of evidence. MEDLINE, EMBASE and PsycINFO, The Cochrane Review, CINAHL, and Web of Science were searched for systematic and narrative reviews on outcomes used in haemophilia clinical trials. Three different clinical goals were identified as typical objectives of future research. RESULTS: Out of 1322 unique citations, 24 reviews published in the period 2002-2019 were included. We identified 113 outcome measures, categorized in 6 domains: health-related quality of life (HRQoL), comorbidities and mortality, overall physical functioning and participation, bleeding and hemostasis, joint health, and costs and resource use. Three different clinical goals were identified as typical objectives of future research: Episodic 'on demand' replacement therapy, prevention of bleeding (Prophylaxis), and long-term and overall impact of bleeding. For each of these scenarios, specific outcomes were recommended. CONCLUSIONS: Primary outcomes for clinical trials assessing the efficacy of hemostatic treatment in achieving control, prevention and limiting long-term consequences of bleeding in inherited bleeding disorders are suggested, and their strength and limitations discussed.

Natural history study of factor IX deficiency with focus on treatment and complications (B-Natural).

INTRODUCTION: Haemophilia B (HB) is less well studied than haemophilia A (HA); despite similarities between the two inherited bleeding disorders, important differences remain that require further research. AIM: B-Natural is a multi-centre, prospective, observational study of HB, designed to increase understanding of clinical manifestations, treatment, quality-of-life (QoL), inhibitor development, immune tolerance induction (ITI) outcome, renal function and create a biorepository for future investigations. METHODS: Participants include sibling pairs/groups without a current/history of inhibitors and singletons or siblings with a current/history of inhibitors followed for six months. Demographics, medical, social history and treatment were recorded. A physical examination including joint range of motion (ROM) was performed; QoL was assessed. Samples were collected for F9 gene mutation, HLA typing, non-inhibitory antibodies and renal function testing. RESULTS: Twenty-four centres enrolled 224 individuals from 107 families including 29 with current/history of inhibitors. Of these, 68, 30.4%, had severe (<1% FIX level of normal); 114, 50.9%, moderate (1%-5%); and 42, 18.8%, mild (>5-<40%) disease. At enrolment, 53.1% had 50 + exposure days to exogenous FIX. Comparison of joint scores showed significant (P < .05) differences between those with severe (with/without inhibitors), and those with moderate/mild disease. The majority with severe disease, 80.0% with current/history of inhibitors and 64.3% of those without, were treated with prophylaxis. CONCLUSION: B-Natural provides data supporting an increased understanding of HB and its impact throughout life. The need for optimal disease control to normalize physical and psychosocial outcomes is underscored, and further analyses will contribute to an increased understanding of critical issues in HB.

2021 clinical trials update: Innovations in hemophilia therapy.

Therapies engineered to prolong clotting factor protein circulation time, manipulate the balance of pro-coagulant and anti-coagulant proteins, or introduce new genetic material to enable endogenous factor protein production dominate the clinical trial landscape of hemophilia. The availability of clotting factor concentrates and the establishment of primary prophylaxis have dramatically improved health outcomes for hemophilia patients. But, the burden of hemostatic therapy remains significant, and many barriers to consistent longitudinal use of prophylaxis exist. Several types of emerging therapeutics including engineered factor concentrates, substitutive therapies, rebalancing therapies, and gene transfer/editing all aim to reduce the challenges of current hemophilia treatment. Emerging treatment options may reduce treatment frequency or need for intravenous administration. They may also introduce new challenges in laboratory assessment of hemostasis. These novel therapies must not introduce significant new health risks and continue to support similar or improved outcomes. The potential ramifications of rebalancing the coagulation cascade, particularly in a stress or inflammatory state, or introduction of new genetic material are not trivial. The focus of this review is to provide an overview of active and recently completed clinical trials as well as emerging preclinical data investigating new therapeutic possibilities for hemophilia patients and potentially other rare bleeding disorders.

Utility of Blood Cultures and Empiric Antibiotics in Febrile Pediatric Hemophilia Patients With Central Venous Access Devices.

BACKGROUND: Children with hemophilia frequently require long-term central venous access devices (CVADs) for regular infusion of factor products. Hemophilia patients are not immunocompromised, but the presence and use of CVADs are associated with infections including bacteremia. Currently, the utility of blood cultures in evaluation of the febrile hemophilia patient with an indwelling CVAD is unknown, nor is optimal empiric antibiotic use. METHODS: We performed a retrospective cross-sectional study of febrile immunocompetent hemophilia patients with CVADs presenting to a large academic urban pediatric emergency department from 1995 to 2017. We used a natural language processing electronic search, followed by manual chart review to construct the cohort. We analyzed rate of pathogen recovery from cultures of blood in subgroups of hemophilia patients, the pathogen profile, and the reported pathogen susceptibilities to ceftriaxone. RESULTS: Natural language processing electronic search identified 181 visits for fever among hemophilia patients with indwelling CVADs of which 147 cases from 44 unique patients met study criteria. Cultures of blood were positive in 56 (38%) of 147 patients (95% confidence interval, 30%-47%). Seventeen different organisms were isolated (10 pathogens and 7 possible pathogens) with Staphylococcus aureus and coagulase-negative Staphylococcus species as the most common. Thirty-four percent of isolates were reported as susceptible to ceftriaxone. Positive blood cultures were more common in cases involving patients with inhibitors (n = 71) versus those without (n = 76), odds ratio, 7.4 (95% confidence interval, 3.5-15.9). This was observed irrespective of hemophilia type. CONCLUSIONS: Febrile immunocompetent hemophilia patients with indwelling CVADs have high rates of bacteremia. Empiric antimicrobial therapy should be targeted to anticipated pathogens and take into consideration local susceptibility patterns for Staphylococcus aureus.

Clinical application of Web Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo): Patterns of blood sampling and patient characteristics among clinician users.

BACKGROUND: Use of population pharmacokinetics (PopPK) to facilitate PK-informed prophylaxis in clinical practice has gained momentum among haemophilia providers due to the accessibility of tools such as the Web Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo) and availability of extended half-life (EHL) factor concentrates. It is unknown how clinicians implement PopPK. AIM: To investigate the evolution of PopPK use in clinical practice by comparing blood sampling strategies, patient features, and factor group between initial and recent periods of WAPPS-Hemo availability. METHODS: PK data for haemophilia A and haemophilia B patients from two time periods were extracted from the WAPPS-Hemo database: early availability (10/2015-09/2016) and recent use (10/2017-09/2018). We compared patient characteristics (age, body weight, haemophilia type), product type and dose, and blood sampling times between the time frames. RESULTS: Over 1900 eligible infusions were submitted to WAPPS-Hemo during the periods studied, with 85% representing FVIII concentrates. In the recent cohort, PK profiles were requested for younger patients (median age 18 vs 26 years), with increased proportional EHL FVIII use (29% vs 14% of infusions). High-use centres generally submitted fewer blood samples per infusion than non-high-use centres, although the number of samples collected by non-high-use centres decreased significantly over time. During both periods, blood sample timing was generally consistent with ISTH recommended windows. CONCLUSION: The use of WAPPS-Hemo by haemophilia providers grew by over threefold between the time periods investigated. While sampling times have included key time points proposed first by Björkman since early WAPPS-Hemo usage, a trend towards minimizing sampling was observed.

Awareness, Care and Treatment In Obesity maNagement to inform Haemophilia Obesity Patient Empowerment (ACTION-TO-HOPE): Results of a survey of US patients with haemophilia and obesity (PwHO) and their partners and caregivers.

BACKGROUND: The ACTION study identified barriers to initiating and maintaining weight loss in patients with obesity; however, joint-related issues (pain, mobility and bleeding) may affect perceptions of patients with haemophilia and obesity (PwHO). AIM: To identify patient and caregiver insights on the unique challenges of PwHO. METHODS: Following IRB approval, adults who self-identified as PwHO, spouses/partners of adult PwHO, and caregivers of adolescent PwHO (aged 12-17 years) completed an online survey between December 2017 and April 2018. RESULTS: Respondents included 124 adult PwHO, 45 spouses/partners and 42 caregivers. By calculated BMI, most adults were overweight (43%) or had obesity (51%); this differed from self-reported weight category. PwHO goals were improving health conditions (60%), having more energy (54%), reducing risks of weight (46%), and losing any weight (44%). Issues related to joint health were secondary for PwHO but frequently reported by spouses/parents. Most perceived weight loss to be a high priority (66%) and their responsibility (64%) but required a complete lifestyle change (63%). Most anticipated that weight loss would reduce joint pain (62%), bleeding (58%) and factor use (52%) and increase mobility (62%). Weight discussions with healthcare providers (HCPs) were commonly reported (51%). HCP discussions targeted improving health conditions (46%), achieving any weight loss (44%), being more active (73%) and improving eating habits (72%). Most PwHO (65%) perceived obesity as a disease and believe that 10% weight loss would be extremely beneficial (78%). In the past 5 years, 80% discussed being overweight and 68% losing weight; a minority reported being successful (9%) or somewhat successful (38%) with weight loss. More realistic or specific (51%/47%) goals, resources (46%), referrals to weight-loss programmes (41%) or dietitians (38%), meals or recipes (54%/50%), local or national (42%/41%) programmes for PwHO and success stories of PwHO (40%) are needed or would be helpful. CONCLUSIONS: PwHO, spouse/partners and caregivers exhibited awareness of general and haemophilia-specific consequences of excess body weight. Most have tried general approaches to improve eating and increase activity with little success and desire more education on weight management and more details on specific actionable recommendations distributed through existing haemophilia channels. These insights will better inform the creation of weight-loss programmes for this community.

An emerging role for endothelial barrier support therapy for congenital disorders of glycosylation.

Congenital disorders of glycosylation (CDGs) are clinically heterogeneous disorders defined by a decreased ability to modify biomolecules with oligosaccharides. Critical disruptions in protein recognition, interaction, binding, and anchoring lead to broad physiological effects. Patients present with endocrinopathy, immunodeficiency, hepatopathy, coagulopathy, and neurodevelopmental impairment. Patients may experience mortality/morbidity associated with shock physiology that is frequently culture negative and poorly responsive to standard care. Oedema, pleural and pericardial effusions, ascites, proteinuria, and protein-losing enteropathy are observed with an exaggerated inflammatory response. The negative serum protein steady state results from several mechanisms including reduced hepatic synthesis and secretion, increased consumption, and extravasation. Disruption of the glycocalyx, a layer of glycosylated proteins that lines the endothelium preventing thrombosis and extravasation, is a suspected cause of endothelial dysfunction in CDG patients. We performed a retrospective review of CDG patients admitted to our institution with acute illness over the past 2 years. Longitudinal clinical and laboratory data collected during the sick and well states were assessed for biomarkers of inflammation and efficacy of interventions. Six patients representing 4 CDG subtypes and 14 hospitalisations were identified. Acute D-dimer elevation, proteinuria, decreased serum total protein levels, coagulation proteins, and albumin were observed with acute illness. Infusion of fresh frozen plasma, and in some cases protein C concentrate, was associated with clinical and biomarker improvement. This was notable with intra-patient comparison of treated vs untreated courses. Use of endothelial barrier support therapy may reduce endothelial permeability by restoring both regulatory serum protein homeostasis and supporting the glycocalyx and is likely a critical component of care for this population.

The impact of extended half-life factor concentrates on prophylaxis for severe hemophilia in the United States.

With licensure of extended half-life (EHL) factor products and the changing landscape of available hemophilia products, patients and providers have options for less treatment-intense prophylaxis. The impact of these products in clinical practice to date remains understudied. We aimed to quantify the use of EHL products in prophylaxis in the US using the ATHN-dataset, a database of 145 ATHN-affiliated hemophilia treatment centers (HTCs). Further, we aimed to quantify the impact of EHL on key hemophilia indicators including annualized bleed rates (ABRs), hemophilia joint health scores (HJHS) and quality of life (QOL) metrics. The use of EHL vs standard half-life (SHL) products in severe hemophilia was compared between June 2018 and March 2019 using the ATHN-dataset. A cohort of patients was also recruited from seven participating HTCs in order to compare ABR, HJHS and QOL between product classes. By March 2019 the number of individuals with severe Hemophilia A (SHA) receiving EHLs remained relatively stable (28.4%), whereas the number of prescribed non-factor products increased to 7.1%, with a diminishing majority of patients (64.0%) continuing to receive SHLs. The majority of patients with severe hemophilia B (SHB) received treatment with EHLs including 57.5% by March 2019. There was a trend toward lower ABR with use of EHLs in SHA and SHB, although this did not result in improved HJHS nor QOL. EHL use in the United States in severe hemophilia continues to increase, although at a slower rate in SHA with the availability of non-factor therapy. The impact of the EHL therapies in clinical practice should continue to be examined prospectively.

Low von Willebrand factor in pediatric patients: Retrospective analysis of 293 cases informs diagnostic and therapeutic decision making.

Low von Willebrand factor (VWF) poses diagnostic and therapeutic challenges for predicting bleed risk and need for empiric hemostatic therapy, particularly in children. Retrospective review identified 293 low VWF pediatric patients and investigated clinical and laboratory features. Low activity to antigen ratio was observed in 142 patients. When evaluation included VWF activity with gain-of-function glycoprotein Ib fragments (VWF:GPIbM) assay or VWF exon 28 sequencing, low VW was excluded in the majority (62%) of these patients. Application of a condensed bleeding assessment tool to quantify bleeding symptoms and use of the VWF:GPIbM assay may reduce the number of patients with bleed risk anxiety and unnecessary hemostatic management plans.

Neuropsychological function in children with hemophilia: A review of the Hemophilia Growth and Development Study and introduction of the current eTHINK study.

Almost all of what is known about neurologic and cognitive development in hemophilia derives from the Hemophilia Growth and Development Study, conducted during an era when treatment regimens and comorbidities differed significantly from the current environment. Results suggested hemophilia and human immunodeficiency virus had independent effects, and hemophilia negatively impacts academic achievement, attention, and behavior. The introduction of prophylaxis treatment in hemophilia has created the need for re-evaluation of the effects of hemophilia on neurodevelopment and cognition. We outline the Evolving Treatment of Hemophilia's Impact on Neurodevelopment, Intelligence, and Other Cognitive Functions (NCT03660774) study, which aims to meet this need.

Regional variation and cost implications of prescribed extended half-life factor concentrates among U.S. Haemophilia Treatment Centres for patients with moderate and severe haemophilia.

BACKGROUND: Extended half-life (EHL) factor VIII (FVIII) and IX (FIX) products are intended to decrease the burden of prophylaxis for patients with haemophilia A or B. Whether these newer concentrates have led to meaningful clinical practice change remains vague. AIM: To characterize the longitudinal use of standard (SHL) and EHL factor concentrates at haemophilia treatment centres (HTCs), using the ATHNdataset, a US database of 138 ATHN-affiliated HTCs. METHODS: Factor concentrate use among moderate and severe haemophilia A and B patients without inhibitors was analysed at three time points over 18 months. RESULTS: Use of EHL concentrates rose from 10% of patients to 22% during this study. EHL FVIII prophylaxis is prescribed to the minority of patients, 28%; EHL FIX now predominates for prophylaxis, 52%. Rates of prescribed EHL products varied significantly by age group and HTC region. Median prescribed prophylaxis for SHL compared to EHL products was FVIII 6240 and 5200 and FIX 6968 and FIX 3900 IU/kg/y, respectively. On-demand EHL use has grown but has minimal contribution to overall usage (2%). CONCLUSION: Haemophilia treatment centre region and patient age impact the rate of adoption of EHL products; however, EHL prescribing continues to rise nationally, particularly for EHL FIX. Careful attention to annual cost of prophylaxis is imperative as the decrease in median EHL prophylaxis consumption is not offset by the higher unit cost of these products. It is unclear how further growth in use of EHLs will be impacted by emerging non-factor replacement and gene therapies.

Shifting Landscape of Hemophilia Therapy: Implications for Current Clinical Laboratory Coagulation Assays.

Clinical coagulation assays are an integral part of diagnosing and managing patients with hemophilia; however, in this new era of bioengineered factor products and non-factor therapeutics, problems have arisen with use of traditional coagulation tests for the quantification of several of these new products. Discussion over the use of one-stage clotting assays versus chromogenic substrate assays for clinical decision making and potency labeling has been ongoing for many years. Emerging factor concentrates have heightened concern over assay selection and availability. Emicizumab interferes with all aPTT based assays, rendering them unreliable and potentially falsely reassuring to the unaware provider. This review explores considerations for coagulation assays in the clinical setting and highlights how awareness of institutional coagulation assays and potential limitations have never been more critical for providers caring for patients with bleeding disorders. This article is protected by copyright. All rights reserved.