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Madhvi Rajpurkar,1 Stacy E Croteau,2 Lisa Boggio,3 David L Cooper4 1Carman and Ann Adams Department of Pediatrics, Children’s Hospital of Michigan/Wayne State University, Detroit, MI, USA; 2Department of Pediatrics, Boston Children’s Hospital/Harvard Medical School, Boston, MA, USA; 3Hemophilia and Thrombophilia Center, Rush University Medical Center, Chicago, IL, USA; 4Clinical Development and Medical Affairs – Biopharm, Novo Nordisk Inc., Plainsboro, NJ, USACorrespondence: Madhvi RajpurkarCarman and Ann Adams Department of Pediatrics, Children’s Hospital of Michigan, Wayne State University, 3901 Beaubien Blvd, Detroit, MI 48201, USATel +1 313 745 5515Fax +1 313 745 5237Email mrajpurk@med.wayne.eduPurpose: Recombinant activated factor VII (rFVIIa; NovoSeven® RT; Novo Nordisk A/S, Bagsvaerd, Denmark) is approved in the United States for the treatment of bleeding and perioperative management in congenital hemophilia with inhibitors (CHwI), acquired hemophilia (AH), congenital factor VII (FVII) deficiency, and Glanzmann’s thrombasthenia (GT) with refractoriness to platelets. The aim of the current analysis was to review clinical trials and registries pre- and post-licensure for each indication to establish the estimated rate of thrombosis and then to establish the association of all reported thrombotic events (TEs) with certain risk factors listed for many years in the prescribing information (PI).Patients and methods: A retrospective safety assessment of both clinical trials and registries used to support licensure and postmarketing surveillance was performed. The rate of thrombosis was calculated in the 4 indicated disorders and an assessment of TE risk factors was conducted through a review of all narratives within those indications in the safety database.Results: In clinical trials and registries used to support licensure and in postmarketing surveillance, the overall rate of thrombosis was 0.17% of 12,288 bleeding and surgical episodes. The specific risk by indication was 0.11% for CHwI, 0.82% for FVII deficiency, 0.19% for GT, and 1.77% for AH. The most common associated risk factor—“elderly” (29%), defined in the PI as age ≥65 years—was particularly prevalent in patients with AH. TE was also frequently reported with concomitant cardiac or vascular disease (18%) and use of activated prothrombin complex concentrates (18%).Conclusion: Data show that the rate of TEs within the 4 licensed indications is low, as was originally described in the US PI from 1999 to 2009. It has remained stable over time during postapproval surveillance in multiple US and global registries with active surveillance for safety information across the 4 approved indications.Keywords: postmarketing surveillance, acquired hemophilia, congenital hemophilia with inhibitors, congenital factor VII deficiency, Glanzmann’s thrombasthenia

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., Competing Interests: Declaration of Competing Interest CM is a consultant for Novo Nordisk, coauthor of the eTHINK and paradigm study protocols, and site co-PI of the eTHINK study and has served as a speaker for Otsuka Pharmaceutical. KSW is a consultant for Novo Nordisk, coauthor of the eTHINK and paradigm study protocols, a site PI of the eTHINK study, and a consultant for AstraZeneca, Alexion, SpringWorks, and DayOne Biopharmaceuticals. CBB was a site PI of the eTHINK study and has received consultant fees from Novo Nordisk. SEC is a site PI of the eTHINK study and a consultant for Bayer, CSL Behring, Genentech, Octapharma, and Shire and has received research funding from Genentech, Pfizer, Novo Nordisk, Spark Therapeutics, and ATHN/Hemophilia of Georgia Research. AM and MG are full-time employees of Novo Nordisk. CH is a consultant for Novo Nordisk and participated in the eTHINK study. MR has received research grants from Pfizer, Bristol-Myers Squibb, and Novo Nordisk (for clinical studies) and is a consultant for Novo Nordisk. KAS has received fees as a consultant for Novo Nordisk. GNW has received fees as a consultant for Novo Nordisk. PV is a full-time employee of Cogstate. DLC was an employee of Novo Nordisk at the time of the conception of the eTHINK study and data collections. The eTHINK study was funded by Novo Nordisk A/S, Bagsværd, Denmark., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

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., (© 2024 John Wiley & Sons Ltd.)

Background: Acutely ill and medically complex children frequently rely on central venous catheters (CVCs) to provide life-sustaining treatment. Unfortunately, catheter-related thrombosis (CRT) is a serious and common complication. Little is known why some with a CVC develop CRT and others develop venous thromboembolism unrelated to the CVC (non-CRT)., Objectives: The aim of this study was to identify factors associated with CRT in children with hospital-acquired venous thromboembolism (HA-VTE)., Methods: This case-case study included participants in the Children's Hospital Acquired Thrombosis Registry with HA-VTE and CVC aged 0 to 21 years from 8 US children's hospitals. Participants were excluded if they developed HA-VTE prior to CVC insertion or if the CVC insertion date was unknown. Logistic regression models were used to assess associations between clinical factors and CRT status., Results: There were 1144 participants with HA-VTE who had a CVC. CRT developed in 833 participants, and 311 developed non-CRT. Multivariable analysis showed increased odds of CRT (compared with non-CRT) in participants with peripherally inserted central catheters (odds ratio [OR], 3.80; 95% CI, 2.04-7.10; p < .001), CVCs inserted in the femoral vein (OR, 4.45; 95% CI, 1.70-11.65; p = .002), multiple CVCs (OR, 1.42; 95% CI, 1.18-1.71; p < .001), and CVC malfunction (OR, 3.30; 95% CI, 1.80-6.03; p < .001)., Conclusion: The findings of this study provide new insights on risk factor differences between CRT and non-CRT. Prevention efforts should be directed at modifying the type of CVC, insertion location, and/or number of CVCs placed, if possible, to decrease the incidence of CRT., Competing Interests: Declaration of competing interests There are no competing interests to disclose., (Copyright © 2023 International Society on Thrombosis and Haemostasis. Published by Elsevier Inc. All rights reserved.)

Thrombin is a key enzyme in the maintenance of normal hemostatic function and is the central product of an interconnected set of simultaneously occurring cellular and proteolytic events. Antithrombin (AT) is a natural anticoagulant that downregulates different components of the clotting process, particularly thrombin generation. In good health, well-regulated hemostasis is the result of a balance between procoagulant and anticoagulant elements. Cumulative understanding of the regulation of thrombin generation and its central role in hemostasis and bleeding disorders has led to the clinical development of therapeutic strategies that aim to rebalance hemostasis in individuals with hemophilia and other coagulation factor deficiencies to improve bleeding phenotype. The aim of this review is to discuss the rationale for AT lowering in individuals with hemophilia, with a focus on fitusiran, its mechanism of action, and its potential as a prophylactic therapy for individuals with hemophilia A or B, with or without inhibitors. Fitusiran is an investigational small, interfering RNA therapeutic that targets and lowers AT. It is currently in phase III clinical trials and results have shown its potential to increase thrombin generation, leading to enhanced hemostasis and improved quality of life while reducing the overall treatment burden., (© 2023 The Authors.)

Background: The National Hemophilia Foundation (NHF) conducted extensive, inclusive community consultations to guide prioritization of research in coming decades in alignment with its mission to find cures and address and prevent complications enabling people and families with blood disorders to thrive., Research Design and Methods: With the American Thrombosis and Hemostasis Network, NHF recruited multidisciplinary expert working groups (WG) to distill the community-identified priorities into concrete research questions and score their feasibility, impact, and risk. WG6 was charged with identifying the infrastructure, workforce development, and funding and resources to facilitate the prioritized research. Community input on conclusions was gathered at the NHF State of the Science Research Summit., Results: WG6 detailed a minimal research capacity infrastructure threshold, and opportunities to enable its attainment, for bleeding disorders centers to participate in prospective, multicenter national registries. They identified challenges and opportunities to recruit, retain, and train the diverse multidisciplinary care and research workforce required into the future. Innovative collaborative approaches to trial design, resource networking, and funding to surmount obstacles facing research in rare disorders were elucidated., Conclusions: The innovations in infrastructure, workforce development, and resources and funding proposed herein may contribute to facilitating a National Research Blueprint for Inherited Bleeding Disorders.

Many people with hemophilia A (PwHA) undergo surgery in their lifetime, often because of complications of their disease. Emicizumab is the first bispecific monoclonal antibody prophylactic therapy for PwHA, and its efficacy and safety have been previously demonstrated; however, there is a need to build an evidence base on the management of PwHA on emicizumab undergoing surgery. Data from the HAVEN 1-4 phase 3 clinical trials were pooled to provide a summary of all minor and major surgeries in PwHA with or without factor VIII (FVIII) inhibitors who were receiving emicizumab prophylaxis. Overall, 233 surgeries were carried out during the HAVEN 1-4 trials: 215 minor surgeries (including minor dental and joint procedures, central venous access device placement or removal, and endoscopies) in 115 PwHA (64 with FVIII inhibitors) and 18 major surgeries (including arthroplasty and synovectomy) in 18 PwHA (10 with FVIII inhibitors). Perioperative hemostatic support was at the discretion of the treating physician. Overall, the median (interquartile range [IQR]) age was 33.5 (13.0-49.0) years and the median (IQR) emicizumab exposure time before surgery was 278.0 (177.0-431.0) days. Among the 215 minor surgeries, 141 (65.6%) were managed without additional prophylactic factor concentrate, and of those, 121 (85.8%) were not associated with a postoperative bleed. The majority (15 of 18 [83.3%]) of major surgeries were managed with additional prophylactic factor concentrate. Twelve (80.0%) of these 15 surgeries were associated with no intraoperative or postoperative bleeds. The data demonstrate that minor and major surgeries can be performed safely in PwHA receiving emicizumab prophylaxis. These trials are registered at www.clinicaltrials.gov as #NCT02622321, #NCT02795767, #NCT02847637, and #NCT03020160., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Adeno-associated virus (AAV)-mediated gene transfer has successfully raised, and in some cases transiently normalized, FVIII or FIX activity levels in adults with severe hemophilia. Raising FVIII/IX levels, particularly greater than ∼15 IU/dL (mild deficiency), corresponds to a marked decrease in spontaneous and provoked bleeding, dramatic reduction in factor concentrate use, and improved quality of life (QoL). Limited understanding of innate and adaptive immune system responses and hepatocyte transgene expression and stress responses to AAV-mediated gene transfer contribute to the variability in initial and long-term factor protein expression. Lentiviral (LV) and CRISPR/Cas-9 gene therapy approaches may further bolster the range of eligible participants and improve transgene expression and durability., Competing Interests: Disclosure S.E. Croteau has served as a consultant for Bayer, BioMarin, CSL-Behring, HEMA Biologics, Pfizer, Sanofi and received institutional research support from Spark Therapeutics., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Kaposiform lymphangiomatosis is an uncommon generalized lymphatic anomaly with distinctive clinical, radiologic, histopathologic, and molecular findings. Herein, we document the pathology in 43 patients evaluated by the Boston Children's Hospital Vascular Anomalies Center from 1999 to 2020. The most frequent presentations were respiratory difficulty, hemostatic abnormalities, and a soft tissue mass. Imaging commonly revealed involvement of some combination of mediastinal, pulmonary, pleural, and pericardial compartments and most often included spleen and skeleton. Histopathology was characterized by dilated, redundant, and abnormally configured lymphatic channels typically accompanied by dispersed clusters of variably canalized, and often hemosiderotic, spindled lymphatic endothelial cells that were immunopositive for D2-40, PROX1, and CD31. An activating lesional NRAS variant was documented in 9 of 10 patients. The clinical course was typically aggressive, marked by hemorrhage, thrombocytopenia, diminished fibrinogen levels, and a mortality rate of 21%., Competing Interests: Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

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., (© 2022 The Authors. Haemophilia published by John Wiley & Sons Ltd.)

BACKGROUND: Standard of care for patients with severe hemophilia A (HA) is life-long prophylaxis with factor VIII (FVIII) concentrate or other hemostatic agents. Published literature highlights a wide range of treatment costs for patients with HA. OBJECTIVE: To estimate average annual health care costs and resource utilization for a cross-section of adult patients managed with FVIII concentrate prophylaxis using recent data from a large US commercial claims database. METHODS: Adult males with 1 or more claim with HA diagnosis, continuous commercial plan enrollment, and 4 or more FVIII prescription dispenses during 12 months were identified from IBM MarketScan Research Database from January 2013 to September 2019, excluding those with FVIII inhibitors, an HIV/AIDS diagnosis, or diagnosis and treatment for hepatitis B or C. Patients were classified as using FVIII prophylaxis if they met any of the following definitions: (1) 6 or more FVIII dispenses, (2) a gap of 60 days or less between dispenses, and (3) at least 273 days supply in the 12-month period. Additionally, subgroups of patients meeting each individual definition were examined, with some patients included in all 3 subgroups. RESULTS: The overall cohort included 411 patients who met 1 or more of the 3 definitions, with a mean age of 28.9 years. Subgroups of 401, 325, and 237 patients met the first, second, and third FVIII prophylaxis definitions, respectively. Per-patient mean (SD) annual all-cause health care costs were $654,571 ($380,762) in the overall cohort and ranged from $650,065 ($382,196) to $759,661 ($387,040) among subgroups. Cost of FVIII concentrate accounted for more than 96% of total costs in the overall cohort and in each subgroup. Cost of FVIII in the overall cohort varied according to type of concentrate, with the highest among patients who were treated with both standard and extended half-life (SHL and EHL) FVIII ($784,945), followed by EHL FVIII only ($708,928), SHL FVIII only ($647,800), and plasma-derived FVIII ($535,614). The most common treatment type was SHL FVIII only (45.7% of all patients). In the overall cohort, the majority had 1 or more outpatient visits (94.9%), while emergency department visits, hospital admissions, and home health visits occurred less frequently (27.0%, 7.1%, and 7.1%, respectively). CONCLUSIONS: Commercially insured patients with HA incur substantial all-cause annual health care costs, with FVIII concentrate accounting for a majority of costs. DISCLOSURES: This study was funded by BioMarin Pharmaceutical Inc, which was involved in the protocol development, analysis plan development, data interpretation, manuscript preparation, and publication decisions. All authors contributed to protocol development, analysis plan development, data interpretation, and manuscript development and maintained control over the final content. Thornburg has received professional fees from BioMarin Pharmaceutical, CSL Behring, Genentech, Novo Nordisk, Sanofi Genzyme, HEMA Biologics, and Spark Therapeutics and institutional research funding from BioMarin Pharmaceutical, Novo Nordisk, and Sanofi Genzyme. Adamski, Cook, and Sendhil are employees of Analysis Group, a consulting company that was contracted by BioMarin Pharmaceutical to conduct this study and develop the manuscript. Vembusubramanian is a former employee of Analysis Group. Hinds, Chen, and Sammon are employees and shareholders of BioMarin Pharmaceutical. Solari is a former employee of BioMarin Pharmaceutical. Garrison has received consulting fees from BioMarin Pharmaceutical and Analysis Group. Croteau has received professional fees from BioMarin Pharmaceutical, Bayer, CSL Behring, HEMA Biologics, and Pfizer and institutional research funding from Novo Nordisk and Spark Therapeutics.

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., Competing Interests: Dr. Jaffray received grant funding for this study from the National Institutes of Health (NIH) from the National Center for Advancing Translational Science (grant number UL1TR001855), the Children’s Hospital Saban Research Mentored Career Development Award, and The Hemostasis and Thrombosis Research Society Mentored Research Award, supported by an independent educational grant from Takeda Pharmaceuticals U.S.A. Dr. Mahajerin received grant funding from to The Hemostasis and Thrombosis Research Society Mentored Research Award and CHOC Children’s Hospital and University of California Irvine Physician-Scientist Research Award program. Dr. Goldenberg receives salary and research support from NIH National Heart, Lung, and Blood Institute (NHLBI) via a U01 award. Drs. Jaffray, Branchford, and Goldenberg received support for article research from the NIH. Dr. Branchford received funding from Kedrion, Bioproducts Lab, Biomarin, Shire, Innovative Biopharma, Advio, Bayer, and Octapharma. Drs. Branchford and Goldenberg received support for article research from the NHLBI. Dr. Silvey received funding from Genetech and Bayer. Dr. Amankwah received funding from Bristol Myers Squibb and Pfizer. Dr. Goldenberg received funding from the NIH, the NHLBI, Daiici Sankyo, Anthos Therapeutics, and the Academic Research Organization CPC Clinical Research. The remaining authors have disclosed that they do not have any potential conflicts of interest. Funding sources did not have a role in study design, data analysis, writing, or submission of the manuscript. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2021 by the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies.)

Background: Appropriate timing of central venous catheter (CVC) removal, in relation to start of anticoagulation, in children after the diagnosis of a CVC-related thrombosis (CRT) is not well established., Objectives: This retrospective cohort study evaluated the incidence of symptomatic pulmonary embolism (PE) after CVC removal using data from the multi-institutional Children's Hospital-Acquired Thrombosis (CHAT) Consortium Registry., Patients/methods: The CHAT Registry consists of data from children aged 0-21 years with a hospital-acquired venous thromboembolism. Eligible subjects were those with CRT diagnosed <3 days after CVC removal. Subjects were excluded if the CRT was due to a failed CVC insertion. Subjects were divided into three groups: those with CVC removal without anticoagulation, those with CVC removal <48 h after starting anticoagulation, and those with CVC removal ≥48 h after starting anticoagulation., Results: A total of 687 CRT events from 663 subjects were included. A majority of CRT events were in subjects with peripherally inserted central catheters (62.3%, n = 428). For the 611 CRT events in which the CVC was removed, there was only one case of symptomatic PE (0.16%), which occurred <48 h after initiation of anticoagulation., Conclusions: While current guidelines suggest anticoagulation before CVC removal in the setting of a CRT to prevent embolization, CVC removal is not associated with symptomatic PE regardless of duration of anticoagulation before CVC removal., (© 2021 International Society on Thrombosis and Haemostasis.)

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., Competing Interests: H.A. is a consultant of Agios, Dova, and Moderna and receives research funding from Agios and Dova. S.E.C. is a consultant of Bayer, CSL-Behring, Octapharma, Shire, and Novo Nordisk and receives research support from Pfizer, Novo Nordisk, and Spark Therapeutics. The other authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

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  × 10 11 vector genomes (vg) per kilogram of body weight, and the highest-dose cohort received 2 × 10 12 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.)., (Copyright © 2021 Massachusetts Medical Society.)

Background: Correction of von Willebrand factor (VWF) deficiency with replacement products containing VWF can lead to the development of anti-VWF alloantibodies (i.e., VWF inhibitors) in patients with severe von Willebrand disease (VWD)., Objective: Locate inhibitor-reactive regions within VWF using phage display., Methods: We screened a phage library displaying random, overlapping fragments covering the full-length VWF protein sequence for binding to a commercial anti-VWF antibody or to immunoglobulins from three type 3 VWD patients who developed VWF inhibitors in response to treatment with plasma-derived VWF. Immunoreactive phage clones were identified and quantified by next-generation DNA sequencing (NGS)., Results: Next-generation DNA sequencing markedly increased the number of phages analyzed for locating immunoreactive regions within VWF following a single round of selection and identified regions not recognized in previous reports using standard phage display methods. Extending this approach to characterize VWF inhibitors from three type 3 VWD patients (including two siblings homozygous for the same VWF gene deletion) revealed patterns of immunoreactivity distinct from the commercial antibody and between unrelated patients, though with notable areas of overlap. Alloantibody reactivity against the VWF propeptide is consistent with incomplete removal of the propeptide from plasma-derived VWF replacement products., Conclusion: These results demonstrate the utility of phage display and NGS to characterize diverse anti-VWF antibody reactivities., (© 2021 International Society on Thrombosis and Haemostasis.)

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., (© 2021 The Authors. Haemophilia published by John Wiley & Sons Ltd.)

Gene therapy has the potential to overcome many of the limitations of prophylactic hemophilia therapies. Several clinical trials evaluate investigational adeno-associated virus (AAV)-mediated gene transfer approaches for the treatment of hemophilia A and B. The practical application of these approaches is nuanced by differences in AAV serotypes, transgene modifications, manufacturing, dosing, administration, and approach to follow-up. This guide explores mechanisms of AAV gene transfer, identification of appropriate candidates for clinical trial participation, anticipated trial events that follow infusion of an investigational gene therapy including outcomes to be monitored, and future considerations. Patient-accessible infographic summaries of these topics are included to serve as potential visual aids that healthcare providers may choose to utilize or adapt to guide informed consultation. The fundamentals of AAV-mediated, liver-directed gene transfer for hemophilia are reviewed, to facilitate discussion between healthcare providers, patients, and their families and advocates if considering a trial of investigational gene therapy., (Copyright © 2020. Published by Elsevier Ltd.)

Background: Bleeding phenotypes among individuals with severe factor VIII (FVIII) deficiency are variable, even with routine prophylactic FVIII administration. Activated platelets, in addition to their role in primary hemostasis, play a major role in coagulation by providing a phospholipid surface to which coagulation factors bind., Objectives: The aim of this study was to determine whether platelet function is associated with past and/or future bleeding in patients with severe FVIII deficiency on prophylaxis., Patients/methods: Platelet function quantified by platelet surface expression of phosphatidylserine, platelet surface glycoprotein (GP) VI, platelet surface activated GPIIb-IIIa, platelet surface P-selectin, the percentage of coated platelets, and the percentage of platelet-derived microparticles in the presence or absence of in vitro activation by various agonists was assessed in 34 patients., Results: Decreased platelet surface phosphatidylserine expression (identified by annexin V binding), both in the presence and absence of ADP/thrombin receptor activating peptide, demonstrated a significant association with both prior and subsequent bleeding in any location and specifically with hemarthrosis. No significant difference between patients with and without bleeding was observed in any of the other platelet activity markers., Conclusions: Decreased platelet surface phosphatidylserine expression measured by annexin V binding predicts increased bleeding in severe FVIII deficient patients on prophylaxis., (© 2021 International Society on Thrombosis and Haemostasis.)

BACKGROUND: Standard of care for bleed prevention in patients with severe congenital hemophilia A is continuous prophylaxis with factor VIII (FVIII), typically administered intravenously 2-3 times per week in the home setting. Nonfactor prophylaxis and gene therapy are emerging novel prophylaxis strategies for hemophilia A, and it is important to compare their health economics with that of FVIII prophylaxis. Current data on resource utilization and costs in the adult hemophilia A prophylaxis population are limited, and a structured approach to analyze annual costs in these patients using administrative claims data has not been previously reported. OBJECTIVE: To assess health care resource utilization and costs of continuous FVIII prophylaxis in commercially insured adults with hemophilia A without inhibitors. METHODS: Administrative claims records from beneficiaries covered by major selfinsured companies in the United States from January 1999 through March 2017 (OptumHealth Care Solutions) were queried, and records for adult patients (aged 18-64 years) diagnosed with hemophilia A who received FVIII were extracted. Three criteria were defined to distinguish patients most likely to be managed with continuous FVIII prophylaxis from those on episodic treatment based on the frequency and timing of FVIII claims over a 12-month period of continuous enrollment: (1) having ≥ 4 FVIII claims, (2) having ≥ 6 FVIII claims, or (3) having no gaps > 60 days between FVIII claims. Patients with evidence of bypassing agent use were excluded. Health care resource utilization and costs were assessed for all patients with any FVIII use and for patients defined as being managed with continuous FVIII prophylaxis based on each criterion. RESULTS: The analysis included 189 patients with a diagnosis code for hemophilia A (ICD 9-CM code 286.0; ICD-10-CM code D66) from January 1999 through March 2017 who had at least 12 months of continuous enrollment and at least 1 noninpatient/nonemergency department claim for FVIII concentrate (any type) during their last 12 months of continuous enrollment (overall cohort). Within the overall cohort, 118, 94, and 61 patients met the criteria for FVIII prophylaxis based on the first, second, and third definitions, respectively. Per patient mean (SD) total health care costs for the overall cohort was $287,055 (306,933). For patients meeting criteria 1 through 3, per patient costs ranged from $407,752 (321,036) to $551,645 (302,841). FVIII concentrate accounted for over 90% of costs, with mean (SD) annual FVIII costs of $264,777 (292,423) in the overall cohort and $384,197 (303,826), $433,029 (313,711), and $531,098 (297,142) among patients meeting the respective definitions for prophylaxis. CONCLUSIONS: This analysis highlights the substantial economic burden associated with managing adults with hemophilia A on FVIII prophylaxis, where per patient mean total annual health care costs ranged from $407,752 to $551,645. Over 90% of such costs were attributable to FVIII concentrate dispensed. DISCLOSURES: This study was funded by BioMarin Pharmaceutical, which was involved in protocol development, analysis plan development, data interpretation, manuscript preparation, and publication decisions. All authors contributed to protocol development, analysis plan development, data interpretation, and manuscript development. All authors maintained control over the final content. Sammon, Solari, Kim, and Hinds are employees and shareholders of BioMarin Pharmaceutical. Cook, Sheikh, and Chawla are employees of Analysis Group, a consulting company that was contracted by BioMarin Pharmaceutical to conduct this study and develop the manuscript. Croteau has received professional fees from BioMarin Pharmaceutical, Bayer, CSL Behring, Genentech, and Pfizer. Thornberg has received professional fees from BioMarin Pharmaceutical, Genentech, Novo Nordisk, Sanofi, and Spark Therapeutics, as well as research funding from Novo Nordisk and Sanofi.

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., (© 2021 John Wiley & Sons Ltd.)

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., (Copyright © 2020 Elsevier Inc. All rights reserved.)

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., (© 2020 John Wiley & Sons Ltd.)

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., (© 2020 Wiley Periodicals LLC.)

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., (© 2020 Wiley Periodicals LLC.)

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., (© 2020 Wiley Periodicals, Inc.© 2020 Wiley Periodicals, Inc.)

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., (© 2020 SSIEM.)

Background: Clinical application of population pharmacokinetics (popPK) is of increasing interest to patients with hemophilia, providers, and payers. Routine use of popPK profiles in factor replacement prophylaxis decision making has the potential to maintain or improve efficacy and reduce product consumption., Aim: To investigate the feasibility of implementation and longitudinal assessment of pharmacokinetic (PK)-tailored prophylaxis in routine clinical practice for hemophilia A and to describe factors that influence decision making for prescribed hemophilia prophylaxis., Methods: This longitudinal, multicenter, prospective feasibility study of children and adults with hemophilia A without inhibitors used the Web Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo) to generate PK profiles. Assessments over 12 weeks captured data on prescribed prophylaxis, popPK tool use, provider decision making, and patient-reported outcomes., Results: Eighteen participants aged 6 to 39 years enrolled; half used extended half-life concentrates. Patient interest in their PK centered on general curiosity followed by a desire for participation in physical activity and decrease in infusion frequency. Providers used the WAPPS clinical calculator feature to simulate prophylaxis regimens under different dose, infusion, and trough conditions. Most targeted troughs were 1 to 3 IU/dL. The feasibility assessment demonstrated challenges with patient recruitment; however, the majority of participants successfully completed study assessments meeting feasibility targets., Conclusion: A larger-scale study powered to evaluate the impact of PK-tailored prophylaxis on clinical and patient-reported outcomes is feasible with study design modifications to support increased recruitment rate. Shared decision making incorporating patient and provider goals is important and facilitated by regimen simulations with the clinical calculator., (© 2020 The Authors. Research and Practice in Thrombosis and Haemostasis published by Wiley Periodicals, Inc on behalf of International Society on Thrombosis and Haemostasis.)

Background and Objective: Rurioctacog alfa pegol (Adynovate) is a modified recombinant factor VIII concentrate used for treating hemophilia A. Aiming to improve treatment tailoring on the Web-Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo) platform for patients of all ages treated with Adynovate, we have developed and evaluated a population pharmacokinetic (PopPK) model. On the platform, PopPK models are used as priors for Bayesian forecasting that derive individual PK of hemophilia patients and are subsequently used for personalized dose regimen design., Methods: Factor activity measurements and demographic covariate data from patients infused with Adynovate were extracted from the WAPPS-Hemo database. Evaluations testing the appropriateness of Bayesian forecasting included 10-fold cross validation, a limited sampling analysis (LSA), and an external evaluation using additional independent data extracted from the WAPPS-Hemo database at a later date., Results: The model was constructed using 650 plasma factor activity observations (555 one stage assay and 95 chromogenic assay - 4.6% below limit of quantification) measured in 154 patients from 36 hemophilia centres. A two-compartment model including between subject variability on clearance and central volume was selected as the base model. Covariates were fat free mass on clearance and central volume, age on clearance and assay type on activity. The final model was well-suited to predict PK parameters of new individuals (n = 26) from sparse observations., Conclusions: The development of a PopPK model for Adynovate using real-world data increases the covariate space (e.g. age) beyond what is possible from clinical trial data. This model is available on the WAPPS-Hemo platform for tailoring treatment in hemophilia A patients.

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., (© 2019 John Wiley & Sons Ltd.)

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., (© 2019 John Wiley & Sons Ltd.)

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., (© 2019 The Authors. Pediatric Blood & Cancer Published byWiley Periodicals, Inc.)

Hemophilia A (HA) is a bleeding disorder caused by mutations in the F8 gene encoding coagulation factor VIII (FVIII). Current treatments are based on regular infusions of FVIII concentrates throughout a patient's life. Alternatively, viral gene therapies that directly deliver F8 in vivo have shown preliminary successes. However, hurdles remain, including lack of infection specificity and the inability to deliver the full-length version of F8 due to restricted viral cargo sizes. Here, we developed an alternative nonviral ex vivo gene-therapy approach that enables the overexpression of full-length F8 in patients' endothelial cells (ECs). We first generated HA patient-specific induced pluripotent stem cells (HA-iPSCs) from urine epithelial cells and genetically modified them using a piggyBac DNA transposon system to insert multiple copies of full-length F8. We subsequently differentiated the modified HA-iPSCs into competent ECs with high efficiency, and demonstrated that the cells (termed HA-FLF8-iECs) were capable of producing high levels of FVIII. Importantly, following subcutaneous implantation into immunodeficient hemophilic (SCID-f8ko) mice, we demonstrated that HA-FLF8-iECs were able to self-assemble into vascular networks, and that the newly formed microvessels had the capacity to deliver functional FVIII directly into the bloodstream of the mice, effectively correcting the clotting deficiency. Moreover, our implant maintains cellular confinement, which reduces potential safety concerns and allows effective monitoring and reversibility. We envision that this proof-of-concept study could become the basis for a novel autologous ex vivo gene-therapy approach to treat HA., (© 2019 by The American Society of Hematology.)

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., (© 2019 John Wiley & Sons Ltd.)

Extended half-life proteins (EHL) are increasingly used in clinical practice, but there is no standardized approach to sampling, interpretation and implementation of pharmacokinetics (PK) data to maximize treatment benefit. The goal of EHL treatment is to attain a trough level sufficient to protect against spontaneous bleeds and reduce infusion frequency and limitations on individual activity and lifestyle. Performing classical PK assessments requires multiple blood samples, which is burdensome for patients and providers. Herein we review a population pharmacokinetic (popPK) approach to estimate individual PK parameters to transition patients from standard half-life (SHL) to EHL concentrates. We propose that a minimum of two to four post-infusion samples is sufficient to estimate individual PK profiles, with sufficient certainty to maintain factor levels above 1% and achieve bleed-free lifestyles. We also survey current PK use in patients transitioning to EHL, review key PK parameters and popPK models, and recommend an approach to using PK in patients initiating or switching to EHL., (© 2018 International Society on Thrombosis and Haemostasis.)

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., (© 2018 Wiley Periodicals, Inc.)

Rapid expansion of therapeutic options have increased the complexity of hemophilia care. Previously, on-demand therapy aimed to reduce morbidity and early mortality; however, now aggressive prophylaxis, particularly in children, encourages an active lifestyle. Accurate diagnosis, recognition of early threats to musculoskeletal health, and optimization of therapy are critical for both males and females affected by hemophilia. The diversity of emerging hemophilia therapies, from modified factor protein concentrates, to gene therapy, to nonfactor hemostatic strategies, provide an exciting opportunity to target unmet needs in the bleeding disorder community., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Emergence of population pharmacokinetic models for prediction of individual pharmacokinetic (PK) profiles facilitates individualization of prescribed prophylactic therapy for patients with hemophilia A and B and may have a favorable impact on clinical outcomes and annual factor utilization. How providers approach the integration and application of these data into routine clinical practice is not clear., Objective: To explore the potential application of and barriers to incorporating PK profiles into current hemophilia prophylaxis decision making., Methods: A facilitated group discussion of hematologists practicing within the federally-supported United States Hemophilia Treatment Center Network was conducted. Separately, a group of parents of patients with severe hemophilia less than 18 years of age participated in a focus group on individualizing prophylactic factor regimens with the use of PK data., Results: Physician participants constructed a conceptual model for factors that determined their selection of hemophilia prophylaxis. These factors clustered in five groupings. When charged with creating a prophylaxis regimen for a specific clinical case including PK data, eight of nine providers generated a unique regimen. Parent focus group supported PK data use as they preferred data driven treatment decisions., Conclusions: Clinician application of PK data for prophylaxis decision making is heterogeneous. Prospective evaluation of the use of PK-tailored prophylaxis in routine care and its impact on patient outcomes is needed. Parents perceived that, while obtaining blood draws could be challenging, images of factor activity decay informed their decisions about physical activity timing and provided an opportunity for partnership and shared decision making with their provider.

Objectives: In a separate document, we have provided specific guidance on performing individual pharmacokinetic (PK) studies using limited samples in persons with hemophilia with the goal to optimize prophylaxis with clotting factor concentrates. This paper, intended for clinicians, aims to describe how to interpret and apply PK properties obtained in persons with hemophilia., Methods: The members of the Working Party on population PK (PopPK) of the ISTH SSC Subcommittee on Factor VIII and IX and rare bleeding disorders, together with additional hemophilia and PK experts, completed a survey and ranking exercise whereby key areas of interest in the field were identified. The group had regular web conferences to refine the manuscript's scope and structure, taking into account comments from the external feedback to the earlier document., Results: Many clinical decisions in hemophilia are based on some form of explicit or implicit PK assessment. Individual patient PK profiles can be analyzed through traditional or PopPK methods, with the latter providing the advantage of fewer samples needing to be collected on any prophylaxis regimen, and without the need the for a washout period. The most useful presentation of PK results for clinical decision making are a curve of the factor activity level over time, the time to achieve a certain activity level, or related parameters like half-life or exposure (AUC). Software platforms have been developed to deliver this information to clinicians at the point of care. Key characteristics of studies measuring average PK parameters were reviewed, outlining what makes a credible head-to-head comparison among different concentrates. Large data collections of PK and treatment outcomes currently ongoing will advance care in the future., Conclusions: Traditionally used to compare different concentrates, PK can support tailoring of hemophilia treatment by individual profiling, which is greatly simplified by adopting a PopPK/Bayesian method and limited sampling protocol.

Although hemophilia B affects 1 in 25,000 males there may be 3 female hemophilia B carriers per affected male. This clinical review highlights the unique challenges faced by hemophilia B carriers including the under-recognition of bleeding symptoms associated with and without FIX deficiency, discrepancies in correlation between genotype and bleeding phenotype and therapeutic considerations utilizing clinical vignettes of common scenarios., (2017 The Authors. Haemophilia Published by John Wiley & Sons Ltd.)

The incidence of diagnosed venous thromboembolism (VTE) has been increasing concurrent with advances in technology and medical care that enhance our ability to treat pediatric patients with critical illness or complex multiorgan system dysfunction. Although the overall incidence of VTE is estimated at 0.07-0.49 per 10,000 children, higher rates are observed in specific populations including hospitalized children, those with central venous catheters (CVCs) or patients convalescing from a major surgery. While the absolute number of pediatric VTE events may seem trivial compared to adults, the increasing incidence, associated with increased mortality and morbidity, the availability of novel therapies, and the impact on the cost of care have made investigation of VTE risk factors and prevention strategies a high priority. Many putative risk factors for pediatric VTE have been reported, primarily from single-institution, retrospective studies which lack appropriate methods for verifying independent risk factors. In addition, some risk factors have inconsistent definitions, which vex meta-analyses. CVCs are the most prevalent risk factors but have not consistently been assigned the highest level of risk as defined by odds ratios from retrospective, case-control studies. Few risk-assessment models for hospital-acquired pediatric VTE have been published. Some models focus exclusively on hospitalized pediatric patients, while others target specific populations such as patients with cancer or severe trauma. Multicenter, prospective studies are needed to identify and confirm risk factors in order to create a pediatric risk-assessment tool and optimize preventive measures and reduce unintended harm.

Introduction: High-titre factor VIII (FVIII) inhibitors complicate peri-operative haemostasis. Recombinant porcine FVIII (r-pFVIII) may provide an alternative haemostatic agent for high-risk procedures and allow FVIII activity monitoring., Aim: Devise an effective haemostatic plan for repair of a progressively symptomatic aortic coarctation in a 5-year-old male with immune tolerance induction (ITI) refractory high-titre FVIII inhibitors., Methods: Preprocedure human FVIII inhibitor titre was 58 Bethesda Units mL -1 (BU) and cross-reacted to neutralize porcine FVIII at 30 BU. Daily ITI with plasma-derived FVIII concentrate was supplemented with anti-B-cell and anti-plasma cell immunotherapy to reduce FVIII inhibitor titres. Potential haemostatic agents were evaluated in comparative ex vivo thrombin generation assays (TGA)., Results: Four weeks after immunosuppression, human and porcine inhibitor titres declined to 16 and 2 BU respectively. TGA with r-pFVIII was less robust than with activated prothrombin complex concentrate (aPCC); however, r-pFVIII was selected for cardiac surgery to secure the ability to assay FVIII levels throughout this high-bleeding risk procedure. Haemostasis with r-pFVIII was excellent; initial trough FVIII activity levels ranged from 0.81-1.17 IU mL -1 . On postoperative day 3, peak and trough levels markedly declined suggesting a rising porcine inhibitor titre. Postprocedure prophylaxis was transitioned to aPCC, informed by TGA., Conclusions: R-pFVIII provided effective peri-procedural haemostasis with no adverse events. Rapid neutralization of r-pFVIII after the first 60 hours, despite intensive immune suppression, accentuates the importance of careful monitoring. Use of TGA can support bypassing agent selection for convalescence. The comparative cost of r-pFVIII may limit its use to high morbidity clinical scenarios., (© 2017 John Wiley & Sons Ltd.)

A surge in therapeutic clinical trials over recent years is paving the way for transformative treatment options for patients with hemophilia. The introduction of recombinant factor concentrates in the early 1990s facilitated the use of prophylactic replacement as standard care for hemophilia rather than on-demand treatment. This has revolutionized health outcomes for hemophilia patients, enabling participation in physical activities and reducing debilitating, chronic joint damage. Challenges of prophylactic factor infusion include the frequency of infusions needed to maintain factor levels greater than 1%, patient adherence, reliable intravenous access, and development of neutralizing alloantibodies ("inhibitors"). Novel therapeutics seek to improve upon current factor concentrates by several different mechanisms: (1) extending the half-life of circulating exogenous factor protein, (2) replacing the gene necessary for production of endogenous factor protein, (3) employing bispecific antibody technology to mimic the coagulation function of factor VIII, (4) disrupting anticoagulant proteins, such as tissue factor pathway inhibitor (TFPI) or antithrombin (AT3) with antibodies, aptamers, or RNA interference technology. Emerging treatment options may reduce the frequency of (extended half-life products) or eliminate (gene therapy) the need for scheduled factor concentrate infusions, or provide a subcutaneous administration option (bispecific antibody, AT3, and TFPI targeting therapies). In addition, the nonfactor replacement strategies provide a promising treatment option for patients with inhibitors, presently the greatest unmet medical need in hemophilia. This review highlights current and recently completed clinical trials that are driving a paradigm shift in our approach to hemophilia care for patients with and without inhibitors. Am. J. Hematol. 91:1252-1260, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Background: The relative safety and efficacy of recombinant activated coagulation factor VII (rFVIIa, NovoSeven® RT) across pediatric age cohorts is poorly defined. The objective of this analysis was to assess the safety and efficacy of rFVIIa in pediatric patients with congenital hemophilia with inhibitors (CHwI) in the clinical studies supporting the U.S. labeling., Procedure: Pediatric data were derived from seven studies (five acute and two perioperative treatments) and pooled. All data were stratified by age (<2, 2 to <6, 6 to <12, and 12-16 years) and study category (acute treatment of bleeding episodes or surgery)., Results: The pediatric dataset included 172 patients; 144 received rFVIIa for the treatment of bleeding episodes and 28 for the control of bleeding perioperatively. Recombinant FVIIa was effective for 95.4% (1,026/1,076) of the evaluable bleeding episodes and had similar treatment effectiveness across pediatric age groups (range, 94.1-97.2%). The majority received doses of 90 mcg/kg. rFVIIa was effective in achieving perioperative hemostasis across pediatric age groups (range, 91-100%), with greater efficacy observed with the recommended (90 mcg/kg) versus lower dose (35 mcg/kg). A total of 88 pediatric patients experienced a total of 285 adverse drug reactions, similar in type to those reported among adult patients. A total of seven thrombotic events were recorded in seven pediatric patients; only one was confirmed related to rFVIIa upon individual case review., Conclusions: rFVIIa is safe and effective in the treatment of bleeding episodes and prevention of periprocedure bleeding in CHwI with no apparent differences observed among pediatric age groups., (© 2016 Wiley Periodicals, Inc.)

Kasposiform hemoangioendothelioma (KHE) and tufted angioma (TA) are classifed as vascular tumors with locally aggressive and benign growth potential, respectively, within the classification schema proposed by the International Society for the Study of Vascular Anomalies. A unique feature of these vascular tumors is the risk of Kasabach-Merritt phenomenon (KMP), a severe thrombocytopenia with mild to moderate coagulopathy resulting from intralesional platelet trapping. As with many vascular anomalies, accurate description of clinical course, responses to therapy, and long-term outcomes have been hindered by lesion misidentification, imprecise nomenclature, and lack of prospective, randomized clinical trials to assess therapeutic efficacy. The classic dermatologic features of these lesions can facilitate diagnosis for the astute provider; however, the absence of or unusual integumentary involvement or presentation in a less common age group (adolescents/adults) poses a diagnostic challenge. Current approaches to the management of KHE/TA are often informed by lesion features such as presence of KMP, extent and location of the tumor, and symptomatology. Evidence-based treatment guidelines are limited. Corticosteroids, vincristine, interferon, multi-agent regimens and newer therapies, such as sirolimus, have demonstrated efficacy in patient series. The use of surgical excision and interventional radiology guided therapies have been described with mixed clinical benefit. Collaboration among emerging vascular anomaly centers and an increasing number of providers across subspecialties with interest in this field are facilitating the development of standardized approaches to diagnosis and management. The rarity of KHE-spectrum lesions and the heterogeneity of clinical manifestations necessitate rationally designed, multisite clinical trials to investigate risk stratification schemas and formally evaluate the short and long-term efficacy of available and novel therapies., (©2016 Frontline Medical Communications.)