Inhibitors in hemophilia: association with surgery plans and outcomes in a retrospective cohort study.

Background: The development of antibodies (inhibitors) to clotting factors compromises the management of hemophilia A and B, resulting in resistance to clotting factor replacement and, in many cases, the need for bypassing agents to achieve hemostasis. Objectives: To evaluate the association between the presence of inhibitors and achievement of perioperative hemostasis, development of complications, and presurgical plan deviations. Methods: We conducted a retrospective study using data from the Indiana Hemophilia and Thrombosis Center surgical database (1998-2019). Associations between perioperative outcomes and inhibitor status were assessed while controlling for patient and procedural characteristics. Results: A total of 1492 surgeries were performed in 539 persons with hemophilia, with 72 procedures performed in 20 patients with inhibitors (15 with hemophilia A; 5 with hemophilia B). High-responding inhibitors (>5 BU/mL) were present in 27 procedures, low-responding inhibitors (≤5 BU/mL) were present in in 13 procedures, and 32 procedures were performed in patients with historically persistent inhibitors. Adjusting for age, diagnosis, surgery setting, hemostatic agent, data collection period, and surgery type (major/minor), inhibitors were associated with a higher risk of inadequate perioperative hemostasis (33.4% vs 8.6%; adjusted relative risk [adjRR], 3.78; 95% CI, 1.89-7.56; P < .001). Reported complications include hemorrhage, fever, pain, thrombosis, and infections. Complications were not statistically different based on inhibitor status (31.7% vs 14.6%; adjRR, 1.25; 95% CI, 0.63-2.49; P = .526). Presurgical plan deviations (eg, hemostatic medication dose adjustments, procedure rescheduling, and changes in the length of postoperative hospitalization) occurred more frequently in surgeries involving inhibitors (70.8 vs 39.5%; adjRR, 1.47; 95% CI, 1.12-1.93; P = .005). Conclusion: Inhibitors are associated with higher risks of adverse perioperative outcomes. Strategies to address inhibitor development should be prioritized to avoid undesirable perioperative outcomes.

Targeting higher factor VIII levels for prophylaxis in haemophilia A: a narrative review.

INTRODUCTION: The standard of care in severe haemophilia A is prophylaxis, which has historically aimed for a factor VIII (FVIII) trough level of ≥1%. However, despite prophylactic treatment, people with haemophilia remain at risk of bleeds that have physical and quality of life implications, and that impact everyday life. AIM: The aim of this review was to evaluate evidence supporting the relationship between targeting higher FVIII activity levels with prophylaxis and improved outcomes in people with haemophilia A. METHODS: We conducted a narrative review that defined the unmet needs and treatment goals in people with haemophilia A, evaluated evidence to support targeting higher FVIII activity levels, and highlighted therapies that may support higher and sustained FVIII activity levels and improved outcomes for people with haemophilia A. RESULTS: Despite recent advances in treatment, unmet needs remain, and people with haemophilia continue to experience joint and functional impairment, acute and chronic pain, and poor mental health. All these negatively impact their health-related quality of life. Evidence suggests that FVIII activity levels of up to 50% may be needed to achieve a near-zero joint bleed rate. However, achieving high FVIII activity levels with current standard and extended half-life (EHL) FVIII replacement therapies is associated with a high treatment burden. Innovative treatment options may provide high sustained FVIII activity levels and improved patient outcomes. CONCLUSION: Evidence suggests that FVIII activity levels in people with haemophilia A should be sustained at higher levels to improve joint and patient outcomes and enable progression towards health equity.

Recombinant von Willebrand factor and tranexamic acid for heavy menstrual bleeding in patients with mild and moderate von Willebrand disease in the USA (VWDMin): a phase 3, open-label, randomised, crossover trial.

BACKGROUND: Heavy menstrual bleeding occurs in 80% of women with von Willebrand disease and is associated with iron deficiency and poor response to current therapies. International guidelines indicate low certainty regarding effectiveness of hormonal therapy and tranexamic acid. Although von Willebrand factor (VWF) concentrate is approved for bleeds, no prospective trials guide its use in heavy menstrual bleeding. We aimed to compare recombinant VWF with tranexamic acid for reducing heavy menstrual bleeding in patients with von Willebrand disease. METHODS: VWDMin, a phase 3, open-label, randomised crossover trial, was done in 13 haemophilia treatment centres in the USA. Female patients aged 13-45 years with mild or moderate von Willebrand disease, defined as VWF ristocetin cofactor less than 0·50 IU/mL, and heavy menstrual bleeding, defined as a pictorial blood assessment chart (PBAC) score more than 100 in one of the past two cycles were eligible for enrolment. Participants were randomly assigned (1:1) to two consecutive cycles each of intravenous recombinant VWF, 40 IU/kg over 5-10 min on day 1, and oral tranexamic acid 1300 mg three times daily on days 1-5, the order determined by randomisation. The primary outcome was a 40-point reduction in PBAC score by day 5 after two cycles of treatment. Efficacy and safety were analysed in all patients with any post-baseline PBAC scores. The trial was stopped early due to slow recruitment on Feb 15, 2022, by a data safety monitoring board request, and was registered at ClinicalTrials.gov, NCT02606045. FINDINGS: Between Feb 12, 2019, and Nov 16, 2021, 39 patients were enrolled, 36 of whom completed the trial (17 received recombinant VWF then tranexamic acid and 19 received tranexamic acid then recombinant VWF). At the time of this unplanned interim analysis (data cutoff Jan 27, 2022), median follow-up was 23·97 weeks (IQR 21·81-28·14). The primary endpoint was not met, neither treatment corrected PBAC score to the normal range. Median PBAC score was significantly lower after two cycles with tranexamic acid than with recombinant VWF (146 [95% CI 117-199] vs 213 [152-298]; adjusted mean treatment difference 46 [95% CI 2-90]; p=0·039). There were no serious adverse events or treatment-related deaths and no grade 3-4 adverse events. The most common grade 1-2 adverse events were mucosal bleeding (four [6%] patients during tranexamic acid treatment vs zero during recombinant VWF treatment) and other bleeding (four [6%] vs two [3%]). INTERPRETATION: These interim data suggest that recombinant VWF is not superior to tranexamic acid in reducing heavy menstrual bleeding in patients with mild or moderate von Willebrand disease. These findings support discussion of treatment options for heavy menstrual bleeding with patients based on their preferences and lived experience. FUNDING: National Heart Lung Blood Institute (National Institutes of Health).

Building the foundation for a community-generated national research blueprint for inherited bleeding disorders: facilitating research through infrastructure, workforce, resources and funding.

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.

Research is critical to advancing the diagnosis and care of people with inherited bleeding disorders (PWIBD). This research requires significant infrastructure, including people and resources. Hemophilia treatment centers (HTC) need many different skilled care professionals including doctors, nurses, and other providers; also statisticians, data managers, and other experts to process patients' clinical information into research. Attracting diverse qualified professionals to the clinical and research work requires long-term planning, recruiting individuals in training programs and retaining them as they become experts. Research infrastructure includes physical servers running database software, networks that link them, and the environment in which these components function. US Centers for Disease Control and Prevention (CDC) and American Thrombosis and Hemostasis Network (ATHN) coordinate and fund data collection at HTCs on the health and well-being of thousands of PWIBD into a registry used in research studies.National Hemophilia Foundation (NHF) and ATHN asked our group of health care professionals, technology experts, and lived experience experts (LEE) to identify the infrastructure, workforce, and resources needed to do the research most important to PWIBD. We identified the types of CDC/ATHN studies all HTCs should be able to perform, and the physical and human infrastructure this requires. We prioritized finding the best clinical trial designs to study inherited bleeding disorders, identifying ways to share personnel and tools between HTCs, and innovating how research is governed and funded. Involving LEEs in designing, managing, and carrying out research will be key in conducting research to improve the lives of PWIBD.

Recombinant factor VIII Fc fusion protein for first-time immune tolerance induction: final results of the verITI-8 study.

Inhibitor development remains a major challenge in factor VIII (FVIII) replacement therapy. verITI-8 is the first prospective study of a recombinant FVIII Fc fusion protein (rFVIIIFc; efmoroctocog alfa) for first-time immune tolerance induction (ITI) in males with severe hemophilia A and high-titer inhibitors (historical peak ≥5 Bethesda units [BU]/mL). In this single-arm, open-label, multicenter study, screening was followed by ITI (rFVIIIFc 200 IU/kg per day until tolerization or maximum of 48 weeks). Those who achieved ITI success entered a tapering period, returning to standard prophylaxis, and then entered follow-up. Primary end point was time to tolerization with rFVIIIFc defined by inhibitor titer <0.6 BU/mL, incremental recovery (IR) ≥66% of expected IR (IR ≥1.32 IU/dL per IU/kg), and half-life (t½) ≥7 hours within 48 weeks. Sixteen patients received ≥1 rFVIIIFc dose. Twelve (75%), 11 (69%), and 10 patients (63%), respectively, achieved negative inhibitor titers, an IR ≥66%, and a t½ ≥7 hours (ie, tolerance) within 48 weeks. Median times in weeks to achieve these markers of success were 7.4 (interquartile range [IQR], 2.2-17.8), 6.8 (IQR, 5.4-22.4), and 11.7 (IQR, 9.8-26.2), respectively. All patients experienced ≥1 treatment-emergent adverse event (TEAE), and 1 reported ≥1 related TEAE (injection site pain). Nine patients experienced ≥1 treatment-emergent serious AE. No thrombotic events, discontinuations because of AEs, or deaths were reported during the study. As the first extended half-life rFVIII with prospective data in ITI, rFVIIIFc offered short time to tolerization with durable responses in almost two-thirds of patients and was well tolerated. This trial was registered at www.clinicaltrials.gov as #NCT03093480.

Safety and Efficacy of Direct Oral Anticoagulants for Treatment of Venous Thromboembolism in Pediatric Oncology Patients.

BACKGROUND/OBJECTIVES: Children with cancer have an increased risk for developing a venous thromboembolism (VTE) during their treatment course. Direct oral anticoagulants (DOACs) represent a relatively new class of oral medications to treat VTE; however, data are limited to support use in this patient group. Given the safety and efficacy data from numerous perspective adult studies, providers now consider off-label use in select children. METHODS: We performed a single-center, retrospective review of children 0 to 20 years of age from 2012 to 2020 with malignancy and confirmed VTE, with the objective to evaluate the hypothesis that the safety and the efficacy of DOACs are noninferior to enoxaparin in this population. The primary composite efficacy outcome comprises symptomatic recurrent VTE, death due to VTE, and thrombus progression. The principal safety outcome is a combination of major and clinically relevant nonmajor bleeding. RESULTS: The safety and efficacy outcomes collected revealed that DOAC use was equivalent when compared with the enoxaparin group for treatment of VTE. One patient in the DOAC group had clinically relevant, nonmajor bleeding compared with 2 patients in the enoxaparin group. No treatment failures were observed. CONCLUSIONS: This single-center study suggests that DOACs are both safe and efficacious for the treatment of VTE in children with cancer. It also highlights the need for larger studies to address this clinical question.

Current practices in pediatric hospital-acquired thromboembolism: Survey of the Children's Hospital Acquired Thrombosis (CHAT) Consortium.

Background: A rise in hospital-acquired venous thromboembolism (HA-VTE) in children has led to increased awareness regarding VTE prophylaxis and risk assessment. Despite no consensus exists regarding these practices in pediatrics. Objective: To describe common practices in VTE prophylaxis, VTE risk assessment models, and anticoagulation dosing strategies in pediatric hospitals that are members of the Children's Hospital Acquired Thrombosis (CHAT) Consortium. Methods: An electronic survey of 44 questions evaluating practices surrounding pediatric HA-VTE risk assessment and prevention was distributed between August 9, 2021, and August 30, 2021, to the primary investigators from the 32 institutions within the CHAT Consortium. Results: The survey response rate was 100% (n = 32). In total, 85% (n = 27) of the institutions assess HA-VTE, but only 63% (n = 20) have formal hospital guidelines. Within the institutions with formal guidelines, 100% (n = 20) include acute systemic inflammation or infection and presence of a central venous catheter (CVC) as risk factors for VTE. Pharmacologic prophylaxis is prescribed at 87% (28) of institutions, with enoxaparin being the most frequent (96%, n = 27). Variability in responses persisted regarding risk factors, risk assessment, thromboprophylaxis, dosing of prophylactic anticoagulation or anticoagulant drug monitoring. A majority of providers were comfortable providing thromboprophylaxis across all age groups. In addition, the global coronavirus disease 2019 increased the providers' use of prophylactic anticoagulation 78% (n = 25). Conclusion: Practices among institutions are variable in regard to use of HA-VTE prophylaxis, risk assessment, or guideline implementation, highlighting the need for further research and a validated risk assessment model through groups like the CHAT Consortium.

Bleeding patterns in patients before and after diagnosis of von Willebrand disease: Analysis of a US medical claims database.

INTRODUCTION: Von Willebrand disease (VWD) is the most common inherited bleeding disorder. The bleeding phenotype is variable, and some individuals have persistent symptoms post-diagnosis. AIM: To characterize bleeding patterns in patients with VWD before and after diagnosis. METHODS: De-identified claims data for commercially insured patients in the IQVIA PharMetrics® Plus US database (Jan-2006 to Jun-2015) were extracted. Eligible patients had ≥2 claims for VWD (ICD-9 code 286.4), and continuous health-plan enrolment for ≥2 years before and after diagnosis. Bleeding event, treatment and treating-physician type were analysed for 18 months before and 7-24 months after diagnosis, according to pre-diagnosis bleeding phenotype (claims from one vs multiple bleed sites) and post-diagnosis bleeding status (resolved [no post-diagnosis bleed claims] vs continued [≥1 claim]). RESULTS: Data for 3756 eligible patients (72.6% female; 71.0% aged ≥18 years at diagnosis) were analysed. Overall, 642 (17.1%) and 805 (21.4%) patients had single- and multiple-site bleed claims pre-diagnosis, respectively, and 1263 (33.6%) patients (38.5% of women, 20.8% of men) continued to bleed post-diagnosis. Multiple-site bleeding was associated with pre-diagnosis heavy menstrual bleeding (HMB), oral contraceptive (OC) use and nasal cauterization. Continued bleeding post-diagnosis was associated with pre-diagnosis gastrointestinal bleeding, HMB and epistaxis; pre-diagnosis use of OCs, aminocaproic acid and nasal cauterization; and younger age at diagnosis. Few patients consulted a haematologist for bleed management. CONCLUSION: Many patients with VWD have persistent bleeding from multiple sites and continue to bleed post-diagnosis. Our findings suggest a need to optimize management to reduce the symptomatic burden of VWD following diagnosis.

Hemophilia B (Factor IX Deficiency).

The biology of factor IX deficiency leading to hemophilia B has important distinctions from factor VIII deficiency that leads to hemophilia A. In this article, the authors explore the unique biology of factor IX in hemostasis, including the importance of FIX distribution to the extravascular space and the implications on dosing of factor concentrates. The authors review basic treatment principles of hemophilia B, including extended half-life products, and highlight areas of ongoing therapeutic innovation for hemophilia B prophylaxis.

Observational study of recombinant factor VIII-Fc, rFVIIIFc, in hemophilia A.

INTRODUCTION: rFVIIIFc (Eloctate) is an extended-half-life recombinant factor VIII-Fc fusion protein that may promote factor VIII (FVIII) tolerance through Fc immunoregulatory properties. Yet, little is known regarding its immunogenicity in patients with hemophilia A (HA) or in HA with inhibitors (HA-I), including tolerized, immune tolerance induction (ITI)-refractory, or ITI-naïve. METHODS: We reviewed medical records of 60 patients, including 2 previously-untreated patients (PUPs) and 58 previously-treated patients (PTPs), cared for between 01/01/06 and 06/01/17, on whom anti-FVIII antibody data were available before and after initiating rFVIIIFc. Continuous data were analyzed by student's t-test, and discrete data by chi square or Fisher's exact test. RESULTS: After initiating rFVIIIFc, one of two HA PUPs developed a low-responding (LR) inhibitor after 10 exposures, which resolved (anti-VIII<0.6 B.U.) within 8 additional exposures, while none of 41 HA PTPS developed an inhibitor. Among 19 HA-I PTPs with detectable inhibitors prior to rFVIIIFc, 5 developed an anamnestic response to rFVIIIFc, including 1 of 8 (12.5%) low-responding (LR), and 4 of 9 (44.9%) high-responding (HR), of whom 3 were ITI-naïve and 1 ITI-refractory. Inhibitors resolved in 4 HR within 2 months of continuing rFVIIIFc (median) but persisted in 1 LR at low titer. The remaining 11 HA-I PTPs, including 4 HR and seven LR, had no detectable inhibitor at the time of or after initiating rFVIIIFc. DISCUSSION: rFVIIIFc was immunogenic in HA PUPs and in HA-I PTPs persistently ITI-naïve or ITI-refractory, with inhibitor resolution in the majority. rFVIIIFc immunogenicity appears to be similar to other FVIII products.

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.

Nonimmune Anemias.

Anemia in the newborn period can be a diagnostic challenge. This article explores the diagnosis, work-up, and differential diagnosis of anemia in this patient population with a focus on anemia that is not related to blood loss or immune-mediated conditions (isoimmune hemolysis).

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.