Hemophilia A in the third millennium

Application of Artificial Intelligence and Machine Learning Was Not Able to Reliably Predict Poor Outcomes in People With Hemophilia

Background Artificial intelligence (AI) and machine learning (ML) are currently used in the clinical field to improve the outcome predictions on disease diagnosis and prognosis. However, to date, few AI/ML applications have been reported in rare diseases, such as hemophilia. In this study, taking advantage of the ATHNdataset, an extensive repository of hemostasis and thrombosis data, we aimed to demonstrate the application of AI/ML approaches to build predictive models to identify persons with hemophilia (PwH) who are at risk of poor outcome and to inform providers in clinical decision-making towards helping patients prevent long-term complications. Materials and methods This project was carried out in two steps. First, the data were mined from ATHN 7, a subset study of the ATHNdataset, to determine markers that defined "poor outcome." Second, we applied multiple AI/ML approaches on the ATHNdataset to validate our findings and to develop predictive models to identify PwH at risk of poor outcomes. The classical regression-based predictive model was used as a reference to evaluate the performance of various AI/ML models. Results Our models included features similarly distributed to response variables of interest, resulting in a limited ability to distinguish poor outcomes. Low recall (<53%) resulted in no single model reliably predicting poor outcomes out of all actual positive cases. Our results suggest that, to build a more useful AI/ML model, we may need a larger dataset size along with additional features. Furthermore, our results showed that most of the AI/ML models outperformed the classical logistic regression model in both model accuracy and precision. Conclusions Our AI and ML model showed limited ability to predict poor outcomes in people with hemophilia.

Debates Surrounding the Use of Antithrombotic Therapy in Hemophilic Patients with Cardiovascular Disease: Best Strategies to Minimize Severe Bleeding Risk

Navigating through antithrombotic therapy in patients with both hemophilia and cardiovascular pathology presents a complex scenario with inherent challenges and opportunities. The presence of hemophilia, characterized by impaired blood clotting, adds a layer of complexity to the management of cardiovascular conditions requiring antiplatelet therapy and anticoagulation. Striking a delicate balance between the necessity for antithrombotic treatment to prevent cardiovascular events and the heightened risk of severe bleeding in individuals with hemophilia demands a nuanced and carefully considered approach. The challenges revolve around identifying an optimal therapeutic strategy that effectively mitigates cardiovascular risks without exacerbating bleeding tendencies. In hemophilic patients with cardiovascular disease, the decision to use antiplatelet therapy requires careful consideration of the individual's bleeding risk profile, considering factors such as the severity of hemophilia, history of bleeding episodes, and concurrent medications. The goal is to provide effective antithrombotic treatment while minimizing the potential for excessive bleeding complications. Conventional anticoagulants like warfarin pose difficulties due to their potential to increase the risk of bleeding. On the other hand, emerging options like novel direct oral anticoagulants (DOACs) present an opportunity, offering predictable pharmacokinetics and user-friendly administration. However, a comprehensive exploration of their safety and efficacy in hemophilic patients is imperative. Achieving the right equilibrium between preventing cardiovascular events and minimizing bleeding risk is pivotal in selecting the most effective therapeutic option for individuals with hemophilia and cardiovascular pathology. A multidisciplinary approach, integrating the expertise of hematologists and cardiologists, becomes essential to customize treatments and address the intricacies of this medical challenge.

Laser Ablation of Pilonidal Sinus in a Patient With Hemophilia Type A: A Case Report and Review of the Literature

Pilonidal sinus (PNS) is a common occurrence in young men. It is often caused by blockage of the sebaceous glands in the hair follicles in the sacrococcygeal area. Hemophilia type A is a hemorrhagic disorder caused by a deficiency of factor VIII. It presents with excessive bleeding, either spontaneously or secondary to trauma. The mainstay of treatment for PNS is often excision of the sinus; however, recently, laser ablation has started to be commonly used. In this article, we present a case of a young man with hemophilia A presenting with recurrent PNS successfully managed with laser ablation with no complications.

Haemophilia in the era of novel therapies: Where do inhibitors feature in the new landscape?

INTRODUCTION

The advent of therapeutic recombinant factor VIII (FVIII) and factor IX (FIX) protein infusions revolutionized the care of persons with haemophilia in the 1990s. It kicked off an era with the increasing use of prophylactic factor infusions for patients and transformed conversations around the ideal trough activity levels as well as the ultimate goals in tailored, individualized care. Our knowledge surrounding the immunologic basis of inhibitor development and treatment derives from a time when patients were receiving frequent factor infusions and focused on immune tolerance induction following inhibitor development.

DISCUSSION

More recently, care was revolutionized again in haemophilia A with the approval of emicizumab, a bispecific antibody mimicking activated FVIII function, to prevent bleeding. The use of emicizumab prophylaxis has resulted in a significantly slower accumulation of factor exposure days and continued effective prophylaxis in the case of inhibitor development. While emicizumab is effective at reducing the frequency of bleeding events in patients with haemophilia A, management of breakthrough bleeds, trauma, and surgeries still requires additional treatment. Ensuring that FVIII is a therapeutic option, particularly for life-threatening bleeding events and major surgeries is critical to optimizing the care of persons with haemophilia A. Other novel non-factor concentrate therapies, including rebalancing agents, will dramatically change the landscape for persons with haemophilia B with inhibitors.

CONCLUSION

This review discusses the changing landscape regarding the timing of inhibitor development and management strategies after inhibitor development, stressing the importance of education across the community to continue to vigilantly monitor for inhibitors and be prepared to treat persons with inhibitors.

Pharmacokinetic-Pharmacodynamic Modelling in Hemophilia A: Relating Thrombin and Plasmin Generation to Factor VIII Activity After Administration of a VWF/FVIII Concentrate

BACKGROUND

Hemophilia A patients are treated with factor (F) VIII prophylactically to prevent bleeding. In general, dosage and frequency are based on pharmacokinetic measurements. Ideally, an alternative dose adjustment can be based on the hemostatic potential, measured with a thrombin generation assay (TGA), like the Nijmegen hemostasis assay.

OBJECTIVE

The objective of this study was to investigate the predicted performance of a previously developed pharmacokinetic-pharmacodynamic model for FVIII replacement therapy, relating FVIII dose and FVIII activity levels with thrombin and plasmin generation parameters.

METHODS

Pharmacokinetic and pharmacodynamic measurements were obtained from 29 severe hemophilia A patients treated with pdVWF/FVIII concentrate (Haemate P®). The predictive performance of the previously developed pharmacokinetic-pharmacodynamic model was evaluated using nonlinear mixed-effects modeling (NONMEM). When predictions of FVIII activity or TGA parameters were inadequate [median prediction error (MPE) > 20%], a new model was developed.

RESULTS

The original pharmacokinetic model underestimated clearance and was refined based on a two-compartment model. The pharmacodynamic model displays no bias in the observed normalized thrombin peak height and normalized thrombin potential (MPE of 6.83% and 7.46%). After re-estimating pharmacodynamic parameters, EC50 and Emax values were relatively comparable between the original model and this group. Prediction of normalized plasmin peak height was inaccurate (MPE 58.9%).

CONCLUSION

Our predictive performance displayed adequate thrombin pharmacodynamic predictions of the original model, but a new pharmacokinetic model was required. The pharmacodynamic model is not factor specific and applicable to multiple factor concentrates. A prospective study is needed to validate the impact of the FVIII dosing pharmacodynamic model on bleeding reduction in patients.

Surgical Experience from the STASEY Study of Emicizumab Prophylaxis in People with Hemophilia A with Factor VIII Inhibitors

Background  Guidelines surrounding emicizumab prophylaxis and perioperative treatment for people with hemophilia A (PwHA) with factor (F)VIII inhibitors undergoing surgeries are limited. The phase IIIb multicenter, single-arm STASEY study evaluated safety and tolerability of emicizumab prophylaxis in PwHA aged ≥12 years with FVIII inhibitors. This analysis assesses surgeries during study conduct, associated hemophilia medications, and postoperative bleeds (treated and untreated). Methods  PwHA with FVIII inhibitors received emicizumab 3.0 mg/kg/week for 4 weeks, then 1.5 mg/kg/week until 2 years. Surgeries were managed and documented by treating physicians. Bleeds and treatments were recorded by physicians and participants. Results  Forty-six participants had ≥1 on-study surgery, 37 underwent 56 minor surgeries, and 13 underwent 22 major surgeries. Four participants underwent both minor and major surgeries. Of 18 (81.8%) and 4 (18.2%) major surgeries managed with/without additional hemostatic medication, 33.3 and 25.0% were associated with a treated postoperative bleed, respectively. Of 24 (42.9%) and 32 (57.1%) minor surgeries managed with/without additional hemostatic medication, 15.6 and 25.0% were associated with a treated postoperative bleed, respectively. Recombinant activated FVII was the most common medication for prophylaxis and bleed treatment. There were no thrombotic microangiopathies (TMAs). One hypertrophic clot, considered unrelated to emicizumab, occurred following tooth extraction. Conclusion  In this challenging population with a high bleeding risk, major surgeries were performed in PwHA receiving emicizumab with/without additional hemostatic medication. Postoperative bleeds occurred following 59.1% of major surgeries; 53.8% were treated. No arterial/venous thrombotic events or TMAs occurred due to concomitant emicizumab and bypassing agents. Trial registration  This trial is registered at ClinicalTrials.gov (NCT03191799).

Epidemiological study of hereditary hemorrhagic disorders in Najaf province, Iraq

Hemophilia and Von Willbrand disease (VWD) are the most well known types of hereditary hemorrhagic disorders (HHD). Hemophilia affects about 200 000 people worldwide, while VWD affects about 80 000. Because there is a scarcity of epidemiologic studies on hemophilia in Iraq, this study was carried out to evaluate the prevalence and incidence trends, as well as to identify some clinical and epidemiological features of hemophilia patients in Najaf province, Iraq. This study was carried out in the Najaf's hemophilia center. The data were obtained by reviewing all patients' documents, as well as the center registration book from 2011 to 2021. In addition, the Ministry of Health provided relevant population data for Najaf. Notably, there are currently 214 patients registered in Najaf province. The results revealed that the severe form of hemophilia A was the permanent type of HHDs in the patients compared with the rest of the types that include HHD with no significant difference Pat least 0.05. The frequency of this group of disorders appeared to increase in the period between 2011 and 2013, especially in 2012 followed by a decline in the incidence until 2021, which recorded a sudden increase in these disorders. These findings highlight that hemophilia types A and B were the most prevalent disorders of HHD in Najaf province, and the increase in number of newly recorded cases because of consanguineous marriage increased recently in this area.

The Nijmegen ultra-sensitive Bethesda Assay detects very low-titer factor VIII inhibitors in patients with congenital and acquired hemophilia A

BACKGROUND

An inhibitor can develop in congenital hemophilia A (HA) patients against exogenous infused factor (F)VIII, whereas in acquired HA (AHA) inhibitors initially develop against endogenous FVIII. Inhibitors can be detected with the Nijmegen Bethesda Assay (NBA), which has an international cut-off level of 0.60 Nijmegen Bethesda Units/mL (NBU/mL). Thereby, very low-titer inhibitors may remain undetected.

AIM

To describe the design and validation of the Nijmegen ultra-sensitive Bethesda Assay (NusBA) for the detection of very low-titer inhibitors.

METHODS

The NusBA is a modification of the NBA in which the ratio of patient plasma to normal pooled plasma is changed from 1:1 to 9:1. Analytical validation was performed according to the CLSI EP10 guideline in order to determine trueness and reproducibility. Clinical validation was performed in two cohorts of congenital HA patients (82 adults) with pharmacokinetic data and four AHA patients. The limit of quantitation (LOQ) was determined by measuring plasma samples spiked with inhibitor levels in the low range (0.05-0.80 NBU/mL).

RESULTS

The LOQ for the NusBA was 0.10 NusBU/mL, with a coefficient of variation of 24.2 %. Seven (8.5 %) congenital HA patients had a positive NusBA result, of which only one was detected with the NBA. There was no correlation between NusBA and FVIII half-life. In three of the AHA patients the NusBA remained positive, when the NBA became negative.

DISCUSSION

The NusBA is able to detect very low-titer FVIII inhibitors of ≥0.10 NBU/mL. Thereby, it may have added value in early inhibitor detection and therapy adjustments in patients with congenital HA and AHA.

The Use of Bypassing Treatment Strategies in Hemophilia and Their Effect on Laboratory Testing

Factor VIII and IX inhibitors in congenital hemophilia A and B, respectively, neutralize the infused coagulation factor concentrate rendering them ineffective. Bypassing agents (BPAs) that circumvent the block imposed by the inhibitors are used for the prevention and management of bleeding. Activated prothrombin complex concentrate was the original BPA, recombinant activated factor VII was then introduced, and more recently nonfactor agents that target the procoagulant and anticoagulant systems have been developed and are in clinical use (e.g., emicizumab, a bispecific antibody for hemophilia A). Other BPAs are in clinical trials (e.g., fitusiran targets antithrombin, concizumab and marstacimab target tissue factor pathway inhibitor, and SerpinPC targets activated protein C). The BPAs have a varied effect on coagulation assays, and as more patients are exposed to these agents, it is important to be aware of the effects. Herein, we present an overview of the effect of BPAs on routine and specialized coagulation assays including thrombin generation and viscoelastic assays.

Complication Analysis in Korean Patients With Hemophilia A From 2007 to 2019: A Nationwide Study by the Health Insurance Review and Assessment Service Database

BACKGROUND

There has been remarkable progress in hemophilia A (HA) treatment in Korea. Viral inactivation products were developed in 1989, use of recombinant factor VIII (FVIII) concentrates started in 2002, and prophylaxis expanded thereafter. This study was conducted to identify the changes in complications in HA before and after 1989 or 2002.

METHODS

The study was performed using the 2007-2019 Healthcare Big Data Hub of the Health Insurance Review and Assessment Service.

RESULTS

Among 2,557 patients, 1,084 had ≥ 1 complication; 829 had joint problems, 328 had viral infections, 146 had neurologic sequelae, and 87 underwent 113 surgeries or procedures due to complications. Patients born after 1989 had a significantly lower risk of viral infections than those born before 1989; 27.1% vs. 1.4% (P < 0.001, odds ratio [OR], 0.037). Patients born after 2002 had a significantly lower risk of joint problems than those born before 2002; 36.8% vs. 24.7% (P < 0.001, OR, 0.538). Patients born after 2002 had a higher incidence of neurologic sequelae than those born before 2002; 3.7% vs. 11.1% (P < 0.001, OR, 3.210). Medical expenses for complication-associated surgeries or procedures were ₩2,957,557,005.

CONCLUSION

Viral infections have significantly decreased in Korean patients with HA. The degree of reduction of joint problems was lower than we expected, because it took > 10 years to expand prophylaxis widely. Neurologic sequelae have not decreased; thus, additional efforts to decrease intracranial hemorrhage are needed. We suggest personalized dosing of FVIII and more meticulous care during childbirth to further reduce the complications.

How we manage cardiovascular disease in patients with hemophilia

With the striking advances in hemophilia care that have materialized particularly in the last two decades, an increasing number of persons with hemophilia (PWH) have achieved a quality of life and life expectancy very close to that of unaffected individuals. With aging, a growing number of PWH develop age-related co-morbidities, including cancer and cardiovascular disease. The latter (particularly coronary artery disease and atrial fibrillation) represent a new challenge for the hemophilia treatment centers because their management implies a delicate balance between the thrombotic risk and bleeding tendency, that is further enhanced by the concomitant use of antithrombotic agents. Because evidence from clinical trials is lacking, the management of PWH with cardiovascular diseases is mostly based on expert opinions, personal experiences, and the adaptation of the evidence stemming from studies on people without hemophilia. In this article, we focus on how to manage coronary artery disease and atrial fibrillation in patients with hemophilia.

Monitoring prothrombin activation in plasma through loss of Förster resonance energy transfer

BACKGROUND

Current assays that monitor thrombin generation in plasma rely on fluorogenic substrates to follow the kinetics of zymogen activation, which may be complicated by substrate cleavage from other proteases. In addition, these assays depend on activation following cleavage at the prothrombin R320 site and fail to report the cleavage at the alternative R271 site, leading to the shedding of the auxiliary Gla and kringle domains of prothrombin.

OBJECTIVES

To develop a plasma assay that directly monitors prothrombin activation independent of fluorogenic substrate hydrolysis.

METHODS

Cleavage at the R271 site of prothrombin is monitored through loss of Förster resonance energy transfer in plasma coagulated along the extrinsic or intrinsic pathway.

RESULTS

The availability of factor (F)V in plasma strongly influences the rate of prothrombin activation. The rate of thrombin formation is equally perturbed in FV or prothrombin-depleted plasma, implicating that the thrombin-catalyzed feedback reactions that amplify the coagulation response play an important role in generating sufficient amounts of FVa required for the assembly of prothrombinase. Congenital deficiencies in FVIII and FIX significantly slow down cleavage at R271 in plasma coagulated along the extrinsic and intrinsic pathways. Prothrombin activation in FXI-deficient plasma is only perturbed when coagulation is triggered along the intrinsic pathway.

CONCLUSION

The Förster resonance energy transfer assay enables direct monitoring of prothrombin activation through cleavage at R271 without the need for fluorogenic substrates. The assay is sensitive enough to assess how deficiencies in coagulation factors affect thrombin formation.

Clinical pharmacology of emicizumab for the treatment of hemophilia A

INTRODUCTION

Emicizumab is a humanized bispecific antibody approved for the routine prophylaxis of bleeding episodes in patients with hemophilia A (PwHA) regardless of the presence of factor VIII (FVIII) inhibitors. It mimics the cofactor function of missing activated FVIII by bridging activated factor IX and factor X, thereby restoring hemostasis.

AREAS COVERED

This review covers the clinical pharmacology of emicizumab and the translation of its pharmacokinetics (PK) and pharmacodynamics (PD) to clinical efficacy and safety. The PK of emicizumab is linear, with an approximately 1-month half-life. Once-weekly to every-4-week subcutaneous (SC) administrations maintain effective trough concentrations throughout the dosing intervals, associated with a coagulation potential analogous to that in patients with mild hemophilia A. In combination with activated prothrombin complex concentrate, and to a lesser extent with recombinant activated factor VII, emicizumab exerts a synergistic effect, whereas combination with FVIII may result in a non-additive coagulation potential at normal FVIII activity.

EXPERT OPINION

The translation of emicizumab PK/PD into clinical effects was demonstrated in several phase III studies, which showed remarkable bleed control and a favorable safety profile in PwHA. These emicizumab attributes, together with the convenience of use (infrequent SC injections), offer a novel paradigm for the management of PwHA.

Long-term immunogenicity, efficacy and tolerability of simoctocog alfa in patients with severe haemophilia A who had completed the NuProtect study in previously untreated patients

BACKGROUND

The NuProtect study reported data on the immunogenicity, efficacy and tolerability of simoctocog alfa (Nuwiq^® ) in 108 previously untreated patients with severe haemophilia A planned to be treated for ≥100 exposure days or up to 5 years. The NuProtect-Extension study collected long-term prophylaxis data in children with severe haemophilia A.

METHODS

Patients who completed the NuProtect study according to the protocol were eligible for the NuProtect-Extension study, a prospective, multinational, non-controlled, Phase 3b study.

RESULTS

Of 48 patients who entered the extension study, 47 (median age 2.8 years) received prophylaxis with simoctocog alfa for a median of 24 months, with 82%-88% on a twice-weekly or less regimen. No patient developed FVIII inhibitors during the extension study. The median (IQR) annualized bleeding rate (ABR) during prophylaxis was 0 (0-0.5) for spontaneous bleeding episodes (BEs) and 1.00 (0-1.95) for all BEs. ABRs estimated using a negative binomial model were .28 (95% CI: .15, .53) for spontaneous and 1.62 (95% CI: 1.09, 2.42) for all BEs. During the median follow-up of 24 months, 34 (72%) patients had zero spontaneous BEs and 46 (98%) had zero spontaneous joint BEs. Efficacy in treating BEs was excellent or good for 78.2% of rated BEs, and efficacy of surgical prophylaxis was excellent for two rated surgeries. No treatment-related adverse events were reported.

CONCLUSION

No FVIII inhibitors developed during long-term prophylaxis in the NuProtect-Extension study. Prophylaxis with simoctocog alfa was efficacious and well-tolerated, and is therefore an attractive long-term option for children with severe haemophilia A.

Current factor IX replacement options for hemophilia B and the challenges ahead

INTRODUCTION

Therapy for hemophilia B is aimed at replacing the congenital deficiency of coagulation factor IX (FIX). For replacement therapy, several FIX concentrates derived from donated human plasma or engineered by recombinant DNA technology are currently commercially available. The use of these products is well established and permit patients a relatively normal life. To further improve treatment efficacy, recombinant FIX products with a prolonged half-life have been developed, allowing relaxed prophylactic dosing and reducing treatment burden.

AREAS COVERED

In this review, we explore the current FIX replacement options for hemophilia B patients by analyzing the outcomes of their main clinical trials. We cover advances in the FIX molecules with extended half-life (EHL). Published literature on products for replacement of hemophilia B was retrieved using PubMed with no temporal limits.

EXPERT OPINION

The recent introduction of recombinant EHL FIX products has represented a major advance in the therapeutic management of hemophilia B patients, permitting both a reduction of treatment burden and improving patients' compliance to prophylaxis and, ultimately, quality of life.

Thromboembolic Disease in Haemophilic Patients Undergoing Major Orthopaedic Surgery: Is Thromboprophylaxis Mandatory?

Haemophilia is a rare genetic disorder, that results from various degrees of deficiency of coagulation factor VIII (haemophilia A), or factor IX (haemophilia B), with an X-linked transmission. The patients affected are in the majority of cases males (who inherit the affected X-chromosome from the maternal side), with rare cases of females with haemophilia (FVIII or FIX < 40 IU/dL), situations in which both X-chromosomes are affected, or one is affected, and the other one is inactive (known as carrier). The hypocoagulable state due to the deficiency of clotting factors, manifests as an excessive, recurrent tendency to bleeding, which positively correlates with plasmatic levels. Severe haemophilia results in hemarthrosis, although recent data have shown that moderate or even mild disease can lead to joint bleeding. Recurrent episodes of haemorrhages, usually affecting large joints such as knees, elbows, or ankles, lead to joint remodelling and subsequent haemophilic arthropathy, which may require arthroplasty as a last therapeutic option. Orthopaedic patients have the highest risk among all for deep vein thrombosis (DVT) and venous thromboembolism (VTE) with morbid and potentially fatal consequences. While for the rest of the population thromboprophylaxis in orthopaedic surgery is efficient, relatively safe, and widely used, for patients with haemophilia who are considered to have a low thromboembolic risk, there is great controversy. The great heterogeneity of this particular population, and the lack of clinical trials, with only case reports or observational studies, makes thromboprophylaxis in major orthopaedic surgery a tool to be used by every clinician based on experience and case particularities. This review aims to briefly summarise the latest clinical data and to offer an insight into the current recommendations that readers would find useful in daily practice.

Autologous bone marrow-derived MSCs engineered to express oFVIII-FLAG engraft in adult sheep and produce an effective increase in plasma FVIII levels

Introduction

Hemophilia A (HA) is the most common X-linked bleeding disorder, occurring in 1 in 5,000 live male births and affecting >1 million individuals worldwide. Although advances in protein-based HA therapeutics have improved health outcomes, current standard-of-care requires infusion 2-3 times per week for life, and 30% of patients develop inhibitors, significantly increasing morbidity and mortality. There are thus unmet medical needs requiring novel approaches to treat HA.

Methods

We tested, in a highly translational large animal (sheep) model, whether the unique immunological and biological properties of autologous bone marrow (BM)-derived mesenchymal stromal cells (MSCs) could enable them to serve as cellular delivery vehicles to provide long-term expression of FVIII, avoiding the need for frequent infusions.

Results

We show that autologous BM-MSCs can be isolated, transduced with a lentivector to produce high levels of ovine (o)FVIII, extensively expanded, and transplanted into adult animals safely. The transplanted cells engraft in multiple organs, and they stably produce and secrete sufficient quantities of FVIII to yield elevated plasma FVIII levels for at least 15 weeks.

Discussion

These studies thus highlight the promise of cellular-based gene delivery approaches for treating HA.

Co-administration of FVIII with IVIG reduces immune response to FVIII in hemophilia A mice

Hemophilia A is an X-linked recessive congenital bleeding disorder. Exogenous infusion of FVIII is the treatment of choice, and the development of immunoglobulins against FVIII (inhibitors) remains the major challenge in clinical management of the disease. Here, we investigated the effect of co-administration of FVIII with intravenous immunoglobulin (IVIG) on the development of inhibitors in previously untreated hemophilia A mice. A group of hemophilia A mice (C57BL/6^FVIII-/-) received weekly injections of recombinant human FVIII (rFVIII) for twelve consecutive weeks while a second group received co-injections of rFVIII + IVIG. An in-house enzyme-linked immunosorbent assay (ELISA) was designed to detect antibodies to rFVIII. Every mouse in the first group developed antibodies to rFVIII. In contrast, mice treated with rFVIII + IVIG showed significantly lower antibody titers. Interestingly, when co-administration of IVIG was discontinued after 12 weeks in some mice (rFVIII continued), these mice experienced an increase in antibody titer. In contrast, mice that continued to receive rFVIII + IVIG retained significantly lower titers. In conclusion, prophylactic rFVIII co-administration with IVIG modulated the immune response to FVIII and resulted in decreased anti-FVIII antibody titer. These findings suggest that co-injection therapy with IVIG could potentially be effective in the management of hemophilia A patients at risk of inhibitor development.

Thrombin generation assays to personalize treatment in bleeding and thrombotic diseases

Treatment of bleeding and thrombotic disorders is highly standardized and based on evidence-based medicine guidelines. These evidence-based treatment schemes are well accepted but may lead to either insufficient treatment or over-dosing, because the individuals' hemostatic properties are not taken into account. This can potentially introduce bleeding or thrombotic complications in individual patients. With the incorporation of pharmacokinetic (PK) and pharmacodynamic (PK-PD) parameters, based on global assays such as thrombin generation assays (TGAs), a more personalized approach can be applied to treat either bleeding or thrombotic disorders. In this review, we will discuss the recent literature about the technical aspects of TGAs and the relation to diagnosis and management of bleeding and thrombotic disorders. In patients with bleeding disorders, such as hemophilia A or factor VII deficiency, TGAs can be used to identify patients with a more severe bleeding phenotype and also in the management with non-replacement therapy and/or bypassing therapy. These assays have also a role in patients with venous thrombo-embolism, but the usage of TGAs in patients with arterial thrombosis is less clear. However, there is a potential role for TGAs in the monitoring of (long-term) antithrombotic therapy, for example with the use of direct oral anticoagulants. Finally this review will discuss controversies, limitations and knowledge gaps in relation to the introduction of TGAs to personalize medicine in daily medical practice.

The More Recent History of Hemophilia Treatment

The availability first in the 1970s of plasma-derived and then in the 1990s of recombinant clotting factor concentrates represented a milestone in hemophilia care, enabling not only treatment of episodic bleeding events but also implementation of prophylactic regimens. The treatment of hemophilia has recently reached new landmarks. The traditional clotting factor replacement therapy for hemophilia has been substituted over the last 10 years by novel treatments such as bioengineered factor VIII and IX molecules with extended half-life and non-factor treatments including the bispecific antibody emicizumab. This narrative review is dedicated to these newer therapies, which are contributing significantly to improving the long-term management of prophylaxis in hemophilia patients. Another section is focused on the current state of gene therapy, which is a promising definitive cure for severe hemophilia A and B.

Analysis of pooled real-world data from Germany, Italy, and the United States of rVIII-SingleChain compared with standard- and long-acting FVIII products for prophylaxis of hemophilia A

OBJECTIVE

To evaluate real-world annualized bleeding rates (ABRs), dosing frequency, and factor consumption of four recombinant FVIII (rFVIII) products using pooled data from centers in the US, Germany, and Italy.

METHODS

De-identified patient medical chart data were collected from 48 hemophilia treatment centers in the US, Germany, and Italy. Patients included in this analysis had hemophilia A and were treated with rVIII-SingleChain, rFVIIIFc, octocog alfa, or BAY 81-8973 for ≥12 weeks. Where possible, patient selection considered age and disease severity in order to balance patient groups across products. Summary statistics were presented descriptively by product for dosing frequency, consumption, ABR/annualized spontaneous bleeding rate (AsBR), and corresponding percentage of patients with zero bleeds. Logistic regression was performed for patients with zero bleeds or zero spontaneous bleeds (vs. patients with any such bleeds). Generalized linear model regression was performed for ABR, AsBR, and consumption. All regression models included the product variable for comparison as well as additional independent variables for adjustment (age, weight, severity, and country for the consumption model, with the addition of consumption for the bleeding outcomes models).

RESULTS

Overall, 616 patients were included (rVIII-SingleChain, n = 129; rFVIIIFc, n = 159; octocog alfa, n = 181; BAY 81-8973, n = 147). Dosing frequency was ≤2 times a week for 65.9%, 75.5%, 25.4%, and 40.1% of patients treated with rVIII-SingleChain, rFVIIIFc, octocog alfa, and BAY 81-8973, respectively. ABRs were not significantly different among products, with mean (median) values of 1.1 (0.0), 1.0 (0.0), 1.4 (1.0), and 1.9 (1.0) for rVIII-SingleChain, rFVIIIFc, octocog alfa, and BAY 81-8973, respectively. The percentage of patients with zero bleeds was comparable between rVIII-SingleChain and rFVIIIFc (59.7% vs. 62.3%; p =.916) and significantly higher for rVIII-SingleChain compared with octocog alfa (p <.001) and BAY 81-8973 (p =.003). Comparison of mean weekly consumption showed: rVIII-SingleChain (83.0 IU/kg/week) vs. rFVIIIFc (96.9; p =.055) and significantly lower for rVIII-SingleChain vs. octocog alfa (108.6; p <.001) and BAY 81-8973 (104.3; p =.001). The median values for weekly consumption were 85.7, 90.1, 100.1, and 98.5 IU/kg/week for rVIII-SingleChain, rFVIIIFc, octocog alfa, and BAY 91-8973, respectively. Similar trends were observed for all outcomes when analyzing the subgroups of patients aged ≥12 years and patients with severe disease (all age and ≥12 years).

CONCLUSIONS

rVIII-SingleChain prophylaxis may provide improved bleed protection, less frequent dosing, and lower consumption compared with standard-acting FVIII products, and comparable protection and consumption to the other long-acting FVIII product, in patients with hemophilia A.

Pediatric Perioperative Clinical Pharmacy Practice: Clinical Considerations and Management: An Opinion of the Pediatrics and Perioperative Care Practice and Research Networks of the American College of Clinical Pharmacy

Pediatric perioperative clinical pharmacists are uniquely positioned to provide therapeutic and medication management expertise at a particularly vulnerable transition of care from the preoperative space, through surgery, and postoperative setting. There are many direct-patient care activities that are included in the role of the pediatric perioperative pharmacist, as well as many opportunities to develop effective, optimized, and safe medication use processes. This article outlines many of the areas in which a pediatric perioperative clinical pharmacist may intervene.

Neutralizing Antibodies Against Factor VIII Can Occur Through a Non-Germinal Center Pathway

Humoral immunity to factor VIII (FVIII) represents a significant challenge for the treatment of patients with hemophilia A. Current paradigms indicate that neutralizing antibodies against FVIII (inhibitors) occur through a classical CD4 T cell, germinal center (GC) dependent process. However, clinical observations suggest that the nature of the immune response to FVIII may differ between patients. While some patients produce persistent low or high inhibitor titers, others generate a transient response. Moreover, FVIII reactive memory B cells are only detectable in some patients with sustained inhibitor titers. The determinants regulating the type of immune response a patient develops, let alone how the immune response differs in these patients remains incompletely understood. One hypothesis is that polymorphisms within immunoregulatory genes alter the underlying immune response to FVIII, and thereby the inhibitor response. Consistent with this, studies report that inhibitor titers to FVIII differ in animals with the same F8 pathogenic variant but completely distinct backgrounds; though, how these genetic disparities affect the immune response to FVIII remains to be investigated. Given this, we sought to mechanistically dissect how genetics impact the underlying immune response to FVIII. In particular, as the risk of producing inhibitors is weakly associated with differences in HLA, we hypothesized that genetic factors other than HLA influence the immune response to FVIII and downstream inhibitor formation. Our data demonstrate that FVIII deficient mice encoding the same MHC and F8 variant produce disparate inhibitor titers, and that the type of inhibitor response formed associates with the ability to generate GCs. Interestingly, the formation of antibodies through a GC or non-GC pathway does not appear to be due to differences in CD4 T cell immunity, as the CD4 T cell response to an immunodominant epitope in FVIII was similar in these mice. These results indicate that genetics can impact the process by which inhibitors develop and may in part explain the apparent propensity of patients to form distinct inhibitor responses. Moreover, these data highlight an underappreciated immunological pathway of humoral immunity to FVIII and lay the groundwork for identification of biomarkers for the development of approaches to tolerize against FVIII.

Transcutaneous ultrasound mediated gene delivery into canine livers achieves therapeutic levels of FVIII expression

Nonviral UMGD can achieve therapeutic levels of FVIII gene expression in a large animal model.

UMGD targeting liver is safe without evidence of any lasting damage.

A safe, effective, and inclusive gene therapy will significantly benefit a large population of patients with hemophilia. We used a minimally invasive transcutaneous ultrasound-mediated gene delivery (UMGD) strategy combined with microbubbles (MBs) to enhance gene transfer into 4 canine livers. A mixture of high-expressing, liver-specific human factor VIII (hFVIII) plasmid and MBs was injected into the hepatic vein via balloon catheter under fluoroscopy guidance with simultaneous transcutaneous UMGD treatment targeting a specific liver lobe. Therapeutic levels of hFVIII expression were achieved in all 4 dogs, and hFVIII levels were maintained at a detectable level in 3 dogs throughout the 60-day experimental period. Plasmid copy numbers correlated with hFVIII antigen levels, and plasmid-derived messenger RNA (mRNA) was detected in treated livers. Liver transaminase levels and histology analysis indicated minimal liver damage and a rapid recovery after treatment. These results indicate that liver-targeted transcutaneous UMGD is promising as a clinically feasible therapy for hemophilia A and other diseases.

Regression Analysis to Estimate the Factor VIII Activity of Patients with Hemophilia A Without Inhibitor who Received Emicizumab Therapy

BACKGROUND

 Emicizumab, a bispecific monoclonal antibody for hemophilia A (HA), has strong pharmacodynamic effects in several coagulation assays resulting in dosing difficulties with Factor VIII (FVIII) concentrates during bleeding emergencies.

MATERIALS AND METHODS

Single and multiple regression models were studied to estimate FVIII activity using 27 archived plasma samples from three patients with HA without inhibitor under emicizumab treatment. Explanatory variables were FVIII chromogenic assay (CSA), Ad|min1|, Ad|min2|, the number of seconds of APTT, and the FVIII one-stage assay (OSA), which were measured without idiotype antibodies. The response variable was FVIII OSA measured with idiotype antibodies.

RESULTS

In the simple linear model, the FVIII CSA regression coefficient was 1.04 and the intercept was -14.55 (r² = 0.95; p < 0.001). In the multiple regression model, FVIII OSA and FVIII CSA were selected based on the Akaike Information Criterion, with regression coefficients of 1.74 and 1.15, respectively, and an intercept of -92.03 (r² = 0.96, p < 0.001).

CONCLUSIONS

The regression models can estimate the FVIII:C levels in patients with HA receiving emicizumab and would be useful in a bleeding emergency and/or surgery.

Detailed analysis of anti-emicizumab antibody decreasing drug efficacy, using plasma samples from a patient with hemophilia A

BACKGROUND

Emicizumab is a humanized bispecific monoclonal antibody that bridges activated factor IX (FIXa) and factor X (FX) to mimic the function of factor VIII (FVIII). It suppresses the bleeding tendency in hemophilia A patients with or without FVIII inhibitors. A case of an adult FVIII inhibitor-positive hemophilia A patient in whom treatment with emicizumab was discontinued owing to the repeated bleeding events and prolonged activated partial thromboplastin time.

OBJECTIVE

To analyze the mechanisms of decreased efficacy of emicizumab.

METHODS

Residual plasma samples were used to measure the following: emicizumab concentration in plasma, measured by enzyme-linked immunosorbent assay; titer of anti-drug antibody (ADA) against emicizumab, measured by electrochemiluminescence; and neutralizing activity against emicizumab, measured by Bethesda method modified by using emicizumab-spiked FVIII-deficient plasma.

RESULTS

At week 31, emicizumab concentration was 15.0 μg/ml, and ADAs were measured as positive. Emicizumab concentration continued to decrease until emicizumab discontinuation point at week 49, and after week 50, emicizumab concentrations were below the limitation of quantification. The ADA titer increased transiently from week 31, even past the emicizumab discontinuation point at week 49. The ADA titer then gradually decreased until the last sampling point at week 93. Neutralizing activity against emicizumab was detected after emicizumab discontinuation. Epitope analysis showed that the ADAs recognize the anti-FIXa and anti-FX Fab arms of emicizumab, but not the Fc region.

CONCLUSION

The appearance of ADAs with emicizumab-neutralizing activity and potential to accelerate emicizumab clearance decreased the efficacy of emicizumab.

Estimating the risk of thrombotic events in people with congenital hemophilia A using US claims data

Aim: Compare thrombotic risk in people with congenital hemophilia A (PwcHA) to the general non-hemophilia A (HA) population. Patients & methods: US claims databases were analyzed to identify PwcHA. Incidence rates of myocardial infarction, pulmonary embolism, ischemic stroke, deep vein thrombosis and device-related thrombosis were compared with a matched cohort without HA. Results: Over 3490 PwcHA were identified and 16,380 individuals matched. PwcHA had a similar incidence of myocardial infarction and pulmonary embolism compared with the non-HA population, but a slightly higher incidence of ischemic stroke and deep vein thrombosis. The incidence of device-related thrombosis was significantly higher in PwcHA. Conclusion: This analysis suggests that PwcHA are not protected against thrombosis, and provides context to evaluate thrombotic risk of HA treatments.

Low immunogenicity of emicizumab in persons with haemophilia A

INTRODUCTION

Emicizumab is a humanised, bispecific monoclonal antibody mimicking the cofactor function of activated factor (F)VIII. It is indicated for routine prophylaxis of bleeding episodes in persons with haemophilia A (PwHA) with/without FVIII inhibitors.

AIM

To evaluate the development of anti-emicizumab antibodies and their impact on pharmacokinetics (PK), pharmacodynamics (PD), efficacy and safety in PwHA.

METHODS

Data from seven completed or ongoing phase 3 studies were pooled. The assessment of the immunogenicity profile of emicizumab included anti-drug antibody (ADA) measurement and the association of ADAs with PK, PD, bleeding events, and adverse events.

RESULTS

Of 668 PwHA evaluable for immunogenicity analysis, 34 (5.1%) developed ADAs after exposure to emicizumab. ADAs were transient in 14/34 PwHA (41.2%). ADAs were neutralising in vitro in 18/34 PwHA (52.9%) and associated with decreased emicizumab concentration in 4/668 evaluable PwHA (.6%); of those, one (.1%) discontinued emicizumab due to loss of efficacy. ADAs without decreased exposure did not impact emicizumab efficacy. The proportion of PwHA who had injection-site reactions (ISRs) was higher in ADA-positive PwHA (29.4% vs. 20.8%); however, the safety profile was similar between ADA-positive and ADA-negative PwHA, overall. No cases of anaphylaxis or hypersensitivity were reported in ADA-positive participants.

CONCLUSION

The immunogenicity risk of emicizumab in phase 3 studies was low. ADAs, including in vitro neutralising ADAs, were not associated with a change in safety profile. Routine surveillance is, therefore, not warranted; however, in cases where a loss and/or waning of efficacy are observed, prompt evaluation by a healthcare provider should be sought.

Increased endoglin levels correlated with angiogenesis-associated angiopoietin-2 in haemophilia patients

INTRODUCTION

Haemophilia is a bleeding disorder that occurs due to the deficiency of coagulation factors, and the angiogenesis process is an important process underlying the pathophysiology of haemophilic arthropathy. The role of the new adipocytokine endoglin (ENG) in patients with haemophilia is not yet known.

AIM

The aim of this study is to evaluate the association between ENG protein and angiogenesis-related cytokines in patients with haemophilia for the first time.

METHODS

Plasma protein levels and mRNA expressions of ENG and various angiogenesis-associated cytokines were compared in blood samples collected from 28 patients with haemophilia A or B and 29 healthy volunteers. The relationship between the cytokines and ENG were determined by correlation analysis.

RESULTS

Plasma ENG levels and angiogenic markers were found to be significantly higher in patients with haemophilia compared to controls. Real-time PCR studies showed that mRNA expressions of ENG, vascular endothelial growth factor A, hypoxia-inducible factor A, and prostaglandin E2 increased in patients with haemophilia. Correlation analysis showed a significant positive correlation between ENG and angiopoietin-2 levels in the haemophilia group. Besides, a significant decrease in annexin-V binding to platelets in haemophilia patients compared to control was found to be related to the bleeding profiles in the patients.

CONCLUSIONS

This study determined that ENG protein may be involved in the formation of angiogenesis in haemophilia patients and its effects may be related to angiogenetic marker angiopoietin-2 in this process. Our findings contribute to the literature during the determination of target proteins in haemophilia treatment.

Design of an international investigator-initiated study on MOdern Treatment of Inhibitor-positiVe pATiEnts with haemophilia A (MOTIVATE)

Background:

Inhibitor development is the most serious treatment-related complication of replacement coagulation factor VIII (FVIII) therapy for patients with haemophilia A. Immune tolerance induction (ITI), which involves intensive and prolonged treatment with plasma-derived or recombinant FVIII, is the only clinically proven strategy for eradication of inhibitors. The bispecific antibody emicizumab is approved for use in patients with and without inhibitors to prevent bleeding but does not eliminate inhibitors. MOTIVATE (www.motivate-study.com) aims to capture different approaches to the treatment and management of patients with haemophilia A and inhibitors, document current ITI approaches from real-world clinical experience, and evaluate the efficacy and safety of ITI, emicizumab prophylaxis and ITI with emicizumab prophylaxis.

Methods:

The investigator-initiated MOTIVATE study [ClinicalTrials.gov identifier: NCT04023019; EudraCT 2019-003427-38] will investigate in real-life clinical practice the management of patients with haemophilia A of any severity who have developed inhibitors to FVIII. All treatment is at the investigator’s discretion. The following treatment approaches will be evaluated: Group 1 – ITI with Nuwiq^®, octanate^® or wilate^® and aPCC/rFVIIa if needed to treat bleeding episodes (BEs) or during surgery or for prophylaxis; Group 2 – ITI with Nuwiq^®, octanate^® or wilate^® and emicizumab prophylaxis and aPCC/rFVIIa if needed to treat BEs or during surgery; Group 3 – routine prophylaxis with emicizumab, aPCC or rFVIIa without ITI and aPCC/rFVIIa if needed to treat BEs or during surgery. Patients will not be randomised to a treatment group and may change groups during the study.

Conclusions:

It is planned to enrol 120 patients who will be followed for up to 5 years. Optional sub-studies will explore factors that may influence ITI results as well as the impact of different treatment approaches on important aspects of patient health, including joint and bone health and the risk of thrombotic events.

Pharmacokinetic, efficacy and safety evaluation of B-domain-deleted recombinant FVIII (SCT800) for prophylactic treatment in adolescent and adult patients with severe haemophilia A

INTRODUCTION

SCT800 is a recombinant human B-domain-deleted coagulation factor VIII (BDDrFVIII) developed in China.

AIM

To evaluate the repeat pharmacokinetics (PKs), efficacy, and safety of SCT800 in previously treated Chinese adolescent and adult patients with severe haemophilia A.

METHODS

A phase III, multicentre, prospective, open-label, single-arm trial was conducted at 12 medical centres. Subjects received treatment for 24 weeks. PKs were assessed at the initial and repeated dosing 24 weeks later. The primary endpoint was annualized bleeding rate (ABR). Breakthrough bleeding episodes and inhibitor development were assessed.

RESULTS

A total of 71 of 73 patients completed the study, and 18 were enrolled for the repeat PK investigation. Total exposure was 5643 exposure days. Overall, SCT800 showed comparable repeat PK profiles. The total ABR was 2.82 (95% confidence interval 2.01-3.96). During prophylaxis, 43.8% of patients had no bleeding episodes. The majority (89.4%) of bleeding episodes were controlled with 1-2 injections of SCT800, the success rate (defined as 'excellent' or 'good' haemostatic response) for the treatment of bleeding episodes was 92.6%. The incidence of treatment-related adverse events was 53.4%. Drug-related AE incidence was 4.1%. The observed AEs were similar to those of other coagulation factor VIII, but lower in frequency. No subject developed an inhibitor, and no other safety concerns were identified.

CONCLUSIONS

SCT800 has robust PK characteristics, and is safe and efficacious for the prophylaxis and treatment of bleeding episodes in previously treated adolescent and adult patients with severe haemophilia A.

Effects of Shear Stress on Production of FVIII and vWF in a Cell-Based Therapeutic for Hemophilia A

Microfluidic technology enables recapitulation of organ-level physiology to answer pertinent questions regarding biological systems that otherwise would remain unanswered. We have previously reported on the development of a novel product consisting of human placental cells (PLC) engineered to overexpress a therapeutic factor VIII (FVIII) transgene, mcoET3 (PLC-mcoET3), to treat Hemophilia A (HA). Here, microfluidic devices were manufactured to model the physiological shear stress in liver sinusoids, where infused PLC-mcoET3 are thought to lodge after administration, to help us predict the therapeutic outcome of this novel biological strategy. In addition to the therapeutic transgene, PLC-mcoET3 also constitutively produce endogenous FVIII and von Willebrand factor (vWF), which plays a critical role in FVIII function, immunogenicity, stability, and clearance. While vWF is known to respond to flow by changing conformation, whether and how shear stress affects the production and secretion of vWF and FVIII has not been explored. We demonstrated that exposure of PLC-mcoET3 to physiological levels of shear stress present within the liver sinusoids significantly reduced mRNA levels and secreted FVIII and vWF when compared to static conditions. In contrast, mRNA for the vector-encoded mcoET3 was unaltered by flow. To determine the mechanism responsible for the observed decrease in FVIII and vWF mRNA, PCR arrays were performed to evaluate expression of genes involved in shear mechanosensing pathways. We found that flow conditions led to a significant increase in KLF2, which induces miRNAs that negatively regulate expression of FVIII and vWF, providing a mechanistic explanation for the reduced expression of these proteins in PLC under conditions of flow. In conclusion, microfluidic technology allowed us to unmask novel pathways by which endogenous FVIII and vWF are affected by shear stress, while demonstrating that expression of the therapeutic mcoET3 gene will be maintained in the gene-modified PLCs upon transplantation, irrespective of whether they engraft within sites that expose them to conditions of shear stress.

Emicizumab prophylaxis in haemophilia patients older than 50 years with cardiovascular risk factors: Real-world data

INTRODUCTION

Emicizumab (Hemlibra™) is approved for prophylaxis of Haemophilia A (HA) patients with and without inhibitors. However, real-world data on emicizumab use in the elderly HA patients with concomitant cardiovascular risk factors are lacking.

AIM

To evaluate the safety and efficacy of emicizumab in a real-world cohort of elderly HA patients.

METHODS

A prospective longitudinal observational study on HA patients over 50 years old treated, followed and monitored during emicizumab prophylaxis was conducted. We documented any bleeding or adverse events and collected plasma samples for emicizumab levels, aPTT and thrombin generation (TG).

RESULTS

Seventeen HA patients (2 with inhibitor), whose median age was 62.4 years (range: 51.5-77.1) composed the cohort, including 9/17 with multiple cardiovascular risk factors (high risk group). Seven patients had chronic HIV infection. The median follow-up of our cohort was 400 days (range 89-805, IQR 211-479 days). The median annualized bleeding rate (ABR) significantly decreased for all patients. Among patients who displayed significant bleeding tendencies, emicizumab steady state levels as well as TG were lower as compared with the group. The ABR of four patients concomitantly treated by antiplatelet agents was significantly higher compared with the rest of the cohort. Neither thrombosis nor thrombotic microangiopathy (TMA) was encountered.

CONCLUSIONS

Emicizumab prophylaxis for HA patients older than 50 years including those with cardiovascular risk factors was well tolerated. As lower emicizumab and TG levels were observed among bleeding patients, we suggest that monitoring laboratory assays could be of value within this age group.

Mortality in congenital hemophilia A - a systematic literature review

Against a background of a rapidly evolving treatment landscape, a contemporary, evidence-based consolidated understanding of mortality in people with congenital hemophilia A (PwcHA) is lacking. This systematic literature review examines the available data on mortality and causes of death in PwcHA to enable a better understanding of fatalities in PwcHA and evaluate the impact of new treatment paradigms on mortality. A systematic literature review of observational studies was conducted by searching Medline, Embase, and clinical trials registries for articles published from January 2010 to March 2020, using the search terms: hemophilia A (HA), mortality, cause of death. Interventional studies, studies not reporting fatalities, and those reporting only on hemophilia B, acquired HA, or mixed other coagulopathies were excluded. Overall, 7818 unique records were identified and 17 were analyzed. Of these, six reported mortality rates and five reported mortality ratios. Mortality generally decreased over time, despite a spike associated with human immunodeficiency virus (HIV)/hepatitis C virus (HCV) infection in the 1980s and 1990s. Mortality was strongly correlated with age and hemophilia severity. People with hemophilia had a raised mortality risk compared with the general population, particularly in severe hemophilia, and when infected with HIV or HCV. Causes of death varied across populations, countries, and time in 15 identified studies; however, incomplete and heterogeneous reporting limits evidence. Hemorrhage, HIV, HCV, and hepatic disease were the leading causes of death. A unified approach to reporting mortality and cause of death is needed to understand mortality in PwcHA as treatments continue to advance.

Incidence of inhibitor development in PUPs with severe Haemophilia A in the CEE region between 2005 and 2015

INTRODUCTION

This study analyses real-world data on 144 previously untreated patients (PUPs) with severe Haemophilia A, from seven countries in Central and Eastern Europe (CEE: Bulgaria, Croatia, Czech Republic, Hungary, Latvia, Serbia, and Slovenia), over a period of 11 years. It analyses the risk factors associated with development of inhibitors to factor VIII concentrates.

METHODS

Cox proportional hazard models were used to estimate the hazard risk of factors possibly influencing the development of inhibitors. Patients were followed for up to 100 exposure days (EDs).

RESULTS

Cumulative inhibitor incidence at the time of 100 EDs was 18.7%, slightly lower than the 25-35% incidence reported in most studies. Of PUPs who developed inhibitors, a majority (56%) developed them within the first 20 EDs and 88% by the 50th ED. FVIII class (recombinant or plasma-derived) did not influence the inhibitors' incidence rate (p = 0.64). We found a significant protective effect of prophylaxis compared to on-demand treatment (p = 0.003). PUPs who had an intensive peak treatment during the first 50 EDs were at significantly higher risk for inhibitor development (HR (95% CI) 5.3 (2.3-12.5), p < 0.001).

CONCLUSION

Inhibitors are and will continue to be the most significant complication of haemophilia treatment with factor concentrates. This is particularly true for haemophilia A. In our cohort, we were able to show that the treatment regimen used during first 50EDs influenced significantly the inhibitor risk, but the class of the factor concentrate did not play an important role. Real world data will remain one of the important resources for improving our knowledge of haemophilia.

Cost-effectiveness of emicizumab vs bypassing agents in the prevention of bleeding episodes in haemophilia A patients with anti-FVIII inhibitors in France

INTRODUCTION

The development of an anti-FVIII inhibitor is the most serious complication of haemophilia A occurring in up to 30% of severe haemophilic patients. The current management of haemophilia A with inhibitor uses bypassing agents (BPA) and represents a significant therapeutic burden together with a limited adherence to prophylactic treatment. Emicizumab is the first monoclonal antibody developed in haemophilia A approved for the prevention of bleeding episodes in patients with anti-FVIII inhibitor.

AIM

The purpose of this study is to evaluate the incremental cost-effectiveness ratio (ICER) of emicizumab versus BPAs.

METHODS

A Markov model was developed over a five-year time horizon to estimate the comparative costs and benefits of the different therapeutic approaches in this rare disease. Model inputs were clinical, including annual bleeding rate and quality of life, and economical including mainly costs of prophylaxis, bleeds and adverse events.

RESULTS

Emicizumab treatment is dominant, ie lest costly and more effective, in the base-case analysis saving 234 191 € for a gain of 0.88 QALY. This is confirmed by both the deterministic and probabilistic sensitivity analyses. The main limit of the study remains the absence of long-term clinical data allowing to relate treatment consumption to clinical benefit, especially in the progression of haemophilic arthropathy.

CONCLUSION

Our results show that emicizumab is a cost-effective treatment allowing to consider an easy to implement prophylactic treatment for haemophilia A patients with anti-FVIII inhibitors.

Factors Involved in the Development of Inhibitory Antibodies in Patients with Hemophilia in Colombia: A Case-Control Study

Background:

The appearance of inhibitory antibodies against antihemophilic factors is one of the most serious complications related to hemophilia.

Objective:

The objective of this study was to identify variables and factors related to the development of inhibitory antibodies in a group of patients undergoing antihemophilic therapy in Colombia.

Methods:

A case-control study in patients with hemophilia treated in Specialized Healthcare Provider Institutions (IPS-E) in 21 cities of Colombia of any age and with a diagnosis of inhibitory antibodies against factor VIII or IX during 2016. Four controls per case paired by age and type of hemophilia were used. Sociodemographic, clinical, and pharmacological variables were identified and analyzed.

Results:

Seventeen patients with inhibitory antibodies and 68 controls with hemophilia were identified. The mean age was 28.3 ± 17.8 years. A total of 94.1% had hemophilia A, and 88.2% of the cases and 50.0% of the controls had severe hemophilia; 47.1% of the cases and 54.4% of the controls were receiving prophylaxis with coagulation factors. Multivariate analysis showed that having severe hemophilia (OR:17.0, 95%CI:1.32–219.60) and lack of knowledge of the coagulation factor with which the patient was treated before entering the care program in the IPS-E (OR:8.9, 95%CI:1.82–43.75) were significantly associated with a higher probability of developing inhibitory antibodies.

Conclusion and relevance:

Coagulation factors associated with the development of inhibitory antibodies were severe hemophilia and lack of knowledge of the type of factor used prior to entering the follow-up cohort.

Life expectancy and cause of death in individuals with haemophilia A and B in Norway, 1986-2018

OBJECTIVES

Evaluate trends over time in age- and cause of death in males with haemophilia (PWH) in Norway compared with the general male population and investigate its correlates with improvements in haemophilia treatment.

METHODS

Data about age and cause of death in the period of 1986-2018, from two independent, high-quality national registries: the Norwegian Cause of Death Registry (NCoDR) and the patient registry at Centre for Rare Disorders (CRD), Oslo University Hospital.

RESULTS

Life expectancy increased significantly from 1986 to 2018. However, PWH still had a decreased mean age at death of 56.8 years (SD = 24.7) in the NCoDR and 58.6 years (SD = 21.7) in the CRD data, compared with 73.9 years (SD = 16.3) in the general male population. There was a distinct shift in the most frequently reported haemophilia-related causes of death, such as haemorrhage and AIDS, to more age-related causes of death, such as cancer, reflecting an ageing population.

CONCLUSION

Haemophilia treatment has improved significantly in the last three decades. Despite treatment-related improvements, PWH in Norway still have a decreased life expectancy compared with the general male population.

Bridging the Missing Link with Emicizumab: A Bispecific Antibody for Treatment of Hemophilia A

Hemophilia A, characterized by absent or ineffective coagulation factor VIII (FVIII), is a serious bleeding disorder that entails severe and potentially life-threatening bleeding events. Current standard therapy still involves replacement of FVIII, but is often complicated by the occurrence of neutralizing alloantibodies (inhibitors). Management of patients with inhibitors is challenging and necessitates immune tolerance induction for inhibitor eradication and the use of bypassing agents (activated prothrombin complex concentrates or recombinant activated factor VII), which are expensive and not always effective. Emicizumab is the first humanized bispecific monoclonal therapeutic antibody designed to replace the hemostatic function of activated FVIII by bridging activated factor IX and factor X (FX) to activate FX and allow the coagulation cascade to continue. In the majority of hemophilic patients with and without inhibitors, emicizumab reduced the annualized bleeding rate to almost zero in several clinical trials and demonstrated a good safety profile. However, the concurrent use of emicizumab and activated prothrombin complex concentrate imposes a high risk of thrombotic microangiopathy and thromboembolic events on patients and should be avoided. Yet, the management of breakthrough bleeds and surgery remains challenging with only limited evidence-based recommendations being available. This review summarizes published clinical trials and preliminary reports of emicizumab and discusses the clinical implications of emicizumab in treatment of hemophilia A.

Is the Detection of Factor IX Inhibitors in Hemophilia B Orphan than Factor VIII Inhibitors in Hemophilia A? A Concise, Systematic Review

OBJECTIVE

Development of inhibitors in hemophilia A and B comprise significant challenge for patients, hematologists, and health provider systems. It has recommended by the World Federation of Hemophilia (WFH) to check inhibitors every 3-4 months. The incidence of inhibitor in hemophilia B is lower than hemophilia A. Here, it tried to unravel whether the detection of inhibitors in hemophilia B neglected compared to hemophilia A or not?

METHODS

A comprehensive review carried out using six international and local medical search engines on published contributions about inhibitors in hemophilia A and B in Iran.

RESULTS

From 699 titles, 12 relevant papers were selected. The mean of factor VIII inhibitors in hemophilia A was 14.8%. The mean of factor IX inhibitors in hemophilia B was 6%. The minimum and maximum reported percentages of factor VIII inhibitors were 4% and 19.6%, while the minimum and maximum of reported percentages of factor IX inhibitors were 0% and 11.8%, respectively. The inhibitors in hemophilia A had reported in 6 papers. One paper had covered the inhibitors in hemophilia B. There were five papers on inhibitors in both hemophilia A and B. The comparison between the reported patients showed that 3020 patients with hemophilia A and 314 patients with hemophilia B had studied.

CONCLUSION

Consistent with the lower frequency of hemophilia B and the lower development of inhibitors in hemophilia B compared to hemophilia A, it was concluded that hemophilia B had not neglected in Iran. It seems to be rational that each country, check rates of detection of inhibitors in hemophilia B to identify whether it has neglected or not.

Evaluation of the Pharmacokinetics, Pharmacodynamics, and Safety of a Single Dose of Emicizumab in Healthy Chinese Subjects

This phase 1, open‐label, single‐center study evaluated the pharmacokinetics (PK), pharmacodynamics, safety, and tolerability of single‐dose emicizumab in healthy Chinese males. Overall, 16 subjects received a single subcutaneous dose of 1‐mg/kg emicizumab. Blood samples were obtained before dosing on day 1 and at regular intervals over 16 weeks after dosing for PK evaluation. A single 1‐mg/kg subcutaneous dose of emicizumab was safe and well tolerated in healthy Chinese male subjects in the study. Mean (± standard deviation) area under the concentration‐time curve from time 0 to infinity and maximum concentration were 287 ± 74.2 μg⋅d/mL and 7.11 ± 1.77 μg/mL, respectively, with a terminal half‐life of 26.7 (±4.3) days. Emicizumab administration did not show significant impact on pharmacodynamic markers tested, which mostly remained stable throughout the study. One subject tested positive for antidrug antibody, with no impact on his PK or safety profile. Compared with results from healthy Japanese and Caucasian subjects receiving the same dose in previous clinical trials, the current results further indicated the absence of difference of emicizumab PK profile across Chinese, Japanese, and Caucasian subjects, validating the use of similar therapeutic doses in Asian and non‐Asian populations.

Real-world analysis of haemophilia patients in China: A single centre's experience

INTRODUCTION

The management of haemophilia is critical to minimize the risk of disability and reduce the burden on China's healthcare system.

AIM

This study was based on a single centre in China and was conducted to understand the evolution of real-world haemophilia care over the past 15 years.

METHODS

We retrospectively analysed clinical characteristics, diagnosis, treatment and medical expenditures of 428 patients with haemophilia from January 2004 to December 2018 from the Institute of Hematology & Blood Diseases Hospital in Tianjin, China.

RESULTS

The delayed diagnosis time significantly decreased from 13.3 ± 5.1 years before 2004 to 0.4 ± 0.4 year in 2014-2018 (P < .05). Among children and adults receiving prophylactic treatment, the annual factor consumption increased from 2004-2008 (168.8 IU/kg in children and 120.7 IU/kg in adults) to 2009-2013 (389.2 IU/kg in children and 316.2 IU/kg in adults) and 2014-2018 (1328.0 IU/kg in children and 878.8 IU/kg in adults, P < .001). The annual medical insurance expenditure for haemophilia had increased steadily over the past 10 years. The number of patients tested regularly for inhibitors increased from 2004 (1.9% [2/105]) to 2018 (21.5% [59/275]). The seroprevalence of hepatitis C virus (HCV) was 33.8% during the years examined, while the incidence rates of HCV among patients significantly decreased (7.3% in 2008 to 0.4% in 2018).

CONCLUSION

Significant improvements in the management of haemophilia were observed from 2004 to 2018. These results highlight the joint effort of the reimbursement policy and drug regulatory management paving the way for a better future for patients with haemophilia in China.

Social support and resilience in persons with severe haemophilia: An interpretative phenomenological analysis

Introduction

Haemophilia is a hereditary haemorrhagic disorder characterized by deficiency or dysfunction of coagulation factors. Recurrent joint and muscle bleeds lead to progressive musculoskeletal damage. Haemophilia affects patients physically but also socially and psychologically. Traumatic experiences, chronic stress and illnesses can lead to mental disorders, but many persons with haemophilia maintain a highly positive outlook.

Aim

To explore qualitatively which coping mechanisms persons with haemophilia use and in what way they help them to live with their diagnosis.

Methods

We recruited five adults with haemophilia and conducted semi‐structured face‐to‐face interviews. Transcripts were analysed using interpretative phenomenological analysis (IPA).

Results

Two core themes emerged from the analysis: social support as an external factor and resilience as an internal factor of coping with the disease. Persons with haemophilia usually need help with health‐related complications, and this affects the social support they require. Their wider support network tends to involve family and friends but also healthcare professionals and other specialists. This network provides practical help but also functions as an important psychological protective factor. An unexpected finding was that persons with haemophilia want not only to receive support but are also keen to offer support to others.

Conclusion

These findings can help identify persons who provide most support to people suffering from haemophilia. Haemophilic centres should include in their teams psychologists and social workers and offer individual and group therapy to their clients, group meetings for friends and families of persons with haemophilia, provide learning resources to teachers aiming to incorporate children with haemophilia in their peer group, and organize Balint groups for physicians, psychologists and other healthcare professionals.

Recombinant factor VIII Fc fusion protein for the treatment of severe haemophilia A: Final results from the ASPIRE extension study

Introduction

The efficacy and safety of recombinant factor VIII Fc fusion protein (rFVIIIFc) as an extended half‐life treatment for severe haemophilia A were demonstrated in the Phase 3 A‐LONG and Kids A‐LONG studies. Eligible subjects who completed A‐LONG and Kids A‐LONG could enrol in ASPIRE (NCT01454739), an open‐label extension study.

Aim

To report the long‐term safety and efficacy of rFVIIIFc in subjects with severe haemophilia A who enrolled in ASPIRE.

Methods

Previously treated subjects received one or more of the following regimens: individualized prophylaxis (IP), weekly prophylaxis, modified prophylaxis or episodic treatment. Subjects could switch treatment regimen at any time. The primary endpoint was inhibitor development.

Results

A total of 150 subjects from A‐LONG and 61 subjects from Kids A‐LONG enrolled in ASPIRE. Most subjects received the IP regimen (A‐LONG: n = 110; Kids A‐LONG: n = 59). Median (range) treatment duration in ASPIRE for subjects from A‐LONG and Kids A‐LONG was 3.9 (0.1‐5.3) years and 3.2 (0.3‐3.9) years, respectively. No inhibitors were observed (0 per 1000 subject‐years; 95% confidence interval, 0‐5.2) and the overall rFVIIIFc safety profile was consistent with prior studies. For subjects on the IP regimen, annualized bleed rates (ABR) remained low (median overall ABR for adults and adolescents was <1.0) and extended‐dosing intervals were maintained (median of 3.5 days) for the majority of subjects in ASPIRE.

Conclusion

ASPIRE results, which include up to 5 years of follow‐up data, confirm earlier reports on the consistent and well‐characterized safety and efficacy of rFVIIIFc treatment for severe haemophilia A.