Hemophilia gene therapy: first, do no harm.

The introduction of adeno-associated virus-mediated, liver-directed gene therapy into the hemophilia treatment landscape brings not only great promise but also considerable uncertainty to a community that has a history punctuated by the devastating effects of HIV and hepatitis C virus. These infections were introduced into people with hemophilia through the innovation of factor concentrates in the 1970s and 1980s. Concentrates, heralded as a major advance in treatment at the time, brought devastation and death to the community already challenged by the complications of bleeding into joints, vital organs, and the brain. Over the past 5 decades, considerable advances in hemophilia treatment have improved the survival, quality of life, and participation of people with hemophilia, although challenges remain and health equity with their unaffected peers has not yet been achieved. The decision to take a gene therapy product is one in which an informed, holistic, and shared decision-making approach must be employed. Bias on the part of health care professionals and people with hemophilia must be addressed and minimized. Here, we review data leading to the regulatory authorization of valoctocogene roxaparvovec, an adeno-associated virus 5 gene therapy, in Europe to treat hemophilia A and etranacogene dezaparvovec-drlb in the United States and Europe to treat hemophilia B. We also provide an overview of the decision-making process and recommend steps that should be taken by the hemophilia community to ensure the safety of and optimal outcomes for people with hemophilia who choose to receive a gene therapy product.

Management and outcomes of mild hemophiliacs and hemophilia carriers during pregnancy and peripartum period: a hemophilia treatment center experience in the United States.

BACKGROUND: Pregnancy, peripartum management, and outcomes of mild hemophiliacs and hemophilia carriers in the United States are not well established. AIM: To describe the management and outcomes of mild hemophiliacs and hemophilia carriers during assisted conception, pregnancy, peripartum and post-partum period at our hemophilia treatment center (HTC). METHODS: Retrospective review of electronic medical records of pregnant women with mild hemophilia A or B (Factor VIII [FVIII] or Factor IX [FIX] level <0.4 IU/mL) and hemophilia A and B carriers followed at our HTC from January 2008 to October 2020. Demographics, the reason for diagnosis, FVIII and FIX levels at baseline and third trimester, bleeding phenotype and genotype were obtained. Method of conception, factor replacement, iron supplementation, mode of delivery, type of anesthesia, peripartum complications, and offspring outcomes was recorded. RESULTS: There was a total of 18 pregnancies in 12 women (2 with mild hemophilia A, 2 mild hemophilia B, 6 hemophilia A carriers, and 2 hemophilia B carriers). Eleven pregnancies (61%) were conceived naturally and 7 (39%) via in-vitro fertilization (IVF). Eight (44.4%) and 10 (55.6%) pregnancies were vaginal and C-section deliveries, respectively. Neuraxial anesthesia was administered in 17 (94.4%) deliveries without complications. Four pregnancies (22.2%) had bleeding complications, 2 of which were post-partum hemorrhages not requiring transfusion. CONCLUSION: In our case series of pregnant hemophilia carriers and mild hemophiliacs, successful outcomes were achieved with a carefully detailed multidisciplinary-driven approach.

[Educational needs of parents of hemophiliac children: An approach to comprehensive care]. / Necesidades educativas de padres de niños hemofílicos: Una aproximación hacia el cuidado integral.

INTRODUCTION: In Chile, hemophilia was incorporated into the System of Explicit Health Guarantees (GES), which ensures access to treatment and financial protection for these patients. To support patients and their families, educational programs have been proposed that focus on managing possible complications of the pathology, first aid, and prophylaxis, however, there are no educational instances focused on the needs of the patients. OBJECTIVE: To know the educational needs of parents with hemophilic chil dren and adolescents regarding contents, people, place, methodology, and stage of the illness. Sub jects and Method: Descriptive qualitative study of 15 parents with hemophilic children in outpatient care. For the data collection, we used a semi-structured interview with five open questions, aimed at the search for educational needs such as what (contents), how (methodology), when (moment), who (person), and where (place) is education needed. For data analysis, were used the Berelson's content analysis technique. To guarantee the scientific validity of the qualitative results, the methodological rigor criteria of Guba and Lincoln were used. RESULTS: The most frequent educational needs reported by parents include content such as venipuncture training, injury prevention, pathophysiological as pects of the disease, among others; with methodology developed in group workshops and guided by a peer; in a comfortable and familiar place; in three stages of the disease's development (diagnosis, blee ding events, and development of autonomous activities), and provided by professionals and peers. CONCLUSION: Knowledge of educational needs is the basis for the creation of an educational program that guides the comprehensive care of hemophilic children and their parents.

Gene therapy for hemophilia B using CB 2679d-GT: a novel factor IX variant with higher potency than factor IX Padua.

Sustained expression of therapeutic factor IX (FIX) levels has been achieved after adeno-associated viral (AAV) vector-based gene therapy in patients with hemophilia B. Nevertheless, patients are still at risk of vector dose-limiting toxicity, particularly liver inflammation, justifying the need for more efficient vectors and a lower dosing regimen. A novel increased potency FIX (designated as CB 2679d-GT), containing 3 amino acid substitutions (R318Y, R338E, T343R), significantly outperformed the R338L-Padua variant after gene therapy. CB 2679d-GT demonstrated a statistically significant approximately threefold improvement in clotting activity when compared with R338L-Padua after AAV-based gene therapy in hemophilic mice. Moreover, CB 2679d-GT gene therapy showed significantly reduced bleeding time (approximately fivefold to eightfold) and total blood loss volume (approximately fourfold) compared with mice treated with the R338L-Padua, thus achieving more rapid and robust hemostatic correction. FIX expression was sustained for at least 20 weeks with both CB 2679d-GT and R338L-Padua whereas immunogenicity was not significantly increased. This is a novel gene therapy study demonstrating the superiority of CB 2679d-GT, highlighting its potential to obtain higher FIX activity levels and superior hemostatic efficacy following AAV-directed gene therapy in hemophilia B patients than what is currently achievable with the R338L-Padua variant.

The changing treatment landscape in haemophilia: from standard half-life clotting factor concentrates to gene editing.

Congenital haemophilia A (factor VIII deficiency) and B (factor IX deficiency) are X-linked bleeding disorders. Replacement therapy has been the cornerstone of the management of haemophilia, aiming to reduce the mortality and morbidity of chronic crippling arthropathy. Frequent intravenous injections are burdensome and costly for patients, consequently with poor adherence and restricted access to therapy for many patients worldwide. Bioengineered clotting factors with enhanced pharmacokinetic profiles can reduce the burden of treatment. However, replacement therapy is associated with a risk for inhibitor development that adversely affects bleeding prevention and outcomes. Novel molecules that are subcutaneously delivered provide effective prophylaxis in the presence or absence of inhibitors, either substituting for the procoagulant function of clotting factors (eg, emicizumab) or targeting the natural inhibitors of coagulation (ie, antithrombin, tissue factor pathway inhibitor, or activated protein C). The ultimate goal of haemophilia treatment would be a phenotypical cure achievable with gene therapy, currently under late phase clinical investigation.

Manual therapy in the treatment of patients with hemophilia B and inhibitor.

BACKGROUND: The main clinical manifestations of hemophilia are muscle and joint bleeding. Recurrent bleeding leads to a degenerative process known as hemophilic arthropathy. The development of inhibitors (antibodies against FVIII/FIX concentrates) is the main complication in the treatment of hemophilia. The objective was to assess the safety and efficacy of manual therapy treatment in a patient with hemophilia and inhibitor. CASE PRESENTATION: A 26-year-old patient with hemophilia B and inhibitor received physiotherapy treatment based on manual therapy for 3 months, with a frequency of 2 sessions per week. The joint status was evaluated using the Hemophilia Joint Health Score; pain was assessed with the Visual Analog Scale; and the range of movement was evaluated using a universal goniometer. The patient developed no joint bleeding in the knees or ankles as a result of the physiotherapy treatment. Following treatment, improvements were noted in the range of movement of knees and ankles, the perception of pain in both knees, and ankle functionality. CONCLUSIONS: Until now, manual therapy using joint traction was contraindicated in patients with hemophilia and inhibitor, as it was feared to cause possible joint bleeding. This is the first case study to address the safety and efficacy of manual therapy in a patient with hemophilia and an inhibitor. The results of this study may help to establish which manual therapy treatments are indicated in patients with hemophilic arthropathy and inhibitors. Thus, a physiotherapy program based on manual therapy may be safe in patients with hemophilia and inhibitor and such therapy may improve joint condition, pain, and joint range of motion in patients with hemophilia and inhibitor. Randomized clinical trials are needed to confirm the results of this case study.

Systemic delivery of factor IX messenger RNA for protein replacement therapy.

Safe and efficient delivery of messenger RNAs for protein replacement therapies offers great promise but remains challenging. In this report, we demonstrate systemic, in vivo, nonviral mRNA delivery through lipid nanoparticles (LNPs) to treat a Factor IX (FIX)-deficient mouse model of hemophilia B. Delivery of human FIX (hFIX) mRNA encapsulated in our LUNAR LNPs results in a rapid pulse of FIX protein (within 4-6 h) that remains stable for up to 4-6 d and is therapeutically effective, like the recombinant human factor IX protein (rhFIX) that is the current standard of care. Extensive cytokine and liver enzyme profiling showed that repeated administration of the mRNA-LUNAR complex does not cause any adverse innate or adaptive immune responses in immune-competent, hemophilic mice. The levels of hFIX protein that were produced also remained consistent during repeated administrations. These results suggest that delivery of long mRNAs is a viable therapeutic alternative for many clotting disorders and for other hepatic diseases where recombinant proteins may be unaffordable or unsuitable.

Current view and outcome of ITI therapy - A change over time?

INTRODUCTION: Inhibitor development in people with haemophilia is a serious complication that may require intensive and costly interventions. The goal of inhibitor management should be permanent inhibitor eradication through immune tolerance induction (ITI), but well-designed studies are lacking and the management of patients is therefore defined by the experience and views of the clinician. OBJECTIVES: To explore the current clinical practice and outcome of ITI therapy in Europe and how this may have changed over the last decade, as well as to provide consensus recommendations to guide clinicians in their clinical practice. METHODS: A survey was conducted among 16 European haemophilia comprehensive care centres to evaluate current ITI treatment regimens and success rates in severe and mild/moderate haemophilia A and haemophilia B. In addition, an updated literature review was performed as guidance for providing recommendations. RESULTS: We demonstrated successful inhibitor treatment in 86% of severe haemophilia A patients with low responding (LR) and 59% of patients with high responding (HR) inhibitors. Some new trends in the management of patients with inhibitors were identified, including a tendency to use low-dose regimens (<50IU/kg/d) in both children and adults with HR inhibitors possibly based on similar success rates demonstrated in the I-ITI study compared to a high-dose protocol. Data on ITI therapy in mild and moderate haemophilia as well as haemophilia B were limited. CONCLUSIONS: The outcome of ITI therapy seems to be stable over time, and treatment regimens remain heterogeneous. The use of low dose regimens however is considered more frequently.

The evolution of comprehensive haemophilia care in the United States: perspectives from the frontline.

The establishment of dedicated comprehensive treatment centres more than a half century ago transformed the management of haemophilia in the United States. Formerly, a disease associated with crippling disability and premature death, today, persons with haemophilia who are treated appropriately from infancy and do not develop inhibitors can expect a normal life expectancy and relatively few bleeding episodes. The evolution of the comprehensive haemophilia care, while chastened by the viral epidemics of the 1980s, has been marked by ongoing advances, including prophylaxis, immune tolerance induction, new drugs and gene therapy research. Current challenges include sustaining the comprehensive care model despite decreased funding and expanding the delivery and affordability of comprehensive haemophilia care.

Entering new areas in known fields: recombinant fusion protein linking recombinant factor VIIa with recombinant albumin (rVIIa-FP) - advancing the journey.

The novel fusion protein linking recombinant factor VIIa with recombinant albumin (rVIIa-FP) is designed to extend the half-life of recombinant factor VIIa (rFVIIa) and improve the care of hemophilia A or B patients with inhibitors. Preclinical studies in various animal models have demonstrated markedly improved pharmacokinetic and pharmacodynamic properties, as well as prolonged retention in the joint tissues, of rVIIa-FP compared with a commercially available rFVIIa (NovoSeven®). A phase I study in healthy volunteers - the first study in the PROLONG-7FP program - confirmed that rVIIa-FP has a good tolerability profile in doses of up to 1,000µg/kg and has demonstrated enhanced pharmacodynamic activity relative to rFVIIa. The half-life of rVIIa-FP at the highest dose investigated in the study was 8.5hours, which represents a 3- to 4-fold half-life extension compared with rFVIIa. Encouraging results from preclinical and phase I studies have led to the initiation of clinical studies of rVIIa-FP in patients with congenital hemophilia A or B and inhibitors, and in patients with confirmed factor VII deficiency. The results from these studies are awaited with interest by clinicians and patients alike.

Current and future prospects for hemophilia gene therapy.

Here we review the recent literature on Hemophilia gene transfer/therapy. Gene therapy is one of several new technologies being developed as a treatment for bleeding disorders. We will discuss current and pending clinical efforts and attempt to relate how the field is trending. In doing so, we will focus on the use of recombinant Adeno-associated viral (rAAV) vector-mediated gene transfer since all currently active trials are using this vector. Recent exciting results embody nearly 20 years of preclinical and translational research. After several early clinical attempts, therapeutic factor levels that can now be achieved reflect several modifications of the original vectors. Patterns of results are slowly starting to emerge as different AAV vectors are being tested. As with any new technology, there are drawbacks, and the potential for immune/inflammatory and oncogenic risks have emerged and will be discussed.

Costs and utilization of treatment in patients with hemophilia.

BACKGROUND: Although hemophilia has a potentially high economic impact, there are no published estimates of healthcare costs for this disease in Portugal. The aim of this study was to evaluate costs of treatment and hospital utilization among patients with hemophilia A and B, with and without inhibitors, over a 3-year period in a Portuguese Comprehensive Care Hemophilia Centre. This is the first study on the financial impact of healthcare costs in patients with hemophilia in Portugal. METHODS: This retrospective, observational study identified patients diagnosed with hemophilia A and B using medical and pharmacy electronic medical records and data from Centro Hospitalar São João, between January 2011 and December 2013. Patients with inhibitors were all high responders (>5 Bethesda Units [BU]). Severity was classified as mild, moderate or severe based on clotting factor levels. Two main outcomes were measured: (1) cost associated with hospital pharmacy claims (clotting factor) and (2) number of hospital visits/hospitalization. RESULTS: A cohort of 103 patients were identified: 72 (69.9 %) with hemophilia A and 31 (30.1 %) with hemophilia B. Among these, five individuals were classified as patients with inhibitors (four with hemophilia A and one with hemophilia B). From the cohort of hemophilia A patients, 36 individuals (35.0 %) were identified as having severe disease; 20 (19.4 %) moderate; and 16 (15.5 %) mild. In the cohort of hemophilia B patients, 14 (13.6 %) were identified as having severe disease; 14 (13.6 %) moderate; and three (2.9 %) mild. The total mean aggregate cost per year (including clotting factor and hospital utilization) for patients with severe hemophilia B was €112,469, compared with €793 for mild hemophilia A. Clotting factor concentrate amounted for 90 % of total cost in severe cases and hospital utilization was also higher in these cases. CONCLUSIONS: Hemophilia treatment is expensive, particularly for patients with severe disease and especially if they develop inhibitors to replacement clotting factors. In our study, severe hemophilia is associated with greater annual total costs in both types of hemophilia (A = €77,587 and B = € 112,469). Patients with inhibitors have costs 3.3 times higher than patients without inhibitors. Age was not associated with significantly greater total costs (clotting factor and hospital visits/hospitalizations).

Plant-based oral tolerance to hemophilia therapy employs a complex immune regulatory response including LAP+CD4+ T cells.

Coagulation factor replacement therapy for the X-linked bleeding disorder hemophilia is severely complicated by antibody ("inhibitor") formation. We previously found that oral delivery to hemophilic mice of cholera toxin B subunit-coagulation factor fusion proteins expressed in chloroplasts of transgenic plants suppressed inhibitor formation directed against factors VIII and IX and anaphylaxis against factor IX (FIX). This observation and the relatively high concentration of antigen in the chloroplasts prompted us to evaluate the underlying tolerance mechanisms. The combination of oral delivery of bioencapsulated FIX and intravenous replacement therapy induced a complex, interleukin-10 (IL-10)-dependent, antigen-specific systemic immune suppression of pathogenic antibody formation (immunoglobulin [Ig] 1/inhibitors, IgE) in hemophilia B mice. Tolerance induction was also successful in preimmune mice but required prolonged oral delivery once replacement therapy was resumed. Orally delivered antigen, initially targeted to epithelial cells, was taken up by dendritic cells throughout the small intestine and additionally by F4/80(+) cells in the duodenum. Consistent with the immunomodulatory responses, frequencies of tolerogenic CD103(+) and plasmacytoid dendritic cells were increased. Ultimately, latency-associated peptide expressing CD4(+) regulatory T cells (CD4(+)CD25(-)LAP(+) cells with upregulated IL-10 and transforming growth factor-ß (TGF-ß) expression) as well as conventional CD4(+)CD25(+) regulatory T cells systemically suppressed anti-FIX responses.

Employing a gain-of-function factor IX variant R338L to advance the efficacy and safety of hemophilia B human gene therapy: preclinical evaluation supporting an ongoing adeno-associated virus clinical trial.

Vector capsid dose-dependent inflammation of transduced liver has limited the ability of adeno-associated virus (AAV) factor IX (FIX) gene therapy vectors to reliably convert severe to mild hemophilia B in human clinical trials. These trials also identified the need to understand AAV neutralizing antibodies and empty AAV capsids regarding their impact on clinical success. To address these safety concerns, we have used a scalable manufacturing process to produce GMP-grade AAV8 expressing the FIXR338L gain-of-function variant with minimal (<10%) empty capsid and have performed comprehensive dose-response, biodistribution, and safety evaluations in clinically relevant hemophilia models. The scAAV8.FIXR338L vector produced greater than 6-fold increased FIX specific activity compared with wild-type FIX and demonstrated linear dose responses from doses that produced 2-500% FIX activity, associated with dose-dependent hemostasis in a tail transection bleeding challenge. More importantly, using a bleeding model that closely mimics the clinical morbidity of hemophilic arthropathy, mice that received the scAAV8.FIXR338L vector developed minimal histopathological findings of synovitis after hemarthrosis, when compared with mice that received identical doses of wild-type FIX vector. Hemostatically normal mice (n=20) and hemophilic mice (n=88) developed no FIX antibodies after peripheral intravenous vector delivery. No CD8(+) T cell liver infiltrates were observed, despite the marked tropism of scAAV8.FIXR338L for the liver in a comprehensive biodistribution evaluation (n=60 animals). With respect to the role of empty capsids, we demonstrated that in vivo FIXR338L expression was not influenced by the presence of empty AAV particles, either in the presence or absence of various titers of AAV8-neutralizing antibodies. Necropsy of FIX(-/-) mice 8-10 months after vector delivery revealed no microvascular or macrovascular thrombosis in mice expressing FIXR338L (plasma FIX activity, 100-500%). These preclinical studies demonstrate a safety:efficacy profile supporting an ongoing phase 1/2 human clinical trial of the scAAV8.FIXR338L vector (designated BAX335).

Effectiveness of an educational intervention of physiotherapy in parents of children with haemophilia.

Haemophilia is a haematological disorder with an orthopaedic outcome. It requires not only medical but rather comprehensive care from infancy. The aim of this study was to assess the effectiveness of an educational intervention of Physiotherapy in parents of children with haemophilia under 4 years old. This is a non-randomized clinical trial, in which 22 parents participated children's with haemophilia under 4 years old. Half of them received an educational intervention of Physiotherapy. At the beginning and end of the study, a psychologist blinded to the assignment of subjects to each of the study groups, assessed the perceived quality of life, anxiety, perceived stress and family functioning of parents. A significant improvement was observed in the variables of perceived stress and family functioning of parents in the experimental group. The realization of an educational intervention in parents of children with haemophilia under 4 years old is effective. It reduces the stressors perceived by the parents and improves family cohesion and adaptability, as a consequence of the disease. It is necessary to carry out studies with follow-up periods to assess the effectiveness of educational programs of Physiotherapy for long term.

Structure-activity relationship of the pro- and anticoagulant effects of Fucus vesiculosus fucoidan.

Fucoidan is a highly complex sulfated polysaccharide commonly extracted from brown seaweed. In addition to their many biological activities, fucoidans have recently been demonstrated to inhibit or increase coagulation at different concentration ranges. Their structural features, i.e. molecular weight (Mw), Mw distribution, degree of sulfation, monosaccharide composition, and different linkages, are known to affect these activities. Therefore, structure-activity relationship (SAR) analysis of fucoidan is crucial for its potential use as a procoagulant. In this study, Fucus vesiculosus (F.v.) fucoidan was fractionated by charge and size as well as over- and desulfated to different degrees to yield preparations with various structural properties. The fractions' pro- and anticoagulant activities were assessed by calibrated automated thrombography (CAT) and activated partial thromboplastin time(aPTT) assays. Binding to and inhibition of the anticoagulant protein tissue factor pathway inhibitor (TFPI) and the ability to activate coagulation via the contact pathway were also investigated. This paper discusses the impact of charge density, size, and sugar composition on fucoidan's pro- and anticoagulant activities. Fucoidan requires a minimal charge density of 0.5 sulfates per sugar unit and a size of 70 sugar units to demonstrate desired procoagulant activities for improvement of haemostasis in factor VIII/factor IX-deficient plasma.

Animal models of hemophilia and related bleeding disorders.

Animal models of hemophilia and related diseases are important for the development of novel treatments and to understand the pathophysiology of bleeding disorders in humans. Testing in animals with the equivalent human disorder provides informed estimates of doses and measures of efficacy, which aids in design of human trials. Many models of hemophilia A, hemophilia B, and von Willebrand disease (VWD) have been developed from animals with spontaneous mutations (hemophilia A dogs, rats, sheep; hemophilia B dogs; and VWD pigs and dogs), or by targeted gene disruption in mice to create hemophilia A, B, or VWD models. Animal models have been used to generate new insights into the pathophysiology of each bleeding disorder and also to perform preclinical assessments of standard protein replacement therapies, as well as novel gene transfer technology. The differences both between species and in underlying causative mutations must be considered in choosing the best animal for a specific scientific study.