Modern haemophilia care

Oral Delivery of Protein Drugs Bioencapsulated in Plant Cells

Plants cells are now approved by the FDA for cost-effective production of protein drugs (PDs) in large-scale current Good Manufacturing Practice (cGMP) hydroponic growth facilities. In lyophilized plant cells, PDs are stable at ambient temperature for several years, maintaining their folding and efficacy. Upon oral delivery, PDs bioencapsulated in plant cells are protected in the stomach from acids and enzymes but are subsequently released into the gut lumen by microbes that digest the plant cell wall. The large mucosal area of the human intestine offers an ideal system for oral drug delivery. When tags (receptor-binding proteins or cell-penetrating peptides) are fused to PDs, they efficiently cross the intestinal epithelium and are delivered to the circulatory or immune system. Unique tags to deliver PDs to human immune or nonimmune cells have been developed recently. After crossing the epithelium, ubiquitous proteases cleave off tags at engineered sites. PDs are also delivered to the brain or retina by crossing the blood–brain or retinal barriers. This review highlights recent advances in PD delivery to treat Alzheimer's disease, diabetes, hypertension, Gaucher's or ocular diseases, as well as the development of affordable drugs by eliminating prohibitively expensive purification, cold chain and sterile delivery.

Registry-based outcome assessment in haemophilia: a scoping study to explore the available evidence

Haemophilia is a congenital disorder with bleeding episodes as its primary symptom. These episodes can result in negative outcomes including joint damage, loss of active days due to hospitalization and reduced quality of life. Effective treatment, however, can improve the outcome. Registries have been used as a valuable source of information regarding the monitoring of treatment and outcome. The two main aims of this exploratory study were to establish which haemophilia registries publish peer-reviewed outcome assessment research and then to extract, classify and report the treatment outcomes and their extent of use in the retrieved registries. Using relevant keywords, we searched PubMed and Web of Science databases for publications during the period 1990-2015. Retrieved references were screened in a stepwise process. Eligible papers were original full articles on haemophilia outcomes that used data from a computerized patient database. Descriptive results were summarized. Of 2352 references reviewed, 25 full texts were eligible for inclusion in the study. These papers were published by 11 registries ranging from local to international in coverage. It is still relatively rare for registries to produce peer-reviewed publications about outcomes, and most that currently do produce such papers are located in Europe and North America. More information is available on traditional outcomes such as comorbidities and arthropathy than on health-related quality of life or the social and developmental impact of haemophilia on patients. Inhibitors, HIV and viral hepatitis are amongst the most commonly reported comorbidities. Research has focused more on factor consumption and less on hospitalization or time lost at school or work due to haemophilia. Haemophilia registries, especially those at the national level, are valuable resources for the delivery of effective health care to patients. Validated outcome measurement instruments are essential for the production of reliable and accurate evidence. Finally, such evidence should be communicated to physicians, patients, the public and health policymakers.

Gene therapy returns to centre stage

Recent clinical trials of gene therapy have shown remarkable therapeutic benefits and an excellent safety record. They provide evidence for the long-sought promise of gene therapy to deliver 'cures' for some otherwise terminal or severely disabling conditions. Behind these advances lie improved vector designs that enable the safe delivery of therapeutic genes to specific cells. Technologies for editing genes and correcting inherited mutations, the engagement of stem cells to regenerate tissues and the effective exploitation of powerful immune responses to fight cancer are also contributing to the revitalization of gene therapy.

Social/economic costs and quality of life in patients with haemophilia in Europe

OBJECTIVE

The aim of this study was to determine the economic burden from a societal perspective and the health-related quality of life (HRQOL) of patients with haemophilia in Europe.

METHODS

We conducted a cross-sectional study of patients with haemophilia from Bulgaria, France, Germany, Hungary, Italy, Spain Sweden and the UK. Data on demographic characteristics, health resource utilisation, informal care, loss of labour productivity and HRQOL were collected from the questionnaires completed by patients or their caregivers. HRQOL was measured with the EuroQol 5-domain (EQ-5D) questionnaire. The costs have been estimated from a societal perspective adopting a bottom-up approach.

RESULTS

A total of 401 questionnaires were included in the study, of which 339 were collected from patients with haemophilia and 62 from caregivers. The lowest average annual cost per person was reported in Bulgaria (€6,660) and the highest in Germany (€194,490). Our results demonstrate both a large difference from country to country in the average annual cost per patient in 2012 and the driving role of drugs in costs. Drugs represent nearly 90 % of direct healthcare costs in a majority of the countries analysed (Hungary, Italy, Spain and Germany). In Bulgaria, France and Sweden, however, healthcare services (visits, tests and hospitalisations) prevail. Costs are also shown to differ between children and adults. The mean EQ-5D index score for adult patients was 0.69 and mean EQ-5D VAS was 66.6. The mean EQ-5D index score for carers was 0.87 and mean EQ-5D VAS was 75.5. In the disability score, 60 % showed no disability and measuring caregiver burden with the Zarit Index produced an overall mean score of 25.3.

CONCLUSION

We have shown that haemophilia is associated with a substantial economic burden and impaired HRQOL. Studies on cost of illness and HRQOL are important for haemophilia as the future of this disease is likely to change with the development of new innovative treatments. The introduction of these treatments will most likely impact future costs related to haemophilia.

Malignancies in Swedish persons with haemophilia: a longitudinal registry study

The aim of the study was to investigate, over time, the incidence of and mortality due to malignant diseases among persons with haemophilia, compared to matched controls. Persons with haemophilia A or B were enrolled via registries at each haemophilia centre, as well as from the National Patient Registry, and were compared to five sex and age-matched controls per patient. Data from the national Cancer Registry were linked to the study participants. A total of 1431 persons with haemophilia and 7150 matched controls were enrolled. Between the years 1972 and 2008, 164 malignancies were reported. The most common type of cancer among patients was prostate cancer, followed by haematologic malignancies, including lymphoma and leukaemia, which were significantly more frequent in patients [n = 35 (2.4%) vs. n = 60 (0.8%); P < 0.001]. Malignancies in bladder and other urinary organs were also significantly different [n = 21 (1.5%) vs. n = 46 (0.6%); P < 0.01]. The overall incidence rate ratio of malignancies per 1000 person-years compared to the controls was 1.3 [95% confidence interval (CI) 1.1, 1.6]. In subgroup analysis, the corresponding incidence rate ratios per 1000 person-years for persons with severe haemophilia was 1.7 (95% CI 0.9, 3.1) and that for mild/moderate haemophilia 1.1 (95% CI 0.8, 1.5). Swedish persons with haemophilia had a significantly higher incidence of malignant diseases than controls. These were primarily haematologic malignancies and cancer in urinary organs, and the difference independent of any co-infections with HIV and/or viral hepatitis. The findings indicate the importance of further studies and close follow-up of malignancies in persons with haemophilia.

Megakaryocyte- and megakaryocyte precursor-related gene therapies

Hematopoietic stem cells (HSCs) can be safely collected from the body, genetically modified, and re-infused into a patient with the goal to express the transgene product for an individual's lifetime. Hematologic defects that can be corrected with an allogeneic bone marrow transplant can theoretically also be treated with gene replacement therapy. Because some genetic disorders affect distinct cell lineages, researchers are utilizing HSC gene transfer techniques using lineage-specific endogenous gene promoters to confine transgene expression to individual cell types (eg, ITGA2B for inherited platelet defects). HSCs appear to be an ideal target for platelet gene therapy because they can differentiate into megakaryocytes which are capable of forming several thousand anucleate platelets that circulate within blood vessels to establish hemostasis by repairing vascular injury. Platelets play an essential role in other biological processes (immune response, angiogenesis) as well as diseased states (atherosclerosis, cancer, thrombosis). Thus, recent advances in genetic manipulation of megakaryocytes could lead to new and improved therapies for treating a variety of disorders. In summary, genetic manipulation of megakaryocytes has progressed to the point where clinically relevant strategies are being developed for human trials for genetic disorders affecting platelets. Nevertheless, challenges still need to be overcome to perfect this field; therefore, strategies to increase the safety and benefit of megakaryocyte gene therapy will be discussed.

Liver-directed lentiviral gene therapy in a dog model of hemophilia B

We investigated the efficacy of liver-directed gene therapy using lentiviral vectors in a large animal model of hemophilia B and evaluated the risk of insertional mutagenesis in tumor-prone mouse models. We showed that gene therapy using lentiviral vectors targeting the expression of a canine factor IX transgene in hepatocytes was well tolerated and provided a stable long-term production of coagulation factor IX in dogs with hemophilia B. By exploiting three different mouse models designed to amplify the consequences of insertional mutagenesis, we showed that no genotoxicity was detected with these lentiviral vectors. Our findings suggest that lentiviral vectors may be an attractive candidate for gene therapy targeted to the liver and may be potentially useful for the treatment of hemophilia.

Vascular remodeling underlies rebleeding in hemophilic arthropathy

Hemophilic arthropathy is a debilitating condition that can develop as a consequence of frequent joint bleeding despite adequate clotting factor replacement. The mechanisms leading to repeated spontaneous bleeding are unknown. We investigated synovial, vascular, stromal, and cartilage changes in response to a single induced hemarthrosis in the FVIII-deficient mouse. We found soft-tissue hyperproliferation with marked induction of neoangiogenesis and evolving abnormal vascular architecture. While soft-tissue changes were rapidly reversible, abnormal vascularity persisted for months and, surprisingly, was also seen in uninjured joints. Vascular changes in FVIII-deficient mice involved pronounced remodeling with expression of α-Smooth Muscle Actin (SMA), Endoglin (CD105), and vascular endothelial growth factor, as well as alterations of joint perfusion as determined by in vivo imaging. Vascular architecture changes and pronounced expression of α-SMA appeared unique to hemophilia, as these were not found in joint tissue obtained from mouse models of rheumatoid arthritis and osteoarthritis and from patients with the same conditions. Evidence that vascular changes in hemophilia were significantly associated with bleeding and joint deterioration was obtained prospectively by dynamic in vivo imaging with musculoskeletal ultrasound and power Doppler of 156 joints (elbows, knees, and ankles) in a cohort of 26 patients with hemophilia at baseline and during painful episodes. These observations support the hypothesis that vascular remodeling contributes significantly to bleed propagation and development of hemophilic arthropathy. Based on these findings, the development of molecular targets for angiogenesis inhibition may be considered in this disease.

Low cost industrial production of coagulation factor IX bioencapsulated in lettuce cells for oral tolerance induction in hemophilia B

Antibodies (inhibitors) developed by hemophilia B patients against coagulation factor IX (FIX) are challenging to eliminate because of anaphylaxis or nephrotic syndrome after continued infusion. To address this urgent unmet medical need, FIX fused with a transmucosal carrier (CTB) was produced in a commercial lettuce (Simpson Elite) cultivar using species specific chloroplast vectors regulated by endogenous psbA sequences. CTB-FIX (∼1 mg/g) in lyophilized cells was stable with proper folding, disulfide bonds and pentamer assembly when stored ∼2 years at ambient temperature. Feeding lettuce cells to hemophilia B mice delivered CTB-FIX efficiently to the gut immune system, induced LAP(+) regulatory T cells and suppressed inhibitor/IgE formation and anaphylaxis against FIX. Lyophilized cells enabled 10-fold dose escalation studies and successful induction of oral tolerance was observed in all tested doses. Induction of tolerance in such a broad dose range should enable oral delivery to patients of different age groups and diverse genetic background. Using Fraunhofer cGMP hydroponic system, ∼870 kg fresh or 43.5 kg dry weight can be harvested per 1000 ft(2) per annum yielding 24,000-36,000 doses for 20-kg pediatric patients, enabling first commercial development of an oral drug, addressing prohibitively expensive purification, cold storage/transportation and short shelf life of current protein drugs.

Advances and challenges in hemophilic arthropathy

Hemophilic arthropathy is a form of joint disease that develops secondary to joint bleeding and presents with synovial hypertrophy, cartilage and bony destruction. The arthropathy can develop despite clotting factor replacement and is especially disabling in the aging population. Pathobiological tissue changes are triggered by release of hemoglobin and iron deposition in the joint, but the sequence of events and the molecular mechanisms resulting in joint deterioration are incompletely understood. Treatment options other than clotting factor replacement are limited. Improvements in the treatment of hemophilia necessitate a better understanding of the processes that lead to this disabling condition and better diagnostic tools. Towards that end, studies of the molecular mechanisms leading to the arthropathy, as well as the development of sensitive imaging techniques and biomarkers are needed. These will pave the way to identify the cause of acute pain such as joint bleeding or synovitis, detect early, potentially reversible structural changes, and predict progression of disease. This review describes current imaging techniques and the development of high resolution musculoskeletal ultrasound with power Doppler to afford point-of-care diagnosis and management, the potential utility of diagnostic biomarkers, and summarizes our current knowledge of the pathobiology of hemophilic arthropathy.

Improved coagulation and haemostasis in haemophilia with inhibitors by combinations of superFactor Va and Factor VIIa

Bypassing inhibitors in haemophilia patients is limited to activated (a) Factor(F)VII products. We introduced "FVa activity augmentation" as another bypassing strategy and studied effects of an engineered FVa variant designated superFVa. Procoagulant and clot stabilising properties of superFVa and recombinant human (rh)FVIIa, either alone or in combination, were studied in thrombin generation and clot lysis assays in normal human plasma (NHP) with or without anti-FVIII inhibitors, in haemophilia plasma, and in FVIII-deficient mice or in wild-type mice with anti-FVIII inhibitors. SuperFVa was as effective as rhFVIIa to improve thrombin generation or clot lysis. Furthermore, procoagulant effects were significantly enhanced when these compounds were combined. RhFVIIa at 40 nM (a therapeutic concentration) improved thrombin generation mildly, but markedly improved thrombin generation when combined with a low concentration (e. g. 3 nM) of superFVa. In clot lysis studies, the concentration of rhFVIIa to normalise clot lysis times could be reduced by 100-fold (e. g. from 40 nM to 0.4 nM) when combined with a low concentration (0.37 nM) of superFVa. In haemostasis studies of FVIII-deficient mice, blood loss was dose-dependently reduced by either superFVa or rhFVIIa. SuperFVa (200 U/kg) corrected mean blood loss indistinguishably from rhFVIII. Blood loss correction by rhFVIIa was greatly improved when combined with superFVa. Similar blood loss correction results were observed for therapies in wild-type mice after infusion with anti-FVIII inhibitors. Thus, superFVa may be an effective procoagulant agent in the setting of haemophilia with inhibitors and it merits further evaluation for new bypassing strategies.

Hemophilic arthropathy of the elbow: prophylaxis, imaging, and the role of invasive management

Hemophilia is an X-linked recessive deficiency of clotting factor VIII (hemophilia A) or IX (hemophilia B) that can result in hemarthrosis of various joints, including the elbow. Left unchecked, this can lead to progressive joint destruction and significant morbidity. Appropriate management of the elbow joint through prophylactic measures, accurate imaging, and timely intervention is essential. Replacing or supplementing deficient factor with a plasma-derived or recombinant factor concentrate can minimize bleeding episodes. Joints should be routinely monitored for damage. Plain films offer an inexpensive window into bone disease and joint space changes but lack soft tissue detail and may not detect early changes. Magnetic resonance imaging provides a high level of detail but may be limited by its cost and need for sedation in younger patients. Ultrasound may not achieve the same level of resolution as magnetic resonance imaging, but it is increasingly used as a convenient, effective, and relatively inexpensive alternative. Patients who experience hemarthrosis of the elbow with joint damage often require more invasive treatment. Radiosynovectomy and arthroscopic synovectomy are effective at minimizing pain and preventing future bleeding episodes, whereas extensive joint damage may necessitate total elbow replacement.

Inflammatory focal bone destruction in femoral heads with end-stage haemophilic arthropathy: a study on clinic samples with micro-CT and histological analyses

INTRODUCTION

Focal bone destruction has a high prevalence in haemophilic arthropathy (HA) affected joints, but the mechanism remains unclear.

AIM

We undertook this study on clinic samples to explore the focal bone destruction in femoral heads suffered with end-stage HA.

METHODS

Twenty-one femoral heads from HA patients and 19 femoral heads from rheumatoid arthritis (RA) patients were scanned by micro-CT. Histological analysis, including TRAP staining of subchondral bone were performed to evaluate the bone destruction and osteoclasts activity. RANKL, OPG as well as pro-inflammatory cytokines, such as TNF-α and IL-1β in subchondral bone were detected by immunohistochemistry (IHC) method.

RESULTS

Severe focal lesion was observed in all the HA and RA femoral heads by micro-CT imaging and histological analysis. The mean percentage of lesion volume to total volume of the femoral heads from HA patients was significantly higher than those from RA patients. There was no significant difference in osteoclasts numbers in subchondral bone between HA and RA groups. By IHC analysis, high expression of RANKL, TNF-α, IL-1β and low expression of OPG and RANK were observed in subchondral bone, and there were no significant differences in the expression of RANKL, OPG, RANK, TNF-α and IL-1β in femoral heads derived from HA and RA patients.

CONCLUSION

Our findings demonstrated the focal bone destruction coupled with inflammatory osteoclastogenesis at subchondral bone in femoral heads from patients with end-stage HA, and that was similar to the changes in the femoral heads of RA patients.

Classification and regression tree analysis vs. multivariable linear and logistic regression methods as statistical tools for studying haemophilia

INTRODUCTION

Haemophilia is a rare genetic haemorrhagic disease characterized by partial or complete deficiency of coagulation factor VIII, for haemophilia A, or IX, for haemophilia B. As in any other medical research domain, the field of haemophilia research is increasingly concerned with finding factors associated with binary or continuous outcomes through multivariable models. Traditional models include multiple logistic regressions, for binary outcomes, and multiple linear regressions for continuous outcomes. Yet these regression models are at times difficult to implement, especially for non-statisticians, and can be difficult to interpret.

AIMS

The present paper sought to didactically explain how, why, and when to use classification and regression tree (CART) analysis for haemophilia research.

MATERIALS & METHODS

The CART method is non-parametric and non-linear, based on the repeated partitioning of a sample into subgroups based on a certain criterion. Breiman developed this method in 1984. Classification trees (CTs) are used to analyse categorical outcomes and regression trees (RTs) to analyse continuous ones.

RESULTS

The CART methodology has become increasingly popular in the medical field, yet only a few examples of studies using this methodology specifically in haemophilia have to date been published. Two examples using CART analysis and previously published in this field are didactically explained in details.

CONCLUSION

There is increasing interest in using CART analysis in the health domain, primarily due to its ease of implementation, use, and interpretation, thus facilitating medical decision-making. This method should be promoted for analysing continuous or categorical outcomes in haemophilia, when applicable.

FcRn Rescues Recombinant Factor VIII Fc Fusion Protein from a VWF Independent FVIII Clearance Pathway in Mouse Hepatocytes

We recently developed a longer lasting recombinant factor VIII-Fc fusion protein, rFVIIIFc, to extend the half-life of replacement FVIII for the treatment of people with hemophilia A. In order to elucidate the biological mechanism for the elongated half-life of rFVIIIFc at a cellular level we delineated the roles of VWF and the tissue-specific expression of the neonatal Fc receptor (FcRn) in the biodistribution, clearance and cycling of rFVIIIFc. We find the tissue biodistribution is similar for rFVIIIFc and rFVIII and that liver is the major clearance organ for both molecules. VWF reduces the clearance and the initial liver uptake of rFVIIIFc. Pharmacokinetic studies in FcRn chimeric mice show that FcRn expressed in somatic cells (hepatocytes or liver sinusoidal endothelial cells) mediates the decreased clearance of rFVIIIFc, but FcRn in hematopoietic cells (Kupffer cells) does not affect clearance. Immunohistochemical studies show that when rFVIII or rFVIIIFc is in dynamic equilibrium binding with VWF, they mostly co localize with VWF in Kupffer cells and macrophages, confirming a major role for liver macrophages in the internalization and clearance of the VWF-FVIII complex. In the absence of VWF a clear difference in cellular localization of VWF-free rFVIII and rFVIIIFc is observed and neither molecule is detected in Kupffer cells. Instead, rFVIII is observed in hepatocytes, indicating that free rFVIII is cleared by hepatocytes, while rFVIIIFc is observed as a diffuse liver sinusoidal staining, suggesting recycling of free-rFVIIIFc out of hepatocytes. These studies reveal two parallel linked clearance pathways, with a dominant pathway in which both rFVIIIFc and rFVIII complexed with VWF are cleared mainly by Kupffer cells without FcRn cycling. In contrast, the free fraction of rFVIII or rFVIIIFc unbound by VWF enters hepatocytes, where FcRn reduces the degradation and clearance of rFVIIIFc relative to rFVIII by cycling rFVIIIFc back to the liver sinusoid and into circulation, enabling the elongated half-life of rFVIIIFc.

Hemostatic agents of broad applicability produced by selective tuning of factor Xa zymogenicity

There is a clinical need to develop safe therapeutic strategies to mitigate bleeding. Previously, we found that a novel zymogen-like factor Xa variant (FXa-I16L) was effective in correcting the coagulation defect in hemophilic mice. Here we expand the mutational framework to tune the FX(a) zymogen-like state. Alteration of FXa zymogenicity yields variants (V17M, I16L, I16M, V17T, V17S, and I16T) with a wide range (≤1000-fold) of reduced function toward physiologic substrates and inhibitors. The extent of zymogen-like character, including resistance to antithrombin III, correlates well with plasma half-life (<2 minutes to >4 hours). Importantly, biologic function, including that of the most zymogen-like variant (FXa-I16T), was greatly enhanced when bound to FVa membranes. This resulted in improvement of clotting times and thrombin generation in hemophilic plasma. The FXa variants were remarkably effective in mouse injury models. In these systems, the data show that the more active the protease, the more difficult it is to overcome the protective mechanism of circulating inhibitors to achieve a therapeutic benefit. Depending on the treatment situation, the more zymogen-like variants (V17S and I16T) were most useful when given before injury whereas variants exhibiting greater activity but shorter half-lives (I16L and I16M) were most effective when administered after injury. This new class of FXa variants provides a useful and flexible platform for selectively bioengineering biologic function and half-life to target different clinical bleeding scenarios.

Biological therapies for inherited diseases: social and bioethical considerations. Hemophilia as an example

INTRODUCTION

In hemophilia, advanced therapies are warranted from a conceptual and methodological standpoint. Current advanced therapy strategies are centered on the use of adeno-associated viral vectors, although problems related to immunogenicity and hepatotoxicity still remain.

AREAS COVERED

Future clinical trials will have to scrupulously observe international bioethical standards in terms of patient selection, particularly children. Patient recruitment rates are likely to remain low due to the stringent exclusion criteria usually imposed on the trial population regarding their hepatic and immunological markers and the presence of viral coinfection; and to the existence of an optimal palliative treatment.

EXPERT OPINION

Accordingly, the results obtained are likely to be of low statistical significance, which could hinder their application to clinical practice. Another important issue is the degree to which society embraces these new emerging therapies. The unfamiliarity of society with these new methods, together with the many unresolved questions about them that remain, may threaten their acceptance not only by society at large but also by health-care professionals, which would limit their translational application to clinical practice.

MALDI imaging of predictive ferritin, fibrinogen and proteases in haemophilic arthropathy

Arthropathy as a result of repeated joint bleeding is a severe complication in patients with haemophilia. In the evaluation of synovial tissue specimens, histology alone is non-specific and there is considerable morphological overlap with other joint diseases. Formalin-fixed paraffin-embedded specimens are available in pathological institutes and can be studied to understand the pathogenesis of haemophilic arthropathy. A powerful technique to identify hundreds of proteins in a tissue section combining proteomics with morphology is imaging mass spectrometry (IMS). We determined whether matrix-assisted laser desorption/ionization (MALDI) IMS can be used to identify and map protein signatures in the synovial tissue of patients with haemophilic arthropathy. MALDI IMS was applied to synovial tissue of six patients with haemophilic arthropathy. We detected several peaks predictive in mass with ferritin light (m/z 1608) and heavy chain (m/z 1345), alpha- (m/z 1071) and beta (m/z 1274) haemoglobin subunits, truncated coagulation factor VIII peptide (m/z 1502, 1176), beta- and gamma fibrinogen peptides (m/z 980, 1032, 1117 and 1683), and annexin A2 (m/z 1111, 1268, 1460, 2164). In addition, the distribution of these proteins in synovial tissue sections was demonstrated. MALDI IMS identified and mapped specific proteins in the synovial membrane of patients with haemophilic arthropathy known to be involved in the pathogenesis of other joint diseases. This technique is a powerful tool to analyse the distribution of proteins in synovial tissue sections.

Managing haemophilia for life: 4th Haemophilia Global Summit

The 4th Haemophilia Global Summit was held in Potsdam, Germany, in September 2013 and brought together an international faculty of haemophilia experts and delegates from multidisciplinary backgrounds. The programme was designed by an independent Scientific Steering Committee of haemophilia experts and explored global perspectives in haemophilia care, discussing practical approaches to the optimal management of haemophilia now and in the future. The topics outlined in this supplement were selected by the Scientific Steering Committee for their relevance and potential to influence haemophilia care globally. In this supplement from the meeting, Jan Astermark reviews current understanding of risk factors for the development of inhibitory antibodies and discusses whether this risk can be modulated and minimized. Factors key to the improvement of joint health in people with haemophilia are explored, with Carlo Martinoli and Víctor Jiménez-Yuste discussing the utility of ultrasound for the early detection of haemophilic arthropathy. Other aspects of care necessary for the prevention and management of joint disease in people with haemophilia are outlined by Thomas Hilberg and Sébastian Lobet, who highlight the therapeutic benefits of physiotherapy and sports therapy. Riitta Lassila and Carlo-Federico Perno describe current knowledge surrounding the risk of transmission of infectious agents via clotting factor concentrates. Finally, different types of extended half-life technology are evaluated by Mike Laffan, with a focus on the practicalities and challenges associated with these products.

Point-of-care musculoskeletal ultrasound is critical for the diagnosis of hemarthroses, inflammation and soft tissue abnormalities in adult patients with painful haemophilic arthropathy

We previously demonstrated in adult patients with haemophilia (PWH) that hemarthrosis is present in only ~1/3rd of acutely painful joints by using point-of-care-musculoskeletal ultrasound (MSKUS). Therefore, other unrecognized tissue abnormalities must contribute to pain. Using high resolution MSKUS, employing grey scale and power Doppler, we sought to retrospectively (i) investigate soft tissue abnormalities in painful haemophilic joints and (ii) to determine to what extent MSKUS findings, functional or radiographic joint scores correlate with biomarkers of inflammation in PWH. Findings were correlated with Hemophilia Joint Health Scores (HJHS), Pettersson scores, high sensitivity C-reactive protein and von Willebrand factor activity and antigen levels. A total of 65 MSKUS examinations for acute and chronic joint pains were performed for 34 adult haemophilia patients, mostly for chronic joint pains (72.3%). The most prominent findings (66.5%) pertained to inflammatory soft tissue changes including synovitis, tendinitis, enthesitis, bursitis and fat pad inflammation. Effusions were present in 55.5% and 46.8% of MSKUS performed for acute and chronic pain, respectively. Of those, 90.0% were bloody during acute and 47.6% during persistent pains. While inflammatory biomarkers correlated well with overall HJHS and total Pettersson scores (P < 0.05), they did not differ between those patients with synovitis and those without. MSKUS is emerging as an important modality to diagnose treatable musculoskeletal abnormalities contributing to pain in haemophilic arthropathy, and therefore seems critical for a personalized approach to haemophilia care. The role of biomarkers in this setting remains less clear and requires further investigation.

Inhibitors in haemophilia: what have we learned from registries? A systematic review

Congenital haemophilia A and B are genetic disorders affecting factor VIII and factor IX production, respectively. Factor replacement is the only effective treatment for these deficiencies, but a patient's immune system can develop inhibitory antibodies which bind and interfere with the function of the replaced factor in a variety of ways. The main treatment goal for patients with inhibitors is to induce immune tolerance to the injected factor. If not successful, a different treatment termed bypass therapy is needed to treat bleeds. The goal of this review is to demonstrate the usefulness of haemophilia registries as information sources to supplement available evidence regarding predictors of inhibitor development and immune tolerance induction (ITI) outcomes. In this systematic review, relevant keywords were used to search online academic databases during February 2014. Inclusion criteria were original publication and data obtained from a haemophilia or ITI registry with a minimum of 30 patients. A data collection form was created to extract information from selected manuscripts. Titles, abstracts and then full texts were screened to determine the eligibility of reports for this review. Eleven manuscripts from nine registries were determined eligible and included in the study. Registries have reported on some core variables, but are inconsistent in reporting less practiced predicting variables. Variables that may affect inhibitor and ITI outcomes were each divided into two categories: patient characteristics (such as age and family history) and treatment-related variables (including exposure days, treatment duration and dose). It is recommended that, in addition to exploratory hypothesis testing, a minimum set of variables should be collected and reported by registries. International collaboration and well-designed prospective registries are of major importance to advance this field in order to determine inhibitor risks and ITI outcomes and facilitate the development of new treatments.

Novel products for haemostasis

The primary major issue in haemophilia treatment remains the development of inhibitors. Recently two novel bypassing products have been developed. First, a humanized bispecific antibody against FIXa and FX, termed hBS23, was produced utilizing these two molecules placed into a spatially appropriate position to mimic FVIIIa, and recently this mimetic activity and the pharmacokinetics of the original antibody were improved by engineering the charge properties of the variable region within the immunoglobulin. Using the new antibody, termed ACE910, a phase 1 study in 64 Japanese and Caucasian healthy adults was performed and data from this trial suggested that the product had medically acceptable safety and tolerability profiles. The other new bypassing agent is named MC710, and consists of a mixture of plasma-derived FVIIa and FX. Preclinical studies using in vitro and in vivo haemophilia B inhibitor monkey models indicated that the haemostatic effects of FVIIa and FX were enhanced by simultaneous administration. Results from phase I and II clinical studies suggested that MC710 had equal or greater pharmacokinetic (PK), pharmacodynamic (PD), efficacy and safety profiles than conventional bypassing agents in the treatment of joint bleeding in haemophilia patients with inhibitors. Another significant current issue in this context is the increased medical cost of conventional treatment due to the higher consumption of concentrates. Biosimilar products may offer advantages in these circumstances and may offer a less expensive alternative. Regulatory issues, however, together with acceptability of biosimilar materials and reimbursement policies as well as supply and demand incentives remain to be considered. Rare bleeding disorders (RBDs) have attracted less attention from the pharmaceutical industry than haemophilia or von Willebrand disease due to the limited number of patients involved. Many cases of this type have been treated, therefore, using fresh frozen plasma (FFP) or prothrombin complex concentrates (PCCs) which carry serious risks of infections, allergic reactions and fluid overload. Several specific plasma-derived or recombinant products including fibrinogen, FVIIa, FXI and FXIII have now become available, however, and a phase III clinical study of recombinant FXIIIa has recently been completed demonstrating safety and efficacy of substances of this nature.

Anti-factor IXa/X bispecific antibody ACE910 prevents joint bleeds in a long-term primate model of acquired hemophilia A

ACE910 is a humanized anti-factor IXa/X bispecific antibody mimicking the function of factor VIII (FVIII). We previously demonstrated in nonhuman primates that a single IV dose of ACE910 exerted hemostatic activity against hemophilic bleeds artificially induced in muscles and subcutis, and that a subcutaneous (SC) dose of ACE910 showed a 3-week half-life and nearly 100% bioavailability, offering support for effective prophylaxis for hemophilia A by user-friendly SC dosing. However, there was no direct evidence that such SC dosing of ACE910 would prevent spontaneous bleeds occurring in daily life. In this study, we newly established a long-term primate model of acquired hemophilia A by multiple IV injections of an anti-primate FVIII neutralizing antibody engineered in mouse-monkey chimeric form to reduce its antigenicity. The monkeys in the control group exhibited various spontaneous bleeding symptoms as well as continuous prolongation of activated partial thromboplastin time; notably, all exhibited joint bleeds, which are a hallmark of hemophilia. Weekly SC doses of ACE910 (initial 3.97 mg/kg followed by 1 mg/kg) significantly prevented these bleeding symptoms; notably, no joint bleeding symptoms were observed. ACE910 is expected to prevent spontaneous bleeds and joint damage in hemophilia A patients even with weekly SC dosing, although appropriate clinical investigation is required.

Recombinant factor VIII products and inhibitor development in previously untreated boys with severe hemophilia A

Six recombinant factor VIII (rFVIII) products have been marketed worldwide. In 2013, the Research of Determinants of Inhibitor Development (RODIN) study group reported an unexpectedly high risk of inhibitor development with a second-generation full-length rFVIII (Product D) in previously untreated patients (PUPs) with severe hemophilia A (HA). In 1994, French public health authorities established a prospective cohort to monitor hemophilia treatment safety. A PUP subgroup was designed to investigate inhibitor risk factors. We analyzed this subcohort in view of the RODIN findings. After excluding 50 patients who participated in the RODIN study, the primary analysis focused on 303 boys with severe HA first treated with a rFVIII product. A clinically significant inhibitor was detected in 114 boys (37.6%). The inhibitor incidence was higher with Product D vs the most widely used rFVIII product (adjusted hazard ratio [aHR], 1.55; 95% confidence interval [CI], 0.97-2.49). Similar results were found for high-titer inhibitors and in 10 sensitivity analyses. No heterogeneity was observed between RODIN and our results. Combined aHRs were 1.58 (95% CI, 1.17-2.14) for all inhibitors and 1.70 (95% CI, 1.15-2.52) for high-titer inhibitors. Our results confirm the higher immunogenicity of Product D vs other rFVIII products in PUPs with severe HA.

Minimizing the Risk of Perioperative Bleeding in a Child with Hemophilia A during Dental Rehabilitation under General Anesthesia: A Case Report

Hemophilia, among other bleeding disorders, raises concerns for dental service providers who routinely use sharp hand and rotary instruments, address highly vascular soft tissue and provide dental extractions. In pediatric dentistry, dealing with fearful or irritable children increases the possibility of trauma and subsequent bleeding risks in hemophilic pediatric dental patients. In the current report, we discuss how anesthetic, pediatric and dental management may contribute to the delivery of safe and complete dental treatment for such children. This report describes the safe performance of dental treatments, including multiple extractions under general anesthesia, in a hemophilic child.

How to cite this article: El Batawi HY. Minimizing the Risk of Perioperative Bleeding in a Child with Hemophilia A during Dental Rehabilitation under General Anesthesia: A Case Report. Int J Clin Pediatr Dent 2013;6(3):217-222.

Suppression of inhibitor formation against FVIII in a murine model of hemophilia A by oral delivery of antigens bioencapsulated in plant cells

Hemophilia A is the X-linked bleeding disorder caused by deficiency of coagulation factor VIII (FVIII). To address serious complications of inhibitory antibody formation in current replacement therapy, we created tobacco transplastomic lines expressing FVIII antigens, heavy chain (HC) and C2, fused with the transmucosal carrier, cholera toxin B subunit. Cholera toxin B-HC and cholera toxin B-C2 fusion proteins expressed up to 80 or 370 µg/g in fresh leaves, assembled into pentameric forms, and bound to GM1 receptors. Protection of FVIII antigen through bioencapsulation in plant cells and oral delivery to the gut immune system was confirmed by immunostaining. Feeding of HC/C2 mixture substantially suppressed T helper cell responses and inhibitor formation against FVIII in mice of 2 different strain backgrounds with hemophilia A. Prolonged oral delivery was required to control inhibitor formation long-term. Substantial reduction of inhibitor titers in preimmune mice demonstrated that the protocol could also reverse inhibitor formation. Gene expression and flow cytometry analyses showed upregulation of immune suppressive cytokines (transforming growth factor β and interleukin 10). Adoptive transfer experiments confirmed an active suppression mechanism and revealed induction of CD4(+)CD25(+) and CD4(+)CD25(-) T cells that potently suppressed anti-FVIII formation. In sum, these data support plant cell-based oral tolerance for suppression of inhibitor formation against FVIII.

On-demand treatment in persons with severe haemophilia

There are two main modes of replacement therapy for haemophilia patients: either to stop bleeding (on-demand) or regular infusions of clotting factor to prevent bleeds (prophylaxis). Fifty yr of clinical experience have provided evidence of the superiority of prophylaxis by showing a reduction in bleeds and development of arthropathy. Prophylaxis has been described extensively in terms of efficacy and health-economic aspects; however, on-demand treatment has received less attention. The aim of this study was to critically review the published literature on PubMed and discuss potential gaps of knowledge in on-demand treatment in persons with severe haemophilia without inhibitors by focusing on two key aspects: how on-demand treatment is provided and what outcome measures have been reported. We identified 134 papers of which 112 were excluded. Of the remaining 22 papers, 16 were comparative studies between prophylaxis and on-demand treatment and six were descriptions of on-demand treatment. The results showed limited reporting on data related to the key aspects of treatment on-demand. Early studies looked at degrees of joint bleeds and different treatment regimens in finding the optimal dose. However, from the late 1980s, there was almost no research into on-demand therapy except efficacy and safety studies of new rFVIII products and studies to prove superiority of prophylaxis over treatment on-demand. The success of on-demand therapy may depend on several factors, for example time to initial dose after a bleed and duration of treatment. Data on these key factors are limited and highlight the necessity of research to optimise replacement therapy.

Platelet-targeted gene therapy with human factor VIII establishes haemostasis in dogs with haemophilia A

It is essential to improve therapies for controlling excessive bleeding in patients with haemorrhagic disorders. As activated blood platelets mediate the primary response to vascular injury, we hypothesize that storage of coagulation Factor VIII within platelets may provide a locally inducible treatment to maintain haemostasis for haemophilia A. Here we show that haematopoietic stem cell gene therapy can prevent the occurrence of severe bleeding episodes in dogs with haemophilia A for at least 2.5 years after transplantation. We employ a clinically relevant strategy based on a lentiviral vector encoding the ITGA2B gene promoter, which drives platelet-specific expression of human FVIII permitting storage and release of FVIII from activated platelets. One animal receives a hybrid molecule of FVIII fused to the von Willebrand Factor propeptide-D2 domain that traffics FVIII more effectively into α-granules. The absence of inhibitory antibodies to platelet-derived FVIII indicates that this approach may have benefit in patients who reject FVIII replacement therapies. Thus, platelet FVIII may provide effective long-term control of bleeding in patients with haemophilia A.

Increased burden on caregivers of having a child with haemophilia complicated by inhibitors

INTRODUCTION

Having a child with a chronic disease often increases the burden in the family with more hospital visits, treatment administration, and increased worries for the ill child. A cross-sectional, international, multi-centre study in caregivers of children <18 years with haemophilia and inhibitor was performed at Haemophilia Treatment Centres in Sweden, UK, and Canada to evaluate caregivers' burden and their health-related quality of life (HRQoL) compared to that of caregivers of children on prophylaxis without inhibitors and caregivers of healthy children.

METHODS

Caregivers of children with haemophilia completed several questionnaires (SF-36, Visual Analogue Scale of Interference (VAS), Caregivers' Burden Scale and Impact on Family Scale (IOF). Caregivers of healthy children completed only the SF-36. In addition, socio-demographic data were collected.

RESULTS

In total, 143 caregivers were included in the study. Comparing the two haemophilia groups with caregivers of healthy children revealed significant differences for all SF-34 domains except 'pain' and 'general health'. In Caregivers' Burden Scale, caregivers of children with inhibitors reported higher impact of haemophilia (P < 0.0001) and higher impact on VAS (P < 0.0001) compared to caregivers of children without inhibitors. In IOF, caregivers of children with inhibitors reported significant negative impact of the disease, except for aspect of coping.

CONCLUSION

Caregivers of children with inhibitors reported higher impact of the disease compared to caregivers of children with no inhibitors. No differences between mothers and fathers in the two groups for SF-36, Caregivers' Burden Scale, VAS and IOF, except for domain pain in SF-36 where mothers reported higher impairments.