Development of inhibitors in hemophilia A: An illustrated review

Cost of hemophilia A in Brazil: a microcosting study

BACKGROUND

Patients with Hemophilia are continually monitored at treatment centers to avoid and control bleeding episodes. This study estimated the direct and indirect costs per patient with hemophilia A in Brazil and evaluated the cost variability across different age groups.

METHODS

A prospective observational research was conducted with retrospective data collection of patients assisted at three referral blood centers in Brazil. Time-driven Activity-based Costing method was used to analyze direct costs, while indirect costs were estimated based on interviews with family and caregivers. Cost per patient was analyzed according to age categories, stratified into 3 groups (0-11;12-18 or older than 19 years old). The non-parametric Mann-Whitney test was used to confirm the differences in costs across groups.

RESULTS

Data from 140 hemophilia A patients were analyzed; 53 were 0-11 years, 29 were 12-18 years, and the remaining were older than 19 years. The median cost per patient per year was R$450,831 (IQR R$219,842; R$785,149; $174,566), being possible to confirm age as a cost driver: older patients had higher costs than younger's (p = 0.001; median cost: 0-11 yrs R$299,320; 12-18 yrs R$521,936; ≥19 yrs R$718,969).

CONCLUSION

This study is innovative in providing cost information for hemophilia A using a microcosting technique. The variation in costs across patient age groups can sustain more accurate health policies driven to increase access to cutting-edge technologies and reduce the burden of the disease.

Prediction of inhibitor development in previously untreated and minimally treated children with severe and moderately severe hemophilia A using a machine-learning network

BACKGROUND

Prediction of inhibitor development in patients with hemophilia A (HA) remains a challenge.

OBJECTIVES

To construct a predictive model for inhibitor development in HA using a network of clinical variables and biomarkers based on the individual similarity network.

METHODS

Previously untreated and minimally treated children with severe/moderately severe HA, participants of the HEMFIL Cohort Study, were followed up until reaching 75 exposure days (EDs) without inhibitor (INH-) or upon inhibitor development (INH+). Clinical data and biological samples were collected before the start of factor (F)VIII replacement (T0). A predictive model (HemfilNET) was built to compare the networks and potential global topological differences between INH- and INH+ at T0, considering the network robustness. For validation, the "leave-one-out" cross-validation technique was employed. Accuracy, precision, recall, and F1-score were used as evaluation metrics for the machine-learning model.

RESULTS

We included 95 children with HA (CHA), of whom 31 (33%) developed inhibitors. The algorithm, featuring 37 variables, identified distinct patterns of networks at T0 for INH+ and INH-. The accuracy of the model was 74.2% for CHA INH+ and 98.4% for INH-. By focusing the analysis on CHA with high-risk F8 mutations for inhibitor development, the accuracy in identifying CHA INH+ increased to 82.1%.

CONCLUSION

Our machine-learning algorithm demonstrated an overall accuracy of 90.5% for predicting inhibitor development in CHA, which further improved when restricting the analysis to CHA with a high-risk F8 genotype. However, our model requires validation in other cohorts. Yet, missing data for some variables hindered more precise predictions.

Expert Opinions on the Management of Hemophilia A in India: The Role of Emicizumab

Hemophilia A (HA) is a genetic disorder of hemostasis associated with a deficiency or reduced activity of clotting factor VIII (FVIII). This disorder remains unacceptably underdiagnosed in India. Early diagnosis and appropriate management of HA can substantially prevent morbidity and mortality. Currently, HA is managed with regular replacement therapy using standard or extended half-life FVIII concentrates or non-factor drug products. The challenges associated with FVIII concentrates include plateauing of drug effect, issues with its administration and adherence to treatment, breakthrough bleeds, and the development of inhibiting antibodies against administered clotting factors. Emicizumab is a bispecific antibody, launched in India in April 2019, for managing patients with HA. To investigate the role of emicizumab in Indian patients with HA, opinions were sought from 13 eminent hematologists and experts from India on the effectiveness of emicizumab in preventing all bleeds, spontaneous bleeds, perioperative bleeds, and intracranial hemorrhage; resolving target joints; and reducing the rate of hospitalizations and fatality associated with HA in children and adults, with or without inhibitors. The benefits of emicizumab over traditional FVIII concentrates include the subcutaneous route of delivery, less frequent dosing, and a lack of inhibitor development, in addition to providing sustained hemostasis without in-depth monitoring. It is a safe and effective management option for all HA patients, especially for patients with certain archetypes, such as those with inhibitors, those with high annualized bleed rates, those living far away from hemophilia care centers, pediatric patients and infants with intravenous access challenges, and those with a history of life-threatening bleeding events.

Recapitulating the immune system of hemophilia A patients with inhibitors using immunodeficient mice

BACKGROUND AND AIM

Treating hemophilia A patients who develop inhibitors remains a clinical challenge. A mouse model of hemophilia A can be used to test the efficacy of strategies for inhibitor suppression, but the differences in the immune systems of mice and humans limit its utility. To address this shortcoming, we established a humanized NOD/SCID-IL2rγnull hemophilia A (hu-NSG-HA) mouse model with a severely deficient mouse immune system presenting a patient's adapted immune cells.

METHODS AND RESULTS

Through intrasplenic injection with patient inhibitor-positive peripheral blood mononuclear cells (PBMCs), utilizing an adeno-associated viral delivery system expressing human BLyS, and regular FVIII challenge, human C19+ B cells were expanded in vivo to secrete anti-FVIII antibodies. Both the inhibitor and the human anti-FVIII IgG, including the predominant subclasses (IgG1 and IgG4) present in the majority of inhibitor patients, were detected in the mouse model. We further segregated and expanded the different clones of human anti-FVIII-secreting cells through subsequent transplantation of splenocytes derived from hu-NSG-HA mice into another NSG-HA mouse. By transplanting a patient's PBMCs into the NSG-HA mouse model, we demonstrated the success of reintroducing a strong anti-FVIII immune response for a short period in mice with the immune systems of inhibitor-positive patients.

CONCLUSION

Our results demonstrate a potential tool for directly obtaining functional human-derived antigen-specific antibodies and antibody-secreting cells, which may have therapeutic value for testing patient-specific immune responses to treatment options to assist in clinical decisions.

New orphan disease therapies from the proteome of industrial plasma processing waste- a treatment for aceruloplasminemia

Plasma-derived therapeutic proteins are produced through an industrial fractionation process where proteins are purified from individual intermediates, some of which remain unused and are discarded. Relatively few plasma-derived proteins are exploited clinically, with most of available plasma being directed towards the manufacture of immunoglobulin and albumin. Although the plasma proteome provides opportunities to develop novel protein replacement therapies, particularly for rare diseases, the high cost of plasma together with small patient populations impact negatively on the development of plasma-derived orphan drugs. Enabling therapeutics development from unused plasma fractionation intermediates would therefore constitute a substantial innovation. To this objective, we characterized the proteome of unused plasma fractionation intermediates and prioritized proteins for their potential as new candidate therapies for human disease. We selected ceruloplasmin, a plasma ferroxidase, as a potential therapy for aceruloplasminemia, an adult-onset ultra-rare neurological disease caused by iron accumulation as a result of ceruloplasmin mutations. Intraperitoneally administered ceruloplasmin, purified from an unused plasma fractionation intermediate, was able to prevent neurological, hepatic and hematological phenotypes in ceruloplasmin-deficient mice. These data demonstrate the feasibility of transforming industrial waste plasma fraction into a raw material for manufacturing of new candidate proteins for replacement therapies, optimizing plasma use and reducing waste generation.

Immunogenicity, safety, and efficacy of rurioctocog alfa pegol in previously untreated patients with severe hemophilia A: interim results from a phase 3, prospective, multicenter, open-label study

AIM

To determine the immunogenicity, safety, and efficacy of rurioctocog alfa pegol in previously untreated patients (PUPs) with severe hemophilia A (HA).

METHODS

This prospective, phase 3 study (NCT02615691) was conducted in PUPs, or patients with ≤2 exposure days (EDs) prior to screening, aged <6 years with severe HA. The primary endpoint was incidence of factor VIII (FVIII) inhibitor development. This protocol-specified interim analysis was conducted after 50 patients had completed ≥50 EDs without developing FVIII inhibitors or had developed a confirmed inhibitor at any time.

RESULTS

Of the enrolled patients, 59/80 (73.8%) received ≥1 dose of rurioctocog alfa pegol; 54 received prophylaxis, and 35 on-demand treatment. Incidence of inhibitor development was 0.19 (10/52). Total annualized bleeding rate (95% CIs) was 3.2 (2.0-5.0) for patients receiving prophylaxis and 3.2 (1.6-6.3) for on-demand treatment. Hemostatic efficacy of most bleedings was rated as 'excellent' or 'good' after 24 hours (122/131 [93.1%]) and at resolution (161/170 [94.7%]). Five patients received ≥1 dose of rurioctocog alfa pegol for immune tolerance induction (ITI) and 1 patient was defined as having ITI success. Thirteen patients experienced 14 treatment-related adverse events, including 10 cases of FVIII inhibitor development.

CONCLUSION

This is the first prospective study of rurioctocog alfa pegol for the treatment of PUPs with severe HA.

TRIAL REGISTRATION

This trial is registered at ClinicalTrials.gov (CT.gov identifier: NCT02615691).

Effectiveness of myofascial therapy on hemophilic arthropathy: A systematic review and meta-analysis of clinical trials

Background

Recurrent hemarthrosis is one of the major complications affecting joint functions, and causing chronic pain in hemophilia patients.

Objective

To summarize the existing evidence of the effects of myofascial therapy (MFT) on joint status, joint pain, and hemarthrosis in hemophilic arthropathy.

Methods

This systematic review and meta-analysis was done according to PRISMA checklist. Finally, four clinical trials included and were pooled using STATA 13. Standardized mean difference (SMD) considered as the effect size.

Results

All patients in the case group received 3 interventions of MFT over a 3-week period and were evaluated for 1-5 months. Joint pain with and without load was significantly decreased after three weeks in the intervention group compared to controls (SMD: -0.61, 95% CI: -1.02, -0.21 and 0.58, 95% CI: -0.88, -0.28 respectively). Also, joint status significantly improved three weeks later in patients with MFT compared to controls. (SMD: -0.49, 95% CI: -0.79, -0.19) and this improvement remained until the end of the follow-up period (SMD: -0.54, 95% CI: -0.84, -0.24).

Conclusion

This meta-analysis showed that MFT can be an effective intervention improving the joint status and decreasing pain perception in patients with hemophilic arthropathy. Consequently, it can play an important role in achieving higher functionality and quality of life in these patients. However, due to the small number of studies and other limitations, further well-designed trials and updated meta-analysis are needed for more accurate results and interpretation.

Clinico-epidemiological and sociodemographic profile of patients with hemophilia in the Brazilian Amazon: High prevalence of hepatitis C infection and its possible corrrelation with inhibitor development

Hemophilia is a recessive genetic disease caused by a mutation on the X chromosome that has been linked to a high risk of transfusion-transmitted infections, especially sexually transmitted infections. The purpose of this retrospective study was to characterize the clinical and epidemiological profile and describe the prevalence of sexually transmitted viral infections in patients with hemophilia in the Northern Brazilian state of Amazonas. We assessed clinical, laboratory and sociodemographic data of hemophiliac patients (n = 311) for the period 2011-2019. The majority of the study population was composed of people with a low level of education aged 21-30 years old. The prevalence of HCV, HBV, and HTLV-1/2 infections among the study population were 10.52, 0.52, and 1.05%, respectively. No HIV infection was found among the patients. Between 2011 and 2015 the prevalence of HCV increased by over 100% and the incidence peaked in 2013. The severe hemophilia was associated with the presence of inhibitor factor (Odds Ratio [OD] 9.83; 95% IC: 3.41-27.62, p < 0.0001) or target joint (OD 6.59; 95% IC: 3.27-13.34, p < 0.0001). The presence of inhibitor was positive and significantly correlated with HCV infection (r = 1.00, p < 0.0001). Our results showed that HCV infection is highly prevalent in patients with hemophilia and might be involved in the development of inhibitors. Thus, these data provide new insights into the clinical and epidemiological profile of patients suffering from hemophilia in the Northern Brazilian state of Amazonas.

Hemophilia A Gene Therapy: Current and Next-Generation Approaches

INTRODUCTION

: Hemophilia comprises a group of X-linked hemorrhagic disorders that result from a deficiency of coagulation factors. The disorder affects mainly males and leads to chronic pain, joint deformity, reduced mobility, and increased mortality. Current therapies require frequent administration of replacement clotting factors, but the emergence of alloantibodies (inhibitors) diminishes their efficacy. New therapies are being developed to produce the deficient clotting factors and prevent the emergence of inhibitors.

AREAS COVERED

: This article provides an update on the characteristics and disease pathophysiology of hemophilia A, as well as current treatments, with a special focus on ongoing clinical trials related to gene replacement therapies.

EXPERT OPINION

: Gene replacement therapies provide safe, durable, and stable transgene expression while avoiding the challenges of clotting factor replacement therapies in patients with hemophilia. Improving the specificity of the viral construct and decreasing the therapeutic dose are critical toward minimizing cellular stress, induction of the unfolded protein response, and the resulting loss of protein production in liver cells. Next-generation gene therapies incorporating chimeric DNA sequences in the transgene can increase clotting factor synthesis and secretion, and advance the efficacy, safety, and durability of gene replacement therapy for hemophilia A as well as other blood clotting disorders.

Risk factors for antibody formation in children with hemophilia: methodological aspects and clinical characteristics of the HEMFIL cohort study

Up to 35% of patients with hemophilia A and 5% with hemophilia B develop neutralizing antibodies which can inhibit the therapeutic activity of factor replacement (inhibitors). Despite the clinical relevance of antifactor VIII and IX neutralizing antibodies, there is still a major gap on the knowledge of risk factors for their development. Furthermore, most of the studies on risk factors for inhibitor development come from Caucasian and Afro-American populations. The HEMFIL is a Brazilian prospective cohort study of previously untreated children with hemophilia, which primary aim is to identify new risk factors related to inhibitor development. This manuscript aims at describing the study design and its methodology. After the diagnosis, children are followed up to 75 exposure days or to inhibitor development. Standardized forms and blood samples are collected to describe clinical characteristics and to perform the measurement of immunological and genetic biomarkers at three time points; Inclusion time (T0), at inhibitor development or at 75 exposure days without inhibitors (T1) and after immune tolerance induction for patients in whom it is indicated and performed (T2). Currently, 120 children have been included, of whom, 95 have completed the follow-up. For severe/moderately severe hemophilia A, the cumulative incidence of inhibitors at 75 exposure days was 35% (95% confidence interval, 26-46%). The inclusion of additional patients and a longer follow-up will allow the analysis of risk factors for inhibitor development.

Experimental validation of a predicted microRNA within human FVIII gene

Hemophilia A is an X-linked bleeding disorder that occurs due to the deficiency of Factor VIII (FVIII) protein clotting activity. The mutations in the F8 gene, which encodes FVIII coagulating protein have been widely reviewed. However, there is a wide range of criteria that in addition to F8 gene mutations, different molecular mechanisms may be associated with hemophilia A. Various functions of FVIII could be related to the hypothetical small non-coding RNAs, located within the F8 gene sequence. Therefore, miRNAs that can post-transcriptionally regulate gene expression might confer susceptibility to developing hemophilia A. Here, we have selected a bioinformatically predicted hairpin structure sequence in the first intron of the F8 gene that has the potential to produce a real miRNA (named put-miR1). We tried to experimentally detect the predicted miRNA via RT-PCR following its precursor overexpression in HEK 293 cell lines. Despite the accuracy of miRNA prediction, according to the reliable bioinformatics studies, we couldn't confirm the existence of considered mature miRNA in transfected cells. We hope that through changing experimental conditions, designing new primers, or altering cell lines and expression vectors, the exogenous and endogenous expression of the predicted miRNA will be confirmed.

Structure of blood coagulation factor VIII in complex with an anti-C1 domain pathogenic antibody inhibitor

Antibody inhibitor development in hemophilia A represents the most significant complication resulting from factor VIII (fVIII) replacement therapy. Recent studies have demonstrated that epitopes present in the C1 domain contribute to a pathogenic inhibitor response. In this study, we report the structure of a group A anti-C1 domain inhibitor, termed 2A9, in complex with a B domain-deleted, bioengineered fVIII construct (ET3i). The 2A9 epitope forms direct contacts to the C1 domain at 3 different surface loops consisting of Lys2065-Trp2070, Arg2150-Tyr2156, and Lys2110-Trp2112. Additional contacts are observed between 2A9 and the A3 domain, including the Phe1743-Tyr1748 loop and the N-linked glycosylation at Asn1810. Most of the C1 domain loops in the 2A9 epitope also represent a putative interface between fVIII and von Willebrand factor. Lastly, the C2 domain in the ET3i:2A9 complex adopts a large, novel conformational change, translocating outward from the structure of fVIII by 20 Å. This study reports the first structure of an anti-C1 domain antibody inhibitor and the first fVIII:inhibitor complex with a therapeutically active fVIII construct. Further structural understanding of fVIII immunogenicity may result in the development of more effective and safe fVIII replacement therapies.