The effect of emicizumab prophylaxis on health-related outcomes in persons with haemophilia A with inhibitors: HAVEN 1 Study

Strategies for Performing Factor Assays in the Presence of Emicizumab or Other Novel/Emerging Hemostatic Agents

For several decades, therapeutic options for inherited deficiencies of factor VIII or IX (hemophilia A or B, respectively) have largely been the replacement of the missing clotting factor with plasma-derived or recombinant products. Hemostasis laboratories use standard activated partial thromboplastin time (aPTT)-based clotting or chromogenic assays to monitor plasma factor levels to guide therapy. The emergence in the past 10 years of extended half-life replacement products and other novel therapies for hemophilia has led to a reappraisal of assay suitability, with studies of product measurement showing some existing assay types or reagents to be unsuitable for some products. The hemostasis laboratory must adapt to the changing landscape by adding new assays or modifying existing assays to ensure accurate results for product measurement. These strategies include switching from a chromogenic assay to a clotting assay, or vice versa, changing an aPTT reagent brand, or introducing product specific calibrators. This article evaluates the effects of some of the newer treatment options on the laboratory testing of factor levels and related assays.

Comprehensive evaluation of anti-emicizumab antibodies in acquired hemophilia A: a detailed case study and methodological evaluation

BACKGROUND

Acquired hemophilia A (AHA) is a rare and severe bleeding disorder characterized by autoantibodies inhibiting coagulation factor (F)VIII. Current treatment of AHA involves bypassing agents or FVIII replacement therapy, yet their efficacy is limited in cases of high inhibitor titers. Emicizumab, a humanized bispecific monoclonal antibody, has shown promising hemostatic effectiveness in persons with congenital hemophilia A (HA) and AHA, but a minority of patients developed anti-drug antibodies (ADAs), compromising its efficacy.

OBJECTIVES

This study aims to characterize the development and impact of anti-emicizumab antibodies in a patient with acquired hemophilia A (AHA) who experienced reduced efficacy of emicizumab treatment.

METHODS

We present a comprehensive characterization of anti-emicizumab antibodies in a patient with AHA experiencing diminished emicizumab efficacy from week 10 of treatment. We developed a method for analysis of anti-emicizumab antibodies, distinguishing immunoglobulin (Ig) subclasses and IgG subtype profiling. ADAs' neutralizing activity was evaluated using a modified clotting assay.

RESULTS

The Luminex-based assay demonstrated the presence of anti-emicizumab antibodies, confirmed through competitive analysis. We detected anti-emicizumab IgG antibodies in the patient's plasma between week 16 and 29. IgG1 and IgG2 subclasses were identified. Longitudinal analysis showed IgG isotype antibodies against both emicizumab and FVIII. Anti-emicizumab antibodies exhibited noninhibitory activity, confirmed by a modified Bethesda assay. Moreover, no accelerated clearance of emicizumab was observed in plasma samples from the patient.

CONCLUSION

This study presents the first documented case of anti-emicizumab antibodies in AHA. Our study provides insights into ADA development against emicizumab, emphasizing the need for monitoring tools. The developed method enables comprehensive evaluation of ADAs, aiding in personalized treatment strategies. These findings contribute to understanding emicizumab's immunogenicity profile in AHA, facilitating its optimized clinical use.

Evaluating the benefits of emicizumab prophylaxis for haemophilia A with inhibitors: A cost-effectiveness and budget impact analysis in Thailand's upper-middle income setting

BACKGROUND

In Thailand, an upper-middle-income country, managing haemophilia A (HA) with inhibitors poses significant challenges, often necessitating bypassing agents (BPAs) for bleeding control. This study evaluates the cost-effectiveness and budget impact of emicizumab, a novel prophylactic agent, as an alternative to both episodic and prophylactic BPA treatments from a societal perspective.

METHODS

A Markov model was employed to estimate the lifetime societal costs and outcomes of emicizumab prophylaxis for HA patients with inhibitors. Treatment efficacy, cost, and epidemiological data were obtained through a comprehensive literature review and incorporated into the model. A 5-year budget impact analysis complemented the cost-utility analysis, with a 3% annual discount rate applied to future costs and outcomes.

RESULTS

In the base-case scenario, emicizumab prophylaxis in HA patients aged 2 years and above demonstrated superior cost-effectiveness, yielding 18.1 quality-adjusted life years (QALYs) per patient over a lifetime and resulting in cost savings of 138 million Thai Baht (THB) compared to BPA prophylaxis. Compared to episodic BPA treatment, emicizumab yielded 30.5 QALYs and saved 25 million THB per patient. The 5-year budget impact was projected at 1775 million THB.

CONCLUSIONS

Emicizumab offers a cost-saving approach for HA treatment with inhibitors in Thailand, promising significant health benefits and budgetary savings. This supports its potential inclusion in Thailand's National List of Essential Medicines to enhance haemophilia care access.

HIGHLIGHTS

Managing haemophilia A (HA) with inhibitors in Thailand, an upper-middle-income country, faces challenges due to limited access to effective treatments or newer drugs for bleeding management. Emicizumab prophylaxis found to as a cost-effective and viable alternative to traditional treatments, effectively preventing bleeding in Thai HA patients over 2 years old with inhibitors. Demonstrating improved clinical outcomes and reduced costs, emicizumab prophylaxis outperforms episodic BPA treatments, positioning it as a superior treatment option for HA patients with inhibitors in Thailand.

Emicizumab and unmet needs of patients with hemophilia a who are managed with replacement therapies

INTRODUCTION

Hemophilia A is managed with coagulation clotting factor VIII (FVIII) therapy that poses significant challenges, such as a high treatment burden, immunogenicity, inconsistent hemostatic cover, poor treatment outcomes, and musculoskeletal progression despite adequate prophylactic treatment. Various non-factor therapies, such as several natural anticoagulant inhibitors and factor FVIII mimetics, have been developed to address these unmet needs. However, the role of emicizumab in addressing these unmet needs remains underexplored.

AREAS COVERED

This review delves into the evolution of hemophilia A replacement clotting therapy from plasma-derived products to recombinant products and, more recently, nonfactor therapies. It underscores the unmet needs of replacement therapy and explores the nonfactor therapies developed to address them. The review then comprehensively summarizes the clinical trial and real-world experience data, demonstrating how emicizumab tackles these unsatisfied demands.

EXPERT OPINION

Replacement clotting factor therapies as the standard of care has exposed several needs that have yet to be addressed. However, data from numerous emicizumab clinical trials and real-world experience offer a promising outlook, suggesting that it may effectively address many unmet needs. As hemophilia treatment goals continue to evolve, the role of currently developed nonfactor therapies in hemophilia management is yet to be fully defined.

Emicizumab prophylaxis in people with hemophilia A and inhibitors: a systematic review and meta-analysis

BACKGROUND

Until recently, the treatment of people with hemophilia A and inhibitors (PwHAi) was based on the use of bypassing agents (BPA). However, the advent of emicizumab as prophylaxis has demonstrated promising results.

OBJECTIVES

We aimed to compare the bleeding endpoints between PwHAi on BPA and those on emicizumab prophylaxis.

DESIGN AND SETTING

Systematic review of interventions and meta-analysis conducted at the Universidade Federal de Goiás, Goiânia, Goiás, Brazil.

METHODS

The CENTRAL, MEDLINE, Scopus, and LILACS databases were searched on February 21, 2023. Two authors conducted the literature search, publication selection, and data extraction. The selected publications evaluated the bleeding endpoints between PwHAi on emicizumab prophylaxis and those on BPA prophylaxis. The risk of bias was evaluated according to the Joanna Briggs Institute criteria. A meta-analysis was performed to determine the annualized bleeding rate (ABR) for treated bleeds.

RESULTS

Five publications (56 PwHAi) were selected from the 543 retrieved records. Overall, bleeding endpoints were lower during emicizumab prophylaxis than during BPA prophylaxis. All the publications had at least one risk of bias. The only common parameter for the meta-analysis was the ABR for treated bleeds. During emicizumab prophylaxis, the ABR for treated bleeds was lower than during BPA prophylaxis (standard mean difference: -1.58; 95% confidence interval -2.50, -0.66, P = 0.0008; I2 = 68.4%, P = 0.0031).

CONCLUSION

Emicizumab was superior to BPA in bleeding prophylaxis in PwHAi. However, both the small population size and potential risk of bias should be considered when evaluating these results.

SYSTEMATIC REVIEW REGISTRATION

CRD42021278726, https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=278726.

Emicizumab is well tolerated and effective in people with congenital hemophilia A regardless of age, severity of disease, or inhibitor status: a scoping review

Background

With the treatment landscape continually evolving, it is vital that the hemophilia community have an overview of all published data for approved therapies, such as emicizumab, to support shared decision making.

Objectives

To bring together the clinical and real-world data for emicizumab use in people with congenital hemophilia A, regardless of age, disease severity, or factor VIII inhibitor status. Key focus areas were safety, efficacy, and quality of life (QoL).

Methods

This scoping review used citation databases (PubMed, Embase, and the Cochrane Library) and manual searches of abstract books. Publications reporting original data for emicizumab in people with hemophilia A, published in English after December 2014, and reporting select endpoints were included. This narrative synthesis focused on zero bleeds, treated annualized bleeding rate (ABR), adverse events, and QoL measures.

Results

Overall, 97 publications were included (cut-off: August 9, 2022). Treated ABR remained low (calculated mean and median treated ABRs ranged between 0.7-1.3 and 0.0-1.4, respectively), and the median percentage of people with zero treated bleeds was 66.7%. The proportion of people experiencing treatment-related adverse events ranged from 0.0% to 60.0%; most were injection-site reactions. Across 37 publications reporting on safety and enrolling >2300 individuals, 11 thrombotic events and 4 thrombotic microangiopathies were reported. Data from well-established tools show QoL benefits with emicizumab.

Conclusion

This scoping review consolidates the global published experience for emicizumab in people with hemophilia A and supports the fact that emicizumab has an acceptable safety profile, is effective and efficacious in bleed prevention, and is associated with improvements in QoL.

Cost-effectiveness analysis of emicizumab prophylaxis in patients with haemophilia A in India

INTRODUCTION

Emicizumab is the initial subcutaneously administered bispecific antibody approved as a prophylactic treatment for patients with haemophilia A (PwHA).

AIM

This study assessed the economic evaluation of emicizumab treatment for non-inhibitor severe haemophilia A (HA) patients in India.

METHODS

A Markov model evaluated the cost-effectiveness of emicizumab prophylaxis compared to on-demand therapy (ODT), low-dose prophylaxis (LDP; 1565 IU/kg/year), intermediate-dose prophylaxis (IDP; 3915 IU/kg/year) and high-dose prophylaxis (HDP; 7125 IU/kg/year) for HA patients without factor VIII inhibitors. Inputs from HAVEN-1 and HAVEN-3 trials included transition probabilities of different bleeding types. Costs and benefits were discounted at a 3.5% annual rate.

RESULTS

In the base-case analysis, emicizumab was cost-effective compared to HDP, with an incremental cost-effectiveness ratio (ICER) per quality-adjusted life-years (QALY) of Indian rupees (INR) 27,869. Compared to IDP, ODT and LDP, emicizumab prophylaxis could be considered a cost-effective option if the paying threshold is >1 per capita gross domestic product (GDP) with ICER/QALY values of INR 264,592, INR 255,876 and INR 305,398, respectively. One-way sensitivity analysis (OWSA) highlighted emicizumab cost as the parameter with the greatest impact on ICERs. Probabilistic sensitivity analysis (PSA) indicated that emicizumab had a 94.7% and 49.4% probability of being cost-effective at willingness-to-pay (WTP) thresholds of three and two-times per capita GDP.

CONCLUSION

Emicizumab prophylaxis is cost-effective compared to HDP and provides value for money compared to ODT, IDP, and LDP for severe non-inhibitor PwHA in India. Its long-term humanistic, clinical and economic benefits outweigh alternative options, making it a valuable choice in resource-constrained settings.

Knowledge gaps in health-related quality of life research performed in children with bleeding disorders - A scoping review

INTRODUCTION

Bleeding disorders (BDs) may influence health-related quality of life (HRQoL) in children and caregivers. Measuring HRQoL gives insight into domains requiring support and provides an opportunity to evaluate the effects of novel therapies.

AIM

To gain insight in the current body of literature on HRQoL in children with BDs in order to identify knowledge gaps for research and further development of this field.

METHODS

Scoping review.

RESULTS

We included 53 articles, describing studies mainly performed in Europe and North-America (60.4%) and mostly within the last ten years. Only 32% studies included children <4 years. Almost all studies (47/53, 88.7%) were performed in boys with haemophilia, pooling haemophilia A and B (n = 21) and different disease severities (n = 20). Thirteen different generic and five disease-specific HRQoL-questionnaires were applied; all questionnaires were validated for haemophilia specifically. Six (11,3%) combined generic and disease-specific questionnaires. Self-reports were most frequently applied (40/53, 75.5%), sometimes combined with proxy and/or parent-reports (17/53, 32.1%). Eleven studies used a reference group (20.8%). Statistical analyses mostly consisted of mean and SD (77.4%).

CONCLUSION

HRQoL-research is mainly performed in school-aged boys with haemophilia, treated in developed countries. Pitfalls encountered are the pooling of various BDs, subtypes and severities, as well as the application of multiple generic questionnaires prohibiting comparison of results. More attention is needed for broader study populations including other BDs, young children, feminine bleeding issues and platelet disorders, as well as the use of HRQoL as an effect-measurement tool for medical interventions, and more thorough statistical analysis.

Non-clotting factor therapies for preventing bleeds in people with congenital hemophilia A or B

BACKGROUND

Management of congenital hemophilia A and B is by prophylactic or on-demand replacement therapy with clotting factor concentrates. The effects of newer non-clotting factor therapies such as emicizumab, concizumab, marstacimab, and fitusiran compared with existing standards of care are yet to be systematically reviewed.

OBJECTIVES

To assess the effects (clinical, economic, patient-reported, and adverse outcomes) of non-clotting factor therapies for preventing bleeding and bleeding-related complications in people with congenital hemophilia A or B compared with prophylaxis with clotting factor therapies, bypassing agents, placebo, or no prophylaxis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Coagulopathies Trials Register, electronic databases, conference proceedings, and reference lists of relevant articles and reviews. The date of the last search was 16 August 2023.

SELECTION CRITERIA

Randomized controlled trials (RCTs) evaluating people with congenital hemophilia A or B with and without inhibitors, who were treated with non-clotting factor therapies to prevent bleeds.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed studies for eligibility, assessed risk of bias, and extracted data for the primary outcomes (bleeding rates, health-related quality of life (HRQoL), adverse events) and secondary outcomes (joint health, pain scores, and economic outcomes). We assessed the mean difference (MD), risk ratio (RR), 95% confidence interval (CI) of effect estimates, and evaluated the certainty of the evidence using GRADE.

MAIN RESULTS

Six RCTs (including 397 males aged 12 to 75 years) were eligible for inclusion. Prophylaxis versus on-demand therapy in people with inhibitors Four trials (189 participants) compared emicizumab, fitusiran, and concizumab with on-demand therapy in people with inhibitors. Prophylaxis using emicizumab likely reduced annualized bleeding rates (ABR) for all bleeds (MD -22.80, 95% CI -37.39 to -8.21), treated bleeds (MD -20.40, 95% CI -35.19 to -5.61), and annualized spontaneous bleeds (MD -15.50, 95% CI -24.06 to -6.94), but did not significantly reduce annualized joint and target joint bleeding rates (AjBR and AtjBR) (1 trial; 53 participants; moderate-certainty evidence). Fitusiran also likely reduced ABR for all bleeds (MD -28.80, 95% CI -40.07 to -17.53), treated bleeds (MD -16.80, 95% CI -25.80 to -7.80), joint bleeds (MD -12.50, 95% CI -19.91 to -5.09), and spontaneous bleeds (MD -14.80, 95% CI -24.90 to -4.71; 1 trial; 57 participants; moderate-certainty evidence). No evidence was available on the effect of bleed prophylaxis using fitusiran versus on-demand therapy on AtjBR. Concizumab may reduce ABR for all bleeds (MD -12.31, 95% CI -19.17 to -5.45), treated bleeds (MD -10.10, 95% CI -17.74 to -2.46), joint bleeds (MD -9.55, 95% CI -13.55 to -5.55), and spontaneous bleeds (MD -11.96, 95% CI -19.89 to -4.03; 2 trials; 78 participants; very low-certainty evidence), but not target joint bleeds (MD -1.00, 95% CI -3.26 to 1.26). Emicizumab prophylaxis resulted in an 11.31-fold increase, fitusiran in a 12.5-fold increase, and concizumab in a 1.59-fold increase in the proportion of participants with no bleeds. HRQoL measured using the Haemophilia Quality of Life Questionnaire for Adults (Haem-A-QoL) physical and total health scores was improved with emicizumab, fitusiran, and concizumab prophylaxis (low-certainty evidence). Non-serious adverse events were higher with non-clotting factor therapies versus on-demand therapy, with injection site reactions being the most frequently reported adverse events. Transient antidrug antibodies were reported for fitusiran and concizumab. Prophylaxis versus on-demand therapy in people without inhibitors Two trials (208 participants) compared emicizumab and fitusiran with on-demand therapy in people without inhibitors. One trial assessed two doses of emicizumab (1.5 mg/kg weekly and 3.0 mg/kg bi-weekly). Fitusiran 80 mg monthly, emicizumab 1.5 mg/kg/week, and emicizumab 3.0 mg/kg bi-weekly all likely resulted in a large reduction in ABR for all bleeds, all treated bleeds, and joint bleeds. AtjBR was not reduced with either of the emicizumab dosing regimens. The effect of fitusiran prophylaxis on target joint bleeds was not assessed. Spontaneous bleeds were likely reduced with fitusiran (MD -20.21, 95% CI -32.12 to -8.30) and emicizumab 3.0 mg/kg bi-weekly (MD -15.30, 95% CI -30.46 to -0.14), but not with emicizumab 1.5 mg/kg/week (MD -14.60, 95% CI -29.78 to 0.58). The percentage of participants with zero bleeds was higher following emicizumab 1.5 mg/kg/week (50% versus 0%), emicizumab 3.0 mg/kg bi-weekly (40% versus 0%), and fitusiran prophylaxis (40% versus 5%) compared with on-demand therapy. Emicizumab 1.5 mg/kg/week did not improve Haem-A-QoL physical and total health scores, EQ-5D-5L VAS, or utility index scores (low-certainty evidence) when compared with on-demand therapy at 25 weeks. Emicizumab 3.0 mg/kg bi-weekly may improve HRQoL measured by the Haem-A-QoL physical health score (MD -15.97, 95% CI -29.14 to -2.80) and EQ-5D-5L VAS (MD 9.15, 95% CI 2.05 to 16.25; 1 trial; 43 participants; low-certainty evidence). Fitusiran may result in improved HRQoL shown as a reduction in Haem-A-QoL total score (MD -7.06, 95% CI -11.50 to -2.62) and physical health score (MD -19.75, 95% CI -25.76 to -11.94; 1 trial; 103 participants; low-certainty evidence). The risk of serious adverse events in participants without inhibitors also likely did not differ following prophylaxis with either emicizumab or fitusiran versus on-demand therapy (moderate-certainty evidence). Transient antidrug antibodies were reported in 4% (3/80) participants to fitusiran, with no observed effect on antithrombin lowering. A comparison of the different dosing regimens of emicizumab identified no differences in bleeding, safety, or patient-reported outcomes. No case of treatment-related cancer or mortality was reported in any study group. None of the included studies assessed our secondary outcomes of joint health, clinical joint function, and economic outcomes. None of the included studies evaluated marstacimab.

AUTHORS' CONCLUSIONS

Evidence from RCTs shows that prophylaxis using non-clotting factor therapies compared with on-demand treatment may reduce bleeding events, increase the percentage of individuals with zero bleeds, increase the incidence of non-serious adverse events, and improve HRQoL. Comparative assessments with other prophylaxis regimens, assessment of long-term joint outcomes, and assessment of economic outcomes will improve evidence-based decision-making for the use of these therapies in bleed prevention.

Thrombin generation on vascular cells in the presence of factor VIII and/or emicizumab

BACKGROUND

The effect of factor VIII (FVIII) or emicizumab on thrombin generation is usually assessed in assays using synthetic phospholipids. Here, we assessed thrombin generation at the surface of human arterial cells (aortic endothelial cells [hAECs] and aortic vascular smooth muscle cells [hVSMCs]).

OBJECTIVES

To explore the capacity of hAECs (resting or stimulated) and hVSMCs to support thrombin generation by FVIII or emicizumab.

METHODS

Primary hVSMCs and hAECs were analyzed for tissue factor (TF)-activity and antigen, phosphatidylserine (PS)-exposure, tissue factor pathway inhibitor (TFPI)-content and thrombomodulin expression. Cells were incubated with FVIII-deficient plasma spiked with FVIII, emicizumab, activated prothrombin complex concentrate (APCC) or combinations thereof.

RESULTS

TF activity and PS-exposure were present on both hVSMCs and hAECs. In contrast, thrombomodulin and TFPI were expressed on hAECs, while virtually lacking on hVSMCs, confirming the procoagulant nature of hVSMCs. Tumor necrosis factor α-mediated stimulation of hAECs increased not only TF antigen, TF activity, and PS-exposure but also TFPI and thrombomodulin expression. As expected, FVIII and emicizumab promoted thrombin generation on nonstimulated hAECs and hVSMCs, with more thrombin being generated on hVSMCs. Unexpectedly, FVIII and emicizumab increased thrombin generation to a lesser extent on stimulated hAECs compared with nonstimulated hAECs. Finally, adding emicizumab to FVIII did not further increase thrombin generation, whereas the addition of emicizumab to APCC resulted in exaggerated thrombin generation.

CONCLUSION

Tumor necrosis factor stimulation of hAECs increases both pro- and anticoagulant activity. Unexpectedly, the increased anticoagulant activity is sufficient to limit both FVIII- and emicizumab-induced thrombin generation. This protective effect disappears when emicizumab is combined with APCC.

Emicizumab Prophylaxis in Patients with Severe Hemophilia A: Insights from A Resource Limited Country

METHODS

In this prospective study, severe HA patients were recruited from January 2022 to June 2023. Inhibitor positive and inhibitor negative patients with annual bleeding rate (ABR) 8 or greater and past histories of bleeding like intra-cranial, intra-abdominal, and pseudo-tumors were included. Emicizumab loading dose was 3 mg/kg in the first 4 weeks, and the maintenance dose was started at week 5 at 6 mg/kg/month. Patients' detailed bleeding history and demographics were recorded. The five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) was used to evaluate patients' HRQoL. Furthermore, Hemophilia Joint Health Score (HJHS) and Functional Independence score in Hemophilia (FISH) were applied for the assessment of joints at different time points. Results were analyzed by SPSS version 21.

RESULTS

A total of 36 HA male patients with the mean age of 19.7 ± 14.42 years were recruited in the study; among them, 19 patients were inhibitor positive, while 17 were negative. Patients clinically presented with bleeding symptoms which included: hemarthrosis 95%, GI bleeding 13.8%, and bruises and gums bleeding 13.8%. Significant reduction was observed in the bleeding episodes after the therapeutic intervention, and joints assessment and Euro-Quality-of-life Visual Analog Scale showed a significant improvement in health after treatment. Similarly, there was a remarkable reduction in bleeding episodes and improved quality of life among HA patients. The ABR decreased from 53.6% episodes per year prior to treatment to 2.4% during Emicizumab therapy. Prior to initiating Emicizumab therapy, participants exhibited an average FISH score of 16 and HJHS score of 10, indicating moderate limitations due to joint-related issues. After treatment, the mean FISH score improved to 9 and HJHS score to 4 reflecting a substantial enhancement in participants' ability to perform daily activities (P < 0.057).

CONCLUSION

Our results showed that HA patients on prophylactic treatment with Emicizumab were less restricted and had improved quality of life due to marked decrease in bleeding episodes which resulted in improved health and social lives. In addition, it was well tolerated, and no participant discontinued treatment because of adverse events.

Efficacy, safety and cost of emicizumab prophylaxis in haemophilia A patients with inhibitors: A nationwide observational study in Taiwan

INTRODUCTION

Emicizumab mimicking the cofactor function of activated factor VIII (FVIII) restores haemostasis.

METHODS

This nationwide observational study aimed to retrospectively investigate efficacy, safety, and cost in 1 year before and up to 3 years after emicizumab prophylaxis for haemophilia A (HA) patients with FVIII inhibitors.

RESULTS AND DISCUSSION

A total of 39 severe HA patients with a median age of 23.0 years were enrolled. The median historical peak FVIII inhibitor titre was 174.2 BU/mL with an interquartile range of 56.5-578.8 BU/mL. The median annualized bleeding rate reduced from 24 to 0 events in the first year after emicizumab prophylaxis (p < .01) and sustained in the second and third years. The median annualized joint bleeding rate reduced to 0 and maintained up to 3 years (p < .01). Twenty-seven patients (69.2%) had target joints before emicizumab prophylaxis and only seven patients (17.9%) of them had target joints after prophylaxis. Medical costs, including cost of haemostatic therapy, frequency of outpatient department visits, emergency room visits and hospital admission, were significantly reduced after emicizumab prophylaxis (p < .01). FVIII inhibitor titre decreased after emicizumab prophylaxis. Overall, three (7.7%) patients experienced 202 grade 1 drug-related adverse events after emicizumab prophylaxis. No serious adverse events were reported during emicizumab prophylaxis period. The adherence to emicizumab prophylaxis was 100% up to 3 years.

CONCLUSIONS

HA patients with FVIII inhibitors treated with emicizumab prophylaxis resulted in a significant reduction in treated bleeds and associated costs. No new safety events were observed.

Imlifidase, a new option to optimize the management of patients with hemophilia A on emicizumab

BACKGROUND

Emicizumab is a bispecific, chimeric, humanized immunoglobulin G (IgG)4 that mimics the procoagulant activity of factor (F) VIII (FVIII). Its long half-life and subcutaneous route of administration have been life-changing in treating patients with hemophilia A (HA) with or without FVIII inhibitors. However, emicizumab only partially mimics FVIII activity; it prevents but does not treat acute bleeds. Emergency management is particularly complicated in patients with FVIII inhibitors receiving emicizumab prophylaxis in whom exogenous FVIII is inefficient. We have shown recently that Imlifidase (IdeS), a bacterial IgG-degrading enzyme, efficiently eliminates human anti-FVIII IgG in a mouse model of severe HA with inhibitors and opens a therapeutic window for the administration of exogenous FVIII.

OBJECTIVES

To investigate the impact of IdeS treatment in inhibitor-positive HA mice injected with emicizumab.

METHODS

IdeS was injected to HA mice reconstituted with human neutralizing anti-FVIII IgG and treated with emicizumab.

RESULTS

IdeS hydrolyzed emicizumab in vitro and in vivo, albeit, at slower rates than another recombinant human monoclonal IgG4. While F(ab')2 fragments were rapidly cleared from the circulation, thus leading to a rapid loss of emicizumab procoagulant activity, low amounts of single-cleaved intermediate IgG persisted for several days. Moreover, the IdeS-mediated elimination of the neutralizing anti-FVIII IgG and restoration of the hemostatic efficacy of exogenous FVIII were not impaired by the presence of emicizumab and polyclonal human IgG in inhibitor-positive HA mice.

CONCLUSION

Our results suggest that IdeS could be administered to inhibitor-positive patients with HA receiving emicizumab prophylaxis to improve and ease the management of breakthrough bleeds or programmed major surgeries.

Coagulant potentials of emicizumab in the plasmas from infant and toddler patients with hemophilia A

BACKGROUND

Emicizumab significantly reduces bleedings in patients with hemophilia A (PwHA). A clinical study (HAVEN 7; NCT04431726) for PwHA aged less than or equal to 12 months is ongoing, but emicizumab-driven coagulation potential in PwHA in early childhood remains to be clarified.

AIM

To investigate the in vitro or in vivo coagulation potential of emicizumab in plasmas obtained from infant and toddler PwHA.

METHODS

Twenty-seven plasma samples from 14 infant/toddler PwHA (aged 0-42 months, median 19 months) who received emicizumab (n = 9), factor (F)VIII products (n = 8), or no treatment (n = 10) were obtained. FVIII activity in FVIII-treated plasmas was cancelled by the addition of anti-FVIII monoclonal antibody (mAb). Emicizumab-treated plasmas (in vivo) and emicizumab-spiked plasmas (in vitro) were analyzed. Emicizumab-untreated plasma or emicizumab-treated plasma supplemented with two anti-emicizumab mAbs were used as references. Adjusted maximum coagulation velocity (Ad|min1|) by clot waveform analysis and peak thrombin (Peak-Th) by thrombin generation assay was assessed.

RESULTS

Ad|min1| values in 24 samples were improved by the presence of emicizumab. Values did not improve in the three remaining samples (aged 1, 23, and 31 months). Although the presence of emicizumab showed an age-dependent increase in Peak-Th in 20 samples, this increase was not observed in seven samples (aged 0, 1, 1, 2, 8, 19, and 36 months). Emicizumab-dependent increases in both Ad|min1| and Peak-Th were shown in 18 samples, and increases in either parameter were shown in eight samples. One sample (from patient aged 1 month) showed no increase in both, however.

CONCLUSION

Emicizumab could improve coagulant potential in plasmas from infant/toddler patients with hemophilia A.

Efficacy/effectiveness and safety of emicizumab prophylaxis of people with hemophilia A: a systematic review and meta-analysis

BACKGROUND

Emicizumab is a monoclonal antibody approved for prophylaxis against bleeds for people with hemophilia A (PwHA). A systematic review was conducted evaluating the efficacy/effectiveness and the safety of emicizumab as prophylaxis for PwHA compared to prophylaxis with factor VIII (FVIII) or bypassing agents (BPA), respectively in patients without and with inhibitors.

RESEARCH DESIGN AND METHODS

Database-directed search strategies were performed in Aug/26/2022 and updated in Mar/16/2023. Studies evaluating the prophylaxis with emicizumab versus prophylaxis with FVIII or BPA in PwHA without or with inhibitors, respectively, were selected by two independent reviewers. Data were extracted by two independent reviewers. Annualized bleeding rates for total treated bleeding events (ABR-all) were evaluated by meta-analysis. The quality of studies and certainty of evidence were assessed.

RESULTS

A total of 11 studies were included. The standard mean differences for ABR-all were -0.6 (95%CI -1.0 to -0.2, p-value = 0.0002), among PwHA without inhibitors, and -1.7 (95%CI -2.4 to -0.9, p-value <0.00001), among PwHA with inhibitors. However, there was moderate heterogeneity in both meta-analyses. The most frequent adverse event was injection site reaction.

CONCLUSIONS

Emicizumab prophylaxis was superior in reducing the ABR-all when compared with prophylaxis with FVIII or BPA.

Evaluation of the Care Pathway in the Context of the Dispensing of Emicizumab (Hemlibra) in Community Pharmacies in France: Protocol for a Cross-sectional Study Based on the Kirkpatrick Model

BACKGROUND

Commercialized since 2019, emicizumab (Hemlibra) was available only in French hospital pharmacies for prophylaxis of hemophilia A with or without inhibitors. Since June 15, 2021, patients can choose between a hospital and community pharmacy. These changes in the care pathway have important organizational consequences for patients, their relatives, and health professionals. Two training programs are available for community pharmacists: the "HEMOPHAR" training program proposed by the national reference center for hemophilia and the Roche training program proposed by the laboratory that markets the product.

OBJECTIVE

The PASODOBLEDEMI study aims to evaluate the direct impact of the training programs provided to community pharmacists in the context of the dispensing of emicizumab, and to evaluate patients' satisfaction with their treatment whether they choose dispensation from a community pharmacy or retained dispensation from the hospital pharmacy.

METHODS

We designed a cross-sectional study based on the 4-level Kirkpatrick evaluation model: the immediate reaction of community pharmacists following training (Reaction), the knowledge acquired during the training (Learning), the professional practice of community pharmacists during dispensing of the product (Behavior), and patients' satisfaction related to the treatment whether it is dispensed from a hospital or from a community pharmacy (Results).

RESULTS

Considering that single outcome measures cannot adequately reflect the complexity of this new organization, the Kirkpatrick evaluation model provides 4 distinct outcomes: the immediate reaction after the HEMOPHAR training program, the level of knowledge acquired after the HEMOPHAR training program, the impact of training on professional practice, and patient satisfaction with access to emicizumab. We developed specialized questionnaires for each of the 4 levels of the Kirkpatrick evaluation model. All community pharmacists involved in dispensing emicizumab, whether they have followed the HEMOPHAR or the Roche training program or neither, were eligible for inclusion. All patients with severe hemophilia A were eligible, irrespective of inhibitor use, age, treatment with emicizumab, and whether they chose dispensation from a community pharmacy or retained dispensation from a hospital pharmacy.

CONCLUSIONS

The new organization for dispensing emicizumab to patients with hemophilia A in French community pharmacies must be accompanied by optimal safety and quality conditions due to the risk of serious and urgent bleeding situations in the management of rare bleeding diseases. The elaboration of the PASODOBLEDEMI protocol has already a positive impact with the commitment of all health professionals, physicians, hospital and community pharmacists, and the patient community. The results will be disseminated among the French authorities and will enable, if necessary, proposing this access model to other rare diseases.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05449197, https://clinicaltrials.gov/ct2/show/NCT05449197?term=NCT05449197; ClinicalTrials.gov NCT05450640, https://clinicaltrials.gov/ct2/show/NCT05450640?term=NCT05450640.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/43091.

Hemophilia A: Emicizumab monitoring and impact on coagulation testing

Hemophilia A is an X-linked recessive bleeding disorder characterized by absent or ineffective coagulation factor VIII, a condition that could result in a severe and potentially life-threatening bleed. Although the current standard of care involves prophylactic replacement therapy of factor VIII, the development of neutralizing anti-factor VIII alloantibody inhibitors often complicates such therapeutic treatment. Emicizumab (Hemlibra®), a novel recombinant therapeutic agent for patients with hemophilia A, is a humanized asymmetric bispecific IgG4 monoclonal antibody designed to mimic activated factor VIII by bridging factor IXa and factor X thus effecting hemostasis. Importantly, this drug eliminates the need for factor VIII and complications associated with inhibitor generation. Emicizumab has been approved for use in several countries including the United States and Japan for prophylaxis of bleeding episodes in hemophilia A with and without FVIII inhibitors. Therapy is also approved in the European Union for routine prophylaxis of bleeds in hemophilia A with inhibitors or severe hemophilia A without inhibitors. Unfortunately, emicizumab therapy presents unique challenges for routine and specialty coagulation tests currently used to monitor hemophilia A. In this review, hemophilia A is presented, the biochemistry of factor VIII is discussed, and the impact of the therapeutic agent emicizumab is highlighted.

Hemophilia a patients with inhibitors: Mechanistic insights and novel therapeutic implications

The development of coagulation factor VIII (FVIII) inhibitory antibodies is a serious complication in hemophilia A (HA) patients after FVIII replacement therapy. Inhibitors render regular prophylaxis ineffective and increase the risk of morbidity and mortality. Immune tolerance induction (ITI) regimens have become the only clinically proven therapy for eradicating these inhibitors. However, this is a lengthy and costly strategy. For HA patients with high titer inhibitors, bypassing or new hemostatic agents must be used in clinical prophylaxis due to the ineffective ITI regimens. Since multiple genetic and environmental factors are involved in the pathogenesis of inhibitor generation, understanding the mechanisms by which inhibitors develop could help identify critical targets that can be exploited to prevent or eradicate inhibitors. In this review, we provide a comprehensive overview of the recent advances related to mechanistic insights into anti-FVIII antibody development and discuss novel therapeutic approaches for HA patients with inhibitors.

Safety and efficacy of long-term emicizumab prophylaxis in hemophilia A with factor VIII inhibitors: A phase 3b, multicenter, single-arm study (STASEY)

Background

The bispecific monoclonal antibody emicizumab bridges activated factor IX and factor X, mimicking the cofactor function of activated factor VIII (FVIII), restoring hemostasis.

Objectives

The Phase 3b STASEY study was designed to assess the safety of emicizumab prophylaxis in people with hemophilia A (HA) with FVIII inhibitors.

Methods

People with HA received 3 mg/kg emicizumab once weekly (QW) for 4 weeks followed by 1.5 mg/kg QW for 2 years. The primary objective was the safety of emicizumab prophylaxis, including incidence and severity of adverse events (AEs) and AEs of special interest (thrombotic events [TEs] and thrombotic microangiopathies). Secondary objectives included efficacy (annualized bleed rates [ABRs]).

Results

Overall, 195 participants were enrolled; 193 received emicizumab. The median (range) duration of exposure was 103.1 (1.1-108.3) weeks. Seven (3.6%) participants discontinued emicizumab. The most common AEs were arthralgia (n = 33, 17.1%) and nasopharyngitis (n = 30, 15.5%). The most common treatment-related AE was injection-site reaction (n = 19, 9.8%). Two fatalities were reported (polytrauma with fatal head injuries and abdominal compartment syndrome); both were deemed unrelated to emicizumab by study investigators. Two TEs occurred (myocardial infarction and localized clot following tooth extraction), also deemed unrelated to emicizumab. The negative binomial regression model-based ABR (95% confidence interval) for treated bleeds was 0.5 (0.27-0.89). Overall, 161 participants (82.6%) had zero treated bleeds.

Conclusions

The safety profile of emicizumab prophylaxis was confirmed in a large population of people with HA with FVIII inhibitors and no new safety signals occurred. The majority of participants had zero treated bleeds.

Emicizumab: a novel drug in hemophilia A prophylaxis - a narrative review

INTRODUCTION

Hemophilia A is a genetically conditioned disease leading to hemostatic disorders due to factor VIII (FVIII) deficiency. The treatment of hemophilia has evolved throughout the past years and has significantly changed. One of the newest drugs for prophylactic treatment is the humanized bispecific IgG antibody - emicizumab, which binds with factor IXa and factor X, bridging those factors and thus mimicking the activity of factor VIII.

AREAS COVERED

The literature search was made via PubMed database, with the emphasis on clinical trials and case reports, describing the off-label emicizumab use. This review presents an extensive summary and considers advantages and disadvantages (side-effects) of emicizumab, describing additional clinical situations, where emicizumab has been successfully used. In our review we cover information about the mechanisms of action, indications, efficacy and discuss some chosen case reports about off-label emicizumab use.

EXPERT OPINION

Its convenient administration method (subcutaneous) and frequency of injections (from once a week to once a month) makes it a more comfortable treatment, limiting injection-site reactions, hospital stays, costs of prophylaxis, and significantly increasing patients' quality of life. Adverse effects are scarce and rarely serious - the most common ones are reactions at the injection-site and upper respiratory tract infections.

Advances in Hemophilia A Management

Hemophilia A is an inherited insufficiency of Factor VIII (FVIII), one of the critical clotting factors. The gold standard for the management of moderate-to-severe hemophilia A is prophylaxis using regular replacement therapy with clotting factor concentrates. Compared with conventional treatment, extended half-life products reduce the burden of frequent factor replacement injections. Of note, up to 30% of patients with hemophilia A receiving prophylactic factor infusions develop "inhibitors," neutralizing anti-FVIII autoantibodies. Therapeutic options for patients with hemophilia A and inhibitors include the immune tolerance induction (ie, eradication of inhibitors) and the management of acute bleeds with bypassing agents and/or emicizumab. Emicizumab is a biphasic monoclonal antibody mimicking activated FVIII, approved for patients with hemophilia A with/without inhibitors. Gene therapy is an emerging therapy for hemophilia A, essentially curing patients with hemophilia A or transforming them to a milder phenotype by establishing continuous endogenous expression of FVIII after one-time treatment.

Liver gene therapy with intein-mediated F8 trans-splicing corrects mouse haemophilia A

Liver gene therapy with adeno‐associated viral (AAV) vectors is under clinical investigation for haemophilia A (HemA), the most common inherited X‐linked bleeding disorder. Major limitations are the large size of the F8 transgene, which makes packaging in a single AAV vector a challenge, as well as the development of circulating anti‐F8 antibodies which neutralise F8 activity. Taking advantage of split‐intein‐mediated protein trans‐splicing, we divided the coding sequence of the large and highly secreted F8‐N6 variant in two separate AAV‐intein vectors whose co‐administration to HemA mice results in the expression of therapeutic levels of F8 over time. This occurred without eliciting circulating anti‐F8 antibodies unlike animals treated with the single oversized AAV‐F8 vector under clinical development. Therefore, liver gene therapy with AAV‐F8‐N6 intein should be considered as a potential therapeutic strategy for HemA.

Traumatic Tonsillar Hemorrhage during Hemophilia A Treatment with Emicizumab

Reports on the treatment of bleeding associated with emicizumab administration are scarce. Herein, we report the case of an eight-year-old boy with moderate hemophilia A with an inhibitor who experienced tonsillar hemorrhage while undergoing emicizumab treatment. He visited our hospital for postprandial bloody vomiting. The activated partial thromboplastin time was 20.8 s; only a small amount of hemorrhage was observed in the retropharyngeal space, and tranexamic acid was administered. He experienced hematemesis on Day 2 of hospitalization, and fiberoptic laryngoscopy confirmed hemorrhage from the posterior tonsil. Varicose vessels were observed at the soft palate, and considering thrombosis, an emergency cauterization was performed instead of bypass therapy. In small children, observing the tonsils is difficult, and the coagulation ability of the patient with hemophilia A is inferior to that of healthy people, even under emicizumab administration. Thus, active hemorrhage assessment and appropriate hemostatic control are necessary.

Recombinant porcine factor VIII in acquired hemophilia A: Experience from two patients and literature review

Background

Acquired hemophilia A (AHA) is a disease caused by antibody formation inhibiting the function of factor VIII, causing bleeding. Recombinant porcine factor VIII (rpFVIII) escapes human FVIII antibody recognition and can provide life-saving hemostasis. However, the development of antibodies against pFVIII can limit its use. We report two cases in which loss of response to rpFVIII occurred, likely because of inhibiting antibodies. In case 1, the patient achieved hemostasis but lost response to rpFVIII within a few days. In the second case, rpFVIII controlled bleeding but the patient experienced diminishing half-life of rpFVIII infusions over time, necessitating a switch to emicizumab which provided lasting hemostasis.

Key Clinical Question

Based on our experience with these cases, we reviewed the available literature regarding the use of rpFVIII in AHA. The Key Clinical Question was to determine how often inhibitors were associated with rpFVIII treatment failure.

Clinical approach and conclusions

We identified 43 AHA patients across five studies who were treated with rpFVIII. Twenty-two patients (51%) developed pFVIII inhibitors and seven cases (16%) reported loss of efficacy associated with an inhibitor. In conclusion, rpFVIII can be a life-saving therapy in AHA. However, clinicians should be aware that pFVIII antibody development can reduce the efficacy and duration of response. Recombinant pFVIII's limitations support the utility of further investigation of alternative therapies such as emicizumab in early AHA management.

Anticoagulation for Stroke Prevention after Restoration of Haemostasis with Emicizumab in Acquired Haemophilia A

Acquired haemophilia A (AHA) is a rare haemorrhagic disorder caused by the development of autoantibodies inhibiting factor VIII function. It predominantly affects the elderly, who are often burdened with a considerable number of comorbidities, and can result in life-threatening bleeding. The management of AHA consists of two aspects: inhibitor eradication with an immunomodulator and bleed control with a bypassing agent. Here we present a case of AHA with a high titre inhibitor in a patient with extensive comorbidities and atrial fibrillation in whom inhibitor eradication could not be achieved within a few weeks using corticosteroids alone. Due to coronavirus disease (COVID)-19 restrictions and complications of care, emicizumab offered an effective and convenient therapy, not only sparing the need for continued and intensified inhibitor eradication, but also allowing anticoagulation for stroke prophylaxis.

LEARNING POINTS

Emicizumab may offer a suitable option for bleeding prophylaxis when inhibitor eradication is not achievable with immunotolerance treatment, especially in the age of the COVID-19 pandemic when the consequences of immunosuppression can be detrimental.Bleeding prophylaxis with emicizumab may enable long-term anticoagulation in patients with acquired haemophilia A during inhibitor eradication.The prothrombotic risks of emicizumab are not yet sufficiently characterized.

Off-label use of emicizumab in persons with acquired haemophilia A and von Willebrand disease: A scoping review of the literature

INTRODUCTION

Since the approval of emicizumab, a bispecific, factor VIII-mimetic antibody, for use in persons with congenital haemophilia A in 2018, there have been increasing case reports and case series of off-label use of emicizumab in other bleeding disorders, including acquired haemophilia A (AHA) and von Willebrand disease (VWD).

AIM

We conducted a scoping review on the use of emicizumab in AHA and VWD, focusing on the clinical presentation and outcomes.

METHODS

We conducted a comprehensive search in PubMed, EMBASE and Scopus up to July 15, 2021. The following criteria were applied to the studies identified in the initial search: patients had a diagnosis of AHA or VWD; and the study reported on the clinical outcome of emicizumab use.

RESULTS

Seventeen studies were included in the final review for a total of 41 patients (33 AHA, eight type 3 VWD). The majority of AHA patients and all type 3 VWD patients were started on emicizumab for active/recurrent bleeds. The dosing regimen of emicizumab used varied significantly in AHA patients. All patients had a clinical response to emicizumab use. One AHA patient developed a stroke on emicizumab use in association with concomitant recombinant FVIIa use for surgery. Data on adverse events from emicizumab use were not specifically reported in 24.4% of patients (four AHA, six type 3 VWD).

CONCLUSION

Based on published case reports and case series, emicizumab appears to be an effective haemostatic therapy for AHA and VWD. Larger confirmatory clinical trials are needed to confirm these findings.

A comparison between on-demand usage of rFVIIa vs prophylaxis use of emicizumab in high titer inhibitory hemophilia A patients in Iran: A cost-utility analysis

BACKGROUND

Hemophilia A (HA) is an inherited X-linked bleeding disease with costly treatment, especially for high titer inhibitory patients. Emicizumab, a new humanized bispecific antibody, has been approved for use to prevent or reduce the frequency of bleeding episodes in HA patients with inhibitors. This study evaluated the cost-utility of emicizumab prophylaxis (EP) in comparison with recombinant factor VII activated on-demand treatment in HA patients with inhibitors.

METHODS

A life-time Markov model with payer and societal perspectives was developed in different age groups with different annual bleeding rates (ABR). Efficacy of treatments were extracted from HAVEN trials. Utilities were retrieved from published evidence. Costs were calculated based on Iran food and drug administration official website, national tariff book for medical services and hospital data. One-way deterministic sensitivity analysis was performed.

RESULTS

EP was dominant choice in comparison with on-demand administration of recombinant factor VII activated in all age groups with ABR 20 and 25, and it remained dominant in patients with age 2 and age 12 at start point with ABR 16 and 17. The reported incremental cost-effectiveness ratio for the group with ABR 18 at the age 20, was 12,936 United States Dollars which is lower than the acceptable threshold of cost-effectiveness in Iran (1-3 gross domestic product per capita) and EP can be considered as cost-effective choice in this scenario.

CONCLUSION

EP was found to be a dominant and cost-effective choice for Iranian HA patients with factor VIII inhibitors with ABR 18 and above with considerable cost saving.

Current therapeutic approaches in the management of hemophilia-a consensus view by the Romanian Society of Hematology

Hemophilia A (HA) and hemophilia B (HB) are rare disorders, being caused by the total lack or under-expression of two factors from the coagulation cascade coded by genes of the X chromosome. Thus, in hemophilic patients, the blood does not clot properly. This results in spontaneous bleeding episodes after an injury or surgical intervention. A patient-centered regimen is considered optimal. Age, pharmacokinetics, bleeding phenotype, joint status, adherence, physical activity, personal goals are all factors that should be considered when individualizing therapy. In the past 10 years, many innovations in the diagnostic and treatment options were presented as being either approved or in development, thus helping clinicians to improve the standard-of-care for patients with hemophilia. Recombinant factors still remain the standard of care in hemophilia, however they pose a challenge to treatment adherence because they have short half-life, which where the extended half-life (EHL) factors come with the solution, increasing the half-life to 96 hours. Gene therapies have a promising future with proven beneficial effects in clinical trials. We present and critically analyze in the current manuscript the pros and cons of all the major discoveries in the diagnosis and treatment of HA and HB, as well as identify key areas of hemophilia research where improvements are needed.

Clotting factor concentrates for preventing bleeding and bleeding-related complications in previously treated individuals with haemophilia A or B

BACKGROUND

The hallmark of severe hemophilia (A or B) is recurrent bleeding into joints and soft tissues with progressive joint damage, despite on-demand treatment. Prophylaxis has long been used, but not universally adopted, because of medical, psychosocial, and cost controversies.

OBJECTIVES

To determine the effectiveness of clotting factor concentrate prophylaxis in managing previously-treated individuals with hemophilia A or B.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Coagulopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. In addition, we searched MEDLINE and Embase and online trial registries. Most recent search of Group's Coagulopathies Trials Register: 24 February 2021.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs evaluating people with hemophilia A or hemophilia B, who were previously treated with clotting factor concentrates to manage their hemophilia.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed trials for eligibility, assessed risk of bias and extracted data. The authors used the GRADE criteria to assess the certainty of the evidence.

MAIN RESULTS

Ten trials (including 608 participants) were eligible for inclusion. Eight of the trials (477 participants) had arms comparing two or more prophylactic regimens to one another and four of the trials (n = 258) compared prophylaxis to on-demand treatment (two trials had multiple arms and were included in both comparisons). Comparison of two or more prophylactic regimens For trials comparing one prophylaxis regimen to another, given the heterogeneity of the data, none of the data were pooled for this comparison. Considering the individual trials, three trials reported the primary outcome of joint bleeding, and none showed a dfference between dosing regimens (low-certainty evidence). For the secondary outcome of total bleeding events, prophylaxis with a twice-weekly regimen of FIX likely results in reduced total bleeds compared to a once-a-week regimen of the same dose, mean difference (MD) 11.2 (5.81 to 16.59) (one trial, 10 participants, low-certainty evidence). Transient low-titer anti-FVIII inhibitors were reported in one of the trials. Blood-transmitted infections were not identified. Other adverse events reported include hypersensitivity, oedema, and weight gain. These were, however, rare and unrelated to study drugs (very low-certainty evidence). Comparison of prophylactic and on-demand regimens Four of the trials (258 participants) had arms that compared prophylaxis to on-demand treatment. Prophylaxis may result in a large decrease in the number of joint bleeds compared to on-demand treatment, MD -30.34 (95% CI -46.95 to -13.73) (two trials, 164 participants, low-certainty evidence). One of these trials (84 participants) also reported the long-term effects of prophylaxis versus on-demand therapy showing improved joint function, quality of life, and pain; but no differences between groups in joint structure when assessed by magnetic resonance imaging (MRI). In one trial (84 participants) validated measures for joint health and pain assessment showed that prophylaxis likely improves joint health compared to an on-demand regimen with an estimated change difference of 0.94 points (95% CI 0.23 to 1.65) and improves total pain scores, MD -17.20 (95% CI -27.48 to -6.92 (moderate-certainty evidence). Two trials (131 participants) reported that prophylaxis likely results in a slight increase in adverse events, risk ratio 1.71 (1.24 to 2.37) (moderate-certainty evidence). No inhibitor development and blood-transmitted infections were identified. Overall, the certainty of the body of evidence was judged to be low because of different types of bias that could have altered the effect.   AUTHORS' CONCLUSIONS: There is evidence from RCTs that prophylaxis, as compared to on-demand treatment, may reduce bleeding frequency in previously-treated people with hemophilia. Prophylaxis may also improve joint function, pain and quality of life, even though this does not translate into a detectable improvement of articular damage when assessed by MRI.  When comparing two different prophylaxis regimens, no significant differences in terms of protection from bleeding were found. Dose optimization could, however, result in improved efficacy. Given the heterogeneity of the data, pooled estimates were not obtained for most comparisons.  Well-designed RCTs and prospective observational controlled studies with standardised definitions and measurements are needed to establish the optimal and most cost-effective treatment regimens.

Haemophilia: factoring in new therapies

Haemophilia is an inherited bleeding disorder in which the haemostatic defect results from deficiency of coagulation factor VIII (FVIII) in haemophilia A or factor IX (FIX) in haemophilia B. Traditional treatments for haemophilia have largely worked by directly replacing the missing coagulation factor, but face challenges due to the short half-life of FVIII and FIX, the need for frequent intravenous access and development of neutralising antibodies to coagulation factors (inhibitors). Recent advances in haemophilia therapy have worked to eliminate these challenges. Half-life extension of factor concentrates has lengthened the time needed between infusions, enhancing quality of life. Subcutaneous administration of therapeutics utilising alternative mechanisms to overcome inhibitors have expanded the options to prevent bleeding. Finally, initial successes with gene therapy offer a cautious hope for durable cure. In the present review, we will discuss currently available treatments, as well as highlight therapeutics in various stages of clinical development for the treatment of haemophilia A and B. In this review, we present therapies that are currently clinically available and highlight therapeutics that are in various stages of clinical development for the treatment of haemophilia A and B.

Surgery with emicizumab prophylaxis for two paediatric patients with severe haemophilia A with inhibitors

Emicizumab is a prophylaxis for patients with severe haemophilia A with and without inhibitor. Despite weekly administration of emicizumab, coagulation states stay below normal value and cannot be assessed by standard haemostasis tests. In our two patients, we used the thrombin-generation assay (endogenous thrombin potential and Peak) to monitor the patient's clotting status. Under emicizumab, it is necessary to add a bypassing agent (BPA) such as rFVIIa (Novoseven) to avoid bleeding before surgery. The BPA dosage was based on a thrombin-generation assay and collegial consultation.

Adoption of emicizumab (Hemlibra®) for hemophilia A in Europe: Data from the 2020 European Association for Haemophilia and Allied Disorders survey

BACKGROUND

Emicizumab, a bispecific monoclonal antibody administered subcutaneously, mimicking the action of activated coagulation factor VIII, has been approved in Europe for use in patients with severe hemophilia of all ages.

AIMS

To assess availability, acceptance, adverse events, efficacy and laboratory monitoring of emicizumab and the effect of the coronavirus disease 2019 (COVID-19) pandemic on its use.

METHODS

Online questionnaire sent to 144 hemophilia treatment centres (November 2020 to January 2021).

RESULTS

Forty-six physicians from 21 countries responded, with a total of 3420 patients with severe HA under their care. Emicizumab was widely available, for 100% of inhibitor patients and 88% of non-inhibitor patients. No major adverse events were reported. Four reported deaths in patients on emicizumab were not thought to be related to emicizumab. An annualized bleeding rate (ABR) of zero was achieved in 73% of inhibitors patients. Haemostasis was satisfactory in the majority of minor (93.7%) and major (90.7%) surgical procedures performed while on emicizumab. Inhibitor titers were monitored in 78.4% of inhibitor patients on emicizumab, but chromogenic FVIII assay was only available in 73% of centres. The COVID-19 pandemic did not have a major impact on the adoption of emicizumab in most centres (64.9%).

CONCLUSION

Three years after its rollout in Europe, emicizumab is widely available. Clinical efficacy and safety were evaluated to be very good, keeping in mind the inherent limitations of the study. Unmet needs include establishment of treatment guidelines for surgery and breakthrough bleeding, limited expertise, especially in young children, and availability of laboratory assays.

The effect of emicizumab prophylaxis on long-term, self-reported physical health in persons with haemophilia A without factor VIII inhibitors in the HAVEN 3 and HAVEN 4 studies

Introduction

Severe haemophilia A (HA) has a major impact on health‐related quality of life (HRQoL).

Aim

Assess the impact of emicizumab on HRQoL in persons with severe HA (PwHA) without factor VIII (FVIII) inhibitors in the phase 3 HAVEN 3 and 4 studies.

Methods

This pooled analysis examines the HRQoL of PwHA aged ≥ 18 years treated with emicizumab prophylaxis via Haemophilia‐Specific Quality of Life Questionnaire for Adults (Haem‐A‐QoL) and EuroQoL 5‐Dimensions 5‐levels (EQ‐5D‐5L). In particular, changes from baseline in Haem‐A‐QoL ‘Physical Health’ (PH) domain and ‘Total Score’ (TS) are evaluated.

Results

Among 176 evaluable participants, 96 (55%) had received prior episodic treatment and 80 (45%) prophylaxis; 70% had ≥ 1 target joint and 51% had experienced ≥ 9 bleeds in the previous 24 weeks. Mean Haem‐A‐QoL PH and TS improved after emicizumab initiation. Mean (standard deviation) –12.0 (21.26)‐ and –8.6 (12.57)‐point improvements were observed in PH and TS from baseline to Week 73; Week 73 scores were 27.9 (24.54) and 22.0 (14.38), respectively. Fifty‐four percent of participants reported a clinically meaningful improvement in PH scores (≥ 10 points) by Week 73. Subgroups with poorer HRQoL prior to starting emicizumab (i.e. receiving episodic treatment, ≥ 9 bleeds, target joints) had the greatest improvements in PH scores, and corresponding reductions in missed workdays; change was not detected among those previously taking prophylaxis. No change over time was detected by the EQ‐5D‐5L questionnaire.

Conclusions

Emicizumab prophylaxis in PwHA without FVIII inhibitors resulted in persistent and meaningful improvements in Haem‐A‐QoL PH and less work disruption than previous treatment.

Real-world cost estimates of initiating emicizumab in US patients with haemophilia A

INTRODUCTION

Emicizumab is the first approved non-factor therapy for haemophilia A. It provides superior prophylactic bleeding control compared to other products in both patients with and patients without inhibitors. However, there is no real-world data about the monetary consequences of starting emicizumab.

AIM

To examine the estimated costs of starting emicizumab in a cohort of real-world haemophilia A patients with and without inhibitors.

METHODS

The cost of haemostatic therapy for 6 months before and after initiating emicizumab for participants in a multicentre observational study was calculated based on the type of product and dosing that was used for prophylaxis and treating breakthrough bleeds, the number of treated bleeds and the participant weight.

RESULTS

Ninety-two patients were included, 18 with an active inhibitor. The median age was 8.7 years. The median total cost for all patients decreased from $176,720 to $128,099 (p = .04) after initiating emicizumab, largely because of decrease in the total cost of high-cost outliers. The cost of prophylaxis and the total cost of bleeds also significantly decreased after starting emicizumab, both for patient with and patients without inhibitors.

CONCLUSIONS

Starting or switching to prophylaxis with emicizumab results in decreased costs for the treatment of patients with haemophilia A. This real-world data could inform on payer decisions as well as future cost-effective analysis.

Emicizumab for the treatment of acquired hemophilia A

Acquired hemophilia A (AHA) is a severe bleeding disorder caused by inhibiting autoantibodies to coagulation factor VIII (FVIII). For hemostatic treatment, bypassing agents and human or porcine FVIII are currently standard of care. Emicizumab is a bispecific, FVIII-mimetic therapeutic antibody that reduced the annualized bleeding rates in congenital hemophiliacs. Here, we report on 6 male and 6 female patients with AHA treated with emicizumab (all data medians and interquartile range), age 74 (64-80) years, initial FVIII <1%; inhibitor titer 22.3 Bethesda units (BU)/mL (range, 3-2000). Eight patients had severe bleeding. Emicizumab was started, 3 mg/kg subcutaneously, weekly for 2 to 3 doses, followed by 1.5 mg/kg every 3 weeks to keep the lowest effective FVIII levels. For FVIII monitoring, chromogenic assays with human and bovine reagents were used. All patients received immunosuppression with steroids and/or rituximab. After the first dose of emicizumab, activated partial thromboplastin time normalized in 1 to 3 days, FVIII (human reagents) exceeded 10% after 11 (7.5-12) days. Hemostatic efficacy was obtained and bypassing therapy stopped after 1.5 (1-4) days. FVIII (bovine reagents) exceeded 50%, indicating complete remission after 115 (67-185) days, and emicizumab was stopped after 31 (15-79) days. A median of 5 injections (range, 3-9) were given. No patient died of bleeding or thromboembolism, and no breakthrough bleeding was observed after the first dose of emicizumab. In conclusion, emicizumab seems to be an effective hemostatic therapy for AHA, with the advantages of subcutaneous therapy, good hemostatic efficacy, early discharge, and reduction of immunosuppression and adverse events.

Patient-reported Outcome Measures in Pediatric Non-Malignant Hematology: A Systematic Review

Patient-reported outcome measures (PROMs) are questionnaires completed by patients or caregivers without influence by health care professionals. As such, PROMs show subjective health experiences, enhance the clinical information available to providers, and inform clinical action. The objective of this systematic review is to identify and list which validated PROMs have been used to monitor health-related quality of life in pediatric patients with nonmalignant hematology (hemophilia, immune thrombocytopenia, sickle cell disease, and thalassemia). Databases (MEDLINE, Embase, HaPI, CINAHL, and PsycTESTS) were searched to identify publications that validated or used PROMs as an outcome measure in the 4 disease groups. Overall, 209 articles met the inclusion criteria, identifying 113 PROMs. Of the 113 identified PROMs, 95 are generic and can be used in multiple disease groups. The Pediatric Quality of Life Generic Core Scales was the most frequently used generic PROM (68 studies). The 18 remaining PROMs were disease specific. The results of this review, together with the COSMIN tool for selecting outcome measures, will allow clinicians to evaluate the PROMs that are best suited to their patient population. In addition, the focus groups are currently being conducted with patients, parents, and clinicians to determine the optimal use of PROMs in the clinical environment.

Practical considerations for nonfactor-replacement therapies in the treatment of haemophilia with inhibitors

New therapeutic agents for haemophilia with inhibitors that are in development or already licensed are expected to provide transformative treatment options. Many of these new therapies are not based on simply replacing the missing factor; new strategies include bispecific antibody technology that mimics factor VIII coagulation function (emicizumab), and inhibition of anticoagulant proteins such as tissue factor pathway inhibitor (eg PF-06741086) and antithrombin (eg fitusiran). These agents are administered subcutaneously and should significantly reduce treatment burden and increase the ability to deliver prophylaxis for patients. Limited real-world data and validated practical guidance on these recently licensed/upcoming treatments resulted in the authors convening to discuss recommendations on their use. Emicizumab is currently the only licenced nonfactor therapy; thus, our recommendations focus on this product. Target candidates for emicizumab prophylaxis are difficult-to-treat patients with haemophilia A and inhibitors and/or venous access issues, frequent bleeds and target joints. In case of breakthrough bleeding while receiving emicizumab, patients still require treatment with bypassing agents; the adjunct treatment of choice is recombinant activated factor VII. This treatment is also recommended to prevent bleeds in patients with inhibitors undergoing surgery. Our recommendations on suitable laboratory assays and monitoring new products, as well as the benefit of patient-reported outcomes (such as pain and physical activity levels), are included. We also briefly discuss future treatment options for patients with haemophilia B and inhibitors. Although these nonfactor treatments offer great promise, further data and real-world evidence are needed.

Should emicizumab be used in patients with acquired hemophilia A?

Emicizumab is currently approved to prevent bleeding in patients with congenital hemophilia A with or without neutralizing antibodies (inhibitors) against factor VIII (FVIII). Here, we present a case-based discussion of its potential use in acquired hemophilia A (AHA), a severe bleeding disorder caused by autoantibodies against FVIII. State-of-the-art management is based on bypassing agents (recombinant factor VIIa, activated prothrombin complex concentrate) and recombinant porcine FVIII; immunosuppressive therapy (corticosteroids, rituximab, cyclophosphamide) is used to suppress autoantibody formation. Case reports and one series suggest that emicizumab can reduce the risk of bleeding and the requirement for hemostatic therapy until remission of AHA is achieved. Further, it may allow to postpone the start of immunosuppressive therapy or to use less intense regimens. However, the risk-benefit assessment of emicizumab in AHA is difficult because demographic and clinical characteristics are different compared with congenital hemophilia. Prospective clinical trials are needed before the use of emicizumab can be recommended in AHA.

Outcome measures in Haemophilia: Beyond ABR (Annualized Bleeding Rate)

Options for management of haemophilia are increasing rapidly with completely novel therapeutic approaches that cannot be compared using traditional factor assays. In addition, as prophylaxis regimens have improved, bleeding rates have decreased, and consequently, it is difficult to show an impact of novel therapies on rates of spontaneous bleeding. There is currently an urgent need for a panel of outcome measures to compare therapies that are dissimilar in many essential ways. Conventional objective outcome measures including joint physical examination and joint imaging continue to hold a central importance. Factor assays are essential for evaluation of products derived from native factor genes, but are not applicable to some extended half-life factors or non-factor bypassing agents. Global assays including thrombin generation and chromogenic assays of factor X activation are under investigation for their usefulness in haemophilia assessment. Bleeding rate is a conventional subjective patient-reported outcome that, while decreasing in frequency, is indispensable as an outcome given that the primary manifestation of haemophilia is bleeding. Other patient-reported outcomes such as pain intensity and interference, health-related quality of life and activities and participation are increasingly important to distinguish superior outcomes in comparative trials. This review of outcome measures for haemophilia presents examples of existing outcome measures with an emphasis on their strengths and limitations.

Application of a hemophilia mortality framework to the Emicizumab Global Safety Database

BACKGROUND

As the first non-factor replacement therapy for persons with congenital hemophilia A (PwcHA), emicizumab's safety profile is of particular interest to the community.

OBJECTIVES

We applied an algorithm for categorization of fatal events contemporaneous to emicizumab using reporter-assessed causality documented in the Roche Emicizumab Global Safety Database.

PATIENTS/METHODS

All fatalities in PwcHA reported to the database (from clinical trials, pre-market access, and spontaneous post-marketing reports) were categorized into: associated with hemophilia A-hemorrhagic, thrombotic, human immunodeficiency virus (HIV)/hepatitis C virus (HCV), hepatic (non-HCV); associated with general population-trauma/suicide, non-HA-associated conditions; or, unspecified. Reported cause of death was not reassessed.

RESULTS

As of cut-off May 15, 2020, 31 fatalities in PwcHA taking emicizumab were reported. Median age at death was 58 years; 51% had factor VIII inhibitors. Fifteen fatalities were considered associated with HA; overall, the most frequent category was hemorrhage (11/31). Of these, six had a history of life-threatening bleeds, and four had a history of intracranial hemorrhage. The remaining HA-associated fatalities were related to HIV/HCV (3/31) and other hepatic causes (1/31). No cases were categorized as thrombotic. Of 10 cases considered not associated with HA, two were categorized as cardiovascular (non-thrombotic), five as infection/sepsis, and one each of trauma/suicide, pulmonary, and malignancy. Six cases were unspecified.

CONCLUSIONS

No unique risk of death was associated with emicizumab prophylaxis in PwcHA. The data reveal that mortality in PwcHA receiving emicizumab was primarily associated with hemorrhage or non-HA-associated conditions, and was not reported by treaters to be related to emicizumab treatment.

Establishment of a framework for assessing mortality in persons with congenital hemophilia A and its application to an adverse event reporting database

BACKGROUND

Despite recent therapeutic advances, life expectancy in persons with congenital hemophilia A (PwcHA) remains below that of the non-HA population. As new therapies are introduced, a uniform approach to the assessment of mortality is required for comprehensive evaluation of risk-benefit profiles, timely identification of emerging safety signals, and comparisons between treatments.

OBJECTIVES

Develop and test a framework for consistent reporting and analysis of mortality across past, current, and future therapies.

PATIENTS/METHODS

We identified known causes of mortality in PwcHA through literature review, analysis of the US Food and Drug Administration Adverse Event Reporting System (FAERS) database, and expert insights. Leading causes of death in general populations are those recognized by the Centers for Disease Control and Prevention and the World Health Organization. We developed an algorithm for assessing fatalities in PwcHA and used this to categorize FAERS data as a proof of concept.

RESULTS

PwcHA share mortality causes with the non-HA population including cardiovascular disease, malignancy, infections, pulmonary disease, dementias, and trauma/suicide. Causes associated with HA include hemorrhage, thrombosis, human immunodeficiency virus, hepatitis C virus, and liver dysfunction. We propose an algorithm employing these classes to categorize fatalities and use it to classify FAERS fatality data between 01/01/2000 and 03/31/2020; the most common causes were hemorrhage (22.2%) and thrombosis (10.4%).

CONCLUSIONS

A conceptual framework for examining mortality in PwcHA receiving any hemophilia therapy is proposed to analyze and interpret fatalities, enabling consistent and objective assessment. Application of the framework using FAERS data suggests a generally consistent pattern of reported mortality across HA treatments, supporting the utility of this unified approach.

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

INTRODUCTION

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Practical Guidance of the GTH Haemophilia Board on the Use of Emicizumab in Patients with Haemophilia A

Emicizumab has been approved for bleeding prophylaxis in patients with haemophilia A (PWHAs) with or without inhibitors. Because of substantial differences between factor VIII (FVIII) and Emicizumab, the 'Ständige Kommission Hämophilie' of the German, Austrian, Swiss Society for Thrombosis and Haemostasis Research (GTH) established a practical guidance for the use of Emicizumab in PWHAs. A systematic literature research was conducted in PubMed. Based on this and on personal experience, this practical guidance has been developed. Each single statement has been discussed among members of the 'Ständige Kommission Hämophilie' and revised accordingly. The final set of recommendations has been approved by all authors analogous to the Delphi method. This practical guidance is provided for physicians treating PWHAs with regard to general aspects, patient education, bleeding treatment, surgery, use of Emicizumab in previously untreated patients (PUPs), patients with newly diagnosed inhibitors and elderly patients. Patients should be treated in expert centres and adequate laboratory tests to monitor Emicizumab levels, FVIII replacement and inhibitors should be available. Early experience of immune tolerance induction protocols integrating Emicizumab is reviewed, and the limited experience in PUPs and very young children is described. So far, no thromboembolic complications have been reported with the concomitant use of FVIII or recombinant activated FVII for bleeding treatment or surgery. Activated prothrombin complex concentrate doses of >100 U/kg for >24 hours should be avoided whenever possible because of the high risk of thrombosis and/or thrombotic microangiopathy. In conclusion, this study is designed to support haemophilia physicians using Emicizumab in physicians treating hemophilia and using (PWHAs). With further post-marketing experience and trials, regular updates are necessary.