ST‐Segment Elevation Myocardial Infarction (STEMI) and Pulmonary Embolism in a Hemophilia A Patient Receiving Emicizumab and recombinant Activated Factor VII

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.

Management of surgery in persons with hemophilia A receiving emicizumab prophylaxis: data from a national hemophilia treatment center

Background

Persons with hemophilia A may require surgical procedures. Real-world data on invasive procedures in persons with hemophilia A receiving emicizumab prophylaxis are limited.

Objectives

To evaluate the safety of invasive procedures in persons with hemophilia A receiving emicizumab prophylaxis and their outcomes in a longitudinally followed cohort.

Methods

Data from medical records of persons with hemophilia A with and without factor VIII (FVIII) inhibitors longitudinally followed at our tertiary center, who received emicizumab prophylaxis and underwent all types of invasive procedures, were retrieved. Outcomes of interest were bleeding and thrombotic complications.

Results

Overall, 35 patients underwent 56 invasive procedures, 18 (32.1%) were major. The median age was 36.3 years (IQR, 8.8-55.9 years); 12 patients (34.3%) were younger than 18 years at the time of procedure; 17 (48.6%) were patients with FVIII inhibitors. Among major procedures, orthopedic surgeries prevailed. All patients who underwent major procedures received factor replacement with either recombinant activated factor VII (patients with inhibitors) or FVIII (patients without inhibitors). Factor concentrates were administered prior to 32 (84.2%) of the minor procedures. Repeated doses were given according to international expert opinion recommendations and patients' condition.There were 7 bleeding events in 6 patients, 5 were major bleeds, including 1 patient who underwent a minor procedure without factor replacement. None of the patients experienced a thrombotic complication.

Conclusion

Invasive procedures can be performed safely in patients receiving emicizumab prophylaxis with close surveillance after surgery. Factor concentrates may be advised in selected patients undergoing minor procedures.

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.

Between Scylla and Charybdis: thrombosis in children with hemophilia

Thromboembolism is an infrequent complication in children with hemophilia that has been traditionally associated with the presence of a central venous access device. Novel rebalancing agents have shown promising results as prophylactic therapies to minimize the risk of bleeding but both thromboembolism and thrombotic microangiopathy have been reported as complications. The management of thrombosis in children with hemophilia is particularly challenging given the inherent risk of bleeding. In this paper, we present clinical vignettes to review the literature, highlight challenges, and describe our approach to managing thromboembolism in children with hemophilia.

Current and future therapies for haemophilia-Beyond factor replacement therapies

Some non-factor products that work by facilitating the coagulation pathway (emicizumab) and blocking the anticoagulant pathway (fitusiran, concizumab and marstacimab) for patients with haemophilia (H) have been developed, and clinical trials using these products are currently ongoing. Prophylaxis using non-factor products by subcutaneous administration provides marked reductions of bleeding episodes in patients with HA or HB, regardless of the presence of inhibitor. Emicizumab has already been approved globally. Emicizumab alters the phenotype of patients with HA from severe to mild by maintaining trough levels of equivalent factor VIII activity (15-20 iu/dl). Phase 3 clinical trials and long-term observations assessing emicizumab revealed tolerable safety and efficacy. However, thrombotic events have occurred in patients receiving these non-factor products. Furthermore, monitoring of the haemostatic function of these products with concomitant therapy is also required in clinical practice. These products have promising haemostatic efficiency, but wider clinical experience is needed to provide optimal therapeutic strategies in the future.

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.

Current Therapeutic Approach to Acute Myocardial Infarction in Patients with Congenital Hemophilia

Advances in the treatment of hemophilia have made the life expectancy of hemophiliacs similar to that of the general population. Physicians have begun to face age-related diseases not previously encountered in individuals with hemophilia. Treatment of acute myocardial infarction (AMI) is particularly challenging because the therapeutic strategies influence both the patient's thrombotic and hemorrhagic risk. As progress has been made in the treatment of AMI over the last decade, we performed an in-depth analysis of the available literature, highlighting the latest advances in the therapy of AMI in hemophiliacs. It is generally accepted that after the optimal substitution therapy has been provided, patients with hemophilia should be treated in the same way as those in the general population. New-generation stents that allow short dual antiplatelet therapy and potent P2Y12 receptor inhibitors have begun to be successfully used. At a time when specific recommendations and relevant data are scarce, our study provides up-to-date information to physicians involved in the treatment of AMI in hemophiliacs.

Bispecific antibodies for the treatment of hemophilia A

INTRODUCTION

Emicizumab is a bispecific antibody exerting cofactor function of FVIIIa irrespective of the presence of FVIII inhibitors. Long-term data of phase 1/2 and phase 3 studies have been accumulated. Various questions such as indicated patients, ITI, application to PUPs, hemostatic treatment including surgeries, and emicizumab-related morbidity remain to be solved.

AREAS COVERED

The review describes the mode of action, data from pre-/post-marketing and ongoing clinical studies according to PubMed search and our own works.

EXPERT OPINION

For patients with a persistent inhibitor, emicizumab is a definite therapeutic option, although the possibility of BPAs-associated thromboembolic/TMA events raises concerns. The use of ITI together with emicizumab prophylaxis is being examined in clinical trials. For non-inhibitor, especially pediatric patients, emicizumab prophylaxis can be an option. Outcome assessment 'beyond ABR' such as joint health, physical/mental activity, QOL is required. Furthermore, continuous data collection for emicizumab-related adverse events and morbidity would be recommended.

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.

Emicizumab prophylaxis: Prospective longitudinal real-world follow-up and monitoring

INTRODUCTION

Real-world data on prophylaxis of severe haemophilia A (HA) patients treated by emicizumab are scarce.

AIM

To study the efficacy and safety of longitudinal emicizumab prophylaxis and assess laboratory monitoring correlations in a large patient cohort.

METHODS

HA patients with and without FVIII inhibitors, initiating emicizumab prophylaxis, were prospectively enrolled. Bleeding, adverse events and surgeries were documented. FVIII inhibitors, emicizumab levels and thrombin generation (TG) were sequentially measured.

RESULTS

A total of 107 patients, including 58 children (whose median (IQR) age was 6 (1-11) years) with severe HA, composed the study cohort. Twenty-nine per cent (31/107) of our HA patients had FVIII inhibitors. Patients were followed for a median of 67 weeks (up to 144 weeks). Fifty-three patients, whose median follow-up was 53 weeks, experienced zero bleeds. Most bleeds (94%) among children were trauma-related, whereas 61% of adults sustained spontaneous joint bleeds. Four patients experienced major bleeds, with a fatal outcome in one infant, who also presented with central venous line thrombosis. No other serious adverse events were encountered. Seven patients have decided to stop emicizumab treatment for various reasons. Emicizumab plasma levels increased after emicizumab prophylaxis initiation, and values were maintained during follow-up, in all but one patient, suspected of anti-drug antibodies. A significant reduction of FVIII inhibitor levels was noted among inhibitor patients. TG was increased and sustained yet could not prognosticate bleeding risk.

CONCLUSION

Emicizumab prophylaxis was mostly well tolerated, although 50% of patients experienced breakthrough bleeds. Routine TG monitoring is not obligatory, and further studies are warranted in selected patient populations.

Safety evaluation of emicizumab prophylaxis in individuals with haemophilia A

INTRODUCTION

Emicizumab is a bispecific-humanized monoclonal antibody that improves hemostasis by bridging activated factor IX and factor X to substitute for the function of missing activated FVIII. It is an alternative to prophylaxis with factor VIII replacement and is associated with improved outcomes in individuals with hemophilia A with and without inhibitors.

AREAS COVERED

Emicizumab is efficacious in reducing bleeding events when compared to on-demand treatment and factor-based prophylaxis. Except for the few thrombotic microangiopathy and thrombotic event cases mainly seen in the HAVEN 1 trial, emicizumab has an overall excellent safety profile with minimal side effects.

EXPERT OPINION

Knowledge gaps include the efficacy and safety of emicizumab in younger age groups and those with mild or moderate hemophilia A. Future directions for research include exploring the risk of inhibitor recurrence in patients with a history of high titer inhibitor who have been successfully tolerized, who switch from factor prophylaxis to emicizumab, as well as conducting 'real world studies' to evaluate the patient's perception of emicizumab in regard to ease and tolerability in order to optimize individualized treatment plans.

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

INTRODUCTION

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The potential role of emicizumab prophylaxis in severe von Willebrand disease

BACKGROUND

Severe von Willebrand disease (VWD) may be associated with chronic joint damage and may require prophylactic therapy. Emicizumab is a humanized bispecific antibody, which mimics the function of coagulation factor VIII (FVIII), and it has been approved for prophylaxis in hemophilia A.

METHODS

This is the first study assessing the potential future role of emicizumab as an alternative prophylactic treatment in patients with severe VWD, based upon a thrombin generation (TG) ex vivo analysis. We report 51 weeks of successful off label emicizumab prophylaxis in a child with severe VWD and recurrent hemarthroses and progressive arthropathy despite adherence to previous prophylaxis with replacement therapy.

RESULTS AND CONCLUSIONS

Our work demonstrated that ex vivo spiking with emicizumab increased TG in plasma from patients with type 3 VWD. Similar TG results were observed in our treated patient, whose therapy was well tolerated without any adverse events. Both in vitro and ex vivo TG data support sufficient hemostasis without exceeding the range seen in healthy volunteers. Further collaborative studies on the efficacy and safety of emicizumab prophylaxis in severe VWD is warranted.