Emicizumab in pediatric hemophilia: Bleeding and surgical outcomes from a single-center retrospective study

Reduced doses of emicizumab achieve good efficacy: Results from a national-wide multicentre real-world study in China

INTRODUCTION

Reduced doses of emicizumab improve the affordability among patients in developing countries. However, the relationship between variant dose selection and efficacy in the real world of China is still unclear.

AIM

This study aimed to investigate the efficacy and safety of emicizumab especially in those on reduced dose regimens in a real-world setting.

METHODS

We carried out a multicentre study from 28 hospitals between June 2019 and June 2023 in China and retrospectively analysed the characteristics including demographics, diagnosis, treatment, bleeding episodes, and surgical procedures.

RESULTS

In total, 127 patients with haemophilia A, including 42 with inhibitors, were followed for a median duration of 16.0 (IQR: 9.0-30.0) months. Median age at emicizumab initiation was 2.0 (IQR: 1.0-4.0) years. Median (IQR) consumption for loading and maintenance was 12.0 (8.0-12.0) and 4.2 (3.0-6.0) mg/kg/4 weeks, respectively. While on emicizumab, 67 (52.8%) patients had no bleeds, whereas 60 (47.2%) patients had any bleeds, including 26 with treated bleeds. Compared to previous treatments, patients on emicizumab had significantly decreased annualized bleeding rate, annualized joint bleeding rate, target joints and intracerebral haemorrhage. Different dosages had similar efficacy except the proportion of patients with treated spontaneous bleeds and target joints. Adverse events were reported in 12 (9.4%) patients. Postoperative excessive bleeding occurred following two of nine procedures.

CONCLUSION

This is the largest study describing patients with HA receiving emicizumab prophylaxis on variant dose regimens in China. We confirmed that nonstandard dose is efficacious and can be considered where full-dose emicizumab is ill affordable.

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.

Expert opinion paper on the treatment of hemophilia a with emicizumab

INTRODUCTION

Prophylaxis with emicizumab, a bispecific monoclonal antibody that mimics FVIII function, has shown encouraging results in clinical trials in terms of efficacy and safety. However, current experience is limited, and many areas of concern to clinicians have yet to be reviewed.

AREAS COVERED

This paper reviews the experience of hemophilia A patients treated with emicizumab based on the results of clinical trials and real-life studies. The authors place special emphasis on issues such as the management of these patients in situations of hemorrhage and/or surgical interventions, joint health or laboratory monitoring.

EXPERT OPINION

Treatment with emicizumab has been shown to improve joint health and reduce bleeding, of particular interest to patients with inhibitors and high bleeding rates. However, there are still concerns about its administration in neonates and previously untreated patients due to limited reported experience. Laboratory monitoring is not strictly necessary due to the stable pharmacokinetics emicizumab has been shown to exhibit, however, tests that globally assess hemostasis may be useful especially in cases of bleeding or surgery. The authors are also of the opinion that prophylaxis before minor surgery is not necessary and that major surgeries can be safely performed with additional prophylactic coagulation factor.Trial registration ClinicalTrials.gov identifier: NCT04431726..

Management of children with hemophilia A on emicizumab who need surgery

The introduction of emicizumab into the treatment regime of persons with hemophilia A has dramatically reduced frequency of bleeding in patients with and without inhibitors. However, in children with Hemophilia A (CwHA) who require surgical or other invasive procedures, additional treatment with factor replacement or other hemostatic agents may still be needed to prevent intraoperative or postoperative bleeding. This review will look at the reported outcomes in CwHA on emicizumab who have had surgery and propose recommendations for the best perioperative management of major and minor procedures.

Surgical outcomes in people with hemophilia A taking emicizumab prophylaxis: experience from the HAVEN 1-4 studies

Many people with hemophilia A (PwHA) undergo surgery in their lifetime, often because of complications of their disease. Emicizumab is the first bispecific monoclonal antibody prophylactic therapy for PwHA, and its efficacy and safety have been previously demonstrated; however, there is a need to build an evidence base on the management of PwHA on emicizumab undergoing surgery. Data from the HAVEN 1-4 phase 3 clinical trials were pooled to provide a summary of all minor and major surgeries in PwHA with or without factor VIII (FVIII) inhibitors who were receiving emicizumab prophylaxis. Overall, 233 surgeries were carried out during the HAVEN 1-4 trials: 215 minor surgeries (including minor dental and joint procedures, central venous access device placement or removal, and endoscopies) in 115 PwHA (64 with FVIII inhibitors) and 18 major surgeries (including arthroplasty and synovectomy) in 18 PwHA (10 with FVIII inhibitors). Perioperative hemostatic support was at the discretion of the treating physician. Overall, the median (interquartile range [IQR]) age was 33.5 (13.0-49.0) years and the median (IQR) emicizumab exposure time before surgery was 278.0 (177.0-431.0) days. Among the 215 minor surgeries, 141 (65.6%) were managed without additional prophylactic factor concentrate, and of those, 121 (85.8%) were not associated with a postoperative bleed. The majority (15 of 18 [83.3%]) of major surgeries were managed with additional prophylactic factor concentrate. Twelve (80.0%) of these 15 surgeries were associated with no intraoperative or postoperative bleeds. The data demonstrate that minor and major surgeries can be performed safely in PwHA receiving emicizumab prophylaxis. These trials are registered at www.clinicaltrials.gov as #NCT02622321, #NCT02795767, #NCT02847637, and #NCT03020160.

Emicizumab state-of-the-art update

Introduction

Emicizumab is a bispecific monoclonal antibody developed to address the unmet needs of clotting factor replacement therapy and has become the benchmark for optimal prophylaxis in managing patients with haemophilia A with inhibitors. We describe the emicizumab rollout and pharmacokinetic strategies and their use in paediatric patients.

Methods

The evolving real‐world experience in using emicizumab has confirmed its safety, efficacy and pharmacokinetic profile in paediatric, adolescent and adult patients receiving emicizumab at various prophylactic dosing regimens. The emicizumab current global rollout includes over 100 countries with 29 low to middle‐income countries accessing emicizumab through the World Federation of Haemophilia (WFH) Humanitarian Aid Program. The diversity of emicizumab dosing and pharmacokinetic tools such as the Calibra® and the WAPPS‐Hemo platforms make it possible to achieve prophylaxis goals in line with the WFH Haemophilia treatment guidelines recommendations, with minimal drug wastage. The emerging experience from long term clinical trials and long‐term real‐world follow‐up confirm the safety, efficacy, and pharmacokinetic profile of emicizumab in paediatric haemophilia A patients. A few questions, including inhibitor recurrence, concurrent use of emicizumab with various replacement therapies and inhibitor eradication, are being addressed through multiple ongoing clinical studies.

Conclusion

The current global rollout of emicizumab is remarkable, and versatile dosing regimens and evolving pharmacokinetic tools such as the Calibra® and WAPPS‐Hemo platforms make it a treatment choice available also for pharmacokinetic guided personalised treatment. Data from paediatric studies are consistent with those seen in adolescent and adult Haemophilia A.

Real-world experience of emicizumab prophylaxis in young children with hemophilia A: retrospective data from China

BACKGROUND

As a new non-factor therapy for hemophilia A (HA), real-world study of emicizumab is still scarce. This study aimed to investigate the real-world use of emicizumab in Chinese boys with HA.

METHODS

Patients with moderate or severe HA were enrolled at Beijing Children's Hospital. They take emicizumab weekly (3 mg/kg) for a month and then went into a maintenance period with a different dosing regimen. After obtaining platelet-poor plasma at end of the loading period and during the maintenance period, coagulation ability and FVIII inhibitor were determined using human and bovine chromogenic Bethesda assay. Patients' bleeding rates were calculated through patients' records from 24 weeks before to at least 6 months after the switch (to emicizumab).

RESULT

In total, 13 pediatric patients with HA (severe: moderate = 11:2) were enrolled in this study. The patients' age was 3.51 (0.73-6.65) years. Eight had FVIII inhibitors at enrollment and one of them developed FVIII inhibitors again during the switch. The coagulation level of the maintenance period was 19.6 (13.5-32.8) IU/dL (N = 10). The median dose of each emicizumab injection was 2.7 (1.3-3.8) mg/kg and the monthly consumption of emicizumab was 5.2 (3.2-6.8) mg/kg/month. After switching to emicizumab, reduced annualized bleeding rate (ABR) [0.5 (0-4) vs. 4 (0-18), P < 0.01], annualized joint bleeding rate (AJBR) [0 (0-1.1) vs. 1.0 (0-12), P < 0.01], and annualized spontaneous bleeding rate (ASBR) [0 (0-1) vs. 2.0 (0-18), P < 0.01] were observed. In patients with or without FVIII inhibitor, similar ABR [0.33 (0-4) vs. 0.5 (0-3), P = 0.78], AJBR [0 (0-1.1) vs. 0 (0-0.5), P = 0.63], and ASBR [0 (0-1) vs. 0 (0-1.5), P = 0.73] were also noticed. Five inhibitor-positive patients (at enrollment) all had their inhibitor titer reduced. In addition, all target joints vanished after switching to emicizumab.

CONCLUSION

Emicizumab could reduce bleeds in pediatric patients with/without FVIII inhibitors and eliminate target joints.