Bleeding events in people with congenital haemophilia A without factor VIII inhibitors receiving prophylactic factor VIII treatment: A systematic literature review

Defining success in haemophilia care - Are we doing it right?

INTRODUCTION

Transformational advances have occurred in the management of haemophilia in the last decade leading to much better outcomes. However, a detailed and critical examination of its assessment and reporting show gaps in many aspects. These are discussed in this review.

METHODS

The relevant literature related to different aspects of management of haemophilia was reviewed to identify gaps which need to be addressed. These include detection and diagnosis of haemophilia, documentation and reporting of joint bleeding, its management and methods of reporting in clinical trials and practice, aspects of personalizing care as well as access to therapeutic products and the need for and organization of comprehensive care.

RESULTS

Current diagnostic approaches have more than doubled the identified number of persons with haemophilia (PWH) over the last 25 years but still constitute only ∼30% of the expected number. Joint bleeding is the primary indicator of disease severity and treatment efficacy, but there is lack of consistency and standardization in the way it is recorded and reported. Its continued use as an efficacy measure of modern treatments which maintain steady state factor levels or equivalence of >5% will lack sensitivity. The treatment of acute haemarthrosis has focussed on haemostasis and pain control, ignoring the role of inflammation in joint damage. Phenotypic heterogeneity of severe haemophilia has recognized clinical and laboratory variations based on haemostasis but not differences in local response to blood in the joint. At the organizational level, IU/capita provides a relevant measure of access to therapeutic products when the detection rate is ∼100% but is fallaciously low when detection rates are very low. With highly effective modern therapies for haemophilia and nearly no bleeding, the concept of comprehensive care team will need modifications.

CONCLUSION

As haemophilia care advances, a deeper dive is needed into the details of various aspects its management to ensure consistency and contemporary relevance.

Long-term outcomes with emicizumab in hemophilia A without inhibitors: results from the HAVEN 3 and 4 studies

Background

Emicizumab, a bispecific monoclonal antibody, bridges activated factor (F) IX and FX, mimicking the function of missing or deficient activated FVIII in people with hemophilia A (HA).

Objectives

To evaluate the long-term efficacy and safety of emicizumab prophylaxis in people with HA without FVIII inhibitors in the HAVEN 3 and 4 studies.

Methods

HAVEN 3 and 4 were phase 3 open-label studies. Participants received emicizumab maintenance doses of 1.5 mg/kg every week or 3 mg/kg every 2 weeks (HAVEN 3), or 6 mg/kg every 4 weeks (HAVEN 4). Long-term efficacy and safety were assessed.

Results

A total of 151 and 40 individuals without FVIII inhibitors received emicizumab in HAVEN 3 and 4, respectively. At the last patient, last visit dates (May 12, 2022 [HAVEN 3] and June 29, 2022 [HAVEN 4]), the median (range) duration of emicizumab exposure across the 2 studies was 248.1 (6.1-287.1) weeks. The mean (95% CI) annualized bleed rate for treated bleeds was 2.0 (0.23-7.15) for weeks 1 to 24, decreasing to 0.9 (0.01-5.28) by weeks 217 to 240. Overall, 188 (98.4%) participants experienced ≥1 adverse event (AE), with 185 treatment-related AEs in 71 (37.2%) participants. Forty-four (23.0%) participants reported a serious AE. Two thromboembolic events were reported, which were deemed unrelated to emicizumab by the investigator. No thrombotic microangiopathies were reported.

Conclusion

With nearly 5 years of emicizumab exposure across the HAVEN 3 and 4 studies in people with HA without inhibitors, these data indicate continued bleed control with no new safety signals observed during long-term follow-up.

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.