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

Efficacy and Safety of Recombinant Factor VIII in Previously Untreated and Previously Treated Children with Hemophilia A: A Systematic Review

INTRODUCTION

Inhibitor development is a primary concern for pediatric patients with hemophilia A (HA) undergoing recombinant factor VIII (rFVIII) therapy, yet relevant research is lacking. We aimed to compare the efficacy and safety of standard (SHL) and extended half-life (EHL) rFVIII products in previously treated (PTPs) and untreated (PUPs) pediatric patients with HA.

METHODS

Following PRISMA guidelines, we searched clinical studies from PubMed, Embase, and Cochrane Library. Data were extracted and a single-arm meta-analysis was performed.

RESULTS

This systematic review included 16 studies involving 1145 patients. Three studies reported changes in annual bleeding rate (ABR); their results displayed no statistically significant difference in ABR changes in pediatric patients with HA after rFVIII treatment. Ten studies reported inhibitor development, nine focused on PUPs. Here, EHL rFVIII showed a proportion of inhibitors at 27.5% (95% confidence interval [CI] 22.6%; 32.6%), and third-generation SHL rFVIII showed a proportion of inhibitors at 36.4% (27.2%; 46.2%), with a high-titer proportion of 20.9% (12.9%; 30.3%) for the latter. Both SHL rFVIII (octocog alfa) and EHL rFVIII (rurioctocog alfa pegol) presented low proportions of inhibitor development. Octocog alfa exhibited the lowest high-titer inhibitor incidence, marked at 12.7% (5.3%; 24.5%). Eleven studies addressed adverse events (AEs), with octocog alfa showing low reported treatment-related AEs at a proportion of 14.5% (6.5%; 26.7%).

CONCLUSION

Our analysis revealed that both octocog alfa and rurioctocog alfa pegol showed low inhibitor development, with octocog alfa having few treatment-related AEs. Regular monitoring for inhibitors during rFVIII therapy is important.

Bleeding Episodes in Patients With Haemophilia B Receiving Prophylactic Factor IX Treatment: A Systematic Review and Meta-Analysis

BACKGROUND

Prophylaxis with coagulation factor concentrates is the mainstay of treatment in severe hemophilia A and B. Data on bleeding rates in persons with congenital haemophilia B (PwcHB) receiving prophylaxis are inconsistent.

AIM

This systematic review and meta-analysis were aimed at assessing bleeding outcomes, including annualised bleeding rates (ABR) and the proportion of patients with zero bleeding events, in PwcHB receiving prophylaxis with plasma-derived or recombinant FIX products with standard (rSHL) or extended half-life (rEHL).

METHODS

A systematic search was conducted using the bibliographic database Medline, Embase and Cochrane Central Register. The protocol was registered on PROSPERO (registration number: CRD42024592785).

RESULTS

The search yielded 2440 citations and a total of 42 studies (2 randomised and 40 nonrandomised) were included in the final analysis. The pooled estimated mean (95% confidence interval [CI]) ABR was significantly lower in PwcHB treated prophylactically with rEHL FIX than in those receiving rSHL FIX products (1.29 [95% CI: 0.91, 1.66] vs. 3.12 [95% CI: 2.63, 3.62], p < 0.01). The proportion of participants with zero bleeding events was significantly higher in PwcHB treated prophylactically with rEHL FIX than in those receiving rSHL FIX (0.53 [95% CI: 0.37, 0.69] vs. 0.24 [95% CI: 0.14, 0.39], p = 0.01). The ABR did not differ according to age groups (more or less than 12 years).

CONCLUSION

The results of this meta-analysis suggest that compared to standard half-life FIX concentrates, prophylaxis with rEHL FIX products is associated with a reduction in ABR and a higher proportion of patients with no bleeding episodes.

The Evolution of Hemophilia Pharmacological Treatments and Therapeutic Targets at the Turn of the Third Millennium

Historically, the aim of treatment for hemophilia, the congenital X-linked hemorrhagic disorder due to deficiencies of coagulation Factor (F) VIII (hemophilia A) or FIX (hemophilia B), has been the replacement through factor concentrates, whose regular administration (i.e., prophylaxis) has been shown to be highly effective in preventing bleeding complications and it is currently considered the gold standard of hemophilia treatment. However, continuous technological progress (i.e., plasma-derived factor concentrates, recombinant standard and extended half-life [EHL] products) has allowed clinicians operating at hemophilia treatment centers to individualize the management of persons with hemophilia, improving outcomes, adherence to therapy, and their quality of life. The achievement of normal hemostasis, the final goal that now seems possible with new-generation EHL products, non-replacement and gene therapies, will translate into normalization of life for persons with hemophilia, also addressing health equity (i.e., rendering them indistinguishable from their healthy peers). The evolution of hemophilia treatment and, in parallel, of therapeutic targets in the management of hemophilia patients over the last decades will be critically discussed in this narrative review.

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.

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.