Mortality in congenital hemophilia A - a systematic literature review

Optimizing liver health before and after gene therapy for hemophilia A

ABSTRACT

Gene therapy for severe hemophilia A uses an adeno-associated virus (AAV) vector and liver-specific promoters that depend on healthy hepatocyte function to achieve safe and long-lasting increases in factor VIII (FVIII) activity. Thus, hepatocyte health is an essential aspect of safe and successful gene therapy. Many people living with hemophilia A have current or past chronic hepatitis C virus infection, metabolic dysfunction-associated steatosis or steatohepatitis, or other conditions that may compromise the efficacy and safety of AAV-mediated gene therapy. In addition, gene therapy may induce an immune response to transduced hepatocytes, leading to liver inflammation and reduced FVIII activity. The immune response can be treated with immunosuppression, but close monitoring of liver function tests and factor levels is necessary. The long-term risk of hepatocellular carcinoma associated with gene therapy is unknown. Routine screening by imaging for hepatocellular carcinoma, preferable every 6 months, is essential in patients at high risk and recommended in all recipients of hemophilia A gene therapy. This paper describes our current understanding of the biologic underpinnings of how liver health affects hemophilia A gene therapy, and provides practical clinical guidance for assessing, monitoring, and managing liver health both before and after gene therapy.

Liver health in hemophilia in the era of gene therapy

Gene therapy for hemophilia is a groundbreaking treatment approach with promising results and potential to reduce the burden of the disease. However, uncertainties remain, particularly regarding the liver side effects of AAV gene therapy, which are more common in hemophilia A. Unlike some other diseases, such as spinal muscular atrophy, where the target cell for gene therapy is different from the one affected by side effects, hemophilia gene therapy operates within the same cellular domain-the hepatocyte. This overlap is challenging and requires a targeted strategy to mitigate the risks associated with liver injury, which often requires temporary immunosuppressive therapy. A comprehensive approach is essential to increase the efficacy of gene therapy and reduce the likelihood of hepatocyte damage. Key components of this strategy include a thorough pre-gene therapy assessment of liver health, careful post-gene therapy liver monitoring, and prompt therapeutic intervention for loss of transgene expression and liver injury. Collaboration between hematologists and hepatologists is essential to ensure a well-coordinated management plan for patients undergoing hemophilia gene therapy. This review addresses the critical aspect of hepatic comorbidities in patients with hemophilia, emphasizing the need to identify and address these issues prior to initiating gene therapy. It examines the known mechanisms of liver damage and emphasizes the importance of liver monitoring after gene therapy. In addition, the review draws insights from experiences with other AAV-based gene therapies, providing valuable lessons that can guide hemophilia centers in effectively managing liver damage associated with hemophilia gene therapy.

Evaluating Factor VIII Concentrates Using Clot Waveform Analysis

Background/Objectives: FVIII reagent activity varies across different assays, as well as activated partial thromboplastin time (APTT) reagents. The hemostatic ability of various FVIII reagents was examined via clot waveform analysis (CWA). Methods: APTT was measured using 12 APTT reagents, a small amount of tissue factor-induced FIX activation (sTF/FIXa) and a small amount of thrombin time (sTT) in order to examine 10 FVIII reagents and reference plasma (RP) using CWA. FVIII activity was measured using CWA-APTT, a chromogenic assay, or CWA-sTT. Results: Although the peak time (PT) and peak height (PH) of the CWA-APTT were markedly different in different FVIII reagents using several APTT reagents, the PTs of CWA-APTT were generally normal or shortened and the PHs of CWA-APTT were generally lower than those of RP. The FVIII activity varied, as evaluated using APTT, and was higher when using the CWA-sTT method than the APTT or chromogenic methods. CWA-sTT showed an elevated second peak of first DPH in all FVIII reagents, and both CWA-sTF/FIXa and CWA-sTT were enhanced using APTT reagents. Conclusions: Our evaluation of the hemostatic ability of FVIII reagents varied among APTT reagents. CWA-sTT can be used to further evaluate the hemostatic ability of an FVIII concentrate based on thrombin burst.

Reducing the risk of atherosclerotic cardiovascular disease in people with hemophilia: the importance of primary prevention

Revolutionary advances in the treatment of hemophilia has led to a significant improvement in life expectancy. Associated with this has been an increase in age-related diseases especially atherosclerotic cardiovascular disease (CVD). While people with hemophilia (PWH) develop atherosclerosis at rates similar to those of the general population, rates of atherothrombosis and mortality related to CVD have been much lower, due to their hypocoagulable state. Changing treatment paradigms, aimed at reducing the risk of bleeding by improving hemostasis to levels approaching normality, has meant that the protection they are thought to have had may be lost. CVD risk factors are just as common in PWH as in the general population, but appear to be undertreated. In particular, primary prevention of CVD is vital in all individuals, but particularly in PWH as treatment of established CVD can be difficult. Active identification and management of CVD risk factors, such as obesity, physical inactivity, hypertension, and hypercholesterolemia, is required. In particular, statins have been shown to significantly reduce cardiovascular and all-cause mortality with few adverse events and no increased risk of bleeding in the general population, and their use needs urgent assessment in PWH. Further longitudinal research into preventing CVD in PWH, including accurate CVD risk assessment, is required to optimize prevention and management.

Safety and efficacy of combined dual antiplatelet therapy and factor VIII prophylaxis in patients with haemophilia A after acute coronary syndrome

INTRODUCTION

The increased life expectancy of patients with haemophilia A (HA) has led to a growing prevalence of cardiovascular risk factors and events. There is still scarce evidence on the safety and appropriate duration of dual antiplatelet therapy (DAPT) after acute coronary syndrome (ACS) in HA patients.

AIM

We describe our experience on the clinical management of Italian HA patients after ACS.

METHODS

Nine patients with congenital HA treated with DAPT after a revascularization procedure performed for ACS have been enrolled and followed at the Angelo Bianchi Bonomi Haemophilia and Thrombosis Center in Milan between 2005 and September 2022. The safety and efficacy of DAPT with or without FVIII prophylaxis were assessed.

RESULTS

Ten ACS events occurred in the nine HA patients (four mild and five severe). All events were treated with percutaneous transluminal coronary angioplasty with deployment of 1 to 3 drug-eluting stents followed by DAPT for 1-12 months. All patients except one were treated with FVIII prophylaxis during DAPT aimed at achieving FVIII trough levels ≥20-30 IU/dL. DAPT was effective in all cases in preventing early ACS recurrence, with only a late recurrence. We observed two clinically relevant non-major bleeds (one in a patient without FVIII prophylaxis) and three minor bleeds. No venous thrombosis occurred.

CONCLUSION

The long-term secondary antithrombotic prevention consisting of DAPT and FVIII prophylaxis achieving a trough level of 20-30 IU/dL can be effective and safe in HA patients.

Emicizumab is efficacious in people with hemophilia A with comorbidities aged ≥50 years: analysis of 4 phase III trials

Background

The treatment of older people with hemophilia A (HA) can be complicated by comorbidities.

Objectives

This post hoc analysis evaluates the efficacy and safety of emicizumab in people with HA aged ≥50 years with cardiovascular (CV) risk factors or HIV and/or hepatitis C virus (HCV) infection.

Methods

The HAVEN 1 (NCT02622321), HAVEN 3 (NCT02847637), HAVEN 4 (NCT03020160), and STASEY (NCT03191799) studies enrolled adults/adolescents with severe HA. Participants were categorized as having a comorbidity if they had any CV risk factors (including history of CV disease, hypertension, diabetes, hyperlipidemia, prior stroke, or obesity), HIV, and/or HCV infection. Efficacy and safety outcomes were compared by age (<50 vs ≥50 years).

Results

Of 504 participants at data cutoff, 408 were aged <50 years and 96 were aged ≥50 years. In people with HA aged <50 years, 26.7% had ≥1 CV risk factor and 29.4% had HIV and/or HCV infection. In people with HA aged ≥50 years, 72.9% had ≥1 CV risk factor and 74.0% had HIV and/or HCV infection. The mean (95% CI) annualized bleed rate for treated bleeds was 1.29 (0.07-6.06) for people with HA aged <50 years and 1.82 (0.19-6.93) for people with HA aged ≥50 years. No significant differences in annualized bleed rates were observed for those with comorbidities compared with those without. Safety outcomes were similar regardless of age.

Conclusion

This pooled analysis suggests that emicizumab efficacy and safety in people with HA aged ≥50 years with CV and HIV/HCV comorbidities were consistent with those in people with HA aged <50 years enrolled in the HAVEN 1, 3, and 4 and STASEY studies.

Personalized Prophylaxis with myPKFiTCE: A Real-World Cost-Effectiveness Analysis in Haemophilia A Patients

Background and Objectives: This study aimed to assess the effectiveness and costs associated with pharmacokinetics-driven (PK) prophylaxis based on the myPKFiT® device in patients affected by hemophilia A (HA) in Italy. Materials and Methods: An observational retrospective study was conducted in three Italian hemophilia centers. All patients with moderate or severe HA, aged ≥ 18 years, capable of having PK estimated using the myPKFiT device, and who had had a clinical visit between 1 November 2019 and 31 March 2022 were included. Differences in clinical, treatment, health resources, and cost data were assessed comparing post-PK prophylaxis with pre-PK. The incremental cost-effectiveness ratio (ICER) was estimated as cost (EUR) per bleed avoided. Results: The study enrolled 13 patients with HA. The mean annual bleeding rate decreased by -1.45 (-63.80%, p = 0.0055) after the use of myPKFiT®. Overall, the consumption of FVIII IU increased by 1.73% during follow-up compared to the period prior the use of the myPKFiT. Prophylaxis based on the myPKFiT resulted in an ICER of EUR 5099.89 per bleed avoided. Conclusions: The results of our study support the idea that the use of PK data in clinical practice can be associated with an improvement in the management of patients, as well as clinical outcomes, with a reasonable increase in costs.

Emicizumab prophylaxis for people with hemophilia A: Waste estimation and the Brazilian perspective

Costs of hemophilia A treatment are increasing. Waste of clotting products should be avoided. To estimate the first-year waste of emicizumab prophylaxis for people with hemophilia A and inhibitors (PwHAi) who failed immune tolerance induction (ITI), in Brazil. We evaluated the manufacturer and the Brazilian Ministry of Health (MoH) protocol-recommended regimens in a budget impact model. The loading dose consisted of 3.0 mg/kg/Q1W for 4 weeks, for both recommendations. The manufacturer maintenance regimens comprised 1.5 mg/kg/Q1W, 3.0 mg/kg/Q2W, and 6.0 mg/kg/Q4W. The MoH protocol maintenance regimen encompassed a hybrid Q1W/Q2W administration, depending on the body weight. The Q4W regimen was not recommended by the MoH protocol. Analyses were performed to estimate waste given its expense based on the World Health Organization body weight range (percentiles [P] 15, 50, and 85). The first-year emicizumab waste was estimated individually and for the disclosed PwHAi who failed ITI (n = 114). The highest emicizumab waste was estimated for the lowest body weights and the Q1W regimen. The Q4W regimen resulted in the lowest emicizumab waste, followed by the MoH protocol regimen. The total reconstituted costs estimated for the PwHAi who failed ITI according to the hybrid MoH protocol ranged from US$32,858,777 (P15) to US$47,186,858 (P85), with emicizumab waste ranging from 7.9 % (US$2,594,515) to 3.7 % (US$1,738,750), respectively. Lost resources due to current protocols for emicizumab prophylaxis for PwHAi who failed ITI in Brazil are considerable. Waste was more pronounced due to lower body weight and shorter administration intervals.

Residual burden of liver disease after HCV clearance in hemophilia: a word of caution in the era of gene therapy

Ruling out advanced fibrosis/cirrhosis is mandatory for persons with hemophilia (PWH) who are candidates for gene therapy. However, clinical evaluation and noninvasive tests (NITs) may be inaccurate after hepatitis C virus (HCV) clearance. We conducted a prospective hepatological screening to detect advanced fibrosis/cirrhosis in PWH after HCV clearance. Any risk factor of chronic liver damage was registered by using biochemical data, liver stiffness measurement (LSM), and ultrasound (US). A pre/post-HCV clearance analysis was conducted prospectively in a subgroup of patients who underwent LSM, US, and NITs for fibrosis. We evaluated 119 patients (median age, 53 years; range, 36-87 years) with a previous HCV infection (hemophilia A, n = 108; hemophilia B, n = 11). Ninety-six (81%) presented at least 1 potential risk factor of chronic liver damage. Metabolic risk factors were the most prevalent, with 51 patients (44%) having US steatosis. In 21 patients (18%), clinical, biochemical, liver morphology, and/or LSM were suggestive of advanced fibrosis/cirrhosis. Furthermore, 10 patients (8%) had esophageal varices and 3 (3%) had hepatocellular carcinoma. In 57 patients included in the prospective analysis, LSM and NITs were reduced after HCV clearance (P < .05), but US signs specific of cirrhosis remained unchanged. Overall, 23 of 80 patients (29%) with LSM <10 KPa had at least 1 US sign suggestive of advanced fibrosis/cirrhosis. A similar proportion (18%) was observed for LSM <8 KPa. Overall, risk factors of chronic liver damage are frequent after HCV clearance, but changes in LSM and NITs after clearance may be inaccurate to rule out advanced fibrosis/cirrhosis. A specific diagnostic workup is warranted to evaluate liver health in PWH in the era of gene therapy.

A Qualitative Study Exploring the Experiences and Perceptions of Patients with Hemophilia Regarding Their Health-Related Well-Being, in Salamanca

Hemophilia is a chronic, congenital/hereditary and X-linked disease, characterized by an insufficiency of factors VIII or IX, which are necessary for blood clotting. Those affected by hemophilia often suffer from particular psychosocial problems, both in the acceptance, coping, treatment and self-management of their disease and in their family and social relationships, which are often mediated by these circumstances. The aim of this study was to explore the experiences of people with hemophilia or their family members, of in a specific region of Spain, regarding the impact of having hemophilia. Structured interviews were conducted and developed, using the studies of the World Federation of Hemophilia and Osorio-Guzmán et al. as a guide, as well as a literature review of qualitative work on hemophilia. Data were analyzed using a six-step thematic analysis. A total of 34 interviews were thematically analyzed. The results showed that three key themes emerged from the data: (1) the daily impact of having hemophilia, (2) uncertainty about the disease, (3) the role of associations and (4) support from institutions. The results make it clear that the disease has a major impact on their lives (work, family, leisure and personal environment). The main conclusion is that hemophilia has a negative impact on the daily lives of patients, families and caregivers.

Complication Analysis in Korean Patients With Hemophilia A From 2007 to 2019: A Nationwide Study by the Health Insurance Review and Assessment Service Database

BACKGROUND

There has been remarkable progress in hemophilia A (HA) treatment in Korea. Viral inactivation products were developed in 1989, use of recombinant factor VIII (FVIII) concentrates started in 2002, and prophylaxis expanded thereafter. This study was conducted to identify the changes in complications in HA before and after 1989 or 2002.

METHODS

The study was performed using the 2007-2019 Healthcare Big Data Hub of the Health Insurance Review and Assessment Service.

RESULTS

Among 2,557 patients, 1,084 had ≥ 1 complication; 829 had joint problems, 328 had viral infections, 146 had neurologic sequelae, and 87 underwent 113 surgeries or procedures due to complications. Patients born after 1989 had a significantly lower risk of viral infections than those born before 1989; 27.1% vs. 1.4% (P < 0.001, odds ratio [OR], 0.037). Patients born after 2002 had a significantly lower risk of joint problems than those born before 2002; 36.8% vs. 24.7% (P < 0.001, OR, 0.538). Patients born after 2002 had a higher incidence of neurologic sequelae than those born before 2002; 3.7% vs. 11.1% (P < 0.001, OR, 3.210). Medical expenses for complication-associated surgeries or procedures were ₩2,957,557,005.

CONCLUSION

Viral infections have significantly decreased in Korean patients with HA. The degree of reduction of joint problems was lower than we expected, because it took > 10 years to expand prophylaxis widely. Neurologic sequelae have not decreased; thus, additional efforts to decrease intracranial hemorrhage are needed. We suggest personalized dosing of FVIII and more meticulous care during childbirth to further reduce the complications.

A polymer-based systemic hemostat for managing uncontrolled bleeding

Uncontrolled bleeding is a life-threatening emergency that requires immediate intervention. Currently available on-site bleeding interventions largely rely on the use of tourniquets, pressure dressing, and other topical hemostatic agents, which can only treat bleeding injuries that are known, accessible, and potentially compressible. Synthetic hemostats that are stable at room temperature, easy to carry, field-usable, and able to stop internal bleeding at multiple or unknown sources, are still lacking. We recently developed a hemostatic agent via polymer peptide interfusion (HAPPI), which can selectively bind to activated platelets and injury sites after intravascular administration. Here we report that HAPPI is highly effective in treating multiple lethal traumatic bleeding conditions in normal as well as hemophilia models via either systemic administration or topical application. In a rat liver traumatic model, intravenous injection of HAPPI resulted in a significant decrease in blood loss and a four-fold reduction in mortality rate within 2 h after injury. When applied topically on liver punch biopsy wounds in heparinized rats, HAPPI achieved a 73% of reduction in blood loss and a five-fold increase in survival rate. HAPPI also exhibited hemostatic efficacy in hemophilia A mice by reducing blood loss. Further, HAPPI worked synergistically with rFVIIa to induce immediate hemostasis and 95% reduction in total blood loss compared to the saline-treated group in hemophelia mice models. These results demonstrate that HAPPI is a promising field-usable hemostatic agent for a broad range of different hemorrhagic conditions.

Trends in prescribing practices for management of haemophilia: 1999-2021

INTRODUCTION

People with haemophilia rely on specialists for their care, yet the specific dosing regimens of treatments prescribed by these specialists have not been widely studied.

AIM

The objective of this study is to describe trends in clinician prescribing practices for the management of haemophilia in the United States (US).

METHODS

We administered surveys to members of the Hemostasis and Thrombosis Research Society via paper surveys at its in-person annual symposia in 1999 and 2015, and an online survey in 2021. The surveys collected information on haemophilia treatments including factor dosing, inhibitor therapy and gene therapy.

RESULTS

Clinicians treating haemophilia for more than 50% of their practice time have increased from 37.5% of respondents in 1999 to 46.3% in 2021. Clinicians prescribing factor concentrates at >40 units/kg for routine bleeding events increased from 0% in 1999 to 29.3% in 2021 in haemophilia A (HA) and from 22.5% to 87.8% in haemophilia B (HB). In 2021, the clinicians reported prescribing emicizumab to treat HA patients (>89.5% paediatric, >85.7% adult) with or without inhibitors at least some of the time. Approximately 78.0% of respondents reported that they expected to recommend gene therapy at least some of time.

CONCLUSION

These data indicate changing trends in prescribing practices among US haemophilia specialists during the past 22 years. Preference for high doses of factor (>40 units/kg) has increased during this period. Emicizumab prophylaxis has been prescribed for patients with and without HA inhibitors. Clinicians expect gene therapy to have value for some haemophilia patients.

The von Willebrand factor-binding aptamer rondaptivon pegol as a treatment for severe and nonsevere hemophilia A

Factor VIII (FVIII) circulates in a noncovalent complex with von Willebrand Factor (VWF), the latter determining FVIII half-life. The VWF-binding aptamer rondaptivon pegol (BT200) increases plasma levels of VWF/FVIII in healthy volunteers. This trial assessed its safety, pharmacokinetics, and pharmacodynamics in hemophilia A. Nineteen adult patients (ages 20-62 years, 4 women) with hemophilia A (8 mild, 2 moderate, and 9 severe) received subcutaneous injections of rondaptivon pegol. After an initial fixed dose of 3 mg on days 0 and 4, patients received weekly doses of 2 to 9 mg until day 28. Severe hemophilia A patients underwent sparse-sampling population pharmacokinetics individual profiling after the final dose of rondaptivon pegol. Adverse events, pharmacokinetics, and pharmacodynamics were assessed. FVIII activity and VWF levels were measured. All patients tolerated rondaptivon pegol well. The geometric mean half-life of rondaptivon pegol was 5.4 days and rondaptivon pegol significantly increased VWF levels. In severe hemophilia A, 6 doses of rondaptivon pegol increased the half-lives of 5 different FVIII products from a median of 10.4 hours to 31.1 hours (range, 20.8-56.0 hours). Median FVIII increased from 22% to 48% in mild hemophilia A and from 3% to 7.5% in moderate hemophilia A. Rondaptivon pegol is a first-in-class prohemostatic molecule that extended the half-life of substituted FVIII approximately 3-fold and increased endogenous FVIII levels approximately 2-fold in hemophilia patients. This trial was registered at www.clinicaltrials.gov as #NCT04677803.

Cost-effectiveness analysis of recombinant factor IX Fc fusion protein compared with recombinant factor IX for the treatment of moderate-severe to severe hemophilia B in China

OBJECTIVE

To evaluate the lifetime cost-effectiveness of recombinant factor IX Fc fusion protein (rFIXFc) and recombinant factor IX (rFIX) for the treatment of hemophilia B (HB) in China.

METHODS

We developed a decision-analytic Markov model including three health states: alive, requiring surgery, and dead. This model estimated the lifetime cost and quality-adjusted life-years (QALYs) of prophylaxis in childhood, followed by on-demand treatment in adulthood for moderate-severe to severe HB patients from China's healthcare system perspective. Efficacy data derived from pivotal clinical trials, clinical guideline recommendations, and expert consultation were applied to two scenarios (full dose and low dose). One-way sensitivity analysis and probabilistic sensitivity analysis (PSA) were performed to assess the robustness of the model.

OUTCOMES

Lifetime cost, QALYs, and the incremental cost-effectiveness ratio were calculated, and the results were compared with willingness-to-pay (WTP) thresholds of one to three times the gross domestic product per capita of China in 2021 ($12,551-$37,653).

RESULTS

RFIXFc was associated with lower cost and more QALYs than rFIX in both scenarios, which suggested that it is a dominant strategy (more effective and cheaper) for moderate-severe to severe HB in China. In the full-dose scenario, rFIXFc saved more money and yielded more QALYs than in the low-dose scenario (low doses are the typical clinical reality in China). PSA demonstrated that rFIXFc had an over 90% probability of being cost-effective with full-dose and low-dose treatment at WTP thresholds of $12,551-$37,653.

CONCLUSIONS

Compared with rFIX, rFIXFc appears to be a cost-effective option for the lifetime management of moderate-severe to severe HB patients in China.

Prevalence of selected bleeding and thrombotic events in persons with hemophilia versus the general population: A scoping review

Life expectancy for persons with hemophilia has increased over recent decades due to advances in treatment practice and patient care. Those with hemophilia are now more likely to be affected by conditions associated with aging, such as myocardial infarction, hemorrhagic/ischemic stroke, deep vein thrombosis, pulmonary embolism, and intracranial hemorrhage. Here, we describe the results of a literature search designed to summarize current data on the prevalence of the above selected bleeding and thrombotic events in persons with hemophilia vs the general population. A total of 912 articles published between 2005 and 2022 were identified in a search of BIOSIS Previews, Embase, and MEDLINE databases conducted in July 2022. Case studies, conference abstracts, review articles, studies focusing on hemophilia treatments or surgical outcomes, and studies examining patients with inhibitors only were excluded. After screening, 83 relevant publications were identified. The prevalence of bleeding events was consistently higher in hemophilia populations vs reference populations (hemorrhagic stroke, 1.4%-5.31% vs 0.2%-0.97%; intracranial hemorrhage, 1.1%-10.8% vs 0.04%-0.4%). Serious bleeding events showed a high rate of mortality with standardized mortality ratios for intracranial hemorrhage ranging from 3.5 to 14.88. Although 9 studies reported lower prevalence of arterial thrombosis (myocardial infarction/stroke) in hemophilia vs general populations, 5 studies reported higher or comparable prevalence in hemophilia. Prospective studies are therefore needed to understand the prevalence of bleeding and thrombotic events in hemophilia populations, particularly with the observed increases in life expectancy and availability of novel treatments.

Gene Therapy and Hemophilia: Where Do We Go from Here?

Gene therapy for hemophilia using adeno-associated virus (AAV) derived vectors can reduce or eliminate patients' disease-related complications and improve their quality of life. Broad implementation globally will lead to societal gains and foster health equity. Several vector products each for factor IX (FIX) or factor VIII (FVIII) deficiency are in advanced clinical development. Safety data are reassuring. Efficacy data for up to 8 and 5 years, respectively, vary considerably among vector types and among individuals, but indicate significant reduction in bleeds and factor use. Products will soon be approved for marketing. This review highlights the relevant considerations for implementation of hemophilia gene therapy, specifically across a broad range of socioeconomic backgrounds globally, based on recent publications and our own experience. We address the current efficacy and safety data and relevant aspects of vector immunology. We then discuss pertinent implementation steps including pre-implementation and readiness assessments, considerations on cost, cost-effectiveness and payment models, approaches to education and informed consent, and the operational needs as well as the need for monitoring of health outcomes and implementation outcomes. To prevent a lag or complete lack of establishing access to this life-changing therapy option for all patients with hemophilia worldwide, adaptable pathways supported by collaborative and international efforts of all stakeholders are needed.

Cost-Effectiveness Analysis of Pharmacokinetic-Guided Prophylaxis Versus Standard Prophylaxis in Adults with Severe Hemophilia A in China

INTRODUCTION

Multiple studies have demonstrated the effectiveness of pharmacokinetic (PK)-guided individualized prophylaxis with human coagulation factor VIII (FVIII) compared with standard prophylaxis, but no studies have evaluated the economics of PK-guided prophylaxis in China. Hence, we conducted this study to assess the cost-effectiveness of PK-guided prophylaxis with recombinant FVIII (rFVIII) versus standard prophylaxis in Chinese adult patients with severe hemophilia A.

METHODS

A discrete event simulation model was developed to simulate 10,000 patients with hemophilia A who received rFVIII treatment over a 1-year time horizon. The standard prophylaxis rFVIII dose was 30 IU/kg by intravenous injection. The PK-guided prophylaxis dosage was adjusted for each patient to maintain FVIII trough level at 1-5 IU/dL. Dosing interval for both approaches was kept fixed at 48 h. The health outcomes included annual joint bleed rate (AJBR) and quality-adjusted life years (QALYs). The model considered the costs of drug. Incremental cost-effectiveness ratio (ICER) was estimated and scenario analysis was performed.

RESULTS

A total of 94.3% of patients receiving PK-guided individualized prophylaxis achieved the goal of maintaining the trough concentration at 1-5 IU/dL compared with 62.7% on standard prophylaxis. AJBR and QALYs gained in PK-guided and standard prophylaxis were 1.527 vs 1.601, and 0.8384 vs 0.8383, respectively. Costs of drug prophylaxis and costs of treatment for bleeding events in PK-guided prophylaxis (148,641.47 USD; 4546.43 USD) were lower than those in standard prophylaxis (159,620.93 USD; 4753.39 USD). An average saving of USD 11,186.47 was obtained by the PK-guided approach. The prophylaxis treatment scenarios were the most influential factors.

CONCLUSION

PK-guided individualized prophylaxis appeared to be a dominant treatment compared with standard prophylaxis, with slightly higher QALYs but lower total costs.

Blood pressure in persons with haemophilia with a focus on haemophilia-specific risk factors

INTRODUCTION

Persons with haemophilia (PWH) have a higher prevalence of hypertension compared to the general population, which cannot be explained entirely by the usual cardiovascular risk factors. Neutralizing antibodies (inhibitors) against clotting factors might have some relation to cardiovascular disease in PWH. However, whether inhibitors facilitate hypertension is unknown.

AIM

We investigated the relationship between hypertension/blood pressure and inhibitors in PWH. Additional goals were to determine the relationships with haemophilia type, race, and viral status.

METHODS

Records were extracted retrospectively for PWH (age ≥18 years) between 2003 and 2014 from four Hemophilia Treatment Centers in North America and included demographics, weight, height, haemophilia type/severity, HCV and HIV infection status, hypertension, use of anti-hypertensive medications, and inhibitor status. We fitted semiparametric generalized additive models (GAMs) to describe adjusted curves of blood pressure (BP) against age.

RESULTS

Among 691 PWH, 534 had haemophilia A and 157 had haemophilia B, with a median age of 39 years (range 18 to 79). Forty-four PWH (6.5%) had a history of inhibitors, without evidence for a higher prevalence of hypertension or higher BP. A higher prevalence of hypertension and higher BP were noted for haemophilia A (vs. haemophilia B), coinfection with HCV/HIV (vs. uninfected), or moderate haemophilia (vs. severe haemophilia).

CONCLUSION

While there was no signal to suggest that a history of inhibitors is associated with hypertension, differences based on haemophilia type, severity, and viral infection status were identified, encouraging prospective investigations to better delineate haemophilia-specific risk factors for hypertension.

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.

Cardiovascular disease in hereditary haemophilia: The challenges of longevity

The development of effective and safe treatments has significantly increased the life expectancy of persons with haemophilia (PWH). This has been accompanied by an increase in the comorbidities of ageing including cardiovascular disease, which poses particular challenges due to the opposing risks of bleeding from haemophilia and antithrombotic treatments versus thrombosis. Although mortality secondary to coronary artery disease in PWH is less than in the general population, the rate of atherosclerosis appears similar. The prevalence of atrial fibrillation in PWH and risk of secondary thromboembolic stroke are not well established. PWH can be safely supported through acute coronary interventions but data on the safety and efficacy of long-term antithrombotics are scarce. Increased awareness and research on cardiovascular disease in PWH will be crucial to improve primary prevention, acute management, secondary prevention and to best support ageing PWH.

Determining causes of death among individuals with haemophilia in Afghanistan

INTRODUCTION

Haemophilia is a well-known bleeding disorder that affects people worldwide. The main therapeutic strategy is regular infusion of exogenous factor VIII to ensure an optimal haemostatic standard. Morbidity and mortality of individuals with haemophilia has decreased in developing countries due to improvement in early detection, advanced treatments, and comprehensive population outreach efforts. However, individuals with bleeding disorders in developing countries like Afghanistan do not have access to such therapeutic facilities.

AIMS

The goals of this study were to determine the causes of death and findings related to death among in individuals with bleeding disorders in Afghanistan.

METHODS

This study conducted as a retrospective cross-sectional study of 387 individuals with bleeding disorders (mainly haemophilia) in Afghanistan.

RESULTS

All registered individuals with bleeding disorders in Afghanistan were interviewed by telephone. Among the 387 individuals with bleeding disorders, there were 136 deaths. Most deaths occurred in individuals aged 1-15 years (66.2%). Intracranial haemorrhage was the leading cause of death in individuals with haemophilia A and B.

CONCLUSION

These findings revealed that supply of coagulation factor concentrates, facilities for haemostasis diagnosis, and trained haematologists is inadequate in Afghanistan.

Hemophilia A Gene Therapy: Current and Next-Generation Approaches

INTRODUCTION

: Hemophilia comprises a group of X-linked hemorrhagic disorders that result from a deficiency of coagulation factors. The disorder affects mainly males and leads to chronic pain, joint deformity, reduced mobility, and increased mortality. Current therapies require frequent administration of replacement clotting factors, but the emergence of alloantibodies (inhibitors) diminishes their efficacy. New therapies are being developed to produce the deficient clotting factors and prevent the emergence of inhibitors.

AREAS COVERED

: This article provides an update on the characteristics and disease pathophysiology of hemophilia A, as well as current treatments, with a special focus on ongoing clinical trials related to gene replacement therapies.

EXPERT OPINION

: Gene replacement therapies provide safe, durable, and stable transgene expression while avoiding the challenges of clotting factor replacement therapies in patients with hemophilia. Improving the specificity of the viral construct and decreasing the therapeutic dose are critical toward minimizing cellular stress, induction of the unfolded protein response, and the resulting loss of protein production in liver cells. Next-generation gene therapies incorporating chimeric DNA sequences in the transgene can increase clotting factor synthesis and secretion, and advance the efficacy, safety, and durability of gene replacement therapy for hemophilia A as well as other blood clotting disorders.

Successful treatment of Japanese hemophilia patient co-infected with HIV and HCV genotype 4a by glecaprevir/pibrentasvir therapy

Although direct-acting antiviral (DAA)-based anti-hepatitis C virus (HCV) therapies are very effective for patients with genotypes 1 and 2, evidence of the efficacy of DAA-based therapy for the special population of patients with genotypes 3-6 is insufficient due to the relatively small number of these subjects in Japan. Human immunodeficiency virus (HIV)/HCV-co-infected patients are recommended to be treated as HCV-mono-infected patients by the latest version of the Japan Society of Hepatology guidelines. However, evidence of efficacy in patients with HIV/HCV genotype 3-6 co-infection is insufficient. Currently, HCV genotypes 3-6 can be treated with two DAA-based therapies, including glecaprevir (GLE)/pibrentasvir (PIB) therapy in Japan. We experienced a relatively rare case of a Japanese hemophilia patient co-infected with HIV/HCV genotype 4a. We evaluated resistance-associated substitutions (RASs) against GLE and PIB before GLE/PIB therapy and found that he had no RASs. He was treated with 12 weeks of GLE/PIB therapy and achieved a sustained virologic response at post-treatment weeks 24. Although the treatment was well tolerated, the patient developed hyper-low-density lipoproteinemia that was probably associated with HCV elimination during the therapy. Additional studies are needed to confirm the efficacy and safety of GLE/PIB therapy for this special population in Japan.

All-cause mortality and causes of death in persons with haemophilia: A systematic review and meta-analysis

INTRODUCTION

Improvements in haemophilia treatment over the last decades resulted in increased life expectancy in persons with haemophilia (PWH).

AIM

We conducted a systematic review and meta-analysis to examine all-cause mortality and causes of death among PWH.

METHODS

We systematically searched EMBASE, MEDLINE, Web of Science, CINAHL and Cochrane central register of controlled trials from inception through March 15, 2021. Studies that reported a mortality estimate of PWH compared with the general population and/or reported causes of death were included. Random-effects meta-analysis with inverse variance method was used to obtain pooled estimates. We stratified the analysis by the year of cohort entry (before 2000 vs after 2000).

RESULT

Of the 4769 studies identified, 52 met the eligibility criteria. The pooled all-cause standardized mortality ratio (SMR) from 9 studies in PWH was 1.93 (95% CI 1.38-2.70; I² = 97%). The pooled SMRs before and after the year 2000 were 2.40 (95% CI 1.92-3.00; I² = 87%) and 1.20 (95% CI 1.03-1.40; I² = 62%), respectively. Before the year 2000, 31.2% deaths occurred due to HIV followed by haemorrhage (26.0%), cardiovascular disease (18.2%), liver disease (9.0%), and cancer (8.9%). Fewer (13.9%) deaths were attributable to HIV after the year 2000 with the proportion of deaths due to haemorrhage remaining unchanged.

CONCLUSION

With treatment advances, mortality in PWH has declined over the last few decades approaching that of the general population. However, haemorrhage remains a leading cause of death requiring further attention.

An update of the current pharmacotherapeutic armamentarium for hemophilia A

INTRODUCTION

For several decades, we have seen unprecedented advances in novel therapy development for hemophilia A. These advances address the unmet need of replacement therapy, and they include the development of recombinant products with improved pharmacokinetics, subcutaneously administered products, and those with better efficacy and safety profiles in hemophilia A management.

AREAS COVERED

In this update of hemophilia A treatment, the author summarizes data from completed standard half-life FVIII products, extended half-life FVIII products and FVIII mimetic studies. All products have an acceptable safety profile. The standard half-life products, EHL-FVIII products and emicizumab are efficacious in the prevention and treatment of bleeds and for EHL-FVIII in the perisurgical setting.

EXPERT OPINION

Advances in pharmacotherapy for hemophilia A have been characterized by changing care goals from supportive care to eliminating infections, preventing inhibitors, and more recently achieving zero bleeds in many patients. While gene therapy has the potential for functional cure in hemophilia A, it has many limitations which need to be addressed. Therefore, pharmacotherapy is likely to remain the mainstay in the management of hemophilia A and promises to get better with currently available therapies. Evolving factor and non-factor replacement therapies may also improve current unmet needs in hemophilia A management.

Cost-effectiveness Analysis of Prophylaxis Versus On-demand Treatment for Children With Hemophilia B Without Inhibitors in China

PURPOSE

Hemophilia B (HB) is a hereditary bleeding disorder caused by a deficiency of coagulation factor IX (FIX), which represents 15% to 20% of all patients with hemophilia. Clinical studies have found significant benefits of prophylaxis treatment with FIX versus on-demand (OD) treatment. However, these benefits are associated with an increase in FIX consumption and a considerable increase in cost. Most Chinese children with HB receive OD treatment. Only a small proportion of patients with HB receive prophylaxis treatment in China. The patients with inhibitors could result in more complicated bleeding events, joint status, or treatment patterns. The objective of this study is to assess the cost-effectiveness of prophylaxis compared with OD treatment in children with HB without inhibitors from the Chinese health care perspective.

METHODS

A Markov model was used to analyze cost-effectiveness by comparing prophylaxis with OD treatment. The model uses a 17-year time horizon with a yearly cycle. Transition probabilities and utility weights were estimated using published studies. The cost data for patients with HB were collected from Beijing Children's Hospital and Capital Medical University. One-way and probabilistic sensitivity analyses were performed to assess the robustness of the results.

FINDINGS

The model projects that prophylaxis has an incremental 1.23 quality-adjusted life-years (QALYs). The incremental cost per QALY gained for individuals with HB receiving prophylaxis was ¥155,709.80 ($23,530.36) compared with the OD group, which is under the willingness-to-pay threshold (3 times the gross domestic product per capital according to the World Health Organization recommendations) in China of ¥193,932 ($29,306.37). Moreover, 1-way sensitivity analysis found that the results were sensitive to the utility of nonarticular bleeding. The lower this parameter is, the higher the probability is of the incremental cost-effectiveness ratio for prophylaxis not being cost-effective. This finding infers that when the patients have a better QALY (higher utility) at the beginning, the cost for benefit from prophylaxis treatment is lower. The results of the probabilistic sensitivity analyses indicate that the probability of prophylaxis being cost-effective is 89.3%.

IMPLICATIONS

Although prophylaxis is a costly treatment, the results of this study indicate that it is cost-effective compared with OD treatment for children with HB in China.

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.

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.

Mortality in congenital hemophilia A - a systematic literature review

Against a background of a rapidly evolving treatment landscape, a contemporary, evidence-based consolidated understanding of mortality in people with congenital hemophilia A (PwcHA) is lacking. This systematic literature review examines the available data on mortality and causes of death in PwcHA to enable a better understanding of fatalities in PwcHA and evaluate the impact of new treatment paradigms on mortality. A systematic literature review of observational studies was conducted by searching Medline, Embase, and clinical trials registries for articles published from January 2010 to March 2020, using the search terms: hemophilia A (HA), mortality, cause of death. Interventional studies, studies not reporting fatalities, and those reporting only on hemophilia B, acquired HA, or mixed other coagulopathies were excluded. Overall, 7818 unique records were identified and 17 were analyzed. Of these, six reported mortality rates and five reported mortality ratios. Mortality generally decreased over time, despite a spike associated with human immunodeficiency virus (HIV)/hepatitis C virus (HCV) infection in the 1980s and 1990s. Mortality was strongly correlated with age and hemophilia severity. People with hemophilia had a raised mortality risk compared with the general population, particularly in severe hemophilia, and when infected with HIV or HCV. Causes of death varied across populations, countries, and time in 15 identified studies; however, incomplete and heterogeneous reporting limits evidence. Hemorrhage, HIV, HCV, and hepatic disease were the leading causes of death. A unified approach to reporting mortality and cause of death is needed to understand mortality in PwcHA as treatments continue to advance.