Occurrence rates of haemophilia among males in the United States based on surveillance conducted in specialized haemophilia treatment centres

Clinical Evidence Supporting FDA Approval of Gene and RNA Therapies for Rare Inherited Conditions

BACKGROUND

Gene and RNA therapies have potential to transform the treatment of rare inherited diseases, but there are concerns about the evidence supporting their use and high costs.

OBJECTIVE

We analyze the evidence supporting Food and Drug Administration (FDA) approval of gene and RNA therapies for rare inherited diseases and discuss implications for clinical practice and policy.

METHODS

We conducted a qualitative analysis of FDA documents outlining the basis of approval for gene and RNA therapies approved for rare inherited diseases between 2016 and 2023. For each drug, we gathered five characteristics of the evidence supporting FDA approval (no phase 3 trial, nonrandomized, no clinical endpoint, lack of demonstrated benefit, and significant protocol deviation) and four characteristics of the FDA approval process (prior rejection or complete response, negative committee vote, discrepancy between label and trial population, and boxed warning). The main outcome was the number of drugs with each characteristic.

RESULTS

Between 2016 and 2023, 19 gene and RNA therapies received FDA approval to treat rare inherited diseases. The most common limitations in the evidence supporting approval of these drugs were nonrandomized studies (8/19, 42%), no clinical endpoint (7/19, 37%), lack of demonstrated benefit or inconsistent results (4/19, 21%), and no phase 3 trial (4/19, 21%). Half (3/6) of accelerated approvals and 57% (5/9) of drugs with breakthrough designation had nonrandomized trials, and gene therapies with one-time dosing were overrepresented (5/7, 71%) among the drugs with nonrandomized trials. Five of six accelerated approvals (83%) and five of nine pediatric drugs (56%), most of which were indicated for Duchenne muscular dystrophy, had no clinical endpoint. Four of nine (44%) pediatric drugs and four of six (67%) accelerated approvals failed to demonstrate benefit compared with none of the nonpediatric drugs and none of the traditional approvals. Five drugs, which all had different indications and represented a mix of RNA and gene therapies, did not have any of these evidence characteristics. Among drugs that received prior rejections or negative committee opinions, all four had nonrandomized trials and lacked a clinical endpoint, and 75% (3/4) lacked demonstrated benefit. Five of nine (56%) pediatric drugs were indicated for broader age groups according to the drug label compared with the trial populations. Of the three drugs with boxed warnings, two had pediatric indications and nonrandomized studies, and one had no phase 3 trial.

CONCLUSIONS

Issues related to trial design, outcome, and data integrity in the evidence supporting FDA approval of rare inherited disease gene and RNA therapies raise questions about whether this evidence is adequate to inform prescribing decisions. Gene and RNA therapies with accelerated approval and pediatric indications were overrepresented among drugs lacking clinical endpoints or demonstrated benefit and should be the focus of efforts to reduce uncertainty in the evidence.

Assessing health plan payer's budget impact of etranacogene dezaparvovec for the treatment of hemophilia B in the United States

BACKGROUND

Etranacogene dezaparvovec is a recently approved gene therapy for people with hemophilia B (PwHB). Current standard of care is prophylaxis with factor IX (FIX) to prevent bleeding. Etranacogene dezaparvovec increases blood FIX levels such that FIX prophylaxis could be eliminated.

OBJECTIVE

To estimate the budgetary impact of etranacogene dezaparvovec adoption and utilization in a commercial health plan of the United States.

METHODS

A budget impact model was developed to evaluate the introduction of etranacogene dezaparvovec to treat severe or moderately severe hemophilia B. The model considered a hypothetical 1-million-member plan over a 5-year horizon. FIX therapy prophylaxis use was estimated based on a weighted average of relevant brands using US market share data. A scenario of etranacogene dezaparvovec adoption/utilization was compared with one without etranacogene dezaparvovec utilization. Two etranacogene dezaparvovec uptake (market share growth) analyses were performed: one with gradual uptake and alternatively assuming all eligible PwHB received etranacogene dezaparvovec in year 1. The one-time cost of etranacogene dezaparvovec was assumed to be $3.5 million. Other costs (FIX prophylaxis, disease monitoring, bleed management, and adverse events) were estimated from published literature. All costs were in 2022 US dollars. Bleed and adverse event rates were sourced from the HOPE-B trial comparing etranacogene dezaparvovec to previous FIX therapy prophylaxis. The model estimated annual and per-member per-month costs over 5 years. Secondary analyses were performed considering a 10-year horizon.

RESULTS

In the 1-million-member health plan, an estimated 1.8 PwHB were eligible for treatment with etranacogene dezaparvovec. Gradual uptake of etranacogene dezaparvovec resulted in cumulative 5-year budget impact of $848,509 compared with a scenario without etranacogene dezaparvovec. In years 1-5, the incremental annual and per-member per-month costs ranged from $79,824 to $271,435 and from $0.007 to $0.023, respectively. In the alternative uptake analysis, etranacogene dezaparvovec became cost saving annually beginning in year 2 and cumulatively beginning in year 5, for a 5-year savings of $754,844. Secondary analyses over 10 years found both uptake analyses cost saving. Other scenarios considered did not affect results substantially.

CONCLUSIONS

Introducing etranacogene dezaparvovec as treatment for PwHB would have a modest budget increase within 5 years after treatment but may become cost saving if all eligible PwHB were treated in year 1. Initiating PwHB on etranacogene dezaparvovec sooner may produce greater overall savings and earlier annual savings. Etranacogene dezaparvovec is a treatment option that may provide overall cost savings for US commercial health plans, which would increase as the plan size increases.

The impact of capping health system cost savings on the projected cost-effectiveness of etranacogene dezaparvovec compared with factor IX prophylaxis for the treatment of hemophilia B

This viewpoint discusses cost-effectiveness estimates for EtranaDez, a gene therapy for hemophilia B, using the Institute for Clinical and Economic Review's (ICER) framework for single and short-term therapies (SSTs). EtranaDez offers long-term benefits from a single administration, in contrast to the high costs and frequent dosing required by current factor IX prophylaxis. However, the projected gains in health from EtranaDez are small relative to the cost implications of the therapy, and consequently, how the cost offsets associated with EtranaDez are counted has a substantial impact on assessing its cost-effectiveness. Strategies for assessing cost offsets used in the ICER SST framework include a 50/50 cost-sharing model between the health care system and the manufacturer and a cap of $150,000 annually on health care cost offsets. Results from the standard full cost-offset analysis as reported by ICER depicted EtranaDez as a dominant therapy with substantial cost savings compared with factor IX prophylaxis. However, while considering the ICER SST framework, particularly the $150,000 annual cap scenario, the cost-effectiveness was significantly reduced. The incremental cost-effectiveness ratio varied notably between these scenarios, challenging the conventional perception of value of gene therapy in health care. These cost-sharing scenarios highlight the potential of the ICER SST framework to help curtail inefficient health care spending. In cases in which the cost of existing treatment is exceedingly high, the application of such frameworks would improve efficiency in resource allocation, fostering a balance between incentives for innovation and economic sustainability in managed care systems.

Racial and Ethnic Differences in Distress, Depression, and Quality of Life in people with hemophilia

Hemophilia-related distress (HRD) has been shown to be higher among those with lower educational attainment, but potential racial/ethnic differences have not been previously described. Thus, we examined HRD according to race/ethnicity. This cross-sectional study was a planned secondary analysis of the hemophilia-related distress questionnaire (HRDq) validation study data. Adults aged ≥ 18 years with Hemophilia A or B were recruited from one of two hemophilia treatment centers between July 2017-December 2019. HRDq scores can range from 0-120, and higher scores indicate higher distress. Self-reported race/ethnicity was grouped as Hispanic, non-Hispanic White (NHW) and non-Hispanic Black (NHB). Unadjusted and multivariable linear regression models were used to examine mediators of race/ethnicity and HRDq scores. Among 149 participants enrolled, 143 completed the HRDq and were included in analyses. Approximately 17.5% of participants were NHB, 9.1% were Hispanic and 72.0% were NHW. HRDq scores ranged from 2 to 83, with a mean of 35.1 [standard deviation (SD) = 16.5]. Average HRDq scores were significantly higher among NHB participants (mean = 42.6,SD = 20.6; p-value = .038) and similar in Hispanic participants (mean = 33.8,SD = 16.7, p-value = .89) compared to NHW (mean = 33.2,SD = 14.9) participants. In multivariable models, differences between NHB vs NHW participants persisted when adjusting for inhibitor status, severity, and target joint. However, after household income was adjusted for, differences in HRDq scores were no longer statistically significant (β = 6.0 SD = 3.7; p-value = .10). NHB participants reported higher HRD than NHW participants. Household income mediated higher distress scores in NHB compared to NHW participants, highlighting the urgent need to understand social determinants of health and financial hardship in persons with hemophilia.

Rapid recognition and optimal management of hemophilia in the emergency department: A quality improvement project

Objectives

This study aimed to assess the effectiveness of a continuous quality improvement initiative at the University of Florida Health Physicians practice in reducing the time to administer factor replacement therapy (FRT) for hemophilia patients presenting with bleeding in the emergency department (ED).

Methods

The study, a quasi-experimental, interventional design, was conducted between January 2020 and January 2023. The intervention, implemented in September 2021, involved training ED physicians, creating a specialized medication order set within the electronic health record (EHR), and a rapid triage system. The effectiveness was measured by comparing the time from ED arrival to factor administration before and after the intervention and benchmarking it against the National Bleeding Disorders Foundation's Medical and Scientific Advisory Council (MASAC)-recommended 1-hour timeline for factor administration. An interrupted time series (ITS) analysis with a generalized least squares model assessed the intervention's impact.

Results

A total of 43 ED visits (22 pre-intervention and 21 post-intervention) were recorded. Post-intervention, the average time from ED arrival to factor administration decreased from 5.63 to 3.15 hours. There was no significant increase (27% vs. 29%) in the patients receiving factor within 1-hour of ED arrival. The ITS analysis predicted a 20-hour reduction in the average quarterly time to administer factor by the end of the study, an 84% decrease.

Conclusions

The quality improvement program decreased the time to administer FRT for patients with hemophilia in the ED. However, the majority of patients did not achieve the 1-hour MASAC-recommended timeline for factor administration after ED arrival.

Race and ethnicity reporting and representation in hemophilia clinical trials

ABSTRACT

Racial and ethnic representativeness in clinical trials is crucial to mitigate disparities in outcomes; however, diversity among hemophilia trials is unknown. The aim of this study is to examine the reporting and representation of race and ethnicity in trials of people with hemophilia (PwH). In this cross-sectional study, the ClinicalTrials.gov database was queried in April 2023 for interventional clinical trials involving PwH between 2007 and 2022. The distribution of participants (observed) was compared with expected proportions based on US Hemophilia Treatment Center (HTC) and country-specific census data with observed-to-expected ratios (OERs). Of 129 trials included, 94.6% were industry sponsored, with a mean of 62 participants and mean age of 26.8 years. Overall, 52.0% (n = 66) of trials reported data on race and ethnicity, increasing from 13.9% in 2007-2012 to 22.5% in 2013-2016 to 100% in 2017-2022 (P = .001). Among these 66 trials, 65.8%, 22.8%, 5.1%, 3.9% of participants were White, Asian, Hispanic, and Black, respectively. OERs were 10% to 20% lower for White participants vs US HTC, and US, UK, and Canadian census populations and ∼75% lower for Black or Hispanic participants when compared with US HTC and US census population. OERs for Asian participants were 1.6 to 3 times higher than Canada, US, and UK census populations. The reporting of race and ethnicity in hemophilia trials has drastically improved; however, Black and Hispanic PwH remain especially underrepresented. To address these disparities, stakeholders across the clinical trial enterprise need to implement strategies to ensure equitable participation.

Risk of Intracranial Hemorrhage in Persons with Hemophilia A in the United States: Real-World Retrospective Cohort Study Using the ATHNdataset

Introduction

Intracranial hemorrhage (ICH), a serious complication in persons with hemophilia A (PWHA), causes high rates of mortality and morbidity. Identified ICH risk factors from patient data spanning 1998-2008 require reassessment in light of changes in the current treatment landscape.

Aim and methods

PWHA identified in the ATHNdataset were evaluated retrospectively to assess incidence of ICH and determine the association between ICH risk and key characteristics using time-to-event analyses (Cox proportional-hazards models, survival curves, and sensitivity analyses).

Results

Over a median follow-up time of 10.7 patient-years, 135 of 7837 PWHA over 2 years of age in the ATHNdataset (1.7%) experienced an ICH. Stratification by prophylaxis status and inhibitor status resulted in an incidence rate (IR) ratio (IRR) (IR+/IR-) of 0.63 (95% confidence interval [CI], 0.43-0.94; P=0.020) and 1.76 (95% CI, 0.97-3.20; P=0.059), respectively. Characteristics associated with greater risk of developing ICH include being aged 2-12 years; being covered by Medicaid; having had HIV, hepatitis C, or hypertension; and never having received factor VIII or prophylactic treatment. In multivariable analysis with interaction, the estimated hazard ratio for PWHA never receiving prophylaxis was 7.67 (95% CI, 2.24-26.30), which shrunk to 2.03 (95% CI, 1.30-9.12) in bootstrapping analysis and 3.09 in the highest-penalty ridge-regression analysis but was still significant. Inhibitor status was found not to be statistically associated with ICH in all analyses.

Conclusion

These results align with previous studies demonstrating that prophylaxis confers a protective effect against ICH. Previously, inhibitor positivity had been shown to increase risk for ICH; however, this study did not corroborate those findings.

Adeno-associated virus as a delivery vector for gene therapy of human diseases

Adeno-associated virus (AAV) has emerged as a pivotal delivery tool in clinical gene therapy owing to its minimal pathogenicity and ability to establish long-term gene expression in different tissues. Recombinant AAV (rAAV) has been engineered for enhanced specificity and developed as a tool for treating various diseases. However, as rAAV is being more widely used as a therapy, the increased demand has created challenges for the existing manufacturing methods. Seven rAAV-based gene therapy products have received regulatory approval, but there continue to be concerns about safely using high-dose viral therapies in humans, including immune responses and adverse effects such as genotoxicity, hepatotoxicity, thrombotic microangiopathy, and neurotoxicity. In this review, we explore AAV biology with an emphasis on current vector engineering strategies and manufacturing technologies. We discuss how rAAVs are being employed in ongoing clinical trials for ocular, neurological, metabolic, hematological, neuromuscular, and cardiovascular diseases as well as cancers. We outline immune responses triggered by rAAV, address associated side effects, and discuss strategies to mitigate these reactions. We hope that discussing recent advancements and current challenges in the field will be a helpful guide for researchers and clinicians navigating the ever-evolving landscape of rAAV-based gene therapy.

Emicizumab prophylaxis in infants: Single-centre experience

The hallmark of haemophilia A (HA) therapy is prophylaxis, aimed at spontaneous bleeding prevention. Emicizumab provides a viable alternative to intravenous factor replacement therapy. However, data on its use in infants are limited. This single-centre open arm prospective study reports on emicizumab prophylaxis in infants. We included severe HA patients under 1 year who started emicizumab prophylaxis since 2018, with longitudinal follow-up. The study collected data on demographics, clinical and laboratory variables, the occurrence of bleeding events, surgeries and treatment outcomes. Of the 27 enrolled infants, whose median age at prophylaxis initiation was 7 months, 24 primarily choose to start emicizumab therapy (3/27 switched from FVIII prophylaxis due to development of FVIII inhibitors). The median age for prophylaxis initiation decreased to 3 months in 2023. Following emicizumab initiation, the median calculated ABR decreased, and no intracranial haemorrhages were observed. Thrombin generation showed a significant improvement in peak height and endogenous thrombin potential at steady state after a loading period. Our study highlights a shift towards early prophylaxis in the era of non-replacement therapies. It underscores the need for continuous evaluation and refinement of treatment approaches, emphasizing personalized care and diligent monitoring in the evolving field of paediatric haemophilia care.

Haemophilic arthropathy: Diagnosis, management, and aging patient considerations

Gene therapy and universal use of safer, more effective, and personalised prophylactic regimens (factor, and nonfactor) are expected to prevent joint bleeding and promote joint health in persons with haemophilia (PwH). Growing evidence suggests that subclinical bleeding, with active and inactive synovial proliferation, continues and haemophilic arthropathy remains a major morbidity in PwH despite early institution of joint prophylaxis. Joint health assessment is evolving with physical examination scores complementing imaging scores. Point-of-care ultrasound is emerging as a safe, cost-effective, and readily available tool for acute determination of musculoskeletal abnormalities, serial evaluation of joints for sonographic markers of haemophilic arthropathy, and in providing objective insight into the efficacy of new therapies. In acute haemarthrosis, arthrocentesis expedites recovery and prevent the vicious cycle of bleed-synovitis-rebleed. When synovial proliferation develops, a multidisciplinary team approach is critical with haematology, orthopaedics, and physiotherapy involvement. Synovectomy is considered for patients with chronic synovitis that fail conservative management. Non-surgical and minimally invasive procedures should always be offered and considered first. Careful patient selection, screening and early intervention increase the success of these interventions in reducing bleeding, pain, and improving joint function and quality of life. Chemical synovectomy is practical in developing countries, but radioactive synovectomy appears to be more effective. When surgical synovectomy is considered, arthroscopic/minimally invasive approach should be attempted first. In advanced haemophilic arthropathy, joint replacement and arthrodesis can be considered. While excited about the future of haemophilia management, navigating musculoskeletal challenges in the aging haemophilia population is equally important.

Analysis of long-term clinical and cost impact of etranacogene dezaparvovec for the treatment of hemophilia B population in the United States

INTRODUCTION

Etranacogene dezaparvovec (EDZ), Hemgenix, is a gene therapy recently approved for people with hemophilia B (PwHB).

OBJECTIVE

To estimate long-term clinical impact and cost of EDZ in the United States (US).

METHODS

A decision-analytic model was developed to evaluate the long-term impact of introducing EDZ for PwHB over a 20-year time horizon. Factor IX (FIX) prophylaxis comparator was a weighted average of different FIX prophylaxis regimens based on US market share data. We compared a scenario in which EDZ is introduced in the US versus a scenario without EDZ. Clinical inputs (annualized FIX-treated bleed rate; adverse event rates) were obtained from HOPE-B phase 3 trial. EDZ durability input was sourced from an analysis predicting long-term FIX activity with EDZ. EDZ one-time price was assumed at $3.5 million. Other medical costs, including FIX prophylaxis, disease monitoring, bleed management, and adverse events were from literature. The model estimated annual and cumulative costs, treated bleeds, and joint procedures over 20 years from EDZ introduction.

RESULTS

Approximately 596 PwHB were eligible for EDZ. EDZ uptake was estimated to avert 11,282 bleeds and 64 joint procedures over 20 years. Although adopting EDZ resulted in an annual excess cost over years 1-5 (mean: $53 million annually, total $265 million), annual cost savings were achieved beginning in year 6 (mean: $172 million annually; total $2.58 billion in years 6-20). The total cumulative 20-year cost savings was $2.32 billion, with cumulative cost savings beginning in year 8.

CONCLUSION

Introducing EDZ to treat PwHB is expected to result in cost savings and patient benefit over 20 years. Initiating PwHB on EDZ sooner can produce greater and earlier savings and additional bleeds avoided. These results may be a conservative estimate of the full value of EDZ, as PwHB would continue to accrue savings beyond 20 years.

Targeting the Liver with Nucleic Acid Therapeutics for the Treatment of Systemic Diseases of Liver Origin

Systemic diseases of liver origin (SDLO) are complex diseases in multiple organ systems, such as cardiovascular, musculoskeletal, endocrine, renal, respiratory, and sensory organ systems, caused by irregular liver metabolism and production of functional factors. Examples of such diseases discussed in this article include primary hyperoxaluria, familial hypercholesterolemia, acute hepatic porphyria, hereditary transthyretin amyloidosis, hemophilia, atherosclerotic cardiovascular diseases, α-1 antitrypsin deficiency-associated liver disease, and complement-mediated diseases. Nucleic acid therapeutics use nucleic acids and related compounds as therapeutic agents to alter gene expression for therapeutic purposes. The two most promising, fastest-growing classes of nucleic acid therapeutics are antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs). For each listed SDLO disease, this article discusses epidemiology, symptoms, genetic causes, current treatment options, and advantages and disadvantages of nucleic acid therapeutics by either ASO or siRNA drugs approved or under development. Furthermore, challenges and future perspectives on adverse drug reactions and toxicity of ASO and siRNA drugs for the treatment of SDLO diseases are also discussed. In summary, this review article will highlight the clinical advantages of nucleic acid therapeutics in targeting the liver for the treatment of SDLO diseases. SIGNIFICANCE STATEMENT: Systemic diseases of liver origin (SDLO) contain rare and common complex diseases caused by irregular functions of the liver. Nucleic acid therapeutics have shown promising clinical advantages to treat SDLO. This article aims to provide the most updated information on targeting the liver with antisense oligonucleotides and small interfering RNA drugs. The generated knowledge may stimulate further investigations in this growing field of new therapeutic entities for the treatment of SDLO, which currently have no or limited options for treatment.

Prevalence and perceptions of pain in people with haemophilia: A UK study

INTRODUCTION

Joint bleeds in haemophilia cause destruction of articular structures, impaired function and pain. Up to 70% of people with haemophilia (PWH) report chronic pain. Little is known about the pain experiences in PWH in the UK.

AIM

To identify prevalence and perceptions of pain among PWH living in the UK.

METHODS

A cross-sectional, non-interventional survey study conducted among PWH (all severities). The survey incorporated elements from validated tools (EQ-5D; EQ-VAS) and was distributed via participating treatment centres.

RESULTS

Five hundred and ninety-nine PWH responded, 91% aged > 18. 81% used factor prophylactically or on demand. More pain was reported by those treated on demand versus prophylaxis particularly in those who reported daily pain. 65% reported 'problem joints' based on individual impact rather than medically defined 'target joints', 2/3 reported multiple joint issues. The ankle was most commonly affected. 59% reported frequent pain, with 56% aware of pain constantly or most of the time and were more likely to report less favourable EQ-5D or EQ-VAS scores (p < .001). Pain frequency/awareness was consistent across all severities. Most discussed pain with care teams, 31% only when asked; 25% did not discuss it. Pain discussions resulted in physiotherapy referral (63%) analgesia prescription (48%), and a minority specialist pain referral (9%). Most felt well supported with regard to their pain, but 70% reported learning to live with it.

CONCLUSION

Pain affects PWH of all ages and severities even in a well-resourced country significantly impacting quality of life. Clinicians must be more aware of chronic pain in PWH. Biopsychosocial approaches to pain assessment and management are recommended.

Racial and ethnic differences in reported haemophilia death rates in the United States

INTRODUCTION

People with haemophilia's life expectancies have improved over time. Whether progress has been experienced equitably is unknown.

AIM

To examine recorded haemophilia death (rHD) rates according to race and ethnicity in the United States (US).

METHODS

In this cohort study, rHDs were examined with US National Vital Statistics' 1999-2020 Multiple Cause-of-Death data. rHD was defined as having a haemophilia A (D66) or B (D67) ICD-10 code in the death certificate (underlying or multiple causes of death). Age-adjusted rHD rates were compared with age-adjusted rate ratios (aRR) and 95% Confidence Intervals (CI).

RESULTS

There were 3115 rHDs in males with an rHD rate of 0.98 per 1 million males. Between 1999 and 2020, rHD rates declined by 46% in NH (Non-Hispanic) White, 44% in NH Black (aRR = 0.56, 95%CI 0.43, 0.74), and 42% in Hispanic (aRR = 0.58, 95%CI 0.39, 0.88) males. However, rHD rates remained higher and were on average 30% greater in NH Black versus NH White males (aRR = 1.30 95% CI 1.16, 1.46). Among males with rHD, the median age at death rose from 54.5 to 65.5 years between 1999 and 2020 and was 12 years lower in NH Black (56 years) versus NH White (68 years) males in 2010-2020. There were 930 females with rHD, with an age-adjusted rate of 0.22 per 1 million females, which was consistent between 1999 and 2020.

CONCLUSION

Reported haemophilia-death rates improved in males across all race/ethnicities, but rates were higher Black versus White males. Given the inherent limitations of the current study's data source, further investigation of survival rates and disparities in haemophilia are needed.

Calcium Prevents Enhanced Degradation of Factor VIII in the Condition of Motion

Background: Hemophilia A and B induce recurrent bleeding episodes, mainly in skeletal muscles and joints that are in intermittent motion. We have previously demonstrated that intermittent motion contributes to increased degradation of factors VIII and IX. Objectives: Given that calcium ions are known to enhance factor VIII-von Willebrand factor (vWF) interaction, the present study has investigated the role of these ions on factors VIII and IX in the condition of motion. Methods: The effects of calcium ions were assessed using purified proteins via Western blot, factor VIII activity, immunocytochemistry, and in Institute of Cancer Research (ICR) mice with no specific genetic background. Results: Calcium was found to prevent degradation of plasma-derived factor VIII but not that of factor IX, during intermittent motion. Calcium levels in the microcirculation of mouse striated muscles were elevated following movement, enabling prevention of factor VIII degradation in normal physiology. Calcium supplementation in drinking water increased factor VIII levels in blood and striated muscles of ICR mice during movement. Conclusions: calcium ions decrease factor VIII degradation in the condition of motion. Further research on the impact of calcium salt oral supplementation on hemophilia patients is warranted.

Evaluating Gene Therapy as a Potential Paradigm Shift in Treating Severe Hemophilia

Hemophilia is characterized by a deficiency in coagulation factors VIII or IX. The general standard of care for severe hemophilia is frequent intravenous recombinant or plasma-derived factor replacement to prevent bleeding. While this treatment is effective in preventing bleeding, frequent infusions are burdensome for patients. Nonadherence to the therapeutic regimen leaves people with hemophilia at risk for spontaneous and traumatic bleeds into joints as well as life-threatening bleeds such as intracranial hemorrhage. The chronicity of the disorder often leads to the formation of target joints, causing long-term pain and impairing mobility. As a monogenic disorder with well-understood genetics, hemophilia is an ideal disorder for implementing innovations in gene therapies. Indeed, recent approvals of two gene therapy products have the potential to shift the hemophilia treatment paradigm. Valoctocogene roxaparvovec and etranacogene dezaparvovec-drlb are gene therapies for hemophilia A and B, respectively. These therapies, given as a single intravenous infusion, may improve patients' quality of life, decreasing treatment burden and resulting in factor expression that virtually eliminates the need for factor replacement. Since both treatments involve viral vectors targeted to the liver, short- and long-term safety and efficacy monitoring involves monitoring liver enzymes to track liver health. Long-term monitoring of efficacy, durability of gene expression, and safety are ongoing. Gene therapy presents a promising new therapeutic option for patients with hemophilia and warrants continued innovation and investigation.

Etranacogene dezaparvovec-drlb gene therapy for patients with hemophilia B (congenital factor IX deficiency)

INTRODUCTION

Congenital hemophilia B (HB) is an X-linked bleeding disorder resulting in Factor IX (FIX) deficiency and bleeding of variable severity. There is no cure for HB. Typical management consists of prophylactic intravenous (IV) recombinant or plasma-derived FIX infusions. Etranacogene dezaparvovec-drlb (Hemgenix, AMT-061) is an adeno-associated virus serotype 5 (AAV5) vector containing a codon-optimized Padua variant of the human F9 gene with a liver-specific promoter. Etranacogene dezaparvovec-drlb received FDA approval on 22 November 2022 for the treatment of HB in adult patients who use FIX prophylaxis therapy, have current or historical life-threatening hemorrhage, or have experienced repeated, serious spontaneous bleeding episodes.

AREAS COVERED

This drug profile discusses the safety and efficacy of etranacogene dezaparvovec-drlb in patients with HB.

EXPERT OPINION

Etranacogene dezaparvovec-drlb therapy results in stable and sustained expression of near-normal to normal FIX levels in patients with HB regardless of neutralizing antibodies to AAV5 up to a titer of 678. Its use has led to significant reduction in bleeding and FIX prophylaxis. Etranacogene dezaparvovec-drlb was well tolerated; however, 17% of patients required corticosteroid therapy for alanine aminotransferase (ALT) elevation. Etranacogene dezaparvovec-drlb therapy marks the beginning of an exciting era in HB treatment and opens questions regarding treatment longevity and long-term safety.

Survival analysis of coagulation disorders: A retrospective study with a 5-year follow-up

Objective

Rare bleeding disorders (RBDs) are the diseases in which patients experience a deficiency of coagulation factors. In the management of these disorders, surveillance is a significant challenge. This study aimed to assess the survival of patients with RBDs in a five-year follow-up.

Materials and methods

This descriptive cross-sectional study was conducted on 146 patients with RBDs who had referred to Be'sat Hospital of Hamadan, Iran from July 2017 to August 2022. A computerized record search was performed to identify the patients. The surveillance time for a five-year follow-up was assessed with the Kaplan-Meier curve. A log-rank test also served to compare the survival rates according to the type of factor.

Results

Out of 146 patients, 117 (80.2%) were males and 29 (19.8%) were females. They were in the range of 2-59 years of age with a mean of 23.11 ± 14.6. The most common disorder was FVIII deficiency (65.8%), and the rarest one was FXIII deficiency (4.8%). The rate of survival for any reason was 54.42 ± 1.3 months. The survival in combined FV and FVIII deficiencies was found to be longer than in the other deficiencies (55.9 ± 5.7), but there was no significant difference (P ≥ 0.05). In contrast, the survival in FXIII deficiency was observed to be lower than the other cases (44 ± 9.6); however, no significant difference was found in this regard (P ≥ 0.05).

Conclusion

The results of this study show that patients with RBDs have different rates of survival, which suggests that identifying high-risk patients may be helpful for the improvement of their survival time through timely therapeutic interventions.

Evaluation of clinical characteristics, health care resource utilization, and cost outcomes of hemophilia A carriers and noncarriers in the United States: A real-world comparative analysis

BACKGROUND: Hemophilia A is often viewed as a male disease; females are usually considered asymptomatic hemophilia A carriers. However, hemophilia A carriers may experience mild-to-severe bleeding events. OBJECTIVE: To compare clinical characteristics, health care resource utilization, and costs incurred by hemophilia A carriers compared with a non-hemophilia A carrier female control population in the United States. METHODS: This retrospective observational cohort study used data from IBM MarketScan Commercial Claims and Encounters and Multi-State Medicaid Databases from January 1, 2016, to September 30, 2019. Patients with a hemophilia A carrier diagnosis were matched to a non-hemophilia A carrier female control group in a 1:2 ratio based on sociodemographic characteristics, pregnancy status, and insurance type. Billed annualized bleed rates, health care resource utilization, and annualized costs were evaluated. Generalized linear models compared annualized total costs in the hemophilia A carrier and control groups. RESULTS: After matching, the hemophilia A carrier group included 121 (Commercial) and 55 (Medicaid) patients, matched 1:2 in the control group. Patients in the hemophilia A carrier group (compared with the control group) had numerically higher joint-related health issues (Commercial: 11.6% vs 7.9%; Medicaid: 7.3% vs 4.5%) and lower soft-tissue disorders (Commercial: 13.2% vs 17.4%; Medicaid: 12.7% vs 14.5%). Musculoskeletal pain was higher (33.1% vs 31.0%) and lower (21.8% vs 25.5%) in the Commercial and Medicaid databases, respectively. Billed annualized bleed rates were higher in the hemophilia A carrier group (Commercial: 0.49 vs 0.33; Medicaid: 0.50 vs 0.29). Significantly more patients in the hemophilia A carrier group had minor bleeds (Commercial: 34.7% vs 22.3% [P = 0.001]; Medicaid: 43.6% vs 20.0% [P < 0.001]) and spontaneous bleeds (Commercial: 35.5% vs 21.5%; Medicaid: 47.3% vs 23.6% [P < 0.001 for both]). Outpatient visits represented the majority of health care resource utilization and were higher in the hemophilia A carrier group for all-cause and bleed-related claims; although less frequent, emergency department and inpatient visits followed a similar trend. In the Commercial and Medicaid databases, hemophilia A carriers incurred approximately 2 times higher mean (SD) all-cause health care total costs than patients in the control group (Commercial: $15,345 [21,871] vs $8,358 [11,939] per patient per year [PPPY]; Medicaid: $9,022 [19,461] vs $4,533 [9,532] PPPY). CONCLUSIONS: Hemophilia A carriers experienced more complications and incurred higher costs (resulting from more outpatient, emergency department, and inpatient visits) compared with patients in the control group. These data suggest that hemophilia A carriers have a high disease and economic burden and may benefit from early diagnosis and management to prevent long-term complications. DISCLOSURES: Dr Xing, Dr Bullano, Dr Caicedo, and Mr Farahbakhshian are employees of Takeda Pharmaceuticals U.S.A., Inc., hold Takeda stocks, and have been granted restricted stock shares; Drs Xing and Caicedo received support from Takeda Pharmaceuticals U.S.A., Inc., for travel to THSNA 2022, where the data included in this manuscript were presented. Dr Batt received consulting fees from Complete HEOR Solutions (CHEORS) LLC for the protocol development, data analysis, and interpretation of this study; she also holds stocks from Merck and Sanofi. Ms Kuharic is an employee of the University of Illinois at Chicago and has been supported by a Takeda fellowship during the execution of the study. Ms Chakladar and Ms Markan were employees of CHEORS LLC at the time of the study. CHEORS has received funding from Takeda Pharmaceuticals U.S.A., Inc., for conducting the analysis of this study. This study was funded by Takeda Pharmaceuticals U.S.A., Inc. The sponsor was involved in the study design; collection, analysis, and interpretation of data; development and review of the manuscript; and decision to submit manuscript to publication.

Practices and challenges for hemophilia management under resource constraints in Thailand

Hemophilia is an inherited bleeding disorder caused by deficiency of a specific coagulation factor. Factor VIII deficiency is responsible for hemophilia A while factor IX deficiency is responsible for hemophilia B. As per the 2020 annual global survey by the World Federation of Hemophilia, only 1828 Thai hemophiliacs have been registered to the national healthcare system. The reason for the low number is the underdiagnosis which is a major concern in the real-world practice among Asian countries. In Thailand, most hemophiliacs are diagnosed by general practitioners, pediatricians or internists at rural hospitals and are referred to hemophilia specialists at the Hemophilia Treatment Centers (HTCs). Despite the challenges pertaining to infrastructure and cost of treatment, Thailand has progressed substantially in providing the required hemophilia care, as evidenced by an evolution in acquiring and sharing knowledge as well as collaborative efforts among multiple stakeholders over the past three decades. In this letter-to-the-editor, the authors have summarized the practices for and challenges faced with hemophilia management in Thailand.

Factor VIII inhibitors in hemophilia A treated with emicizumab: longitudinal follow-up of outcomes

Background

Using emicizumab in lieu of immune tolerance induction (ITI) for patients with hemophilia A (HA) and factor (F)VIII inhibitors has been well described. However, decisions regarding ITI initiation, regimen, and preservation of tolerance remain to be elucidated.

Objectives

To study the course of FVIII inhibitors in patients with HA and a history of FVIII inhibitors receiving emicizumab prophylaxis.

Methods

Patients with HA, with and without FVIII inhibitors, initiating emicizumab prophylaxis were prospectively followed up in our center. All patients with current or previous inhibitors were included in this analysis. Plasma samples for FVIII inhibitor assays were obtained every 3 to 6 months or following FVIII exposure. Patients documented annual bleeding rate and any FVIII exposure days (EDs).

Results

Of 162 emicizumab-treated participants, 51 met the inclusion criteria. A decrease in annual bleeding rate was observed in all 51 participants followed up for a median of 3.3 years, with 31 breakthrough bleeding episodes reported in 22 of 51 participants. FVIII inhibitor level transiently increased following FVIII exposures in 5 of 15 failed ITI participants. Eight of 21 participants who did not undergo ITI were exposed to FVIII (1-2 EDs)), and 1 of these 8 participants demonstrated increased FVIII inhibitor levels after head trauma (following 1 ED). Among participants who underwent successful ITI, 8 of 15 patients were exposed to FVIII over a total of 13 EDs (1-2 ED(s) each) for traumatic breakthrough bleeds. In all these participants, inhibitor levels remained zero, indicating successful tolerance maintenance.

Conclusion

Our longitudinal follow-up of emicizumab-treated patients with HA and FVIII inhibitors shows that occasional exposure to FVIII may induce a transient anamnestic response. Nonetheless, no FVIII inhibitor recurrence was noted following FVIII exposures in patients who underwent successful ITI.

Healthcare costs among hemophilia A patients in the United States treated with rurioctocog alfa pegol (FVIII-PEG) or antihemophilic factor (recombinant), FC fusion protein (rFVIIIFc) using real-world data

AIMS

To compare healthcare costs in patients with non-inhibitor hemophilia A treated with Rurioctocog Alfa Pegol (FVIII-PEG) versus Antihemophilic Factor (Recombinant), FC Fusion Protein (rFVIIIFc).

MATERIALS AND METHODS

Administrative claims data from the Merative MarketScan Commercial (Commerical) and Medicaid (Medicaid) databases were used for these analyses. Males with non-inhibitor hemophilia A treated with FVIII-PEG or rFVIIIFc from 1 January 2016 to 31 March 2021 were identified (earliest treatment = index). Patients were required to have continuous database enrollment for six months before and after the index date. Follow-up was variable in length until disenrollment or study end. All-cause and hemophilia-related healthcare costs were reported per-patient per month [PPPM] and the average weekly dose during follow-up was compared between treatment groups. Generalized linear regressions were used to estimate multivariable-adjusted differences in total costs and weekly dosage in the two treatment groups.

RESULTS

A total of 131 FVIII-PEG (66 Commercial; 65 Medicaid) and 204 rFVIIIFc (111 Commercial; 93 Medicaid) patients were eligible. Mean age was 20.5 and 24.4 for FVIII-PEG and rFVIIIFc in Commercial and 14.9 and 17.5 for FVIII-PEG and rFVIIIFc in Medicaid. PPPM mean (standard deviations [SD]) total healthcare costs in Commercially insured patients were $35,868 [$21,717] for FVIII-PEG vs $40,424 [$25,882] for rFVIIIFc. Costs in Medicaid were $27,495 [$23,243] for FVIII-PEG vs $30,237 [$28,430] for rFVIIIFc. After adjusting for baseline characteristics, the costs for rFVIIIFc (vs FVIII-PEG) were higher by $5,215 in Commercial and $3,895 in Medicaid, but the differences were not statistically significant (p > 0.05). Similar findings were observed for hemophilia-specific healthcare costs. The adjusted mean weekly dose was 6,047 vs 4,892 IU, p = 0.21 for FVIII-PEG vs rFVIIIFc in Commercial and 5,549 vs 7,228 IU, p = 0.07 for FVIII-PEG vs rFVIIIFc in Medicaid.

CONCLUSIONS

Healthcare costs and treatment dosing were similar (p > 0.05) for non-inhibitor hemophilia A patients treated with FVIII-PEG and rFVIIIFc.

Gene therapy preferences and informed decision-making: Results from a National Hemophilia Foundation Community Voices in research survey

INTRODUCTION

To inform education and treatment discussions, it is important to understand how persons with haemophilia prefer to learn about and discuss new therapies and to identify variables that influence decision-making.

AIM

The aim of this study was to evaluate preferences and variables which influence decision-making related to gene therapy and other novel haemophilia therapies.

METHODS

An online survey was sent to men with severe haemophilia enrolled in the National Hemophilia Foundation Community Voices in Research online platform for patient-powered research.

RESULTS

One hundred four men completed the survey including 33% Hispanics, 96 who had had not gene therapy and 71/96 (74%) who were on prophylaxis. Ninety-five percent were somewhat or very familiar with gene therapy. Men with haemophilia obtain information about new therapies from several sources, most commonly their haemophilia treatment team, patient advocacy groups and self-study. Participants identified safety and efficacy as well as other educational needs to inform decision-making. Of those without prior gene therapy, 73% indicated a high likelihood of considering gene therapy. Hispanic ethnicity and government-issued insurance were associated with a higher likelihood of considering gene therapy as a treatment option.

CONCLUSION

Haemophilia Treatment Centers and patient advocacy groups must be able to educate persons with haemophilia about aspects of novel therapies which are important to the individual, especially short- and long-term safety and efficacy. Further research is needed to determine how patient activation and health literacy influence decision-making and how to achieve equitable access and valid informed consent for novel therapies.

A Novel Deletion Mutation of the F8 Gene for Hemophilia A

Background: Hemophilia A (HA) is an X-linked recessive blood coagulation disorder caused by a variety of abnormalities in F8 gene, resulting in the absence of impaired molecule production of factor VIII (FVIII) in the plasma. The genetic testing of the F8 gene encoding FVIII is used for confirmation of HA diagnosis, which significantly reduced serious complications of this disease and, ultimately, increased life expectancy. Methods: Sanger sequencing was performed in F8 gene exons of the suspected patients with blood coagulation-related indicators. Results: A novel F8 indel variant c.6343delC, p.Leu2115SerfsTer28 in exon 22 of the F8 gene was identified in the suspected families. The infant with this novel variant appeared the symptom of minor bleeding and oral cavity bleeding, and decreased activity of FVIII, which is consistent with that of F8 deleterious variants. The 3'D protein structural analysis of the novel variant shows a change in FVIII protein stability, which may be responsible for the pathogenesis of HA. Conclusions: A novel deleterious variant was identified in our case, which expands the F8 variants spectrum. Our result is helpful for HA diagnosis and benefits carrier detection and prenatal diagnosis. Our study also reveals that mutation screening of the F8 gene should be necessary for HA suspected patients.

A real-world study comparing pre-post billed annualized bleed rates and total cost of care among non-inhibitor patients with hemophilia A switching from FVIII prophylaxis to emicizumab

OBJECTIVE

Factor VIII (FVIII) replacement and emicizumab have demonstrated efficacy for prevention of bleeds among patients with hemophilia A (PwHA) compared to on-demand (OD) use. Evidence investigating clinical outcomes and healthcare costs of non-inhibitor PwHA switching from prophylaxis with FVIII concentrates to emicizumab has not been well-established within large real-world datasets. This study aimed to investigate billed annualized bleed rates (ABR_b) and total cost of care (TCC) among non-inhibitor PwHA switching from FVIII-prophylaxis to emicizumab-prophylaxis.

METHODS

This retrospective, observational study was conducted using IQVIA PharMetrics Plus, a US administrative claims database. The date of first claim for emicizumab was defined as the index date. OD patients and inhibitor patients were excluded. Bleeds were identified using a list of 535 diagnosis codes. Bayesian models were developed to estimate the probability ABR_b worsens and TCC increases after switching to emicizumab. Wilcoxon rank-sum tests were used to test statistical significance of changes in ABR_b and TCC after switch.

RESULTS

Among the 121 identified patients, the difference in mean ABR_b between FVIII-prophylaxis (0.68 [SD = 1.28]) and emicizumab (0.55 [SD = 1.48]) was insignificant (p = .142). The mean annual TCC significantly increased for patients switching from FVIII-prophylaxis ($518,151 [SD = $289,934]) to emicizumab ($652,679 [SD = $340,126]; p < .0001). The Bayesian models estimated a 21.0% probability of the ABR_b worsening and a 99.9% probability of increasing TCC after switch.

CONCLUSIONS

This study found that in male non-inhibitor PwHA, switching from FVIII prophylaxis to emicizumab incurs substantial cost increase with no significant benefit in ABR_b. This evidence may help guide providers, payers, and patients in shared decision-making conversations around best treatment options.

Results of genetic analysis of 11 341 participants enrolled in the My Life, Our Future hemophilia genotyping initiative in the United States

BACKGROUND

Hemophilia A (HA) and hemophilia B (HB) are rare inherited bleeding disorders. Although causative genetic variants are clinically relevant, in 2012 only 20% of US patients had been genotyped.

OBJECTIVES

My Life, Our Future (MLOF) was a multisector cross-sectional US initiative to improve our understanding of hemophilia through widespread genotyping.

METHODS

Subjects and potential genetic carriers were enrolled at US hemophilia treatment centers (HTCs). Bloodworks performed genotyping and returned results to providers. Clinical data were abstracted from the American Thrombosis and Hemostasis Network dataset. Community education was provided by the National Hemophilia Foundation.

RESULTS

From 2013 to 2017, 107 HTCs enrolled 11 341 subjects (68.8% male, 31.2% female) for testing for HA (n = 8976), HB (n = 2358), HA/HB (n = 3), and hemophilia not otherwise specified (n = 4). Variants were detected in most male patients (98.2%% HA, 98.1% HB). 1914 unique variants were found (1482 F8, 431 F9); 744 were novel (610 F8, 134 F9). Inhibitor data were available for 6986 subjects (5583 HA; 1403 HB). In severe HA, genotypes with the highest inhibitor rates were large deletions (77/80), complex intron 22 inversions (9/17), and no variant found (7/14). In severe HB, the highest rates were large deletions (24/42). Inhibitors were reported in 27.3% of Black versus 16.2% of White patients.

CONCLUSIONS

The findings of MLOF are reported, the largest hemophilia genotyping project performed to date. The results support the need for comprehensive genetic approaches in hemophilia. This effort has contributed significantly towards better understanding variation in the F8 and F9 genes in hemophilia and risks of inhibitor formation.

Associated comorbidities, healthcare utilization & mortality in hospitalized patients with haemophilia in the United States: Contemporary nationally representative estimates

INTRODUCTION

Current in-hospital burden and healthcare utilization patterns for persons with haemophilia (PWH) A and B, including both children (ages < 18 years) and adults (ages ≥ 18 years), in the United States (US) are lacking.

AIM

To evaluate healthcare utilization, the prevalence of comorbidities, and mortality in hospitalized paediatric and adult PWH using a contemporary nationally representative cohort.

METHODS

Hospitalizations of PWH either as the primary reason for admission (principal diagnosis) or one of all listed diagnoses were identified using ICD-10 codes from the 2017 Nationwide Inpatient Sample (NIS), the largest publicly available all-payer inpatient discharge database in the US. Sampling weights were applied to generate nationally representative estimates.

RESULTS

The contemporary cohort included 10,555 hospitalizations (paediatrics, 18.3%; adults, 81.7%) among PWH as one-of-all listed diagnoses (n = 1465 as principal diagnosis). Median age (interquartile range) was 46 (24-66) years overall; adults, 54 (35-70) years and paediatric, 4 (1-11). The most common comorbidities in adults were hypertension (33.4%), hyperlipidaemia (23.6%), and diabetes (21.1%). In children, hemarthrosis (11.4%), contusions (9.6%), and central line infections (9.3%) were the most common. The overall mortality rate was 2.3%. Median hospital charges per haemophilia admission were $52,616 ($24,303-$135,814) compared to $26,841 ($12,969-$54,568) for all-cause admissions in NIS.

CONCLUSION

Bleeding and catheter-related infections are the significant reasons for paediatric haemophilia admissions. Adult haemophilia admissions tend to be associated with age-related comorbidities. Costs for haemophilia-related hospitalizations are higher than the national average for all-cause hospitalizations.

The neurosurgical management of Severe Hemophilia A and Moyamoya (SHAM): challenges, strategies, and literature review

INTRODUCTION

Severe Hemophilia A and Moyamoya arteriopathy (SHAM syndrome) is a rare genetic disorder caused by deletion of portions of the cytogenic band Xq28. A case of SHAM syndrome requiring bilateral cerebral revascularization is described with an emphasis on perioperative management.

CASE REPORT

A 5-year-old boy with severe hemophilia A complicated by factor VIII inhibition presented with right-sided weakness. Imaging revealed multiple strokes and vascular changes consistent with Moyamoya disease. The patient underwent two-staged indirect cerebral bypass revascularizations, first on the left side and several months later on the right. Perioperative management required balancing the administration of agents to prevent coagulopathy and perioperative hemorrhage while mitigating the risk of thromboembolic events associated with bypass surgery. Despite a multidisciplinary effort by the neurosurgery, hematology, critical care, and anesthesiology teams, the post-operative course after both surgeries was complicated by stroke. Fortunately, the patient recovered rapidly to his preoperative functional baseline.

CONCLUSION

We describe a rare case of SHAM syndrome in a pediatric patient who required bilateral revascularizations and discuss strategies for managing the perioperative risk of hemorrhage and stroke. We also review existing literature on SHAM syndrome.

Therapeutic and technological advancements in haemophilia care: Quantum leaps forward

INTRODUCTION

Recent technological innovations in haemophilia have advanced at an astounding pace, including gene therapy programmes and bioengineered molecules for prophylaxis, products that reduce treatment burden through half-life extension, unique mechanisms of action, and subcutaneous administration. Additional technological advancements have emerged that are anticipated to further transform haemophilia care.

AIM

Review new and emerging haemophilia therapies, including replacement and bypassing products, digital applications, utilisation of big data, and personalised medicine.

METHODS

Data were obtained from peer-reviewed presentations/publications, and ongoing studies in haemophilia, ultrasonography, and artificial intelligence (AI).

RESULTS

Available treatments include new recombinant factors VIII (FVIII) and IX (FIX), extended half-life FVIII/IX products, a new FVIIa product for inhibitor patients, and a FVIIIa-mimetic. Several novel therapeutics are in clinical trials, including FVIIIa mimetics and inhibitors of naturally-occurring anticoagulants. Ongoing gene therapy trials suggest that a single vector infusion using an optimised construct can produce factor activity that reduces bleeding to near zero for years. Today, persons with haemophilia (PwH) approach a lifespan comparable to that of the general population, presenting treatment challenges for age-related co-morbidities. Technological innovations have broadened beyond therapeutics to include large database analyses utilising remote data collection with handheld devices, and to tailor AI applications. Current development efforts include patient-performed ultrasonography, algorithms for scan interpretation, and point-of-care haemostatic testing devices.

CONCLUSIONS

We have entered a golden age for haemophilia treatment and care with wide-ranging advancements targeting improved quality of life (QoL). Future-focused efforts by clinical and patient communities may provide equitable access and care for people impacted by haemophilia worldwide.

Bleeding in patients with hemophilia who have inhibitors: Modeling US medical system utilization and cost avoidance between recombinant factor VIIa products with different clinical dosing requirements

BACKGROUND: A mainstay of treatment in patients with hemophilia with inhibitors (PWIs) is the use of a recombinant factor VIIa (rFVIIa) bypassing agent. A new rFVIIa product may allow reduced rFVIIa utilization for on-demand treatment of bleeding episodes (BEs). OBJECTIVE: A decision analytic health economic model was developed to compare the utilization and consequent need for bleed-related clinical encounters of 2 rFVIIa products, with the International Nomenclature Name of eptacog alfa (EA) and eptacog beta (EB). METHODS: This study uses recent, peer-reviewed, and published data from clinical trials with similar endpoints for 1 million insured male lives in the United States. rFVIIa product utilization was modeled in hemophilia (A and B) PWI for on-demand treatment of BEs with rFVIIa treatment. Estimated annual BE rates were modeled to include prophylaxis and on-demand management. The clinical encounter avoidance estimates are based on refractory bleeding through 24 hours. RESULTS: In a cohort of 1 million insured, 5-6 patients with hemophilia A or B with inhibitors annually receive on-demand treatment for a total of 59 mild/moderate BEs. The model suggests that EB requires less unit utilization per BE (13,125 μg and 17,850 μg for the 75μg/kg and 225μg/kg dose regimens, respectively) than EA 90 μg/kg dosing (20,178μg), with wholesale acquisition costs expanding the difference. Further, both EB initial dose regimens would permit decreased total nonmedication health plan spending for the acute treatment of BEs by reducing the need for clinical encounters arising from BEs that fail to respond within 24 hours. CONCLUSIONS: With reduced infusion requirements, the model consistently shows that EB could generate lower insured-cohort drug utilization, as well as reduce costly clinical encounters by keeping mild and moderate BEs amenable to home bypassing agent management. DISCLOSURES: The article was funded by HEMA Biologic, LLC. The authors approved all content and results in this article without being subject to sponsor censorship. Mr Jensen, Mr Cyr, and Ms Hathway are employees of PRECISIONheor, which provides consulting services to the pharmaceutical industry, including HEMA Biologics, LLC. Dr Batt is an advisor to PRECISIONheor. Dr Alexander is a former employee of HEMA Biologics, LLC, and provides consulting services to the pharmaceutical industry.

Resource utilization and treatment costs of patients with severe hemophilia A: Real-world data from the ATHNdataset

Hemophilia A is characterized by unpredictable spontaneous bleeds and chronic comorbidities. However, limited data exists at the national level into detailed management patterns related to patient clinical characteristics, representative real-world dosing and treatment frequency, and costs. To assess and characterize the US severe hemophilia A (SHA) population, including subgroups of patients, in terms of clinical and demographic characteristics, healthcare resource utilization received at hemophilia treatment centers (HTCs), and projected annual costs of treatment utilizing data from the ATHNdataset of the American Thrombosis and Hemostasis Network (ATHN). Adult male people with SHA (PwSHA) (FVIII < 1%) were identified in the ATHNdataset between January 2013 and September 2019. This retrospective cohort study described patients' demographic and clinical characteristics, clinical history, as well as the HTC-related health resource utilization (HRU), treatment utilization, and projected annual treatment costs of US PwSHA received over the most recent year. Results are reported for the overall population and for three mutually exclusive subpopulations of patients: PwSHA with a history of and/or current inhibitors, PwSHA without a history of inhibitors but with (or a history of) one or more transfusion-transmitted infections (hepatitis B virus [HBV], hepatitis C virus [HCV], or human immunodeficiency virus [HIV]), and PwSHA without a history of inhibitors or of transfusion-transmitted infections (HBV, HCV, or HIV). Of the overall PwSHA cohort (N = 3677), there was a high prevalence of HCV (24.1%) and HIV (13.7%), while the prevalence of HBV (4.9%) was lower. Note that 20.5% of PwSHA overall currently or ever had FVIII inhibitors. On average, PwSHA had 2.8 total HTC visits per year, including 0.9 comprehensive care visits, 1.1 telephone contact visits, 0.5 office visits, and 0.1 surgeries or other procedures. However, 23.3% of PwSHA were not seen at an HTC, and 33.8% of PwSHA did not have a comprehensive care visit during their most recent year of data. HTC-related HRU was similar between the overall cohort and across the patient subpopulations, although PwSHA and inhibitors had more frequent HTC visits (a mean of 3.6 visits annually vs. 2.5-2.8 in the other groups). Using reported treatment frequency and dosing, estimated mean annual hemophilia treatment costs varied by treatment and across the three subpopulations: extended half-life factor product ($893,609-934,301 by subpopulation), standard half-life factor product ($798,700-930,812), plasma-derived factor product ($613,220-801,061), and non-factor product treatment ($765,289-833,240). This study summarized recent sociodemographic and clinical characteristics, HTC-related HRU, and HA treatments and projected costs among adult PwSHA, including among key subpopulations of PwSHA. PwSHA experience substantial clinical and resource burden on a chronic basis, despite the care coordination efforts of ATHN-affiliated HTCs. These findings motivate further exploration of the drivers of resource utilization, observed differences across subpopulations and other disparities, and ongoing monitoring of clinical and treatment burden in the face of an evolving care landscape.

Disease-Specific Health Disparities: A Targeted Review Focusing on Race and Ethnicity

Background: Wide disparities in health status exist in the United States across race and ethnicity, broadly driven by social determinants of health—most notably race and ethnic group differences in income, education, and occupational status. However, disparities in disease frequency or severity remain underappreciated for many individual diseases whose distribution in the population varies. Such information is not readily accessible, nor emphasized in treatment guidelines or reviews used by practitioners. Specifically, a summary on disease-specific evidence of disparities from population-based studies is lacking. Our goal was to summarize the published evidence for specific disease disparities in the United States so that this knowledge becomes more widely available “at the bedside”. We hope this summary stimulates health equity research at the disease level so that these disparities can be addressed effectively. Methods: A targeted literature review of disorders in Pfizer’s current pipeline was conducted. The 38 diseases included metabolic disorders, cancers, inflammatory conditions, dermatologic disorders, rare diseases, and infectious targets of vaccines under development. Online searches in Ovid and Google were performed to identify sources focused on differences in disease rates and severity between non-Hispanic Whites and Black/African Americans, and between non-Hispanic Whites and Hispanics. As a model for how this might be accomplished for all disorders, disparities in disease rates and disease severity were scored to make the results of our review most readily accessible. After primary review of each condition by one author, another undertook an independent review. Differences between reviewers were resolved through discussion. Results: For Black/African Americans, 29 of the 38 disorders revealed a robust excess in incidence, prevalence, or severity. After sickle cell anemia, the largest excesses in frequency were identified for multiple myeloma and hidradenitis suppurativa. For Hispanics, there was evidence of disparity in 19 diseases. Most notable were metabolic disorders, including non-alcoholic steatohepatitis (NASH). Conclusions: This review summarized recent disease-specific evidence of disparities based on race and ethnicity across multiple diseases, to inform clinicians and health equity research. Our findings may be well known to researchers and specialists in their respective fields but may not be common knowledge to health care providers or public health and policy institutions. Our hope is that this effort spurs research into the causes of the many disease disparities that exist in the United States.

Gastrointestinal Bleeding in Congenital Bleeding Disorders

Gastrointestinal bleeding (GIB) is serious, intractable, and potentially life-threatening condition. There is considerable heterogeneity in GIB phenotypes among congenital bleeding disorders (CBDs), making GIB difficult to manage. Although GIB is rarely encountered in CBDs, its severity in some patients makes the need for a comprehensive and precise assessment of underlying factors and management approaches imperative. Initial evaluation of GIB begins with assessment of hematological status; GIB should be ruled out in patients with chronic anemia, and in presentations that include hematemesis, hematochezia, or melena. High-risk patients with recurrent GIB require urgent interventions such as replacement therapy for treatment of coagulation factor deficiency (CFD). However, the best management strategy for CFD-related bleeding remains controversial. While several investigations have identified CBDs as potential risk factors for GIB, research has focused on assessing the risks for individual factor deficiencies and other CBDs. This review highlights recent findings on the prevalence, management strategies, and alternative therapies of GIB related to CFDs, and platelet disorders.

Nonneutralizing FVIII-specific antibody signatures in patients with Hemophilia A and in healthy donors

Isotypes and IgG subclasses of nonneutralizing FVIII-specific antibodies are similar in hemophilia A patients and healthy subjects.

Prevalences, titers, and affinities of nonneutralizing antibodies, however, differ significantly between patients and healthy subjects.

Previous studies identified nonneutralizing FVIII-specific antibodies in the circulation of severe and nonsevere hemophilia A (sHA and nsHA) patients without FVIII inhibitors and also in some healthy individuals. To gain a better understanding of the nature of these nonneutralizing antibody responses, we analyzed and compared anti-FVIII antibody signatures in 3 study cohorts: previously treated sHA as well as nsHA patients without FVIII inhibitors, and healthy donors. FVIII-binding IgM, IgG1-4, and IgA antibodies were differentiated, FVIII-specificity was assessed, and associated apparent affinity constants were determined. Our results indicate that the nonneutralizing FVIII-specific antibody response in all study cohorts is dominated by IgG1 and IgA. Prevalences, titers, and affinities of these nonneutralizing antibodies were higher in the hemophilia A cohorts than in healthy donors. Stratification for the anti-hepatitis C virus (HCV) antibody status demonstrated the presence of FVIII-specific IgA with elevated titers in sHA patients with an active or past HCV infection when compared with HCV antibody-positive nsHA patients or HCV antibody-negative patients and healthy donors. Increased titers and affinities of FVIII-specific IgG1 antibodies were observed in a considerable number of hemophilia A patients as opposed to healthy subjects independently of the patients’ anti-HCV antibody status. Overall, our findings support the hypothesis that the generation of nonneutralizing anti-FVIII antibodies in healthy individuals and in noninhibitor hemophilia A patients might be based on similar immune mechanisms. However, differences in prevalences, titers, and affinities of these antibodies indicate distinct differences in the antibody evolution between healthy individuals and patients.

The Clinical Genetics of Hemophilia B (Factor IX Deficiency)

Hemophilia B (HB) is a bleeding disorder caused by deficiency of or defect in blood coagulation factor IX (FIX) inherited in an X-linked manner. It results from one of over 1000 known pathogenic variants in the FIX gene, F9; missense and frameshift changes predominate. Although primarily males are affected with HB, heterozygous females may have excessive bleeding due to random or non-random X chromosome inactivation; in addition, homozygous, compound heterozygous, and hemizygous females have been reported. Somatic and germinal mosaicism for F9 variants has been observed. Development of antibodies to FIX treatment products (inhibitors) is rare and related to the type of causative variant present. Treatment is with products produced by recombinant DNA technology, and gene therapy is in clinical trials. Genetic counseling with up-to-date information is warranted for heterozygotes, potential heterozygotes, and men and women affected with HB.

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.

Real-World Data on Bleeding Patterns of Hemophilia A Patients Treated with Emicizumab

Emicizumab (Hemlibra™) is approved for prophylaxis of hemophilia A (HA) patients. The HAVEN studies addressed bleeding reduction in emicizumab-treated patients, but real-world data on bleeding patterns during emicizumab therapy are lacking. We aimed to compare the occurrence of breakthrough bleeding at different time points, starting from emicizumab initiation. This longitudinal prospective observational cohort study included HA patients (n = 70, aged 1 month to 74.9 years) that completed at least 18 months of follow-up in our center. We analyzed the number of spontaneous and traumatic bleeds during selected time points of the study (“bleeding periods”). The percentage of traumatic and spontaneous bleeding episodes was not significantly different among “bleeding periods” (P = 0.053 and P = 0.092, respectively). Most trauma-related treated bleeds resulted from either hemarthrosis (53%) or head trauma (33%). Spontaneous bleeding episodes were mostly hemarthroses (80%). Potential associations of the patients’ age, annualized bleeding rate before emicizumab treatment, and the presence of inhibitors with spontaneous bleed occurrence were analyzed with binomial logistic regression. The odds of bleeding while on emicizumab increased by a factor of 1.029 (P = 0.034) for every one year of age. Conclusions: Our real-world data revealed that the risk of bleeding persists, especially in older patients, despite therapy with emicizumab. These data may help clinicians in counselling their patients and in planning their management.

Overcoming the challenges of treating hemophilia in resource-limited nations: a focus on medication access and adherence

BACKGROUND

Hemophilia is a high cost low volume disease. Resource limited nations (RLN) usually spend very little on health budget and most of it is spent in dealing with common ailments. Clotting products constitute more than 90% of the total cost of hemophilia care. The manner in which these products can be made accessible for persons with hemophilia (PWH) and how its continuous supply and distribution can be maintained and improved is described in this review.

AREAS COVERED

Number of PWH in the Resource Limited Nations (RLN); minimum amount of concentrate required to keep a PWH relatively free of bleeds; the different products available for management of PWH; means and ways to minimize and optimize the concentrate usage and purchase on a budget; nonfactor therapy; ways and means to improve the management and allow better quality concentrates in higher quantities for PWH in those countries; adherence as a challenge for RLN country and ways to manage them. The time covered is from 1980s till date. Pubmed was searched mainly for review articles with the key words hemophilia, RLN, concentrate access, alternative therapy. Cross references from these reviews as well as some of the abstracts from international conferences were read.

EXPERT OPINION

Developing a patient's society and a bleeding disorder registry are the two most important actions toward ensuring adequate treatment material for PWH in RLN. Government should allocate a budget for hemophilia care depending on the number of PWH diagnosed and future projection of increased numbers of PWH. Population based product requirement may not work initially as only 10-20% of PWH in such a country has been diagnosed hence initial requirement of concentrates should be directed to these patients. Meanwhile efforts should be made to diagnose new cases. Antenatal diagnosis centers should offer antenatal diagnosis and prevent birth of severe hemophilia children. Self sufficiency in plasma based concentrates should be planned and aimed. A national tendering committee can get a good price on the concentrates on global tendering with annual rate contracts (prevents outdating). Avoiding wastage by outdating of the products in large denomination vials will help. Hoarding concentrates in unreasonable amounts should be avoided through good supply chain management. Regular physiotherapy, proper use of optimum amounts of concentrate will reduce per PWH consumption of the factor concentrates. Plasma derived intermediate purity factors, first/second generation recombinant clotting factors are safe and relatively cheaper as well as effective. Also concentrates which are close to their expiry date (>3 < 6 months) are equally effective and cheap. With proper supply chain management such products can be included in the portfolio. Primary prophylaxis with low/ intermediate dose of the concentrates is a cost-effective way to manage the patients and this also reduces inhibitor development. Adherence to therapy is not yet an important issue for RLN countries but will become one in future. With advancement and improvement the country can access alternative non factor concentrates and other newer products.

Regulation and importance of factor VIII levels in hemophilia A carriers

PURPOSE OF REVIEW

To summarize the recent literature related to female hemophilia A carriers with respect to prevalence in the population, the impact of baseline factor VIII levels and other influences on bleeding phenotype, and clinical management needs.

RECENT FINDINGS

Many female hemophilia A carriers are at risk for abnormal bleeding, yet they are underrecognized by healthcare providers and their bleeding symptoms are underreported. Low FVIII levels are consistently associated with clinically significant bleeding and correlate well with skewed X chromosome inactivation (XCI). Most interestingly, bleeding tendency is also observed in some hemophilia A carriers with normal factor VIII levels and requires further investigation. Well controlled studies investigating peripartum and periprocedural FVIII levels and adequate hemostatic treatment are necessary to inform management guidelines.

SUMMARY

Prevalence and bleeding tendency of hemophilia A carriers remain underreported, despite a significant proportion having low FVIII levels. Skewed XCI may explain low FVIII but does not explain the bleeding risk encountered in a larger proportion of hemophilia A carriers with random XCI and borderline/normal FVIII.

Understanding the Pain Management Landscape within the US Bleeding Disorder Community: A Multi-Center Survey

Objectives

Pain is a known complication in persons with hemophilia (PWH) as a result of muscle and joint bleeding. Little is known regarding national Hemophilia Treatment Center (HTC) practice patterns related to pain management. The aim of this study was to: 1) Describe pain management practice patterns of HTC providers, 2) Identify gaps and areas of alignment with the CDC pain guidelines, and 3) Address educational opportunities for pain management. This survey is the first extensive description of multidisciplinary practice patterns of pain management for PWH.

Methods

This descriptive study involved physicians, nurse practitioners, nurses, physical therapists, and social workers from federally funded Hemophilia Treatment Centers (HTC) eligible to complete an online survey exploring pain management practice patterns within the CDC pain guidelines.

Results

Results of this survey shed light on areas of strength and cohesiveness between HTC providers, including the following: dedication to effective pain management, utilization of non-pharmacological pain options, trial of non-opioid medications first before opioids, maintaining follow-up with patients after opioid prescription initiation, recognizing and utilizing clinically important findings before prescribing opioids, and counseling their patients regarding potential risk factors.

Conclusions

There remain opportunities to incorporate into clinical practice consistent use of tools such as formal screening questionnaires, opioid use agreements, written measurable goals, ongoing prescription monitoring, and written plans for discontinuation of opioid therapy. These results provide opportunities for improvement in education of HTC team members thus optimizing pain management in persons with bleeding disorders.

Occurrence rates of von Willebrand disease among people receiving care in specialized treatment centres in the United States

INTRODUCTION

In the network of U.S. comprehensive haemophilia treatment centres (HTCs), von Willebrand disease (VWD) is the most common bleeding disorder other than haemophilia. Estimates of the size and characteristics of the VWD population receiving treatment are useful for healthcare planning.

AIM

Estimate the prevalence and incidence of VWD among males and females receiving care at U.S. HTCs (HTC-treated prevalence and incidence).

METHODS

During the period 2012-2019, de-identified surveillance data were collected on all VWD patients who visited an HTC including year of birth, sex, race, Hispanic ethnicity, VWD type, and laboratory findings and used to calculate period HTC-treated prevalence by VWD type and sex. Data from patients born 1995-1999 were used to estimate HTC-treated incidence rates.

RESULTS

During the period, 24,238 patients with a diagnosis of VWD attended HTCs; for 23,479 (96.9%), VWD type was reported or could be assigned. Age-adjusted HTC-treated prevalence was 8.6 cases/100,000 (7.2/100,000 for Type 1, 1.2/100,000 for Type 2 and 1.7/million for Type 3) and was twice as high in women as men (4.8 vs. 2.4 cases/100,000) for Type 1 and similar by sex for Type 2 and Type 3. HTC-treated Type 1 incidence increased over the period, averaging nearly threefold higher for women than men (26.2 vs. 9.9/100,000 live births). Sex differences were less for Type 2 (2.2 vs. 1.4 cases/100,000 births) and slight in Type 3.

CONCLUSION

Prevalence and incidence of HTC-treated VWD differ by sex and type and are likely strongly influenced by differences in rates of diagnosis.

The Cost-effectiveness of Gene Therapy for Severe Hemophilia B: Microsimulation Study from the United States Perspective

Adeno-associated virus (AAV)-mediated gene therapy is a novel treatment promising to reduce morbidity associated with hemophilia. While multiple clinical trials continue to evaluate efficacy and safety, limited cost-effectiveness data have been published. This study compared the potential cost-effectiveness of AAV-mediated factor IX(FIX)-Padua gene therapy for severe hemophilia B patients in the United States (US) to on-demand FIX replacement and primary FIX prophylaxis, using either standard or extended half-life FIX products. A microsimulation Markov model was constructed and transition probabilities between health states and utilities were informed by published data. Costs were aggregated using a micro-costing approach. An 18-years-old till death time-horizon from the perspective of a third-party payer in the US was conducted. Gene therapy was more cost-effective than both alternatives considering a $150,000/QALY threshold. The price for gene therapy was assumed $2,000,000 in the base-case scenario, yet one of the one-way sensitivity analyses was conducted using observed manufacturing, administration and five-year follow-up cost of $87,198 for AAV-mediated gene therapy vector as derived from the manufacturing facility and clinical practice at St. Jude Children's Research Hospital. One-way sensitivity analyses showed 10/102 scenarios in which gene therapy was not cost-effective compared to alternative treatments. Notably, gene therapy remained cost-effective in a hypothetical scenario in which we estimated that the discounted factor concentrate price was 20% of the wholesale acquisition cost in the US. Probabilistic sensitivity analysis estimated gene therapy cost-effective at 92% of simulations considering $150,000/QALY threshold. In conclusion, based on detailed simulation inputs and assumptions, gene therapy was more cost-effective than on-demand treatment and prophylaxis for patients with severe hemophilia B.

Nonsevere hemophilia A: often overlooked, but not forgotten

PURPOSE OF REVIEW

Nonsevere hemophilia A (NSHA) patients have received relatively little clinical and research attention as compared with their severe counterparts. There is increasing recognition that despite their milder bleeding phenotype, the management of NSHA can be a challenge, with most management decisions largely inferred from severe hemophilia A data. This review focuses on some of the more recent developments in the field of NSHA.

RECENT FINDINGS

Epidemiologic studies suggest that NSHA remain under-recognized and under-diagnosed globally. As the NSHA population ages, they are susceptible to age-related comorbidities. Large cohort studies of NSHA report that the most common primary cause of death is malignancy. NSHA patients have a lifetime risk of inhibitor development with increasing exposure to factor VIII concentrate. Even so, not all patients with inhibitors will require eradication treatment, irrespective of bleeding phenotype at time of inhibitor development.

SUMMARY

As there are currently no evidence-based strategies for inhibitor eradication in NSHA patients, preventive strategies are critical to mitigate inhibitor risk in NSHA. There is a need for active surveillance of NSHA patients by hemophilia treatment centers to address hemophilia-related issues and other age-related comorbidities, in collaboration with primary care physicians and other subspecialists.

Physical activity and bleeding outcomes among people with severe hemophilia on extended half-life or conventional recombinant factors

BACKGROUND

Few have assessed physical activity (PA) and annual bleed rates (ABRs) among people with hemophilia on extended half-life (EHL) factors (recombinant factor VIII Fc [rFVIIIFc]/recombinant factor IX Fc [rFIXFc]) and conventional factors (recombinant factor VIII [rFVIII]/recombinant factor IX [rFIX]).

OBJECTIVE

To assess changes in PA and ABR at consecutive annual visits in individuals with severe hemophilia A and B (HA/HB) on prophylactic treatment with rFVIIIFc/rFIXFc versus rFVIII/rFIX.

PATIENTS/METHODS

We conducted a retrospective chart review of 344 people with severe HA/HB (ages 6-35) receiving prophylaxis with rFVIIIFc/rFIXFc (EHL factors) or rFVIII/rFIX (conventional factors) for ≥6 months in 2014-2015. Differences in changes in outcomes from 2014 to 2015 were compared across the treatment groups.

RESULTS

Baseline characteristics and adherence to the prophylactic regimen were similar across the treatment groups. Greater increase in weekly PA frequency and duration were observed among all EHL groups, except for children treated with rFIXFc. The increase in PA frequency was greater among the children on rFVIIIFc group, adults on rFVIIIFc group, and adults on rFIXFc group by 1.2, 1.2, and 1.4 events/week, respectively, compared to their rFVIII/rFIX counterparts. The increases in PA duration were 44, 60, and 80 min/wk greater among the children on rFVIIIFc, adults on rFVIIIFc, and adults on rFIXFc groups, respectively. Larger reductions in total ABR were observed in children and adults treated with rFVIIIFc compared to rFVIII (0.4 and 0.7 fewer bleeds). Larger reductions were also observed in spontaneous ABR in adult rFVIIIFc and rFIXFc groups (0.8 and 0.3 fewer bleeds, respectively).

CONCLUSIONS

This study suggests that rFVIIIFc/FIXFc agents can positively impact PA while maintaining low ABRs.

Evaluation of anti-factor VIII antibody levels in patients with haemophilia A receiving immune tolerance induction therapy or bypassing agents

INTRODUCTION

Bleeding episodes in patients who have haemophilia A (HA), a hereditary bleeding disorder caused by a deficiency in factor VIII (FVIII), are treated or prophylactically prevented with infusions of exogenous FVIII. Neutralizing antibodies, referred to as inhibitors, against infusion products are a major complication experienced by up to 30% of patients who have severe HA. Bypassing agents (BPA), a class of therapeutics given to patients who have inhibitors, bypass the need for FVIII in the coagulation cascade, and long-term inhibitor eradication is accomplished using immune tolerance induction therapy (ITI). Data examining the antibody levels in patients receiving BPA and ITI are limited.

AIM

Measure anti-FVIII antibody levels in specimens from patients receiving ITI or BPA in order to evaluate the anti-FVIII antibody response in those patients.

METHODS

Specimens were tested using the CDC-modified Nijmegen-Bethesda assay (NBA) and the CDC fluorescence immunoassay (FLI) for anti-FVIII IgG₁ and IgG₄ .

RESULTS

NBA-negative specimens from patients undergoing ITI or receiving BPAs have a higher frequency of anti-FVIII IgG₄ positivity compared with the previously published level for NBA-negative HA patients. Analysis of anti-FVIII antibody levels in serial samples from patients undergoing ITI reveals that antibodies can persist even after the patient's NBA result falls into the negative range.

CONCLUSIONS

Measurement of anti-FVIII antibodies may be a useful means to better contextualize NBA results in specimens from patients receiving BPA or ITI. In addition, assessment of anti-FVIII antibody levels has the potential to improve inhibitor surveillance and clinical decision-making related to the progress of ITI.