Intermediate-dose versus high-dose prophylaxis for severe hemophilia: comparing outcome and costs since the 1970s

Vascular remodeling underlies rebleeding in hemophilic arthropathy

Hemophilic arthropathy is a debilitating condition that can develop as a consequence of frequent joint bleeding despite adequate clotting factor replacement. The mechanisms leading to repeated spontaneous bleeding are unknown. We investigated synovial, vascular, stromal, and cartilage changes in response to a single induced hemarthrosis in the FVIII-deficient mouse. We found soft-tissue hyperproliferation with marked induction of neoangiogenesis and evolving abnormal vascular architecture. While soft-tissue changes were rapidly reversible, abnormal vascularity persisted for months and, surprisingly, was also seen in uninjured joints. Vascular changes in FVIII-deficient mice involved pronounced remodeling with expression of α-Smooth Muscle Actin (SMA), Endoglin (CD105), and vascular endothelial growth factor, as well as alterations of joint perfusion as determined by in vivo imaging. Vascular architecture changes and pronounced expression of α-SMA appeared unique to hemophilia, as these were not found in joint tissue obtained from mouse models of rheumatoid arthritis and osteoarthritis and from patients with the same conditions. Evidence that vascular changes in hemophilia were significantly associated with bleeding and joint deterioration was obtained prospectively by dynamic in vivo imaging with musculoskeletal ultrasound and power Doppler of 156 joints (elbows, knees, and ankles) in a cohort of 26 patients with hemophilia at baseline and during painful episodes. These observations support the hypothesis that vascular remodeling contributes significantly to bleed propagation and development of hemophilic arthropathy. Based on these findings, the development of molecular targets for angiogenesis inhibition may be considered in this disease.

Challenges in hemophilia care in Australia and New Zealand

BACKGROUND

Health and life expectancy for people with hemophilia have improved significantly in recent years, but we face new challenges, especially in the context of resource-constrained health services.

AIM

This paper aims to highlight such challenges and propose practical solutions.

METHODS

Nine hemophilia specialists from Australia and New Zealand reached consensus on areas of greatest need for improvement in hemophilia care in these countries, based on clinical experience and published data, and agreed on how to address these.

RESULTS

Demography, optimizing treatment and assessing treatment success were identified as broad areas of challenge which included: comorbidities in ageing patients; transitioning from pediatric to adult care; equity of care for remote populations; weight-based dosing in obese patients; tailoring prophylaxis; accurate diagnosis of acute joint pain; managing chronic arthropathy; providing psychosocial support; consistency in definitions and assessment; and quantifiable outcome measures. Practice points included increased cross-specialty coordination and including psychologists and rheumatologists as part of comprehensive care teams; close collaboration between pediatric and adult centers to facilitate transition of care; systems such as telehealth that ensure continuity of care for remote populations; using pharmacokinetic data to tailor therapy; rapid and accurate diagnosis of acute joint pain; using data from bleeding registries to assess treatment effects and help with service planning; and ensuring consistency through benchmarking and standardization of HTCs.

SUMMARY

Achieving treatment equity, optimal outcomes and cost savings may be possible through investing in national governance structures, expanding the comprehensive model of care and implementing innovative solutions tailored to local needs.

Advances and challenges in hemophilic arthropathy

Hemophilic arthropathy is a form of joint disease that develops secondary to joint bleeding and presents with synovial hypertrophy, cartilage and bony destruction. The arthropathy can develop despite clotting factor replacement and is especially disabling in the aging population. Pathobiological tissue changes are triggered by release of hemoglobin and iron deposition in the joint, but the sequence of events and the molecular mechanisms resulting in joint deterioration are incompletely understood. Treatment options other than clotting factor replacement are limited. Improvements in the treatment of hemophilia necessitate a better understanding of the processes that lead to this disabling condition and better diagnostic tools. Towards that end, studies of the molecular mechanisms leading to the arthropathy, as well as the development of sensitive imaging techniques and biomarkers are needed. These will pave the way to identify the cause of acute pain such as joint bleeding or synovitis, detect early, potentially reversible structural changes, and predict progression of disease. This review describes current imaging techniques and the development of high resolution musculoskeletal ultrasound with power Doppler to afford point-of-care diagnosis and management, the potential utility of diagnostic biomarkers, and summarizes our current knowledge of the pathobiology of hemophilic arthropathy.

Hemophilic arthropathy of the elbow: prophylaxis, imaging, and the role of invasive management

Hemophilia is an X-linked recessive deficiency of clotting factor VIII (hemophilia A) or IX (hemophilia B) that can result in hemarthrosis of various joints, including the elbow. Left unchecked, this can lead to progressive joint destruction and significant morbidity. Appropriate management of the elbow joint through prophylactic measures, accurate imaging, and timely intervention is essential. Replacing or supplementing deficient factor with a plasma-derived or recombinant factor concentrate can minimize bleeding episodes. Joints should be routinely monitored for damage. Plain films offer an inexpensive window into bone disease and joint space changes but lack soft tissue detail and may not detect early changes. Magnetic resonance imaging provides a high level of detail but may be limited by its cost and need for sedation in younger patients. Ultrasound may not achieve the same level of resolution as magnetic resonance imaging, but it is increasingly used as a convenient, effective, and relatively inexpensive alternative. Patients who experience hemarthrosis of the elbow with joint damage often require more invasive treatment. Radiosynovectomy and arthroscopic synovectomy are effective at minimizing pain and preventing future bleeding episodes, whereas extensive joint damage may necessitate total elbow replacement.

Pharmacokinetics, phenotype and product choice in haemophilia B: how to strike a balance?

At the 7th Annual Congress of the European Association for Haemophilia and Allied Disorders (EAHAD) held in Brussels, Belgium, in February 2014, Pfizer sponsored a satellite symposium entitled: "Pharmacokinetics, phenotype and product choice in haemophilia B: How to strike a balance?" Co-chaired by Cedric Hermans (Cliniques Universitaires Saint Luc, Brussels, Belgium) and Mike Laffan (Imperial College, London, UK), the symposium provided an opportunity to debate whether pharmacokinetic (PK) parameters are good surrogates for clinical efficacy for haemophilia B in clinical practice, consider the perceptions and evidence of disease severity, and examine how these considerations can inform approaches to balancing the potential risks and benefits of the currently available treatment options for haemophilia B. PK parameters are routinely measured in clinical practice and are a requirement of regulatory bodies to demonstrate the clinical efficacy of products; however, the relationship between measured PK parameters and clinical efficacy is yet to be determined, an issue that was debated by Gerry Dolan (University Hospital, Queen's Medical Centre, Nottingham, UK) and Erik Berntorp (Lund University, Malmö Centre for Thrombosis and Haemostasis, Malmö, Sweden). Elena Santagostino (Universita degli Studi di Milano, Milano, Italy) reviewed how differing perceptions on the severity of haemophilia B compared with haemophilia A may have an impact on clinical decision-making. Finally, Andreas Tiede (Hannover Medical School, Hannover, Germany), examined the considerations for balancing the potential risks and benefits of the currently available treatment options for haemophilia B. Although the pathophysiology of haemophilia B has been widely studied and is largely understood, continued investigation and discussion around the optimal management course and appropriate therapeutic choice is warranted.

Assessments of outcome in haemophilia - what is the added value of QoL tools?

INTRODUCTION

Access to treatment and especially to long-term regular replacement treatment with clotting factor concentrates (prophylaxis) have caused dramatic contrasts in the clinical picture between haemophilia populations. An individual patient with severe haemophilia age 20 years can have normal joints or can be severely crippled and unable to work. Assessment of outcome in a standardized way has therefore become essential.

AIM

Discuss the relevance and utility of the different outcome assessment tools in patient groups with different access to treatment.

METHODS

In the last decade new outcome assessment tools specific for haemophilia have been developed that measure all aspects of health according to the International Classification of Functioning, Disability and Health (ICF) model. These tools are directed at assessing the clinical and radiological status of joints as well as overall functioning, such as participation and psychosocial aspects, evaluating overall health-related quality of life (HRQOL). For deciding which tools to use in clinical practice or research, one needs to consider the specific context with regard to disease burden, healthcare environment and socioeconomic background of the patients being evaluated.

CONCLUSION

Prospective systematic assessment of outcome in haemophilia and related bleeding disorders is important. Based upon recent literature a critical appraisal of outcome tools is described.

Optimal treatment strategies for hemophilia: achievements and limitations of current prophylactic regimens

Prophylactic application of clotting factor concentrates is the basis of modern treatment of severe hemophilia A. In children, the early start of prophylaxis as primary or secondary prophylaxis has become the gold standard in most countries with adequate resources. In adults, prophylaxis is reasonably continued when started as primary or secondary prophylaxis in childhood to maintain healthy joint function. Initial data support that adult patients with already existing advanced joint arthropathy benefit from tertiary prophylaxis with significantly lowered number of bleeds, almost complete absence of target joints, and less time off from work. Current prophylactic regimens, although very effective, do not completely prevent joint disease in a long-term perspective. Joint arthropathy in primary prophylaxis develops over many years, sometimes over a decade or even longer time periods. The ankle joints are the first and most severely affected joints in those patients and thus may serve in outcome assessment as an indicator of early joint arthropathy when followed by ultrasound or magnetic resonance imaging. Optimized outcome and best use of available resources is expected from individualization of therapy regimens, which comprises the individual’s bleeding pattern, condition of the musculoskeletal system, level of physical activity and the pharmacokinetic profile of the substituted coagulation factor, and most recently includes novel products with extended half-lives.

Joint Aspiration for Acute Hemarthrosis in Children Receiving Factor VIII Prophylaxis for Severe Hemophilia: 11-year Safety Data

Objective.

The aims of this study were (1) to document the prevalence of acute hemarthrosis in a cohort of 46 boys with severe hemophilia A receiving full primary prophylaxis in Western Australia (WA), and (2) to investigate the safety of the WA protocol over 11 years for management of hemarthrosis.

Methods.

Case review. The WA protocol involves a pediatric rheumatologist washing out all acute hemarthrosis of large joints promptly and then instilling intraarticular (IA) corticosteroids.

Results.

This study showed that joint bleeds occurred in 22 boys of 46 (47.8%). In over 11 years, 84 washouts were performed on 32 joints in 22 boys. No adverse events occurred. Fifteen of 22 boys had normal joints with a Hemophilic Joint Health Score = 0. Fifteen boys who had had all hemarthrosis washed out had clinically normal joints (100%). Seven boys had sustained joint damage prior to full instigation of the protocol, each having had documented hemarthrosis without aspiration. Parents needed to understand that joint bleeds constituted an emergency.

Conclusion.

Of our cohort, 47.8% of patients with severe hemophilia receiving prophylaxis developed joint bleeding. The WA protocol is safe. There is evidence suggesting joint outcomes of hemophilic patients having hemarthrosis despite factor VIII prophylaxis may be much improved if there is access to a center using a procedure similar to the WA protocol.

Prophylaxis in older Canadian adults with hemophilia A: lessons and more questions

BACKGROUND

Although prophylaxis is a standard of care for young children in developed countries, known to reduce the severity of hemophilic arthropathy, older adults with existing arthropathy have not traditionally used prophylaxis. Recent studies have shown that adults with hemophilia A are increasingly adopting prophylaxis but the characteristics of this treatment in older adults are not well understood. This multicenter observational study was conducted to describe how secondary/tertiary prophylaxis is being used in older adults (≥40 years of age) in comparison to younger adults with severe hemophilia A.

METHODS

Eligible adult (≥18 years of age) Canadian males with baseline FVIII:C ≤2% from the participating centres were observed over a 2 year period.

RESULTS

Of the 220 adult severe hemophilia patients enrolled, 70% (155/220) used prophylaxis during the observational period. Only 27% (60/220) are older adults with very few >60 years of age. A lower proportion of older adults use prophylaxis compared to younger adults (58% vs. 75%, p = 0.016), with most patients in both groups using continuous prophylaxis (92 and 94% respectively). When considering all treatment modalities together, younger subjects use more factor concentrate than older subjects (2437 u/kg/year vs. 1702 u/kg/year, p = 0.027); however, older subjects on prophylaxis use 3447 u/kg/year and had an ABR of 12 while those on demand use 560 u/kg/year and had an ABR of 13.

CONCLUSION

A significant number of older adults use secondary/tertiary continuous prophylaxis in Canada, accounting for a significant fraction of factor concentrate utilization.

Estimates of utility weights in hemophilia: implications for cost-utility analysis of clotting factor prophylaxis

Estimates of preference-weighted health outcomes or health state utilities are needed to assess improvements in health in terms of quality-adjusted life-years. Gains in quality-adjusted life-years are used to assess the cost-effectiveness of prophylactic use of clotting factor compared with on-demand treatment among people with hemophilia, a congenital bleeding disorder. Published estimates of health utilities for people with hemophilia vary, contributing to uncertainty in the estimates of cost-effectiveness of prophylaxis. Challenges in estimating utility weights for the purpose of evaluating hemophilia treatment include selection bias in observational data, difficulty in adjusting for predictors of health-related quality of life and lack of preference-based data comparing adults with lifetime or primary prophylaxis versus no prophylaxis living within the same country and healthcare system.

Various regimens for prophylactic treatment of patients with haemophilia

Haemophilia prophylaxis is superior to on-demand treatment to prevent joint damage. 'High-dose prophylaxis' as used in Sweden is more effective in preventing arthropathy than an 'intermediate-dose regimen' (the Netherlands) and the Canadian tailored primary prophylaxis. Prophylaxis may reduce the risk of developing inhibitors. There is no difference in inhibitor risk between plasma derived and recombinant factor VIII (rFVIII) products but the Rodin study showed increased risk with second-generation rFVIII products. MRI is a new and very sensitive tool to detect the symptoms of early arthropathy but some results (soft tissue changes in 'bleed-free joints') still need to be investigated. Ultrasound is a very helpful method to aid diagnosis especially during the acute phase of a bleed. The risk of infection with central venous access remains a matter of debate. A fully implanted central venous access device (CVAD) has a significant lower risk of infection compared to external CVADs. Patient's age under 6 yr and inhibitor presence are additional risk factors for infections. The role of arteriovenous fistulae needs to be investigated because significant complications have been reported. Disease-specific quality of life instruments are complementary to generic instruments evaluating QoL in patients with haemophilia and have become important health outcome measures.

Prophylaxis in real life scenarios

Prophylaxis has become the standard mantra of care for those individuals with severe haemophilia A and B. Primary prophylaxis is advocated to prevent the occurrence of symptomatic acute spontaneous haemarthroses and to preserve joint structure and function. Typically, twice or thrice weekly infusions of factor VIII or IX concentrates are integral to this treatment approach. Secondary prophylaxis is initiated after the relentless cycle of progressive joint damage has been triggered by prior haemarthroses and is intended to preserve existing joint health by preventing additional spontaneous bleeding events. Event-driven prophylaxis involves the administration of clotting factor concentrates to prevent acute traumatic bleeds, which are anticipated to occur in association with surgical or physical trauma. This regimen enhances the effectiveness of primary or secondary prophylaxis protocols or on-demand approaches to replacement therapy. Besides the marked reduction in the so-called annual bleed rate, prophylaxis regimens frequently increase personal self-confidence to embark on a more active and physical lifestyle; however, in reality, prophylaxis must be individualized in accordance with bleeding phenotypes, with the unique pharmacokinetic profile of administered replacement clotting factor concentrates, with the specific clinical scenario, and with the degree of intensity anticipated for any physical activity. The introduction of extended half-life replacement products will also influence how these prophylaxis regimens will be accomplished. The following scenarios will discuss how prophylaxis regimens can be implemented to protect the individual from developing spontaneous and activity-induced acute bleeding complications and to maintain an improved quality of life.

Validation of the manufacturing process used to produce long-acting recombinant factor IX Fc fusion protein

Recombinant factor IX Fc (rFIXFc) fusion protein is the first of a new class of bioengineered long-acting factors approved for the treatment and prevention of bleeding episodes in haemophilia B. The aim of this work was to describe the manufacturing process for rFIXFc, to assess product quality and to evaluate the capacity of the process to remove impurities and viruses. This manufacturing process utilized a transferable and scalable platform approach established for therapeutic antibody manufacturing and adapted for production of the rFIXFc molecule. rFIXFc was produced using a process free of human- and animal-derived raw materials and a host cell line derived from human embryonic kidney (HEK) 293H cells. The process employed multi-step purification and viral clearance processing, including use of a protein A affinity capture chromatography step, which binds to the Fc portion of the rFIXFc molecule with high affinity and specificity, and a 15 nm pore size virus removal nanofilter. Process validation studies were performed to evaluate identity, purity, activity and safety. The manufacturing process produced rFIXFc with consistent product quality and high purity. Impurity clearance validation studies demonstrated robust and reproducible removal of process-related impurities and adventitious viruses. The rFIXFc manufacturing process produces a highly pure product, free of non-human glycan structures. Validation studies demonstrate that this product is produced with consistent quality and purity. In addition, the scalability and transferability of this process are key attributes to ensure consistent and continuous supply of rFIXFc.

Humanistic and economic aspects of haemophilia treatment in Bulgaria. Comparison between two therapeutic approaches: prophylactic vs. on-demand treatment

The aim of the present study was to calculate the cost-effectiveness of on-demand and prophylactic treatments of severe haemophilia A for Bulgarian patients. The point of view is that of all patients suffering from severe haemophilia A. An epidemiological model was created, which includes data regarding the number of patients divided into age groups up to 74 years. In the model, the transition age from prophylactic to on-demand treatment was gradually increased to up to 40 years. Costs of blood clotting factor, hospitalization, major surgery and indirect costs were considered; incremental cost-effectiveness ratio was calculated. The results showed that despite the increase in the costs for factor VIII with 20 million BGN, the saving obtained from other health services and indirect expenses reduce the overall expenses with 5.3 million BGN. If there is a gradual increase in the age when patients are transferred from a prophylactic to an on-demand regimen, the costs for factor VIII would increase from 10.4 million to 19.7 million BGN, but due to a decrease in indirect costs as well as other health service costs, the total costs would decrease. The sensitivity analysis showed that the costs for clotting factor VIII are what influences the cost-effectiveness in both regimes. This indicates that decreases in the factor VIII cost will increase the overall efficiency in both regimes. In conclusion, the application of the prophylactic regime for patients up to 40 years of age will provide better treatment, increase the quality of life and decrease the incremental costs.

Factor VIII therapy for hemophilia A: current and future issues

Hemophilia A is a congenital, recessive, X-linked bleeding disorder that is managed with infusions of plasma-derived or recombinant factor (F) VIII. The primary considerations in FVIII replacement therapy today are the: 1) immunogenicity of FVIII concentrates, 2) role of longer-acting FVIII products, 3) prophylactic use of FVIII in children and adults with severe hemophilia A, and 4) affordability and availability of FVIII products. Improving patient outcomes by increasing the use of FVIII prophylaxis, preventing or eliminating FVIII inhibitors, and expanding access to FVIII concentrates in developing countries are the major challenges confronting clinicians who care for patients with hemophilia A.

Haemophilia Joint Health Score in healthy adults playing sports

To evaluate outcome of prophylactic clotting factor replacement in children with haemophilia, the Haemophilia Joint Health Score (HJHS) was developed aiming at scoring early joint changes in children aged 4-18. The HJHS has been used for adults on long-term prophylaxis but interpretation of small changes remains difficult. Some changes in these patients may be due to sports-related injuries. Evaluation of HJHS score in healthy adults playing sports could improve the interpretation of this score in haemophilic patients. The aim of this study was to evaluate the HJHS scores in a cohort of young, healthy men participating in sports. Concomitant with a project collecting MRI images of ankles and knees in normal young adults, HJHS scores were assessed in 30 healthy men aged 18-26, participating in sports one to three times per week. One physiotherapist assessed their clinical function using the HJHS 2.1. History of joint injuries was documented. MRI images were scored by a single radiologist, using the International Prophylaxis Study Group additive MRI score. Median age of the study group was 24.3 years (range 19.0-26.4) and median frequency of sports activities was three times per week (range 1-4). Six joints (five knees, one ankle) had a history of sports-related injury. The median overall HJHS score was 0 out of 124 (range 0-3), with 60% of subjects showing no abnormalities on HJHS. All joints were normal on MRI. These results suggest that frequent sports participation and related injuries are not related with abnormalities in HJHS scores.