PFA-100 System: A New Method for Assessment of Platelet Dysfunction

This is a celebratory reprint of a historical paper published in STH in 1998. The original Abstract follows.The PFA-100 system is a platelet function analyzer designed to measure platelet-related primary hemostasis. The instrument uses two disposable cartridges: a collagen/epinephrine (CEPI) and a collagen/ADP (CADP) cartridge. Previous experience has shown that CEPI cartridges detect qualitative platelet defects, including acetylsalicylic acid (ASA)-induced abnormalities, while CADP cartridges detect only thrombocytopathies and not ASA use. In this seven-center trial, 206 healthy subjects and 176 persons with various platelet-related defects, including 127 ASA users, were studied. The platelet function status was determined by a platelet function test panel. Comparisons were made as to how well the defects were identified by the PFA-100 system and by platelet aggregometry. The reference intervals for both cartridges, testing the 206 healthy subjects, were similar to values described in smaller studies in the literature (mean closure time [CT] of 132 seconds for CEPI and 93 seconds for CADP). The use of different lot numbers of cartridges or duplicate versus singleton testing revealed no differences. Compared with the platelet function status, the PFA-100 system had a clinical sensitivity of 94.9% and a specificity of 88.8%. For aggregometry, a sensitivity of 94.3% and a specificity of 88.3% were obtained. These values are based on all 382 specimens. A separate analysis of sensitivity by type of platelet defect, ASA use versus congenital thrombocytopathies, revealed for the PFA-100 system a 94.5% sensitivity in identifying ASA users and a 95.9% sensitivity in identifying the other defects. For aggregometry, the values were 100% for ASA users and 79.6% for congenital defects. Analysis of concordance between the PFA-100 system and aggregometry revealed no difference in clinical sensitivity and specificity between the systems (p > 0.9999). The overall agreement was 87.5%, with a Kappa index of 0.751. The two tests are thus equivalent in their ability to identify normal and abnormal platelet defects. Testing 126 subjects who took 325 mg ASA revealed that the PFA-100 system (CEPI) was able to detect 71.7% of ASA-induced defects with a positive predictive value of 97.8%. The overall clinical accuracy of the system, calculated from the area under the receiver operating characteristic curve, was 0.977. The data suggest that the PFA-100 system is highly accurate in discriminating normal from abnormal platelet function. The ease of operation of the instrument makes it a useful tool to use in screening patients for platelet-related hemostasis defects.

Building the foundation for a community-generated national research blueprint for inherited bleeding disorders: facilitating research through infrastructure, workforce, resources and funding

BACKGROUND

The National Hemophilia Foundation (NHF) conducted extensive, inclusive community consultations to guide prioritization of research in coming decades in alignment with its mission to find cures and address and prevent complications enabling people and families with blood disorders to thrive.

RESEARCH DESIGN AND METHODS

With the American Thrombosis and Hemostasis Network, NHF recruited multidisciplinary expert working groups (WG) to distill the community-identified priorities into concrete research questions and score their feasibility, impact, and risk. WG6 was charged with identifying the infrastructure, workforce development, and funding and resources to facilitate the prioritized research. Community input on conclusions was gathered at the NHF State of the Science Research Summit.

RESULTS

WG6 detailed a minimal research capacity infrastructure threshold, and opportunities to enable its attainment, for bleeding disorders centers to participate in prospective, multicenter national registries. They identified challenges and opportunities to recruit, retain, and train the diverse multidisciplinary care and research workforce required into the future. Innovative collaborative approaches to trial design, resource networking, and funding to surmount obstacles facing research in rare disorders were elucidated.

CONCLUSIONS

The innovations in infrastructure, workforce development, and resources and funding proposed herein may contribute to facilitating a National Research Blueprint for Inherited Bleeding Disorders.

Origins and organization of the NHLBI State of the Science Workshop: Generating a national blueprint for future research on factor VIII inhibitors

INTRODUCTION

The major complication of protein replacement therapy for haemophilia A is the development of anti-FVIII antibodies or inhibitors that occur in 25%-30% of persons with severe haemophilia A. Alternative therapeutics such as bypassing agents or immune tolerance induction protocols have additional challenges and are not always effective.

AIM

Assemble a National Heart, Lung and Blood Institute (NHLBI) State of the Science (SOS) Workshop to generate a national blueprint for research on inhibitors to solve the problem of FVIII immunogenicity.

METHODS

An Executive Steering Committee was formed in October 2017 to establish the scientific focus and Scientific Working Groups for the SOS Workshop in May 2018. Four working groups were assembled to address scientific priorities in basic, translational and clinical research on inhibitors.

RESULTS

Working Group 1 was charged with determining the scientific priorities for clinical trials to include the integration of non-intravenous, non-factor therapeutics including gene therapy into the standard of care for people with haemophilia A with inhibitors. Working Group 2 established the scientific priorities for 21st-century data science and biospecimen collection for observational inhibitor cohort studies. The scientific priorities for acquiring an actionable understanding of FVIII immunogenicity and the immunology of the host response and FVIII tolerance were developed by Working Group 3. Working Group 4 designed prospective pregnancy/birth cohorts to study FVIII immunogenicity, inhibitor development and eradication.

CONCLUSION

The NHLBI SOS Workshop generated a focused summary of scientific priorities and implementation strategies to overcome the challenges of eradicating and preventing inhibitors in haemophilia A.

Author Correction: CCR5AS lncRNA variation differentially regulates CCR5, influencing HIV disease outcome

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The need for dried plasma - a national issue

Recent studies have demonstrated that early transfusion of plasma or RBCs improves survival in patients with severe trauma and hemorrhagic shock. Time to initiate transfusion is the critical factor. It is essential that transfusion begin in the prehospital environment when transport times are longer than approximately 15 to 20 minutes. Unfortunately, logistic constraints severely limit the use of blood products in the prehospital setting, especially in military, remote civilian, and mass disaster circumstances, where the need can be most acute. US military requirements for logistically supportable blood products are projected to increase dramatically in future conflicts. Although dried plasma products have been available and safely used in a number of countries for over 20 years, there is no dried plasma product commercially available in the United States. A US Food and Drug Administration-approved dried plasma is urgently needed. Considering the US military, disaster preparedness, and remote civilian trauma perspectives, this is an urgent national health care issue.

The interagency strategic plan for research and development of blood products and related technologies for trauma care and emergency preparedness 2015-2020

Intensive blood use is expected to occur at levels, which will overwhelm blood supplies as they exist with current capabilities and technologies, both in civilian mass casualty events and military battlefield trauma. New technologies are needed for trauma care, and specifically to provide safer, more effective, and more logistically supportable blood products to treat patients with, or at risk of developing, acquired bleeding disorders resulting from trauma, acute radiation exposure, or other causes. Three of the primary agencies with major research and development programs related to blood products, the Biomedical Advanced Research and Development Authority (BARDA), the Department of Defense (DoD), and the National Heart, Lung, and Blood Institute are uniquely positioned to partner in addressing these issues, which have significant implications for each respective agency, as well as for the US population. Providing leadership, coordination, and oversight for the Food and Drug Administration's national and global health security, counterterrorism, and emerging threats portfolios, the US Food and Drug Administration Office of Counterterrorism and Emerging Threats serves in a critical advisory and facilitative role regarding development and availability of blood products. This plan is informed by the 2012 PHEMCE Strategy (US Department of Health and Human Services, 2012), the 2007 "Shaping the Future of Research" Strategic Plan for the National Heart, Lung, and Blood Institute, the 2011 BARDA Strategic Plan, the DoD Combat Casualty Care Research Program: Policy Review, the 2015 DoD Hemorrhage and Resuscitation Research and Development Strategic Plan, and more than 30 participants from other agencies who participated in planning.

The National Heart, Lung, and Blood Institute Strategic Vision Implementation for Health Equity Research

The National Heart, Lung, and Blood Institute (NHLBI) provides global leadership for a research, training, and education program to promote the prevention and treatment of heart, lung, and blood diseases and enhance the health of all individuals so that they can live longer and more fulfilling lives. Inherent in this mission is the commitment to advance health equity research as an avenue for enhancing the health of all individuals. Additionally, the four goals and eight research objectives of the NHLBI Strategic Vision directly support the commitment to health equity. In this article, we present selected examples of the NHLBI Strategic Vision implementation approaches for advancing health equity research in our mission areas of heart, lung, and blood diseases. Examples of diseases for which the burden of health inequities and our strategic vision implementation approaches are discussed include hypertension, heart failure, vascular dementia, asthma, and sickle cell disease. Examples are provided of new avenues of Institute-solicited research to stimulate and address compelling scientific questions and critical challenges to advance health equity. We also highlight the emerging fields of implementation science and predictive analytics as important opportunities to accelerate the translation of discovery science into health impact for all and to advance health equity.

Prospective, Randomised Trial of Two Doses of rFVIIa (NovoSeven) in Haemophilia Patients with Inhibitors Undergoing Surgery

Recombinant factor VIIa (rFVIIa; NovoSeven® ; Novo Nordisk) has proven efficacy in the treatment of haemophilic patients with inhibitors. This prospective, double-blind study compared rFVIIa (35 vs. 90 μg/kg) in the initiation and maintenance of haemostasis during and after elective surgery. Patients with inhibitors (FVIII, n = 26; FIX, n = 3) received rFVIIa immediately prior to incision; intraoperatively as needed; every 2 h for the first 48 h; and every 2-6 h for the following 3 days. Haemostasis was evaluated during surgery, at 0, 8, 24 and 48 h and 3, 4 and 5 days after wound closure. After day 5, open-label rFVIIa (90 μg/kg) was available for maintenance. Intraoperative haemostasis was achieved in 28/29 patients. All high-dose patients and 12/15 low dose patients had satisfactory haemostasis during the first 48 h. Twenty-three patients (13/14 high dose) successfully completed the study. Although the 35 μg/kg dose is probably sub-optimal for post-operative management, at least in major procedures, rFVIIa 90 μg/kg is an effective first-line option in surgery for patients with inhibitors.

Home Treatment of Mild to Moderate Bleeding Episodes Using Recombinant Factor VIIa (Novoseven) in Haemophiliacs with Inhibitors

Objective. To assess the safety and efficacy of a fixed dose of recombinant activated factor VII (rFVIIa; NovoSeven™) in the home setting for mild to moderately severe joint, muscle, and mucocutaneous bleeding episodes in patients with haemophilia A or B with inhibitors. Design. Multicentre, open-label, single arm, phase III study of one year duration. Methods. Patients or their caregivers administered up to three doses of rFVIIa (90 μg/kg i.v.) at 3 h intervals within 8 h of the onset of a mild to moderate bleeding episode. Once the subject considered that rFVIIa had been “effective” with regard to haemostasis (after 1-3 injections), one further (maintenance) dose of rFVIIa was administered. Results. Of 60 patients enrolled, 56 experienced at least one bleed, and 46 completed the one year study. 614 of 877 bleeds (70%) were evaluable according to protocol definitions. Haemostasis was rated as “effective” in 92% (566/614) of evaluable bleeds after a mean of 2.2 injections. For successfully treated episodes, the time from onset of bleeding until administration of the first injection was 1.1 ± 2.0 h (mean ± SD). Twenty-four hours after initial successful response, haemostasis was reported as having been maintained in 95% of cases. Efficacy was comparable for muscle, joint and target joint, and muco-cutaneous bleeding episodes. In an intent-to-treat analysis of all 877 bleeding events, efficacy outcomes were equivalent to the evaluable bleeds, with an effective response in 88% of treated episodes. Treatment-related adverse events occurred in 32 (3% of all) bleeding episodes and consisted of re-bleeds/new bleeds in more than 50% (18/32) of these events. A single episode of superficial thrombophlebitis was the only thrombotic complication encountered, and there were no patient withdrawals due to adverse events. Development of FVII(a) antibodies could not be detected, and hypersensitivity reactions to rFVIIa were not reported. Conclusion. rFVIIa is effective and well tolerated when used in the home setting to treat mild to moderate bleeding episodes in patients with haemophilia A or B with inhibitors.

The importance of genetic factors for the development of arthropathy: a longitudinal study of children and adolescents with haemophilia A

Haemophilia A is a congenital bleeding disorder characterised by recurrent haemorrhages into the major joints. Haemophilic arthropathy is a well-established outcome of recurrent joint bleeding; however, it is clear that multiple factors determine the extent and severity of its occurrence. We sought to identify genetic factors related to abnormalities in range of motion (ROM) in the knees, ankles and elbows in a cohort of children and adolescents with haemophilia A not treated primarily with regular prophylaxis. Using data from the Haemophilia Growth and Development Study, we examined associations between 13,342 genetic markers and ROM scores measured at six-month intervals for up to seven years. As a first step, ordered logistic regression models were fit for each joint separately. A subset of SNP markers showing significant effects (p<0.01) on the right and left sides for at least two joints were included in a full model fit using a multivariate generalised linear mixed model assuming an ordinal response. The models contained all ROM scores obtained at all visits. Twenty-five markers analysed in the full model showed either increased or decreased risk of ROM abnormalities at the p<0.001 level. Several genes identified at either the first or second stage of the analysis have been associated with arthritis in a variety of large studies. Our results support the likelihood that risk for haemophilic arthropathy is associated with genetic factors, the identification of which holds promise for further advancing the individualisation of treatment.

Complications of haemophilia in babies (first two years of life): a report from the Centers for Disease Control and Prevention Universal Data Collection System

AIM

To describe the prevalence and complications in babies ≤2 years with haemophilia.

METHODS

We used a standardized collection tool to obtain consented data on eligible babies aged ≤2 years with haemophilia enrolled in the Centers for Disease Control and Prevention Universal Data Collection System surveillance project at US Hemophilia Treatment Centers (HTCs).

RESULTS

Of 547 babies, 82% had haemophilia A, and 70% were diagnosed within one month of birth. Diagnosis was prompted by known maternal carrier status (40%), positive family history (23%), bleeding (35%) and unknown 2%; 81% bled during the first two years. The most common events were bleeding (circumcision, soft tissue, oral bleeding) and head injury. There were 46 episodes of intracranial haemorrhage (ICH) in 37 babies (7%): 18 spontaneous, 14 delivery related, 11 traumatic, 2 procedure related and 1 unknown cause. Of the 176 central venous access devices (CVADs) in 148 (27%) babies, there were 137 ports, 22 surgically inserted central catheters and 20 peripherally inserted central catheters. Ports had the lowest complication rates. Inhibitors occurred in 109 (20%) babies who experienced higher rates of ICH (14% vs. 5%; P = 0.002), CVAD placement (61% vs. 19%; P < 0.001) and CVAD complications (44% vs. 26%; P < 0.001). The most common replacement therapy was recombinant clotting factor concentrates.

CONCLUSION

Bleeding events in haemophilic babies ≤2 years were common; no detectable difference in the rates of ICH by the mode of delivery was noted. Neonatal factor exposure did not affect the inhibitor rates. Minor head trauma, soft tissue and oropharyngeal bleeding were the leading indications for treatment.

Citation impact of NHLBI R01 grants funded through the American Recovery and Reinvestment Act as compared to R01 grants funded through a standard payline

RATIONALE

The American Recovery and Reinvestment Act (ARRA) allowed National Heart, Lung, and Blood Institute to fund R01 grants that fared less well on peer review than those funded by meeting a payline threshold. It is not clear whether the sudden availability of additional funding enabled research of similar or lesser citation impact than already funded work.

OBJECTIVE

To compare the citation impact of ARRA-funded de novo National Heart, Lung, and Blood Institute R01 grants with concurrent de novo National Heart, Lung, and Blood Institute R01 grants funded by standard payline mechanisms.

METHODS AND RESULTS

We identified de novo (type 1) R01 grants funded by National Heart, Lung, and Blood Institute in fiscal year 2009: these included 458 funded by meeting Institute's published payline and 165 funded only because of ARRA funding. Compared with payline grants, ARRA grants received fewer total funds (median values, $1.03 versus $1.87 million; P<0.001) for a shorter duration (median values including no-cost extensions, 3.0 versus 4.9 years; P<0.001). Through May 2014, the payline R01 grants generated 3895 publications, whereas the ARRA R01 grants generated 996. Using the InCites database from Thomson-Reuters, we calculated a normalized citation impact for each grant by weighting each article for the number of citations it received normalizing for subject, article type, and year of publication. The ARRA R01 grants had a similar normalized citation impact per $1 million spent as the payline grants (median values [interquartile range], 2.15 [0.73-4.68] versus 2.03 [0.75-4.10]; P=0.61). The similar impact of the ARRA grants persisted even after accounting for potential confounders.

CONCLUSIONS

Despite shorter durations and lower budgets, ARRA R01 grants had comparable citation outcomes per $million spent to that of contemporaneously funded payline R01 grants.

An analysis of the NIH-supported sickle cell disease research portfolio

Sickle cell disease (SCD), an inherited blood disorder is due to a single amino acid substitution on the beta chain of hemoglobin, and is characterized by anemia, severe infections, acute and chronic pain, and multi-organ damage. The National Institutes of Health (NIH) is dedicated to support basic, translational and clinical science research to improve care and ultimately, to find a cure for SCD that causes such suffering. This report provides a detailed analysis of grants funded by the NIH for SCD research in Fiscal Years 2007 through 2013. During this period, the NIH supported 247 de novo grants totaling $272,210,367 that address various aspects of SCD. 83% of these funds supported research project grants investigating the following 5 scientific themes: Pathology of Sickle Red Blood Cells; Globin Gene Expression; Adhesion and Vascular Dysfunction; Neurological Complications and Organ-specific Dysfunction; and Pain Management and Intervention. The remaining 17% of total funds supported career development and training grants; Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) grants; large Center grants; and Conference grants. Further analysis showed that the National Heart, Lung, and Blood Institute (NHLBI) is the largest funder of SCD research within NIH with 67% of total grants, contributing 77% of total funds; followed by the National Institute for Digestive Diseases and Kidney (NIDDK) that is funding 19% of grants, contributing 13% of total funds. The remaining 14% of grants totaling 10% of the funds were supported by all other NIH Institutes/Centers (ICs) combined. In summary, the NIH is using multiple funding mechanisms to support a sickle cell disease research agenda that is intended to advance the detection, treatment, and cure of this debilitating genetic disease.

Future directions of sickle cell disease research: the NIH perspective

Efforts to enhance therapy for children and adults with sickle cell disease (SCD) have proven more challenging than might have been predicted from the fact that an understanding of the underlying pathogenesis antedated that of many other diseases for which good treatments presently exist. The multi-organ injury that occurs with SCD certainly contributes to this clinical reality. Research over decades indicates that the primary defect in hemoglobin that results in polymerization of the protein under low oxygen conditions and resultant cellular deformity of the red blood cell initiates a complex downstream pathogenesis associated with vascular injury and organ ischemia. Deciphering this in a manner that informs successful therapies that improve all target organs continues to challenge hematologists. The National Heart, Lung and Blood Institute (NHLBI) is dedicated to support research across the basic science, translational and clinical spectrum to achieve these clinical outcomes. The following provides a brief summary of the research strategies which NHLBI is presently supporting and will support in the future to enhance care and ultimately, to effect cure of this hemoglobin disease that causes such suffering to those who inherit this monogenic disease.

Clinical issues in inhibitors

SUMMARY

Anamestic inhibitors represent the major complication of haemophilia therapy now that clotting factor concentrates are virtually free of pathogen-transmission risk. Conventional clotting factor replacement is usually insufficient to prevent or treat bleeding in a haemophilia patient with a high responding inhibitor so that alternative treatment with bypassing agents is required. Despite their relative efficacy, their use does not achieve the same invariable haemostasis that patients without inhibitors do following treatment with factor concentrate replacement. This has led to the attempt to eradicate such inhibitors with immune tolerance induction. Success is not invariable, however, and many patients with long-term persistent high-titre inhibitors continue to experience great morbidity. Recently, this has given rise on a limited basis to attempts to use bypassing agents in prophylaxis regimens in an effort to alleviate this extreme morbidity. Each of these strategies is discussed in the context of their relative benefits and risks.

IL28B polymorphism does not determine outcomes of hepatitis B virus or HIV infection

An IL28B haplotype strongly determines the outcome of natural and interferon-α treated hepatitis C virus (HCV) infection. To assess whether the polymorphism marking the haplotype (rs12979860) also affects other interferon-α responsive chronic viral illnesses, namely hepatitis B virus (HBV) and human immunodeficiency virus (HIV) type 1 infections, we genotyped 226 individuals with HBV persistence, 384 with HBV recovery, and 2548 with or at high risk for HIV infection. The C/C genotype of rs12979860 was not associated with HBV recovery (odds ratio, 0.99), resistance to HIV infection (odds ratio, 0.97), or HIV disease progression (P > .05). This IL28B single-nucleotide polymorphism affects the immune response to HCV but not to HBV or HIV.

Advances in hemophilia: experimental aspects and therapy

This article describes recent clinical and research advances in hemophilia therapy. Different prophylactic regimens for the management of severe hemophilia are described along with the use of adjuvant treatment options to achieve hemostasis. The safety and efficacy of radionuclide synovectomy with phosphorus 32-sulfur colloid to treat existing joint arthropathy also are described. The development of inhibitors to factor VIII or IX remains a challenge for hemophilia care and recent approaches to achieve immune tolerance induction are discussed. Finally, recent advances in hemophilia are mentioned, including the role of iron, inflammation, and angiogenesis in the pathogenesis of hemophilic arthropathy.

Large-scale candidate gene analysis of spontaneous clearance of hepatitis C virus

Human genetic variation is a determinant of recovery from acute hepatitis C virus (HCV) infection; however, to date, single-nucleotide polymorphisms (SNPs) in only a limited number of genes have been studied with respect to HCV clearance. We determined whether SNPs in 112 selected immune response genes are important for HCV clearance, by genotyping 1536 SNPs in a cohort of 343 persons with natural HCV clearance and 547 persons with HCV persistence. PLINK (version 1.05) and Haploview (version 4.1) software packages were used to perform association, permutation, and haplotype analyses stratified by African American and European American race. Of the 1536 SNPs tested, 1426 (92.8%) were successfully genotyped. In African Americans, we identified 18 SNPs located in 11 gene regions that were associated with HCV infection outcome (empirical P value, < .01). In European Americans, there were 20 SNPs located in 8 gene regions associated with HCV infection outcome. Four of the gene regions studied (TNFSF18, TANK, HAVCR1, and IL18BP) contained SNPs for which the empirical P value was <.01 in both of the race groups. In this large-scale analysis of 1426 genotyped SNPs in 112 candidate genes, we identified 4 gene regions that are likely candidates for a role in HCV clearance or persistence in both African Americans and European Americans.

Arthropathy in inhibitor patients: differences in the joint status

Inhibitor development represents the most significant complication of hemophilia treatment today. Although it has long been established that hemophilia patients with inhibitors face a higher risk (and a greater extent) of joint morbidity than their non-inhibitor counterparts, there remains a paucity of scientific data supporting this observation. Several issues need to be resolved before the risk of greater joint damage in inhibitor patients can be verified. This article explores these issues in an attempt to confirm and explain the differential joint morbidity observed between inhibitor and non-inhibitor patients. However, there remain significant gaps in our knowledge of the biology of inhibitor development, and greater understanding in this area will produce more effective therapies that might ultimately prevent or attenuate their development altogether.

Secondary prophylaxis with recombinant activated factor VII improves health-related quality of life of haemophilia patients with inhibitors

Haemophilia patients with inhibitors characteristically have impaired joint function and reduced health-related quality of life (HRQoL). This analysis examined whether secondary prophylaxis with recombinant activated factor VII (rFVIIa) improves HRQoL vs. conventional on-demand therapy in patients with haemophilia with inhibitors and frequent bleeds. After a 3-month preprophylaxis period, 22 patients received daily rFVIIa prophylaxis (90 or 270 microg kg(-1)) for 3 months, followed by 3 months' postprophylaxis. Days of hospitalization, absence from school/work and mobility aids requirements were recorded. HRQoL was assessed by EuroQoL (EQ-5D) questionnaire, visual analogue scale (VAS), derived Time to Trade-Off (TTO) scores and Quality Adjusted Life Years (QALYs). rFVIIa prophylaxis significantly (P < 0.0001) reduced bleeding frequency vs. prior on-demand therapy. Hospitalization (5.9% vs. 13.5%; P = 0.0026) and absenteeism from school/work (16.7% vs. 38.7%; P = 0.0127) decreased during prophylaxis; these effects tended to be maintained during postprophylaxis. HRQoL (evaluated by EQ-5D) tended to improve during and after rFVIIa prophylaxis. Notably, pain decreased and mobility increased in 40.9% and 27.3% of patients, respectively, at the end of the postprophylaxis period vs. preprophylaxis. Median VAS score increased from 66 to 73 (P = 0.048), and TTO scores suggested better HRQoL (0.62 vs. 0.76; P = 0.054) during postprophylaxis than preprophylaxis. Small to moderate changes in effect sizes were reported for VAS and TTO scores. Median QALYs were 0.68 (VAS) and 0.73 (TTO). Reductions in bleeding frequency with secondary rFVIIa prophylaxis were associated with improved HRQoL vs. on-demand therapy.

Advances in hemophilia: experimental aspects and therapy

This article describes recent clinical and research advances in hemophilia therapy. Different prophylactic regimens for the management of severe hemophilia are described along with the use of adjuvant treatment options to achieve hemostasis. The safety and efficacy of radionuclide synovectomy with phosphorus 32-sulfur colloid to treat existing joint arthropathy also are described. The development of inhibitors to factor VIII or IX remains a challenge for hemophilia care and recent approaches to achieve immune tolerance induction are discussed. Finally, recent advances in hemophilia are mentioned, including the role of iron, inflammation, and angiogenesis in the pathogenesis of hemophilic arthopathy.

Pathogenesis of haemophilic synovitis: experimental studies on blood-induced joint damage

Hemarthrosis is a common manifestation of haemophilia, and joint arthropathy remains a frequent complication. Even though the exact mechanisms related to blood-induced joint disease have not yet been fully elucidated, it is likely that iron deposition in the synovium induces an inflammatory response that causes not only immune system activation but also stimulates angiogenesis. This process ultimately results in cartilage and bone destruction. Investigating the processes that occur in the early stages of blood-induced joint disease in humans has been very limited. Therefore, the use of haemophilic animal models is critical to augment the understanding of this phenomenon. This article discusses three cellular regulators (p53, p21 and TRAIL) induced in synovial tissue that are important for iron metabolism. A cartilage remodelling programme induced by the release of cytokines and growth factors that result in articular damage is also discussed. Full elucidation of the pathogenesis of haemophilic joint disease is required to identify new avenues for prevention and therapy.

Role of prothrombin complex concentrates in reversing warfarin anticoagulation: a review of the literature

Over-anticoagulation is a common problem with warfarin therapy and can lead to major or life-threatening bleeding. The goal of urgent warfarin reversal is to elevate or replace vitamin K-dependent clotting factors. In the United States, fresh frozen plasma (FFP) is considered the standard of care for warfarin reversal. Prothrombin complex concentrates (PCCs) offer an alternative to FFP for rapidly replacing deficient clotting factors and correcting the international normalized ratio (INR). However, few prospective clinical trials have been conducted to evaluate the effectiveness of these concentrates relative to other treatment modalities. A review of the published literature over the last 30 years found that PCCs offer a rapid and specific method for replacing vitamin K-dependent clotting factors and restoring normal hemostasis in the context of over-coagulation. In those studies in which PCCs were compared with FFP, PCCs were found more effective in shortening the time to INR correction and were associated with a low risk of thrombotic adverse events. Evidence-based treatment guidelines are needed to optimize the use of PCCs for warfarin reversal.

Pathogenesis of haemophilic synovitis: clinical aspects

Arthropathy remains a major cause of morbidity in patients with haemophilia. Frequent bleeding into the joints leads to joint damage with resultant contractures, joint deformities and arthritis. This in turn leads to muscle atrophy, limited physical activity, osteoporosis and disability. Even though several studies of prophylactic factor replacement for persons with severe haemophilia demonstrate improved joint function, this therapy is still not readily available to most people with haemophilia around the world and a universal treatment protocol has not been used. In this article, we discuss key issues in the treatment of severe haemophilia: the optimal timing of initiation and termination of therapy, dosing options and goals of therapy. The options for countries where prophylaxis is not readily available are also discussed. Most studies are small and not randomized making consensus treatment recommendations difficult to formulate. Randomized, clinical trials are needed to provide the answers regarding the optimal treatment of patients with severe haemophilia.

Haemostatic efficacy and safety of bolus and continuous infusion of recombinant factor VIIa are comparable in haemophilia patients with inhibitors undergoing major surgery. Results from an open-label, randomized, multicenter trial

Bolus infusion (BI) recombinant factor VIIa (rFVIIa) administration is safe and effective in the surgical management of haemophilia patients with inhibitors but has not been compared directly with continuous infusion (CI). We conducted an open-label, randomized, multicenter trial comparing the efficacy and safety of rFVIIa administered by BI or CI for the surgical management of haemophilia A or B patients with inhibitors to FVIII or FIX. Safety was compared with that of a control group of non-inhibitor patients receiving FVIII or FIX concentrates for major surgery. All inhibitor subjects received an initial bolus dose of 90 microg/kg rFVIIa and were then randomly assigned to BI (n = 12) or CI (n = 12). The BI group received 90 microg/kg rFVIIa every two hours (h) during surgery through day 5, then every four hours for days 6-10. The CI group received 50 microg/kg/h rFVIIa through day 5, then 25 mg/kg/h for days 6-10. The control group (n = 12) received FVIII or FIX per institutional protocols. Twenty-two major surgeries included orthopedic procedures on the knee (n = 13), hip (n = 3), and abdominal/pelvis procedures (n = 4). One patient with an autoimmune FVIII inhibitor randomized to the BI arm was excluded from efficacy analysis. Haemostatic efficacy of rFVIIa in each group was comparable: effective in 8/11 and 9/12 subjects in the BI and CI arms, respectively, and ineffective in three subjects in each arm. Serious adverse events were related to continued or increased bleeding. In conclusion, haemostatic efficacy and safety of BI and CI of rFVIIa are comparable for the surgical management of haemophilia subjects with inhibitors.

Delays in maturation among adolescents with hemophilia and a history of inhibitors

Inhibitory antibodies to factors VIII or IX have the potential to affect a broad range of outcomes among people with hemophilia; however, their possible effect on growth and maturation has not been explored. We evaluated skeletal maturation (bone age), pubertal progression, serum testosterone levels, height velocity, and stature in the multicenter Hemophilia Growth and Development Study. A total of 333 children and adolescents (mean age, 12.4 years) were enrolled from 1989 to 1990 and followed for 7 years. Of these, 18% (n = 60) had a history of inhibitors. Bone age among HIV(-) adolescents with a history of inhibitors lagged 9 or more months behind those without inhibitors at every age from 12 to 15 years. Those with a history of inhibitors were older at every Tanner stage transition, attained a lower maximum growth velocity, and their serum testosterone levels were significantly lower compared with those without inhibitors. Delays were greater among HIV(+) patients with a history of inhibitors compared with those without inhibitors; however, the differences were generally small and not statistically significant. The results of this investigation underscore the importance of monitoring the growth and maturation of children and adolescents with hemophilia, particularly those with inhibitors.

Urgent inhibitor issues: targets for expanded research

Although up to 80% of high-responding inhibitors in patients with severe factor VIII deficiency can be eliminated using heterogeneous regimens for immune tolerance induction, the residual morbidity in this population of haemophilic patients is far from trivial. There is an exigent need for focussed basic, translational and clinical research to extend our understanding of the pathogenesis of haemophilic inhibitor development. In this article, we identify four key research needs, including (i) whether presently available clotting factor concentrates (CFCs) have differential antigenicity, giving rise to clinically relevant immunogenicity; (ii) the interplay of quantitative and qualitative (e.g. age at first exposure) influences of CFCs as well as host-environmental factors (e.g. vaccination effects) on inhibitor development; (iii) the therapeutic role (if any) that concurrent immune tolerance with suppressive or immune-competitive therapeutic strategies play in inhibitor eradication and (iv) pending any major therapeutic advances, alternative or enhanced strategies for treating acute haemorrhage and for preventing chronic haemorrhagic events in these patients.

Prophylaxis versus episodic treatment to prevent joint disease in boys with severe hemophilia

BACKGROUND

Effective ways to prevent arthropathy in severe hemophilia are unknown.

METHODS

We randomly assigned young boys with severe hemophilia A to regular infusions of recombinant factor VIII (prophylaxis) or to an enhanced episodic infusion schedule of at least three doses totaling a minimum of 80 IU of factor VIII per kilogram of body weight at the time of a joint hemorrhage. The primary outcome was the incidence of bone or cartilage damage as detected in index joints (ankles, knees, and elbows) by radiography or magnetic resonance imaging (MRI).

RESULTS

Sixty-five boys younger than 30 months of age were randomly assigned to prophylaxis (32 boys) or enhanced episodic therapy (33 boys). When the boys reached 6 years of age, 93% of those in the prophylaxis group and 55% of those in the episodic-therapy group were considered to have normal index-joint structure on MRI (P=0.006). The relative risk of MRI-detected joint damage with episodic therapy as compared with prophylaxis was 6.1 (95% confidence interval, 1.5 to 24.4). The mean annual numbers of joint and total hemorrhages were higher at study exit in the episodic-therapy group than in the prophylaxis group (P<0.001 for both comparisons). High titers of inhibitors of factor VIII developed in two boys who received prophylaxis; three boys in the episodic-therapy group had a life-threatening hemorrhage. Hospitalizations and infections associated with central-catheter placement did not differ significantly between the two groups.

CONCLUSIONS

Prophylaxis with recombinant factor VIII can prevent joint damage and decrease the frequency of joint and other hemorrhages in young boys with severe hemophilia A. (ClinicalTrials.gov number, NCT00207597 [ClinicalTrials.gov].).

International workshop on immune tolerance induction: consensus recommendations

Although immune tolerance induction (ITI) has been used for 30 years to eliminate inhibitors and restore normal factor pharmacokinetics in patients with hemophilia, there is a paucity of scientific evidence to guide therapeutic decision-making. In an effort to provide direction for physicians and hemophilia treatment center staff members, an international panel of hemophilia opinion leaders met to develop consensus recommendations for ITI in patients with severe and mild hemophilia A and hemophilia B. These recommendations draw on the available published literature and the collective clinical experience of the group and are rated based on the level of supporting evidence.

Assessing the costs for clinical care of patients with high-responding factor VIII and IX inhibitors

The costs of haemophilia-related care and the impact of unusually expensive, or outlier, patients on these costs have been explored in numerous European, American and Canadian studies during the last decade. In particular, antibodies that neutralize infused factor VIII or IX (high-responding inhibitors) make treatment responses, and thereby costs, much less predictable. There is little debate that the health care costs of haemophilic patients with high-responding inhibitors are routinely higher and more variable than those of non-inhibitor patients. However, the extent to which this is attributable to the few outlier inhibitor patients whose expenditures tend to skew the data is not as clear. To compare the variation and range in health care expenditures among patients with inhibitors and those without, we reviewed data originally gathered during a 24-month period in 1995-1997 from a prospectively created cohort as part of a broader cost and utilization study conducted at a large haemophilia treatment centre. We conclude that although the use of outpatient factor replacement products was not significantly greater or more expensive among inhibitor patients, their hospital-related costs greatly increased overall expenditures. Among our study population, the overall costs associated with inhibitor patients are not only higher in absolute monetary terms, but also in terms of the degree of variation. This variation was demonstrated by: (i) the extremely wide range of costs over an extended timeframe among individual inhibitor patients when compared with those without inhibitors, and (ii) the much larger year-to-year variation in costs among the inhibitor group.

Inhibitor treatment in haemophilias A and B: summary statement for the 2006 international consensus conference

Participants in an international conference on the management of haemophilia patients with inhibitors developed a jointly authored summary of the findings and conclusions of the conference. Current knowledge of the genetic and immunologic mechanisms underlying inhibitor development was briefly summarized. Concerning the purported treatment-related risk factors, conference participants commented on the limitations of the available evidence and the need for more rigorous prospective research in a fully genotyped population. Other clinical considerations discussed included the unproved utility of routine surveillance, the need for assay standardization, the management of acute bleeding and approaches to joint disease prophylaxis and immune tolerance induction (ITI). A number of issues were identified as needing further investigation in larger prospective studies, ideally through international cooperation. Such studies should enroll cohorts that have been scrupulously defined in terms of mutation status and treatment exposure. Finally, conference participants urged their colleagues to participate in the currently ongoing international trials of ITI.

Evidence for the benefits of prophylaxis in the management of hemophilia A

The optimal treatment of hemophilia has been evolving since the advent of factor VIII concentrates, continues to vary geographically, and remains a source of debate. There now exists an extensive clinical literature that demonstrates clear benefits of prophylaxis for patients with hemophiliaA compared to on-demand treatment, including a reduction in the number of bleeding episodes, improved joint function, and greater patient well-being. However, the value of these benefits must be weighed against the heavier economic burden of increased factor use. This paper reviews the literature that compares the benefits of prophylaxis with that of on-demand treatment, compares varying prophylaxis dose and administration frequency protocols, and considers the long-term cost-benefit of prophylactic therapy.

Knowledge, attitudes, and behaviors of youths in the US hemophilia population: results of a national survey

OBJECTIVES

The National Hemophilia Foundation and the Centers for Disease Control and Prevention conducted a national survey focusing on knowledge about, attitudes toward, and behaviors associated with key prevention activities among youths with hemophilia and used the data gathered to design a health promotion campaign.

METHODS

A national, random sample of 459 patients was drawn from 20 hemophilia treatment centers and 8 hemophilia associations; 110 (24%) of the respondents were young people. A telephone questionnaire was used to measure knowledge, behaviors, and barriers to prevention.

RESULTS

Thirty-six percent of the youth respondents believed that joint disease cannot be prevented; 60% managed hemophilia by avoiding physical activity. Only 31% of the respondents treated bleeding episodes within 1 hour. Although hepatitis was a clear threat to this hemophilic cohort, 78% did now know transmission routes for hepatitis C, and 67% did not know transmission routes for hepatitis B.

CONCLUSIONS

Young people with chronic disorders need help understanding that they can prevent complications. We identified key messages for a hemophilia prevention campaign, including exercising to ensure healthy joints and treating bleeding episodes early and adequately.

Unresolved issues in diagnosis and management of inherited bleeding disorders in the perinatal period: A White Paper of the Perinatal Task Force of the Medical and Scientific Advisory Council of the National Hemophilia Foundation, USA

Haemophilia and inherited bleeding disorders in newborns and their carrier mothers pose unique challenges. The pattern of bleeding and the causes and risk factors for bleeding are decidedly different than an older child or an adult with haemophilia/inherited bleeding disorder. This document outlines the needs for further research and education, summarizes the state of the art background information and provides guidance regarding research, education and access to care issues in this population.

Pathogenesis of hemophilic arthropathy

Intra-articular bleeding is the most common clinical manifestation of hemophilia, and can adversely affect joints and lead to arthropathy. Affected joints are associated with changes to the synovium, bone, cartilage and blood vessels. Iron plays a critical role in the pathogenesis of this condition, and may exert its effects through a variety of different mechanisms. Hemophilic arthropathy shares some injury characteristics with rheumatoid arthritis, although the degree of analogy is a matter of some debate. The influences of the mechanisms underlying joint inflammation are better understood for rheumatoid arthritis than for hemophilia, and it is hoped that this knowledge can be used to provide a more comprehensive knowledge of the pathological process of hemophilic arthropathy. This, in turn, may enable novel targets for therapeutic intervention to be identified.

Challenges in the Therapeutic Use of a “So-Called” Universal Hemostatic Agent: Recombinant Factor VIIa

Recombinant factor VIIa (rFVIIa) was developed in the early 1990s to provide “bypassing” hemostatic therapy for hemophilia A and B patients with inhibitors. More recently, it has been licensed for use in patients with inherited deficiency of factor VII. Since it was licensed for use in hemophilia with inhibitors in the US, Europe, and other countries for these specific indications, it has been used selectively but in a wide array of clinical settings for uncontrolled hemorrhage in individuals without an inherited bleeding disorder. Many of these uses have been described in the medical literature as case reports or small, uncontrolled series. Several randomized clinical trials (RCT) for these “off-label” medical uses have been published in recent months and will serve as the focus of this review. In particular, a review of an RCT for spontaneous intracranial hemorrhage that has demonstrated clinical efficacy in reducing both mortality and volume of central nervous system hemorrhage will be offered. A brief discussion of hypothesized physiologic mechanisms of supraphysiologic doses of rFVIIa will introduce the clinical discussion of these broad off-label uses. Since rFVIIa is a very expensive therapy, possible strategies for optimizing its use in the these settings will be presented.