Changing pattern of care of boys with haemophilia in western European centres

Compliance with Early Long-Term Prophylaxis Guidelines for Severe Hemophilia A

OBJECTIVES

To evaluate the applicability and compliance with guidelines for early initiation of long-term prophylaxis in infants with severe hemophilia A and to identify factors associated with guideline compliance.

STUDY DESIGN

This real-world, prospective, multicenter, population-based FranceCoag study included almost all French boys with severe hemophilia A, born between 2000 and 2009 (ie, after guideline implementation).

RESULTS

We included 333 boys in the study cohort. The cumulative incidence of long-term prophylaxis use was 61.2% at 3 years of age vs 9.5% in a historical cohort of 39 boys born in 1996 (ie, before guideline implementation). The guidelines were not applicable in 23.1% of patients due to an early intracranial bleeding or inhibitor development. Long-term prophylaxis was delayed in 10.8% of patients. In the multivariate analysis, 2 variables were significantly associated with "timely long-term prophylaxis" as compared with "delayed long-term prophylaxis": hemophilia treating center location in the southern regions of France (OR 23.6, 95% CI 1.9-286.7, P = .013 vs Paris area) and older age at long-term prophylaxis indication (OR 7.2 for each additional year, 95% CI 1.2-43.2, P = .031). Long-term prophylaxis anticipation was observed in 39.0% of patients. Earlier birth year (OR 0.5, 95% CI 0.3-0.8, P = .010 for birth years 2005-2009 vs 2000-2004) and age at first factor replacement (OR 1.9 for each additional year, 95% CI 1.2-3.0, P = .005) were significantly associated with "long-term prophylaxis guideline compliance" vs "long-term prophylaxis anticipation."

CONCLUSIONS

This study suggests that long-term prophylaxis guidelines are associated with increased long-term prophylaxis use. However, early initiation of long-term prophylaxis remains a challenge.

Haemophilia

Haemophilia A and B are rare congenital, recessive X-linked disorders caused by lack or deficiency of clotting factor VIII (FVIII) or IX (FIX), respectively. The severity of the disease depends on the reduction of levels of FVIII or FIX, which are determined by the type of the causative mutation in the genes encoding the factors (F8 and F9, respectively). The hallmark clinical characteristic, especially in untreated severe forms, is bleeding (spontaneous or after trauma) into major joints such as ankles, knees and elbows, which can result in the development of arthropathy. Intracranial bleeds and bleeds into internal organs may be life-threatening. The median life expectancy was ~30 years until the 1960s, but improved understanding of the disorder and development of efficacious therapy based on prophylactic replacement of the missing factor has caused a paradigm shift, and today individuals with haemophilia can look forward to a virtually normal life expectancy and quality of life. Nevertheless, the potential development of inhibitory antibodies to infused factor is still a major hurdle to overcome in a substantial proportion of patients. Finally, gene therapy for both types of haemophilia has progressed remarkably and could soon become a reality.

A history of prophylaxis in haemophilia

: Prophylaxis entails long-term continuous intravenous administration of concentrates of the deficient factor with a view to preventing spontaneous bleeds and the development of hemophilic arthropathy. Initiation of prophylaxis at an early age and continuous uninterrupted factor administration in patients with hemophilia have been hailed as essential by such organizations.The most widely used prophylaxis regimens include the Swedish (Malmö), the Dutch and the Canadian protocols. Different international groups have hailed prophylaxis as the most effective treatment in patients with hemophilia.Prophylaxis is effectiveness in preventing bleeding and arthropathy in children with (particularly early-onset) hemophilia. Although some retrospective trials confirm the benefits of prophylaxis, others point to a lack of conclusive data to support switching adult patients with established hemophilic arthropathy who always received on-demand treatment to prophylactic treatment.The potential effects of prophylaxis on the patients' sex lives, renal status, prostate involvement and cataract must be analyzed before indicating prophylactic treatment in elderly patients.The high efficacy of prophylactic treatment in patients with hemophilia and inhibitors has been widely reported in the literature.

A history of prophylaxis in haemophilia

: Prophylaxis entails long-term continuous intravenous administration of concentrates of the deficient factor with a view to preventing spontaneous bleeds and the development of hemophilic arthropathy. Initiation of prophylaxis at an early age and continuous uninterrupted factor administration in patients with hemophilia have been hailed as essential by such organizations.The most widely used prophylaxis regimens include the Swedish (Malmö), the Dutch and the Canadian protocols. Different international groups have hailed prophylaxis as the most effective treatment in patients with hemophilia.Prophylaxis is effectiveness in preventing bleeding and arthropathy in children with (particularly early-onset) hemophilia. Although some retrospective trials confirm the benefits of prophylaxis, others point to a lack of conclusive data to support switching adult patients with established hemophilic arthropathy who always received on-demand treatment to prophylactic treatment.The potential effects of prophylaxis on the patients' sex lives, renal status, prostate involvement and cataract must be analyzed before indicating prophylactic treatment in elderly patients.The high efficacy of prophylactic treatment in patients with hemophilia and inhibitors has been widely reported in the literature.

Choice of factor VIII/IX regimen in adolescents and young adults with severe or moderately severe haemophilia. A French national observational study (ORTHem 15-25)

INTRODUCTION

The value and challenges of long-term prophylaxis (LTP) in adolescents and young adults need further characterisation.

AIM

To determine the proportions of adolescents and young adults with severe or moderately severe haemophilia in France under LTP and treatment on demand (OD).

METHODS

Patients 15 to 25years old with haemophilia A or B, factor VIII/IX ≤2% and no current inhibitor could be included if they had been under factor VIII/IX treatment at least 12months and kept a treatment and bleeding diary.

RESULTS

LTP was administered to 169/212 patients (79.7%) and OD treatment to 40/212 patients (18.9%). The most frequent reasons for initiating LTP were joint bleeding, target joints and frequent bleeds; whereas OD treatment was most often selected on the basis of mild bleeding phenotype or because of constraints on LTP. The mean annual bleed rate (ABR) in the OD group (6.33) was higher than in the LTP group (3.07, p<0.001). Mean ABR did not differ significantly between age strata (15-18, >18-21 and >21-25years), but was significantly higher for patients with severe haemophilia (4.02) as compared to those with moderate haemophilia (1.97, p=0.002). No significant difference was observed in mean ABR for joint bleeds between the LTP and OD groups. Physician reported LTP compliance was good or excellent in 97.0% of patients.

CONCLUSION

LTP is the predominant factor VIII/IX treatment among adolescents and young adults with severe or moderately severe haemophilia in France. LTP was associated with low ABR and high compliance.

Phase 1 safety, tolerability, and pharmacokinetic study of single ascending doses of XM17 (recombinant human follicle-stimulating hormone) in downregulated healthy women

Background

XM17 is a recombinant human follicle-stimulating hormone (follitropin alfa) for stimulation of multifollicular development in women undergoing controlled ovarian hyper-stimulation during assisted reproductive therapy and for treatment of anovulation. Manufactured using Chinese hamster ovary cells transfected with the human follicle-stimulating hormone gene, XM17 has an identical amino acid sequence to that of the human protein as well as to those of the other approved recombinant human follicle-stimulating hormone products. Glycosylation patterns may differ slightly between products. The objectives of this first-in-human study were to assess the safety, tolerability, pharmacokinetics, and dose-proportionality of single ascending subcutaneous doses of XM17 in healthy young female volunteers.

Methods

Endogenous follicle-stimulating hormone was downregulated by implanting a 1-month depot of goserelin acetate 3.6 mg on day 0 in eligible subjects. On day 14 of the experimental period, subjects received one of four ascending doses of XM17. Blood sampling to obtain the pharmacokinetic profile of XM17 was done at frequent intervals until 168 hours post-dose.

Results

Following downregulation of endogenous follicle-stimulating hormone to <4 IU/L, 40 subjects (of mean age 29±5.4 years) received single subcutaneous doses of 37.5 (n=4, pilot group), 75, 150, or 300 IU (n=12 each) of XM17. The mean serum concentration-time profiles of XM17 revealed dose-related increases in maximum concentration (C_max) within 24 hours followed by monoexponential decay for the three higher dose levels. Slopes estimated by linear regression for C_max and AUC_0–168h were ~1.0 (0.9052 IU/L and 1.0964 IU·h/L, respectively). For each IU of XM17 administered, C_max and AUC_0–168h rose by 0.032 IU/L and 2.60 IU·h/L, respectively. Geometric mean elimination half-life ranged from 54 to 90 hours. No antibodies to XM17 were detected. The most common treatment-emergent adverse events were headache (12 events in eleven [27.5%] subjects) and dizziness (four events in four [10%] subjects); two subjects (5%) reported mild pain on touch at the injection site.

Conclusion

Single subcutaneous doses of XM17 up to 300 IU in healthy young women exhibited dose-proportional pharmacokinetics with good safety and tolerability.

Consequences of switching from prophylactic treatment to on-demand treatment in late teens and early adults with severe haemophilia A: the TEEN/TWEN study

Although many people with haemophilia discontinue prophylaxis in their late teens or early adulthood, the consequences of this decision are largely not known. This 18-month, observational, case-controlled, multicentre study evaluated long-term prophylaxis and the consequences of switching from prophylaxis to on-demand treatment in late teens and young adults with severe haemophilia A. Participants with haemophilia (aged 14-29 years) on prophylaxis ≥ 60% of the time for the 5 years before study entry were enrolled into 1 of 2 prospective or 1 retrospective group. Group 1 was prophylaxis, group 2 had voluntarily discontinued prophylaxis ≤ 12 months before study entry and group 3 had voluntarily discontinued prophylaxis ≥ 13 months before study entry. Assessments included bleeding frequency (primary endpoint), Haemo-QoL-A health-related quality of life (HRQoL) scores, Gilbert score, development of target joints, Haemophilia Activities List, Godin Leisure-Time, treatment satisfaction and State-Trait Anxiety Inventory (secondary and exploratory endpoints). Descriptive statistics were provided for all variables. Thirty-eight participants (group 1, n = 22; group 2, n = 5; group 3, n = 11; median age, 19.5 years) were enrolled. The median annualized number of bleeding events was 0, 4.8 and 24 in groups 1, 2 and 3 respectively. HRQoL was lower in participants who discontinued prophylaxis vs. those who remained on prophylaxis. Changes in the remaining secondary and exploratory variables were small, but were generally worse in participants who discontinued prophylaxis. Following a switch from prophylaxis to on-demand therapy, the number of bleeding events increased and HRQoL worsened in late teens and young adults with severe haemophilia A.

Use of clinical practice guidelines on long-term prophylaxis in severe hemophilia in France: a retrospective audit

OBJECTIVES

To evaluate the impact of the 2002 guidelines on the current status of prophylaxis in French children with severe hemophilia A or B.

STUDY DESIGN

Clinical information was captured, in a prospective way, using FranceCoag Network. We retrospectively studied 291 patients with severe (<1 IU/dL) hemophilia A and B, with no history of inhibitors.

RESULTS

Our results demonstrate that the availability of national medical guidelines has improved clinical practice in France. In the past decade, the proportion of children with severe hemophilia undergoing prophylaxis has shown a significant 2- to 3-fold increase: ∼80% of these children>3 years of age are now receiving prophylaxis. In severe hemophilia A and B, the age at which prophylaxis commences has significantly decreased: 4.0 and 6.1 years for the period 1996-1999 as opposed to 1.8 and 1.4 years for the period 2004-2007 (P=.0001).

CONCLUSIONS

Long-term clinical and physical evaluations of patients will be necessary to establish the benefits of this increase in prophylactic treatment on the prevention of hemophilic arthropathy.

New treatments in hemophilia: insights for the clinician

Hemophilia has evolved from an often fatal hereditary bleeding disorder to a disorder for which safe and effective treatment is available. However, there are several challenges remaining in the treatment of hemophilia. Prophylaxis to prevent bleeding is costly and requires frequent intravenous injections, which are cumbersome for patients. Venous access is often difficult to achieve, especially in small children where central venous lines may need to be implanted. Development of inhibitory antibodies makes treatment of acute bleeds difficult and prophylaxis in patients with inhibitors must also be better addressed. In order to improve treatment, new products are being developed, some of which are already in clinical trials. There are several approaches to prolonging half-lives such as PEGylation, Fc fusion and albumin fusion. Increased activity has been demonstrated in preclinical trials for factor IX and in a human trial with factor VII where the activity of the molecules has been increased by manipulation of the molecular composition. Additional approaches, including blockage of inhibitors of clotting, are also under investigation. Factor VIII and factor IX gene therapy have become a tangible possibility since phase I data recently have been published. Results are promising and there is hope that in the near future substantial progress will be made, perhaps making hemophilia the first genetic condition to be cured.

Modern haemophilia care

Haemophilia care has undergone substantial improvements during the past 40-50 years. Early clotting factor concentrates were not sufficiently refined to enable self-administered treatment at home until the 1970s. Unfortunately, these advances led to transmission of viral diseases including HIV and hepatitis, resulting in an increased burden of morbidity and mortality, especially during the 1980s. Throughout the past two decades, product development, including the advent of recombinant concentrates, has greatly improved the safety and availability of therapy and the focus of care is shifting towards prevention and management of disease sequelae. Long-term substitution therapy (prophylaxis) of the missing clotting factor is the recommended treatment in severe haemophilia, but several research issues remain to be elucidated such as when to start and how to optimise these regimens, and when or whether to stop this expensive treatment. The major side-effect of treatment, development of inhibitors to the infused concentrate, is the main threat to the health of patients and consequently the goal of intense research. Development of new products with improved pharmacokinetics is the next step to improved therapy.

Validity of assessing inhibitor development in haemophilia PUPs using registry data: the EUHASS project

Inhibitory antibodies to exogenous FVIII/FIX are a major complication of haemophilia treatment. Up to 30% of previously untreated patients (PUPs) with severe haemophilia A develop inhibitors, most likely during the initial 50 exposure days to concentrate. In addition to classical cohort studies, a European monitoring system (EUHASS) has been set up to evaluate inhibitor development in PUPs. The present study addresses the reliability of estimating the cumulative incidence of inhibitor development in this registry. Data from the retrospective CANAL cohort study, including 288 PUPs with severe haemophilia A and complete treatment records until the 50th exposure to FVIII, were used to simulate the consequences of several cross-sectional sampling techniques on the estimated incidence of inhibitors. Both mathematical calculus and computer modelling were applied to study the effects of sample size and the introduction of a new product. For existing concentrates, both longitudinal cohort study methods and the EUHASS method yielded similar estimates of the cumulative incidence of inhibitor cases over a 5-year time period: 27.9% (95% CI: 21-36) vs. 29.4% (22-38). For a newly introduced concentrate, a reliable estimate of inhibitor incidence with the EUHASS method could only be made after 3-4 years, even in large datasets. The results from EUHASS in inhibitor incidence in PUPs are expected to be valid. After introduction of a new concentrate, the inhibitor incidence on this concentrate can only be reliably determined after an observation period of several years.

Pharmacotherapy of haemophilia A

INTRODUCTION

Haemophilia A is due to factor VIII (FVIII) deficiency. The main treatment is replacement therapy with FVIII concentrates. However, these concentrates carried a high risk of blood-borne viral infections and still have a high risk of inducing anti-FVIII inhibitors.

AREAS COVERED

An overview of products available and therapeutic options for haemophilia A management in order to help in decision making. A literature search using Medline with the keywords: 'haemophilia', 'factor VIII', 'therapy', 'inhibitor', 'concentrate', 'bleeding', 'prophylaxis', 'on demand', 'plasma-derived', 'recombinant', 'coagulation factors', 'immunotolerance' was performed. The years 1960 - 2010 are included.

EXPERT OPINION

Progress in management of patients with haemophilia A has allowed increased life expectancy and quality of life. There is evidence that prophylaxis prevents or, at least, slows down arthropathy development when started early in childhood. FVIII concentrates have achieved high levels of blood-borne pathogen safety. However, treatment is frequently complicated by development of FVIII-neutralizing inhibitors, which prevent control of bleeding and predispose to a high morbidity and mortality risk. Bypassing agents are effective in bleeding treatment in a high percentage of cases. Prophylaxis with bypassing agents and their use in combination are offering opportunities in management of inhibitor patients. More evidence is necessary to understand how to prevent and manage this complication.

Prevention of haemophilic synovitis: prophylaxis

It has been proven that early prophylactic therapy can prevent bleeding and arthropathy. Numerous retrospective non-randomized cohort studies have demonstrated that prophylaxis, if started early in life, is associated with a considerable reduction of the mean number of joint bleeds and the rate of joint deterioration. It is quite extraordinary that despite the considerable evidence base it has been considered necessary by investigators to pursue the ideal of the controlled randomized trial and expose children to the risk of cerebral bleed. This questionable ethical approach is driven by the reluctance of the 'willingness to pay' but it is important that patients are not subjected to unnecessary investigation at either the behest of the Cochrane Database or those who control the financing of haemophilia care.

Identifying and overcoming barriers to prophylaxis in the management of haemophilia

Haemophilia is often characterized by acute haemarthrosis and synovitis arising from spontaneous bleeding episodes, particularly in the muscles and joints of the elbows, knees and ankles. Current treatment for patients with severe haemophilia involves coagulation factor concentrate (CFC) replacement therapy given on demand at the time of bleeding or through long-term prophylaxis aimed at preventing future bleeds and joint disease. Although prophylaxis has many advantages over on-demand therapy (particularly if started before age 2 and prior to any signs of joint disease), its practice varies widely even among developed countries because of several barriers. Such barriers include CFC costs and availability; patient perceptions, lifestyles and bleeding patterns; difficulties and complications arising from the use of intravenous access devices (IVADs); the development of inhibitors; and the lack of randomized clinical trials. These barriers can be overcome by tailoring treatment regimens according to individual patient bleeding patterns and CFC pharmacokinetic profiles, using IVADs selectively and judiciously, helping patients maintain normal weight and physical exercise and providing the families of patients with continuous support from healthcare providers.

The risk associated with indwelling catheters in children with haemophilia

Infections are the most frequent complications associated with the use of central venous lines (CVLs) in children with haemophilia. Several retrospective studies that include data from a substantial number of patients have reported approximately 0.2-0.3 infections per 1000 catheter-days (mainly Port-A-Cath). Some studies have shown a much higher frequency of infections, 1-2/1000 catheter-days. The most plausible explanations, for the difference seen in frequency of infections with Port-A-Caths, are probably related to the protocol used for the device care and the quality of education and the compliance of the users, whether these are parents or health-care professionals. The figures are low for clinically apparent thrombosis in the larger series on record, but routine venograms were not performed in most of these series. In studies, where this has been performed, a high frequency of abnormalities (>50%) on venograms have been seen in some series but not in others. Despite obvious potential risks with CVLs, they are useful in many cases and facilitate the treatment of a serious disorder. With careful guidelines and surveillance protocols, the risk of complications should be reduced in the future.

Central venous access device infections in children with hemophilia: a comparison of prophylaxis and episodic therapy

Prophylaxis was recommended as the optimal treatment regimen for severe hemophilia by several expert committees. This led to increased utilization of prophylaxis and, subsequently, central venous access devices (CVADs). Although prophylaxis is the preferred treatment, episodic therapy is used by many. CVADs are employed to facilitate administration of prophylactic and episodic infusions; however, there are no data on the risk of CVAD-related infections for prophylaxis compared with episodic therapy. Data from the Study for the Prevention of Joint Disease in Preschool Children with Severe Hemophilia, a randomized clinical trial of prophylaxis versus episodic therapy, were used to evaluate the association between CVAD-related infection and treatment. The crude and adjusted rate ratios for first CVAD-related infection per 1000 CVAD days associated with episodic therapy versus prophylaxis were 1.42 (95% confidence interval: 0.46-4.40) and 1.23 (95% confidence interval: 0.33-4.56), respectively. Although we cannot make a definitive statement about treatment and CVAD-related infection risk, this study suggests that prophylaxis likely does not put children at higher risk of CVAD-related infection than episodic therapy. Given the need for CVADs in some children and the benefits of prophylaxis, we conclude there is no reason to recommend against prophylaxis on the basis of existing knowledge of CVAD-related infection risk.

[Relevance of early paediatric care for boys with severe haemophilia]

Major molecular and genetic findings over the last decades and subsequent applications for diagnosis and therapeutic concerns have dramatically improved the evolution of severe haemophilia in countries with high economic resources. Another major factor of progress consisted in the setting of comprehensive care centres coordinating the care at a regional level. The early involvement of paediatricians for this rare and potentially serious chronic disease, which may be symptomatic from birth, is relevant in this context. Indeed, the early diagnosis of severe haemophilia and the involvement of expert caregivers in a multidisciplinary approach, are essential to make the acceptance of the disease easier. The diagnosis announcement should go together with a therapeutic project, which is nowadays based on long-term prophylaxis. Awaiting for likely curative treatments in the future, such as gene therapy, early implementation of prophylaxis and observance of this gold standard treatment during all the period of growth are critical to prevent the haemophilic arthropathy, to favour the future social and work-related integration and overall to improve the quality of life. The occurrence of an inhibitor represents the major residual complication of replacement therapy, especially for young children with severe haemophilia A. Even though new therapeutic resources brought substantial improvements for inhibitor patients, a better understanding of risk factors is a key issue since more accurate replacement regimen might induce tolerance during the first exposures and subsequently might prevent this complication. Prophylaxis and inhibitors that represent major concerns in paediatric care of severe haemophilia are included as main research objectives for the national registry " FranceCoag Network".

Consideration in Hemophilia Therapy Selection

The risk of pathogen transmission via clotting factor therapies has been reduced over the last two decades through the development of effective and progressively more sensitive pathogen screening and inactivation methods and the introduction of recombinant clotting factors for hemophilia, beginning with recombinant factor VIII (FVIII) in 1992. However, new understanding about the potential for transmission of an emerging infectious agent through blood and blood products has renewed concerns about vulnerabilities that remain in plasma-derived and some recombinant clotting therapies that still use plasma components during some stages of the manufacturing process. In the 1980s, patients with hemophilia became "canaries in the coal mine" for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) in the blood supply. Moving forward, healthcare providers must continue to take a proactive role in educating themselves about new information regarding emerging pathogens and develop approaches to discussing this risk with their patients as part of their therapy selection process.

Optimal haemophilia care versus the reality

Haemophilia A and B are inherited bleeding disorders whose diagnosis and management is generally well established and best provided by specialists in a comprehensive care setting. Patients may be put at unnecessary risk if appropriate expertise is not sought for the management of accidents and surgery. The delivery of a high quality comprehensive service to patients with bleeding disorders depends upon defined standards and a network of haemophilia centres in the UK with similar models in other countries. In developing countries, despite a shortage or absence of treatment products, development of local expertise results in an improved outlook and reduction in mortality. Optimal care for severe haemophilia includes accurate diagnosis, early and adequate factor replacement for bleeding episodes and the provision of prophylaxis from an early age to prevent joint bleeding and the consequent arthropathy. Haemophilia treatment is expensive resulting in considerable inequity in provision of care across the world. Despite decades of experience, optimal treatment levels are not robustly defined. Transfusion-transmitted infections continue to have a significant impact on patient management. The development of inhibitory antibodies seriously complicates the management both in morbidity and cost. While gene therapy has not yet produced the hoped-for cure, new technologies will produce improved products.

The physician's role in selecting a factor replacement therapy

Over the past 20 years, transmissions of human immunodeficiency virus (HIV), hepatitis B virus or hepatitis C virus have been virtually eliminated from plasma-derived or recombinant therapy in the USA, a record that can be largely attributed to the use of effective screening and inactivation technologies for known pathogens. The next significant threat will likely come from the emergence of a new, blood-borne infectious disease, perhaps one transmitted by a non-lipid-enveloped virus or prion, for which current inactivation methods are ineffective. Following the HIV crisis of the 1980s, government, patient advocacy groups, medical and scientific communities and the manufacturers of clotting therapies can learn from the past and approach potential threats from emerging pathogens in a proactive and productive manner. For clinicians, this includes actively engaging patients in a dialogue about all the factors that may influence their choice of clotting factor therapies, including emerging pathogens, patient convenience, consistency and reliability of supply, relative cost/benefit ratios, reimbursement issues (where applicable), patient preference and brand loyalty. It is our obligation as healthcare providers to understand potential risks and help make proactive decisions with our patients, decisions that often must be made in an environment of scientific uncertainty. Threats from infectious agents that were once deemed theoretical can, and often do, ultimately become real, with serious implications for morbidity and mortality.