Experience of prophylaxis treatment in children with severe haemophilia

The practice of prophylactic treatment of boys with severe haemophilia has been evaluated in our centre. Prophylaxis was started at the median age of 3.7 years (range 0.4-12.7 years) in 38/41 children (93%) under 17 years of age. Median follow-up was 4.1 years (range 0.4-12.7 years). The criteria of primary prophylaxis according to the definition by the European Paediatric Network of Haemophilia Management was fulfilled by 9/38 (24%). Although a majority [76%, 29/38] of the children started prophylaxis after a median number of joint bleeds of 3.5, 70% of the children in this group had clinical joint scores of 0. Intravenous catheter insertion was required at a median age of 15.5 months (range 5-36 months) in 21% of the children, resulting in a catheter infection rate of 1.74 per 1000 catheter days. None developed an inhibitor on prophylaxis and three patients who had low-titre inhibitors (< 5 Bethesda units) prior to prophylaxis had undetectable inhibitors after prophylaxis. The home-treatment training programme required considerable time and cost. As a result, 87% of the children used peripheral venous access and hospital visits declined as prophylaxis became established. Parents' incentives for prophylaxis were that the children undertook many physical activities and sports previously not recommended, there was less parental anxiety and an overall improvement in the quality of life for the whole family.     

A modeling approach to evaluate long-term outcome of prophylactic and on demand treatment strategies for severe hemophilia A

Background

Severe hemophilia requires life-long treatment with expensive clotting factor concentrates; studies comparing effects of different therapeutic strategies over decades are very difficult to perform. A simulation model was developed to evaluate the long-term outcome of on demand, prophylactic and mixed treatment strategies for patients with severe hemophilia A.

Design and Methods

A computer model was developed based on individual patients’ data from a Dutch cohort study in which intermediate dose prophylaxis was used and a French cohort study in which on demand treatment was used, and multivariate regression analyses. This model simulated individual patients’ life expectancy, onset of bleeding, life-time joint bleeds, radiological outcome and concentrate use according to the different treatment strategies.

Results

According to the model, life-time on demand treatment would result in an average of 1,494 joint bleeds during the hemophiliac’s life, and consumption of 4.9 million IU of factor VIII concentrate. In contrast, life-time intermediate dose prophylaxis resulted in a mean of 357 joint bleeds and factor consumption of 8.3 million IU. A multiple switch strategy (between prophylactic and on demand treatment based on bleeding pattern) resulted in a mean number of 395 joint bleeds and factor consumption of 6.6 million IU. The estimated proportion of patients with Pettersson scores over 28 points was 32% for both the prophylactic and the multiple switching strategies, compared to 76% for continuous on demand treatment.

Conclusions

The present model allows evaluation of the impact of various treatment strategies on patients’ joint bleeds and clotting factor consumption. It may be expanded with additional data to allow more precise estimates and include economic evaluations of treatment strategies.     

A comparison of traditional vs. Canadian tailored prophylaxis dosing of prophylactic factor infusions in children with haemophilia A and B in a single hemophilia treatment center

Prophylactic infusion of clotting factor concentrates is a developing standard of care for individuals with haemophilia. The ideal schedule and techniques of prophylactic infusions remain incompletely defined. Our aim was to determine the optimal techniques and schedules for factor prophylaxis in paediatric patients. A retrospective electronic medical record review of all children treated with prophylactic factor infusions in a single Haemophilia Treatment Center was conducted. Comparison of traditional vs. Canadian dosing regimens and primary vs. secondary prophylaxis was made. Failure of prophylaxis was defined as the first serious bleed. A total of 58 children were identified for review. Five cases were excluded (four due to high titre inhibitors and one due to repeated non-compliance), thus there were 53 total cases: 46 with severe haemophilia, 2 with moderate haemophilia, 5 with mild haemophilia, 44 with haemophilia A and 9 with haemophilia B; 32 Traditional dosing and 21 Canadian dosing regimens. Patients on primary prophylaxis had a decreased failure rate (25%) compared to children treated with secondary prophylaxis (67%) regardless of technique of prophylaxis. When compared to a 'Traditional' factor prophylaxis schedule, the 'Canadian' tailored prophylaxis protocol was comparable with the exception of a decreased use of implanted venous devices in the 'Canadian' group. Ongoing bleeding (primarily joint bleeds) occurs with all prophylactic regimens. The lowest incidence of treatment failure was noted in children who began primary prophylaxis at a young age and before initial joint bleeds. Primary prophylaxis is superior to secondary prophylaxis regardless of dosing regimen. Traditional and Canadian dosing regimens were equivalent in outcome when measured over several years of follow-up.     

Improved treatment feasibility in children with hemophilia using arteriovenous fistulae: the results after seven years of follow-up

Background

An easy and stable venous access is essential in hemophilic children who receive regular prophylaxis or immune tolerance induction treatment. Central venous access devices improve treatment feasibility, but their use is complicated by infection and/or thrombosis. Arteriovenous fistula (AVF) has been evaluated as an alternative to central venous access devices in hemophilic children since 1999.

Design and Methods

This study provides results obtained in a large series after seven years of follow-up.

Results

From 1999 to 2008, 43 procedures were performed in 38 children (median age: 2.7 years). Thirty-five AVFs (81%) achieved maturation after a median of 58 days and were used for a median of five years (range: 0.4–8.5). A brachial artery caliber larger than 1.2 mm was associated with successful maturation (p<0.05). Complications with some impact on arteriovenous fistula use or duration were observed in 14/43 procedures (32%) and in 13/38 children (34%). Age at arteriovenous fistula creation was younger in children who lost arteriovenous fistula patency (p<0.05) and aneurysms were more frequent in children who were on daily treatment regimen and thus had a greater cumulative number of arteriovenous fistula accesses (p<0.05). At the end of the follow-up period, 22 AVFs were still in use and 9 had been surgically dismantled. Arteriovenous fistula use allowed long-term prophylaxis (up to 8.5 years) in 11 children and the completion of immune tolerance induction without interruptions in 18 children.

Conclusions

This study confirms the feasibility of arteriovenous fistula with an acceptable rate of complications and suggests that its use is particularly favorable in children with inhibitors in whom it should be considered as first-choice venous access.     

Orthopaedic evaluation in children with severe haemophilia A or B submitted to primary prophylaxis therapy in a coagulopathy treatment centre

Summary. There is a lack of publications concerning the use of primary prophylaxis in developing countries. The aim of this study was to evaluate the effectiveness of primary prophylaxis therapy in preventing the development of arthropathy in children with severe haemophilia A or B. From January 1999 to April 2009, a prospective study was carried out involving 39 patients with severe haemophilia A or B. These haemophilia A and haemophilia B patients received 20–40 UI kg^?1 of factors VIII and IX, three and two times per week, respectively. The patients were followed up by a multidisciplinary team. The analysis was carried out in 23 patients who had been on prophylaxis therapy for at least 12 months. The orthopaedic evaluation was performed according to the recommendations of the Orthopedic Advisory Committee of the World Federation of Hemophilia, by evaluating pain and bleeding, and by conducting physical examination and radiological assessment (Pettersson’s Joint Score and magnetic resonance): 82.6% of patients who had used the factor regularly did not present any clinical or radiographic changes in the studied joints; 17.4% used the factor irregularly at the beginning of the treatment and of those, most patients presented mild changes in the joints; and 4.3% presented transient knee and ankle pain in spite of regular factor use. The preliminary results of primary prophylaxis confirm its effectiveness in preventing haemophilic arthropathy. Socioeconomic factors did not play a significant role.     

Low dose secondary prophylaxis reduces joint bleeding in severe and moderate haemophilic children: a pilot study in China

Summary. The most common bleeding in haemophilic patients is in joints, and joint disability is the most common complications in these patients receiving inadequate treatment. Limited by economy and inadequate treatment, developing countries face huge challenge to reduce disability and improve quality of life (QoL) of haemophilic children. The aim of this study was to investigate the effect of low dose secondary prophylaxis in China. Children with moderate and severe haemophilia from the Beijing Children Hospital, Beijing, China, and with established joint disease, were followed for a 12‐week observation period followed by a 12‐week low dose secondary prophylaxis‐study period (for haemophilia A, factor VIII concentrate 10 IU kg^?1 twice weekly; for haemophilia B, factor IX concentrate 20 IU kg^?1 weekly). The reduction of joint bleeding, improvement of joint function and QoL during prophylaxis were analysed. In total 34 children (median age 7.8 years) were analyzable. The number of joint bleeds decreased from a total of 337 (individual range 3–24, mean 9.9) during the observation period to 57 (range 0–6, mean 1.7) during the study period with an overall of reduction 83%. Joint function improved in 66.7% of disease joints, with 23.2% of which were considered good to moderate. School attendance improved in all subjects, sports participation and daily activity improved moderately. Low dose secondary prophylaxis significantly reduces frequency of joint bleeding; with moderate improvement in joint function, school attendance, sport participation and daily activities. Low dose secondary prophylaxis is therefore, cost‐effective as applied to developing countries such as China, although there are still unresolved issues.     

The overall effectiveness of prophylaxis in severe haemophilia

The aim of this retrospective review was to assess the overall effectiveness of prophylaxis when compared with on-demand treatment of haemophilic patients. Twenty-five children (22 with severe haemophilia A and three with severe haemophilia B) were evaluated. Five haemophilia A patients received primary prophylaxis (instituted before the onset of any joint bleed) while the other 17 haemophilia A and all three haemophilia B patients were on secondary prophylaxis. We compared factor usage, number of bleeding episodes, emergency room (ER) visits and hospitalizations while on prophylaxis to those while on demand therapy. All subjects were male, the median age at time of review was 11.4 years and at start of prophylaxis was 4.5 years. Thirteen of the 25 patients (52%) required indwelling venous catheters for access, seven of these had one or more (one-six) episodes of line sepsis. Haemophilia A patients received an average of 23.8 U kg(-1) (20-30 U kg(-1)) of recombinant factor VIII three times a week while haemophilia B patients received 50 U kg(-1) recombinant FIX twice weekly. There was a significant reduction in the mean number of major bleeds on prophylaxis from 15.5 to 1.9 per year and a significant decrease in target joints, ER visits and hospitalizations. Although factor usage per year was higher on prophylaxis, there was an overall reduction in number of bleeds and resultant decrease in hospitalizations and ER visits. By preventing new target joints, prophylaxis can lead to reduction in long-term morbidity and a better quality of life despite increased central lines and higher factor usage.     

Pharmacokinetic dosing in prophylactic treatment of hemophilia A

Abstract: The aim of this study was to investigate individual pharmacokinetics as a tool for dosing of factor VIII (FVIII) in severe hemophilia A. It is assumed that effective prophylaxis against bleedings is maintained if the plasma FVIII:C activity is kept above 1 U/dl, and the present study is based on this assumption. A current standard dosage regimen for FVIII is 25–40 U/kg up to three times weekly. However, there is considerable individual variation in the pharmacokinetics of FVIII:C. Individual pharmacokinetic data were used to computer-simulate plasma activity curves after repeated doses in 8 patients. Going from prophylaxis regimens of normally 2–3 infusions per week to dosing every 2 days would theoretically reduce their average FVIII consumption by 43% with maintained or increased trough levels of FVIII:C. Daily dosing would reduce their mean FVIII usage by 82%. Modified dosage regimens, infusions every 2 days, were implemented in the patients, and plasma samples were drawn to verify the pharmacokinetic models. The feasibility of the method to generally raise trough levels with a decreased consumption of FVIII was confirmed. Dosing of coagulation factors according to kinetic principles can result in more cost-effective utilization of these very expensive preparations.     

When to start and when to stop primary prophylaxis in patients with severe haemophilia

Summary. Primary prophylactic treatment of patients with severe haemophilia has been shown to reduce the number of bleeding episodes and to minimize the development of arthropathy. However, since the use of clotting factor concentrates is associated with considerable cost and not all patients with severe haemophilia have a severe bleeding phenotype, there is still no consensus about when to start prophylaxis, which dosing regimen to use, and if or when the treatment should be stopped when the patient becomes elderly. Some care providers are also concerned about the use of central venous lines in very young children. Even though most available data indicate that prophylaxis should be started during the first years of life, it may be possible to adjust the dose and dose interval depending on the bleeding pattern. The use of an individualized prophylactic regimen may also improve cost‐effectiveness and make the use of this treatment modality more feasible. Studies to further address this issue are warranted.     

When to start and when to stop primary prophylaxis in patients with severe haemophilia

Summary.  Primary prophylactic treatment of patients with severe haemophilia has been shown to reduce the number of bleeding episodes and to minimize the development of arthropathy. However, since the use of clotting factor concentrates is associated with considerable cost and not all patients with severe haemophilia have a severe bleeding phenotype, there is still no consensus about when to start prophylaxis, which dosing regimen to use, and if or when the treatment should be stopped when the patient becomes elderly. Some care providers are also concerned about the use of central venous lines in very young children. Even though most available data indicate that prophylaxis should be started during the first years of life, it may be possible to adjust the dose and dose interval depending on the bleeding pattern. The use of an individualized prophylactic regimen may also improve cost-effectiveness and make the use of this treatment modality more feasible. Studies to further address this issue are warranted.     

Reduced bone density in individuals with severe hemophilia B

Aim: The reduced bone density in individuals with severe hemophilia A (decreased coagulation factor VIII level) and combined factor V and VIII deficiency have been reported. In the current case‐control study we tried to address bone mineral density in individuals with severe hemophilia B (decreased coagulation factor IX). Methods: In our case‐control study, we recruited bone density and biochemical indexes in 14 individuals with severe hemophilia B and compared obtained results with 14 age‐ and sex‐matched control group results. Results: Our results showed individuals with severe hemophilia B had reduced bone density in lumbar (–0.34 ± 0.97) and femur (–0.82 ± 1.37) regions, compared to the control group (0.84 ± 0.53 and 1.02 ± 1.04 respectively; P‐value = 0.000 and 0.000). Conclusion: The foremost complication of coagulation disorders are various types of excessive bleedings. The current study revealed severe hemophiliac B patients are prone to reduced bone density similar to severe hemophiliac A patients.     

Effects of prophylactic treatment regimens in children with severe haemophilia: a comparison of different strategies

Summary.  Both Sweden and the Netherlands have a long experience with primary prophylaxis in children with severe haemophilia. In these countries it has been offered to all children for the last 3–4 decades. In Sweden prophylaxis is generally started at an earlier age with a higher dosage and frequency than in the Netherlands. Patients in the Netherlands receive a more individually tailored regimen, with prophylaxis now started after the first one or two joint bleeds and dosages are increased when breakthrough bleeds occur. The current study evaluated the effect prophylaxis on long-term outcomes and the consumption of clotting factor concentrates in Dutch and Swedish cohorts. Our results show that the orthopaedic outcome in the oldest groups of patients from Sweden and the Dutch cohorts were comparable, although the Swedish patients used twice as much clotting products per year. In the youngest patients, joint status is very good and further follow-up is necessary to demonstrate the benefits of either strategy. In conclusion, more individually tailored regimens aimed at preventing bleeding prevent joint damage in children with severe haemophilia, while clotting factor consumption is about half of that in previously described regimens.     

North American prophylaxis studies for persons with severe haemophilia: background, rationale and design

Summary.  Arthropathy is associated with the greatest cost and morbidity to persons with haemophilia. Clinical protocols have been developed empirically to prevent or retard the development of joint disease using routine infusions of replacement factor concentrate. However, randomized clinical trials to determine optimal therapy to prevent joint disease in persons with severe haemophilia are lacking. Two clinical trials are ongoing to answer important clinical questions about the prevention of arthropathy. The first, a US randomized clinical trial, is comparing an aggressive multiple-infusion episode-based protocol to standard alternate-day prophylaxis to determine whether prevention of joint disease requires prevention of the bleeding event, per se , or can be achieved by promoting complete resolution of each bleeding event in the joint. This study included the development and validation of sensitive new physical and imaging scales to detect the earliest signs of joint disease in young children. The second, a single-arm, open-label Canadian study, is asking whether prevention of joint disease in young children can be individualized by escalating the dose and frequency of routine replacement infusions of factor concentrate based upon the clinical course of haemophilia in the affected child. Both of these studies will contribute valuable information regarding optimal therapy and will help establish evidence-based medicine for the management of severe haemophilia.     

Prevention of bleeds in hemophilia patients with inhibitors: emerging data and clinical direction

In patients with hemophilia, the development of high-responding inhibitors to factor VIII prevents adequate replacement therapy and results in increased risk of serious bleeding episodes, poor control of joint bleeding, and progressive, debilitating joint disease. Immune tolerance therapy can eradicate inhibitors, but it is not uniformly successful. Emerging data suggest that prophylaxis using activated prothrombin complex concentrates may be effective and safe in reducing the incidence of joint bleeding during immune tolerance therapy and for patients in whom immune tolerance induction fails. However, only controlled clinical trials will ultimately demonstrate whether prophylaxis can prevent joint bleeding and damage, and improve quality of life in patients with inhibitors.     

Should prophylaxis be used in adolescent and adult patients with severe haemophilia? An European survey of practice and outcome data

A survey of 21 haemophilia doctors, throughout Europe, who care for a total of approximately 5000 patients with bleeding disorders addressing practice and opinions regarding prophylaxis in patients aged 16-24 years and adults aged over 50 years, is presented. The outcome of adolescent patients who reduced or stopped prophylaxis was recorded. Eighteen of 19 respondents would consider modification of established prophylaxis in the adolescent age group, principal considerations being avoidance of risks of further concentrate exposure, predicted poor compliance and treatment costs. The preferred age for modification was 16-20 years, but there was very little consensus on the particular prophylactic regime recommended. Approximately, half of a cohort of 218 patients with severe haemophilia successfully reduced or stopped prophylaxis when they reached adolescence. Only 26 of 92 (28%) of the patient cohort who stopped prophylaxis, required reintroduction of a prophylactic regime and 12 of 59 (20%) of those who reduced the intensity of prophylaxis had to reintroduce a more intensive regime. A majority of respondents would consider starting prophylaxis in those over 50 years. There was no consensus as to indications for this practice or the nature of the prophylaxis protocol. We conclude that there is an absence of consensus on the management of patients with severe haemophilia, as they pass through adolescence and young adulthood, and reach the age of 50. Aggregate outcome data suggest a significant proportion of patients in the 18-22 years age range may be able to reduce or stop prophylaxis. A substantial number of older patients are on prophylaxis.     

Adherence to prophylaxis and quality of life in children and adolescents with severe haemophilia A

Treatment adherence in adolescents with chronic diseases is around 50%, and failure is more common in preventive therapy. In haemophilia, contradictory results are reported by the published studies. The objective of this study was to evaluate adherence with factor VIII (FVIII) prophylaxis in Spanish patients with severe haemophilia A between age 6 and 20 years. Data were collected retrosp‐ectively in the previous 2 years. The primary endpoint was the absolute adherence index (AAI), and the endpoints were related to clinical status, age, prophylaxis regimen, responsibility for factor administration and quality of life (QoL), assessed by the Haemo‐QoL questionnaires. A total of 78 patients from 14 Spanish hospitals were recruited. Adherence ranged between ?64.4 and 66.7 (mean ?3.08). No differences were observed between children and adolescents (7.11 vs. 6.39; P = 0.809). A statistically significant association (P < 0.010) between infra adherent group and target joint was found, as was a statistically significant difference (P < 0.010) between the number of bleeding episodes experienced by the adherent group (mean 1.4) and by infra adherents (mean 4.5). There was no significant difference between AAI and prophylactic regimen (6.35 vs. 6.96, P = 0.848), neither between AAI and the person responsible for factor administration (5.57 vs. 8.79, P = 0.326). The Haemo‐QoL scores (8–12 years) were related to adherence level (P < 0.05). Adherence was approximately ideal and patients perceived a high QoL. Because of the repercussions for compliance, it is essential to work during puberty on emotional and self‐acceptance aspects of the disease, as well as coping, and the patient's family, school and health team relationships.