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

Effects of replacement therapies with clotting factors in patients with hemophilia: A systematic review and meta-analysis

Background

Different prophylactic and episodic clotting factor treatments are used in the management of hemophilia. A summarize of the evidence is needed inform decision-making.

Objective

To compare the effects of factor replacement therapies in patients with hemophilia.

Methods

We performed a systematic search in PubMed, Central Cochrane Library, and Scopus. We included randomized controlled trials (RCTs) published up to December 2020, which compared different factor replacement therapies in patients with hemophilia. Random-effects meta-analyses were performed whenever possible. The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. The study protocol was registered in PROSPERO (CRD42021225857).

Results

Nine RCTs were included in this review, of which six compared episodic with prophylactic treatment, all of them performed in patients with hemophilia A. Pooled results showed that, compared to the episodic treatment group, the annualized bleeding rate was lower in the low-dose prophylactic group (ratio of means [RM]: 0.27, 95% CI: 0.17 to 0.43), intermediate-dose prophylactic group (RM: 0.15, 95% CI: 0.07 to 0.36), and high-dose prophylactic group (RM: 0.07, 95% CI: 0.04 to 0.13). With significant difference between these subgroups (p = 0.003, I² = 82.9%). In addition, compared to the episodic treatment group, the annualized joint bleeding rate was lower in the low-dose prophylactic group (RM: 0.17, 95% CI: 0.06 to 0.43), intermediate-dose prophylactic group (RM of 0.14, 95% CI: 0.07 to 0.27), and high-dose prophylactic group (RM of 0.08, 95% CI: 0.04 to 0.16). Without significant subgroup differences. The certainty of the evidence was very low for all outcomes according to GRADE methodology. The other studies compared different types of clotting factor concentrates (CFCs), assessed pharmacokinetic prophylaxis, or compared different frequencies of medication administration.

Conclusions

Our results suggest that prophylactic treatment (at either low, intermediate, or high doses) is superior to episodic treatment for bleeding prevention. In patients with hemophilia A, the bleeding rate seems to have a dose-response effect. However, no study compared different doses of prophylactic treatment, and all results had a very low certainty of the evidence. Thus, future studies are needed to confirm these results and inform decision making.

Clotting factor concentrates for preventing bleeding and bleeding-related complications in previously treated individuals with haemophilia A or B

BACKGROUND

The hallmark of severe hemophilia (A or B) is recurrent bleeding into joints and soft tissues with progressive joint damage, despite on-demand treatment. Prophylaxis has long been used, but not universally adopted, because of medical, psychosocial, and cost controversies.

OBJECTIVES

To determine the effectiveness of clotting factor concentrate prophylaxis in managing previously-treated individuals with hemophilia A or B.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Coagulopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. In addition, we searched MEDLINE and Embase and online trial registries. Most recent search of Group's Coagulopathies Trials Register: 24 February 2021.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs evaluating people with hemophilia A or hemophilia B, who were previously treated with clotting factor concentrates to manage their hemophilia.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed trials for eligibility, assessed risk of bias and extracted data. The authors used the GRADE criteria to assess the certainty of the evidence.

MAIN RESULTS

Ten trials (including 608 participants) were eligible for inclusion. Eight of the trials (477 participants) had arms comparing two or more prophylactic regimens to one another and four of the trials (n = 258) compared prophylaxis to on-demand treatment (two trials had multiple arms and were included in both comparisons). Comparison of two or more prophylactic regimens For trials comparing one prophylaxis regimen to another, given the heterogeneity of the data, none of the data were pooled for this comparison. Considering the individual trials, three trials reported the primary outcome of joint bleeding, and none showed a dfference between dosing regimens (low-certainty evidence). For the secondary outcome of total bleeding events, prophylaxis with a twice-weekly regimen of FIX likely results in reduced total bleeds compared to a once-a-week regimen of the same dose, mean difference (MD) 11.2 (5.81 to 16.59) (one trial, 10 participants, low-certainty evidence). Transient low-titer anti-FVIII inhibitors were reported in one of the trials. Blood-transmitted infections were not identified. Other adverse events reported include hypersensitivity, oedema, and weight gain. These were, however, rare and unrelated to study drugs (very low-certainty evidence). Comparison of prophylactic and on-demand regimens Four of the trials (258 participants) had arms that compared prophylaxis to on-demand treatment. Prophylaxis may result in a large decrease in the number of joint bleeds compared to on-demand treatment, MD -30.34 (95% CI -46.95 to -13.73) (two trials, 164 participants, low-certainty evidence). One of these trials (84 participants) also reported the long-term effects of prophylaxis versus on-demand therapy showing improved joint function, quality of life, and pain; but no differences between groups in joint structure when assessed by magnetic resonance imaging (MRI). In one trial (84 participants) validated measures for joint health and pain assessment showed that prophylaxis likely improves joint health compared to an on-demand regimen with an estimated change difference of 0.94 points (95% CI 0.23 to 1.65) and improves total pain scores, MD -17.20 (95% CI -27.48 to -6.92 (moderate-certainty evidence). Two trials (131 participants) reported that prophylaxis likely results in a slight increase in adverse events, risk ratio 1.71 (1.24 to 2.37) (moderate-certainty evidence). No inhibitor development and blood-transmitted infections were identified. Overall, the certainty of the body of evidence was judged to be low because of different types of bias that could have altered the effect.   AUTHORS' CONCLUSIONS: There is evidence from RCTs that prophylaxis, as compared to on-demand treatment, may reduce bleeding frequency in previously-treated people with hemophilia. Prophylaxis may also improve joint function, pain and quality of life, even though this does not translate into a detectable improvement of articular damage when assessed by MRI.  When comparing two different prophylaxis regimens, no significant differences in terms of protection from bleeding were found. Dose optimization could, however, result in improved efficacy. Given the heterogeneity of the data, pooled estimates were not obtained for most comparisons.  Well-designed RCTs and prospective observational controlled studies with standardised definitions and measurements are needed to establish the optimal and most cost-effective treatment regimens.

[Rapid Report Hemophilia - Evidence in treatment of hemophilia from the IQWiG's perspective]

The German Institute for Quality and Efficiency in Health Care (IQWiG) conducted a rapid report to assess the therapy of hemophilia patients. Based on a systematic literature search the IQWiG identified 16 studies which show that there is now sufficient information regarding questions that previously lacked data. A benefit assessment of prophylactic and on-demand-treatment concerning different treatment outcomes shows the superiority of the prophylactic therapy regarding major bleedings for all age groups. For the group of youths and adults the analysis shows additional benefits concerning health status and pain within the preceding four weeks. The alignment of guidelines with the identified evidence shows minor correspondence between the guidelines' references and included studies. However, the guidelines' statements primarily correspond with the results of the conducted benefit assessment.

CONCLUSION

The IQWiG's rapid report shows prophylactic therapy to be superior to on-demand therapy. These findings represent a clear indication for attending physicians and payers for prophylaxis in patients with severe hemophilia A.

Central venous access device (CVAD) complications in Haemophilia with inhibitors undergoing immune tolerance induction: Lessons from the international immune tolerance study

INTRODUCTION

Central venous access devices (CVADs) are frequently required as stable long-lasting venous access in children with haemophilia, especially those requiring immune tolerance induction (ITI) for inhibitors. CVAD infection is one of the most frequently reported catheter-related complications in this patient population.

AIM

Detailed review of CVAD complications from the International ITI (I-ITI) study and analysis of potential risk factors for such complications.

METHODS

Retrospective analysis of prospectively obtained data from the I-ITI study primarily focused on CVAD-related complications.

RESULTS

A total of 115 children were recruited and 183 CVADs were placed in 99 subjects resulting in 121,206 CVAD-days observed on-study. A total of 124 CVAD infections were reported in 41 of 99 (41%) subjects with an overall infection rate of 0.94 per 1000 CVAD-days (interquartile ranges 0-1.7). A similar number of infections were observed in the two treatment arms (median: 2 and 3 in high dose and low dose respectively). Infections occurred more frequently in the presence of external catheters than with fully implanted catheters (P = 0.026). Infected patients were significantly younger at the time of CVAD insertion (median age: 22 vs. 25 months, P = 0.020). Patients with Gram-positive infections were also significantly younger than those with Gram-negative infections (median age: 17 vs. 25 months, P < 0.0001).

CONCLUSION

CVAD infection was the most common complication observed in children with severe haemophilia and inhibitors in the frame of the I-ITI study. Younger age at CVAD insertion and external CVAD were associated with higher risk for infection. ITI outcome was unaffected by CVAD infections.

Treatment trends for haemophilia A and haemophilia B in the United States: results from the 2010 practice patterns survey

Frequent evaluation of haemophilia treatment is necessary to improve patient care. The 2010 Practice Patterns Survey (PPS) investigated current trends in haemophilia treatment in the United States, as reported by nurses. The aim was to document practice patterns for haemophilia A and haemophilia B Survey questionnaires were sent to nurses at haemophilia treatment centres (HTCs) across the United States. Seventy-one of 126 HTCs (56%) responded to the survey. Factor dosage across treatment modalities ranged from 20 to 50 IU kg(-1) for severe haemophilia A. Dosage for severe haemophilia B was more variable (<40 to >100 IU kg(-1)). On-demand dosing regimens were inconsistent for haemophilia A and more so for haemophilia B. Rates of adherence to prescribed treatment were similar for both haemophilia types (∼80%). The main barrier to adherence was identified as inconvenience. More bleeding episodes occurred in adults (16.6 bleeding episodes per year) with severe haemophilia A than in younger patients (11.3 bleeding episodes per year) before switching patients to prophylaxis. For both haemophilia types, most patients who switched from prophylaxis to on-demand treatment were aged 13-24 years; these patients also had the lowest adherence (60-71%). More paediatric patients with severe haemophilia A and inhibitors (53%) received prophylactic bypassing therapy than their haemophilia B counterparts (38%). Adults with severe haemophilia A faced challenges in relation to co-morbidities and long-term care. This PPS provides insights into previously unexplored aspects of haemophilia care that will serve to increase awareness and promote discussion of current issues affecting haemophilia patient care.

Plasma derivatives: new products and new approaches

The infusion of plasma-derived or recombinant factors to treat bleeding disorders such as hemophilia A and B is a success story in the management of a chronic disease. The effectiveness of this approach is however limited by challenges with adverse effects of treatment. The most notable of these are the development of inhibitory antibodies that target the protein therapeutic. The current standard of care for management of hemophiliacs is prophylactic treatment that includes frequent infusions of a Factor VIII product. Failure to comply with the prophylactic regimen is a major hurdle in the management of these patients. We discuss here more recent findings that argue for a pharmacogenetic approach to understanding (and eventually circumventing) immunogenicity. We also review strategies used to bioengineer coagulation factors to extend the half-lives of coagulation proteins. The rapid progress in the last few years to bioengineer coagulation factors in different ways to attain this goal is described. Finally, novel technologies and potential products are emerging that utilize synthetic molecules in lieu of replacement proteins obviating the limitations associated with replacement therapies.

Clotting factor concentrates given to prevent bleeding and bleeding-related complications in people with hemophilia A or B

BACKGROUND

The hallmark of severe hemophilia is recurrent bleeding into joints and soft tissues with progressive joint damage, notwithstanding on-demand treatment. Prophylaxis has long been used but not universally adopted because of medical, psychosocial, and cost controversies.

OBJECTIVES

To determine the effectiveness of clotting factor concentrate prophylaxis in the management of people with hemophilia A or B.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Coagulopathies Trials Register. In addition, we searched major electronic databases (MEDLINE, EMBASE, CENTRAL), handsearched relevant journals and abstract books and reference lists of relevant articles.Last search of Group's Coagulopathies Trials Register: 07 April 2011.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials evaluating people with severe hemophilia A or hemophilia B receiving prophylactic clotting factor concentrates.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed studies for eligibility, assessed risk of bias and extracted data.

MAIN RESULTS

Six studies (including 142 participants) were eligible for inclusion. Two compared three-times-a-week prophylactic administration with on-demand treatment in children with hemophilia. Pooled results from these two studies showed a rate ratio of 0.30 (95% confidence interval; 0.12 to 0.76) for all bleedings and 0.22 (95% confidence interval 0.08 to 0.63) for joint bleedings favouring prophylaxis. Results on the number of patients with preserved joints after three to seven years of follow-up were not pooled due to significant heterogeneity. Three of the remaining four studies evaluated hemophilia A; one showed a statistically significant decrease in frequency of joint bleeds with prophylaxis compared to placebo, with a rate difference of -10.73 (95% confidence interval -16.55 to -4.91) bleeds per year. Two studies compared two prophylaxis regimens, failing to demonstrate an advantage of one regimen over the other in terms of bleeding frequency. The fourth study evaluated hemophilia B and showed fewer joint bleeds with weekly (15 IU/kg) versus bi-weekly (7.5 IU/kg) prophylaxis, rate difference -3.30 (95% confidence interval -5.50 to -1.10) bleeds per year. Non-significant increases in both inhibitor and infectious complications were observed in patients on prophylaxis, which occurred more often when using long-term venous access.

AUTHORS' CONCLUSIONS

There is strong evidence from randomised controlled trials and observational trials that prophylaxis preserves joint function in children with hemophilia as compared to on-demand treatment. There is insufficient evidence from randomised controlled trials to confirm the observational evidence that prophylaxis decreases bleeding and related complications in patients with existing joint damage. Well-designed randomised controlled trials and prospective observational controlled studies are needed to establish the best prophylactic regimen and to assess the effectiveness of prophylactic clotting factor concentrates in adult patients.

Side-effects and venous access issues with immune tolerance therapy

Immune tolerance therapy (ITT) is the most effective approach to eradicate inhibitors in patients with haemophilia who develop high-titre inhibitors. Yet ITT is associated with many adverse side-effects. Rarely, adverse side-effects arise from the various factor concentrates that patients on ITT receive or from adjuvant immunosuppressive agents used during ITT. Most adverse side-effects of ITT are related to the need for frequent and repetitive venous access, which often results in the need for central venous access devices (CVAD). These devices greatly facilitate the ability to give repeated doses of factor concentrates to patients and are particularly useful in young children who often have small and poorly functioning peripheral veins. These devices can become infected, can malfunction or can lead to venous thrombosis. These complications, although rarely causing mortality, may lead to significant morbidity including the need to have the devices removed and new ones inserted. As well, such CVAD complications may lead to reduced effectiveness of ITT through interruptions in ITT.

Central venous access devices for paediatric patients with haemophilia: a single-institution experience

Use of a central venous access device (CVAD) can facilitate early introduction of home-based infusion of factor concentrate for long-term prophylaxis or immune tolerance therapy in children with bleeding disorders. The aim was to review outcomes associated with use of CVAD. Retrospective review of paediatric patients with bleeding disorders was observed at the Mayo Clinic Comprehensive Hemophilia Center. Thirty-seven CVAD were placed in 18 patients (haemophilia A [n = 15], type 3 von Willebrand disease [n = 2] and haemophilia B [n = 1]). Follow-up was for 45 952 CVAD days, and median time that CVAD remained in place was 1361 days per device. Factor VIII (FVIII) inhibitors were present in 4 of the 15 patients. Ten CVAD-related infections occurred (median, 672 days; range, 72-1941 days), of which six were in one patient with FVIII inhibitors. Overall infection rate was 0.22 (95% confidence interval [CI], 0.10-0.40) per 1000 CVAD days, with 0.11 infections in patients without FVIII inhibitors compared with a pooled incidence of 0.66 (95% CI, 0.44-0.97) reported in the literature. Indications for removal of 27 CVAD were blockage, change to peripheral venous access, catheter displacement, infection, leak in the port septum, short catheter and skin erosion. No clinically apparent thrombosis or sequelae of thrombosis were observed. Infection is the most common complication associated with CVAD use and is increased in patients who have inhibitors. The low rate of clinically apparent thrombosis reflects our practice of not screening for thrombosis. The low infection rate reflects our practice of using and reinforcing the aseptic technique.