Setting the stage for individualized therapy in hemophilia: What role can pharmacokinetics play?

Emerging Therapies in Hemophilia: Improving Equitable Access to Care

In recent years, gene therapy and bio-engineered hemostatic molecules have revolutionized treatment for people with hemophilia. These innovative therapies aim to decrease treatment burden and improve patient quality of life. Additional novel therapies, including next-generation mimetics and agents that rebalance hemostasis, are currently being evaluated in clinical trials. Technological advances such as point-of-care musculoskeletal ultrasound and artificial intelligence may improve patient diagnostic and treatment outcomes. However, for the majority of patients with hemophilia worldwide, diagnosis and effective treatment are inaccessible. Achieving health equity for all hemophilia patients requires improved identification of barriers to optimal care, including socioeconomic status, race/ethnicity, gender, disease severity, inhibitor status, age, and use of Hemophilia Treatment Centers. Access to novel hemophilia therapies should be ensured for all patients. Approaches to improving equity include a decision-making partnership between the patient and clinician, stakeholder engagement, and pharmaceutical industry support. The development of novel hemophilia therapies should be leveraged with a patient-centered care approach to improve health equity for all patients.

Advances in biopharmaceutical products for hemophilia

Hemophilia is caused by the deficiency of clotting factors due to a single genetic abnormality. Replacement therapies have evolved from plasma-derived to recombinant coagulation factor concentrates but continue to have certain limitations. Monoclonal antibodies are clinical prophylactic treatment options unaffected by inhibitors and have better compliance than coagulation factor concentrates for patients with hemophilia. Gene therapy is a breakthrough in hemophilia treatment, as it drives the hepatic expression of factor VIII or factor IX and requires only a single administration to enable long-term replacement treatment in adult patients. Furthermore, biopharmaceutical products that target new pathways unaffected by inhibitors, including tissue factor pathway inhibitors, activated protein C, and antithrombin, as well as pharmaceutical technology advances to reduce dosing frequency, have demonstrated promising clinical results. This review provides a comprehensive overview of these biopharmaceutical products and explores the future of hemophilia treatment.

Pharmacokinetic model-based assessment of factor IX prophylaxis treatment regimens in severe hemophilia B

An important aspect of improving care for people with hemophilia B (HB) is developing optimal treatment strategies. Here we aimed to provide in-silico evidence, comparing the estimated optimal posology of factor IX (FIX) products to support the patient-physician decision-making process. A population pharmacokinetic (popPK) model-based assessment comparing the performance of FIX products (rFIX, rIX-FP, rFIXFc, N9-GP) was developed. PopPK analyses were used to determine a product's optimal posology to target predefined steady-state FIX activity trough levels in a hypothetical population of 10,000 people with severe HB. Model-derived optimal posologies were compared across several parameters including trough levels, proportion of patients per regimen and consumption, considering 64 hypothetical patient scenarios of different FIX trough level targets and ages. Results indicated a marked difference between FIX products estimated to achieve target trough levels, consumption and dosing frequencies. rIX-FP was associated with higher trough levels than rFIX and rFIXFc, at a lower weekly dose and administration frequency, across all age groups. N9-GP use in adolescents and adults was associated with lower consumption compared with rIX-FP. Insights from this study may be utilized by clinicians to inform decision-making, by considering the model-generated estimated optimal posologies alongside multiple clinical factors and patient preferences.

Shifting Paradigms and Arising Concerns in Severe Hemophilia A Treatment

The management of hemophilia A has undergone a remarkable revolution, in line with technological advancement. In the recent past, the primary concern associated with Factor VIII (FVIII) concentrates was the risk of infections, which is now almost resolved by advanced blood screening and viral inactivation methods. Improving patients' compliance with prophylaxis has become a key focus, as it can lead to improved health outcomes and reduced health care costs in the long term. Recent bioengineering research is directed toward prolonging the recombinant FVIII (rFVIII) coagulant activity and synthesising higher FVIII yields. As an outcome, B-domain deleted, polyethylene glycolated, single-chain, Fc-fused rFVIII, and rFVIIIFc-von Willebrand Factor-XTEN are available for patients. Moreover, emicizumab, a bispecific antibody, is commercially available, whereas fitusiran and tissue factor pathway inhibitor are in clinical trial stages as alternative strategies for patients with inhibitors. With these advancements, noninfectious complications, such as inhibitor development, allergic reactions, and thrombosis, are emerging concerns requiring careful management. In addition, the recent approval of gene therapy is a major milestone toward a permanent cure for hemophilia A. The vast array of treatment options at our disposal today empowers patients and providers alike, to tailor therapeutic regimens to the unique needs of each individual. Despite significant progress in modern treatment options, these highly effective therapies are markedly more expensive than conventional replacement therapy, limiting their access for patients in developing countries.

The value-based healthcare approach to haemophilia: Development of outcome measures for the evaluation of care of people with haemophilia

INTRODUCTION

Considering the advances in haemophilia management and treatment observed in the last decades, a new set of value-based outcome indicators is needed to assess the quality of care and the impact of these medical innovations.

AIM

The Value-Based Healthcare in Haemophilia project aimed to define a set of clinical outcome indicators (COIs) and patient-reported outcome indicators (PROIs) to assess quality of care in haemophilia in high-income countries with a value-based approach to inform and guide the decision-making process.

METHODS

A Value-based healthcare approach based on the available literature, current guidelines and the involvement of a multidisciplinary group of experts was applied to generate a set of indicators to assess the quality of care of haemophilia.

RESULTS

A final list of three COIs and five PROIs was created and validated. The identified COIs focus on two domains: musculoskeletal health and function, and safety. The identified PROIs cover five domains: bleeding frequency, pain, mobility and physical activities, Health-Related Quality of Life and satisfaction. Finally, two composite outcomes, one based on COIs, and one based on PROIs, were proposed as synthetic outcome indicators of quality of care.

CONCLUSION

The presented standard set of health outcome indicators provides the basis for harmonised longitudinal and cross-sectional monitoring and comparison. The implementation of this value-based approach would enable a more robust assessment of quality of care in haemophilia, within a framework of continuous treatment improvements with potential added value for patients. Moreover, proposed COIs and PROIs should be reviewed and updated routinely.

The road to implementation of pharmacokinetic-guided dosing of factor replacement therapy in hemophilia and allied bleeding disorders. Identifying knowledge gaps by mapping barriers and facilitators

Clinical guidelines and expert groups recommend the use of pharmacokinetic (PK)-guided dosing of factor replacement therapy for the treatment of bleeding disorders, especially for patients with hemophilia. Although PK-guided dosing is increasingly applied, it is generally not considered standard clinical practice. The aim of this scoping review is to map barriers and facilitators for the implementation of PK-guided dosing in clinical practice and to identify knowledge gaps. A literature search was performed and 110 articles were included that describe PK-guided dosing in patients with bleeding disorders, mostly hemophilia A. We defined two overarching themes, efficacy and feasibility, and discuss five topics within each theme. For each topic, barriers, facilitators and knowledge gaps were described. Although consensus was found with regard to some topics, contradicting reports were found for others, especially with respect to the efficacy of PK-guided dosing. These contradictions highlight the need for future research to elucidate current ambiguities.

Relationship between factor VIII levels and bleeding for rFVIII-SingleChain in severe hemophilia A: A repeated time-to-event analysis

Publications on the exposure-effect relationships of factor concentrates for hemophilia treatment are limited, whereas such analyses give insight on treatment efficacy. Our objective was to examine the relationship between the dose, factor VIII (FVIII) levels and bleeding for rFVIII-SingleChain (lonoctocog alfa, Afstyla). Data from persons with severe hemophilia A on rFVIII-SingleChain prophylaxis from three clinical trials were combined. The published rFVIII-SingleChain population pharmacokinetic (PK) model was evaluated and expanded. The probability of bleeding was described with a parametric repeated time-to-event (RTTE) model. Data included 2080 bleeds, 2545 chromogenic stage assay, and 3052 one-stage assay FVIII levels from 241 persons (median age 19 years) followed for median 1090 days. The majority of the bleeds occurred in joints (65%) and the main bleeding reason was trauma (44%). The probability of bleeding decreased during follow-up and a FVIII level of 8.9 IU/dL (95% confidence interval: 6.9-10.9) decreased the bleeding hazard by 50% compared to a situation without FVIII in plasma. Variability in bleeding hazard between persons with similar FVIII levels was large, and the pre-study annual bleeding rate explained part of this variability. When a FVIII trough level of 1 or 3 IU/dL is targeted during prophylaxis, simulations predicted two (90% prediction interval [PI]: 0-17) or one (90% PI: 0-11) bleeds per year, respectively. In conclusion, the developed PK-RTTE model adequately described the relationship between dose, FVIII levels and bleeds for rFVIII-SingleChain. The obtained estimates were in agreement with those published for the FVIII concentrates BAY 81-8973 (octocog alfa) and BAY 94-9027 (damoctocog alfa pegol), indicating similar efficacy to reduce bleeding.

Current Understanding of Inherited Modifiers of FVIII Pharmacokinetic Variation

The inherited bleeding disorder hemophilia A involves the quantitative deficiency of the coagulation cofactor factor VIII (FVIII). Prophylactic treatment of severe hemophilia A patients with FVIII concentrates aims to reduce the frequency of spontaneous joint bleeding and requires personalized tailoring of dosing regimens to account for the substantial inter-individual variability of FVIII pharmacokinetics. The strong reproducibility of FVIII pharmacokinetic (PK) metrics between repeat analyses in the same individual suggests this trait is genetically regulated. While the influence of plasma von Willebrand factor antigen (VWF:Ag) levels, ABO blood group, and patient age on FVIII PK is well established, estimates suggest these factors account for less than 35% of the overall variability in FVIII PK. More recent studies have identified genetic determinants that modify FVIII clearance or half-life including VWF gene variants that impair VWF-FVIII binding resulting in the accelerated clearance of VWF-free FVIII. Additionally, variants in receptors that regulate the clearance of FVIII or the VWF-FVIII complex have been associated with FVIII PK. The characterization of genetic modifiers of FVIII PK will provide mechanistic insight into a subject of clinical significance and support the development of personalized treatment plans for patients with hemophilia A.

Area under the curve: Comparing the value of factor VIII replacement therapies in haemophilia A

INTRODUCTION

In factor VIII (FVIII) prophylaxis for haemophilia A, cost comparisons have used price per international unit (IU) based on the once reasonable assumption of equivalent outcome per IU. Now, with several extended half-life (EHL) products available, new outcome-oriented ways to compare products are needed. Area under the curve (AUC) quantifies FVIII levels over time after infusion providing comparable data.

AIM

To develop a decision analytical model for making indirect comparisons of FVIII replacement products based on AUC.

METHODS

A literature search identified 11 crossover studies with relevant pharmacokinetic data. A common comparator FVIII level curve was calculated using pooled data from selected studies. Absolute curves for other products were estimated based on relative differences to the common comparator (% difference vs the anchor). Three scenarios were investigated: (1) Kogenate^® versus Kovaltry^® and Jivi^® ; (2) Advate^® versus Elocta^® , NovoEight^® , Kovaltry, Adynovate^® , Afstyla^® , and ReFacto^® ; and (3) Jivi versus Elocta, Adynovate, and Kogenate. Sensitivity analyses investigated effects of assay type and dose.

RESULTS

In scenario 1, Jivi (+50%) and Kovaltry (+14%) showed larger AUCs versus Kogenate. In scenario 2, EHL products, Elocta and Adynovate, had the largest AUC (+64% and +58%, respectively) versus Advate. Compared with all other products in scenario 3, Jivi had the largest AUC by +13%-28%.

CONCLUSION

This analysis concludes that EHL products differ in relative AUC, have a larger AUC compared with standard half-life, and thus, different FVIII levels over time after infusion. This model may aid decision makers in the absence of head-to-head data.

The Impact of Pharmacokinetic-Guided Prophylaxis on Clinical Outcomes and Healthcare Resource Utilization in Hemophilia A Patients: Real-World Evidence from the CHESS II Study

Background

Using a pharmacokinetic (PK)-guided approach to personalize the dose and frequency of prophylactic treatment can help achieve and maintain targeted factor VIII (FVIII) trough levels in patients with hemophilia A.

Objective

Investigate clinical and healthcare resource use outcomes in patients with hemophilia A treated with or without PK-guided prophylaxis using data from the Cost of Haemophilia in Europe: A Socioeconomic Survey (CHESS) II database.

Methods

CHESS II was a cross-sectional, retrospective, burden-of-illness study incorporating data from eight European countries. Patients were eligible for this analysis if they were male, ≥18 years of age, and diagnosed with congenital hemophilia A of any severity. The clinical endpoints included annualized bleeding rate (ABR), presence and number of problem/target joints, and occurrence of joint surgeries. Healthcare resource utilization endpoints included the number of hematologist consultations and bleed-related hospitalizations or emergency department admissions. Data from November 2018 to October 2020 were included and were stratified according to treatment regimen and use of PK-guided dosing.

Results

Altogether, 281 patients on prophylaxis had available FVIII trough level data. Mean (SD) age was 35.7 (13.8) years. A specific FVIII trough level was targeted in 120 (42.7%) patients and 47 (39.2%) received PK-guided dosing. Patients receiving PK-guided dosing had a mean (SD) ABR of 2.8 (2.1) and target joint number of 0.5 (0.7), compared with 3.9 (2.7) and 0.9 (1.4), respectively, for patients receiving non-PK-guided treatment. The mean (SD) number of hematologist consultations was 7.1 (5.3) for patients receiving PK-guided dosing versus 10.7 (5.7) for those who were not. A higher proportion of patients in the non-PK-guided group required hospitalization during their lifetime compared with the PK-guided group.

Conclusion

This analysis of real-world data suggests that PK-guided dosing for prophylaxis has a beneficial impact on clinical and healthcare resource utilization outcomes in patients with hemophilia A.

Treatment Individualization Using Pharmacokinetic Studies and Joint Ultrasound Imaging in Pediatric Patients With Hemophilia

Hemophilia is characterized by bleeding diathesis, primarily affecting the joints. Prophylactic use of missing factor aims at limiting the number of bleeds and, in the long term, the risk of permanent joint damage. However, standard prophylactic regimens are usually applied empirically, not adjusting for variations in bleeding phenotype or drug metabolism. Aim of the present study was to evaluate the need for individualizing prophylaxis, with guidance of pharmacokinetic (PK) studies and joint ultrasound in a setting of everyday clinical practice. To evaluate adequacy of applied regimens, joint status was assessed using the Hemophilia Joint Health Score as well as ultrasound imaging, while PK studies were performed using the Web-Accessible Population Pharmacokinetic Service-Hemophilia. Imaging results were consistent with early joint damage in a large proportion of pediatric patients, whereas PK measures were indicative of inadequate prophylaxis in many cases-despite the limited number of bleeds reported by patients. The study revealed the need for prophylaxis adjustment in the majority of patients. Real world data confirm that traditional prophylaxis is often unable to achieve therapeutic goals, while an individualized approach, guided by the use of novel modalities, may be of great benefit to young hemophilia patients.

SYMPHONY consortium: Orchestrating personalized treatment for patients with bleeding disorders

BACKGROUND

Treatment choices for individual patients with an inborn bleeding disorder are increasingly challenging due to increasing options and rising costs for society. We have initiated an integrated interdisciplinary national research programme.

OBJECTIVES

The SYMPHONY consortium strives to orchestrate personalized treatment in patients with an inborn bleeding disorder, by unravelling the mechanisms behind inter-individual variations of bleeding phenotype.

PATIENTS

The SYMPHONY consortium will investigate patients with an inborn bleeding disorder, both diagnosed and not yet diagnosed.

RESULTS

Research questions are categorized under the themes: 1) Diagnosis; 2) Treatment; and 3) Fundamental research and consist of workpackages addressing specific domains. Importantly, collaborations between patients and talented researchers from different areas of expertise promise to augment the impact of the SYMPHONY consortium, leading to unique interactions and intellectual property.

CONCLUSIONS

SYMPHONY will perform research on all aspects of care, treatment individualization in patients with inborn bleeding disorders as well as diagnostic innovations and results of molecular genetics and cellular model technology with regard to the hemostatic process. We believe that these research investments will lead to health care innovations with long-term clinical and societal impact. This consortium has been made possible by a governmental, competitive grant from the Netherlands Organization for Scientific Research (NWO) within the framework of the NWA-ORC Call grant agreement NWA.1160.18.038.

Pharmacokinetic profile of children with haemophilia A receiving low-dose FVIII prophylaxis in Indonesia: A single centre experience

BACKGROUND

Pharmacokinetic (PK) studies of low-dose prophylaxis (LDP) of coagulation factor VIII (FVIII) in children with severe haemophilia A (SHA) are scarce.

OBJECTIVE

This study aims to investigate the PK profile of children with SHA receiving LDP of FVIII.

METHODS

Paediatric patients receiving FVIII infusions (10 IU/kg twice weekly) were included. PK profiles were estimated using the Web Accessible Population Pharmacokinetic Service for Haemophilia (WAPPS-Haemo). The primary outcomes were the terminal half-life (t_1/2 ), concentration-time profile, and time to reach an FVIII level of < 1%. The secondary outcome was the suggested dosing interval of FVIII prophylaxis based on the individual PK profile.

RESULTS

Twenty-five patients were recruited; their mean age was 12.3 ± 3.0 years. The t_1/2 differed among patients receiving LDP of FVIII twice weekly, with a median of t_1/2 was 14.8 h (IQR 12.6-16). The median time to reach an FVIII level of < 1% was 73.8 h (IQR 58.8-80.3). Most patients could maintain a trough level of FVIII > 1% longer than 48 h. At 72-96 h, patients needed a second dose of FVIII infusion because the FVIII level was < 1%. The suggested dosing interval of FVIII prophylaxis ranged from daily to every 96 h, depending on the individual PK profile.

CONCLUSION

Our study identified inter-individual differences in the PK parameters using LDP of FVIII twice weekly. The inter-individual results in different dosing intervals advise the timing of LDP. Estimating individual PK parameters enables the identification of the optimal prophylaxis frequency to prevent bleedings.

Does difference between label and actual potency of factor VIII concentrate affect pharmacokinetic‐guided dosing of replacement therapy in haemophilia A?

Background

Aim

Methods

Results

Conclusion

Estimating the risk of thrombotic events in people with congenital hemophilia A using US claims data

Aim: Compare thrombotic risk in people with congenital hemophilia A (PwcHA) to the general non-hemophilia A (HA) population. Patients & methods: US claims databases were analyzed to identify PwcHA. Incidence rates of myocardial infarction, pulmonary embolism, ischemic stroke, deep vein thrombosis and device-related thrombosis were compared with a matched cohort without HA. Results: Over 3490 PwcHA were identified and 16,380 individuals matched. PwcHA had a similar incidence of myocardial infarction and pulmonary embolism compared with the non-HA population, but a slightly higher incidence of ischemic stroke and deep vein thrombosis. The incidence of device-related thrombosis was significantly higher in PwcHA. Conclusion: This analysis suggests that PwcHA are not protected against thrombosis, and provides context to evaluate thrombotic risk of HA treatments.

Patient-centered approach to managing factor XIII deficiency

Factor XIII (FXIII) is a thrombin-activated protransglutaminase that plays a key role in blood clot formation. Congenital FXIII A-subunit deficiency represents a rare bleeding disorder that affects one in 2-3 million individuals worldwide and is treated with recombinant FXIII (rFXIII). However, due to the rarity of the disease, clinicians are often left to weigh individual variation in FXIII activity and/or symptoms to optimally guide dosing. Cases often become further complicated when patients experience refractory bleeding, which can be difficult to treat. This report describes an approach to rFXIII dosing in two patients who required deviation from standard protocols to maintain therapeutic FXIII troughs. We highlight limitations in our understanding of FXIII deficiency management, while also providing an example of the application of pharmacokinetic data to individualise therapy for improved outcomes. Finally, the case reminds us of the importance of patient-centered, cost-conscious care and multidisplinary teamwork in complex cases.

Significant reduction in hemarthrosis in boys with severe hemophilia A: The China hemophilia individualized low-dose secondary prophylaxis study

INTRODUCTION

In countries with restricted access to clotting factor concentrates, early implementation of low-dose prophylaxis is recommended over episodic treatment.

OBJECTIVE

The objective of this 1-year prospective secondary prophylaxis study was to evaluate the efficacy of a dose/frequency escalating protocol in young boys with hemophilia A in China.

METHODS

Boys were started on a low-dose protocol (minimum 10-15 IU/kg of factor VIII [FVIII] twice weekly). Escalation was based on index joint bleeding, swelling/persistent joint swelling, and serial ultrasound (gray scale and color Doppler) examinations of index joints.

RESULTS

Thirty-three boys, median age 4.8 years (interquartile range, 3.8-6.1) were enrolled in a 3-month observation period that preceded a 1-year prophylaxis phase. A significant reduction in total bleeding events (43.0%, P = .001), index joint bleeds (53.2%, P = .002), and target index joint bleeds (70.0%, P = 0.02) was observed during the prophylaxis phase. During the prophylaxis period, 40% of target joints resolved. The percentage of boys with zero index joint bleeds increased significantly (P = .004) from 51.5% during the observation phase to 81.8% in last quarter of the prophylaxis phase (months 10-12). There was no progression of arthropathy based on physical examination (Hemophilia Joint Health Score), X-ray, and ultrasound obtained at entry into the prophylaxis phase and at study exit. The median FVIII consumption over the prophylaxis phase was 1786 IU/kg/y.

CONCLUSION

A low-dose, individualized prophylaxis protocol, guided by individual bleeding profiles and serial assessment of joint status, enables escalation of treatment intensity in boys with severe hemophilia A, leading to a significant reduction in bleeding events and reduction in target joint bleeding.

Perioperative pharmacokinetic-guided factor VIII concentrate dosing in haemophilia (OPTI-CLOT trial): an open-label, multicentre, randomised, controlled trial

BACKGROUND

Dosing of replacement therapy with factor VIII concentrate in patients with haemophilia A in the perioperative setting is challenging. Underdosing and overdosing of factor VIII concentrate should be avoided to minimise risk of perioperative bleeding and treatment costs. We hypothesised that dosing of factor VIII concentrate on the basis of a patient's pharmacokinetic profile instead of bodyweight, which is standard treatment, would reduce factor VIII consumption and improve the accuracy of attained factor VIII levels.

METHODS

In this open-label, multicentre, randomised, controlled trial (OPTI-CLOT), patients were recruited from nine centres in Rotterdam, Groningen, Utrecht, Nijmegen, The Hague, Leiden, Amsterdam, Eindhoven, and Maastricht in The Netherlands. Eligible patients were aged 12 years or older with severe or moderate haemophilia A (severe haemophilia was defined as factor VIII concentrations of <0·01 IU/mL, and moderate haemophilia as 0·01-0·05 IU/mL), without factor VIII inhibitors, and planned for elective low or medium risk surgery as defined by surgical risk score. Patients were randomly assigned (1:1) using a web-based randomisation system and treatment minimisation, stratified by method of administration of factor VIII concentrate (continuous infusion vs bolus administration) and risk level of surgery (low and medium risk surgery), to the pharmacokinetic-guided or standard treatment group. The primary endpoint was total amount of infused factor VIII concentrate (IU per kg bodyweight) during perioperative period (from day of surgery up to 14 days after surgery). Analysis was by intention to treat and the safety analysis population comprised all participants who underwent surgery with factor VIII concentrate. This study is registered with the Netherlands Trial Registry, NL3955, and is now closed to accrual.

FINDINGS

Between May 1, 2014, and March 1, 2020, 98 patients were assessed for eligibility and 66 were enrolled in the trial and randomly assigned to the pharmacokinetic-guided treatment group (34 [52%]) or the standard treatment group (32 [48%]). Median age was 49·1 years (IQR 35·0 to 62·1) and all participants were male. No difference was seen in consumption of factor VIII concentrate during the perioperative period between groups (mean consumption of 365 IU/kg [SD 202] in pharmacokinetic-guided treatment group vs 379 IU/kg [202] in standard treatment group; adjusted difference -6 IU/kg [95% CI -88 to 100]). Postoperative bleeding occurred in six (18%) of 34 patients in the pharmacokinetic-guided treatment group and three (9%) of 32 in the standard treatment group. One grade 4 postoperative bleeding event occurred, which was in one (3%) patient in the standard treatment group. No treatment-related deaths occurred.

INTERPRETATION

Although perioperative pharmacokinetic-guided dosing is safe, it leads to similar perioperative factor VIII consumption when compared with standard treatment. However, pharmacokinetic-guided dosing showed an improvement in obtaining factor VIII concentrations within the desired perioperative factor VIII range. These findings provide support to further investigation of pharmacokinetic-guided dosing in perioperative haemophilia care.

FUNDING

Dutch Research Council (NWO)-ZonMw and Takeda.

Variability of treatment modalities and intensity in patients with severe haemophilia A on prophylaxis: Results from the Italian national registry

BACKGROUND

A shift from a standard to a personalized prophylaxis has been increasingly adopted in patients with severe haemophilia A (SHA). This approach has raised the likelihood of a significant variability in the prophylactic approaches and the relative Factor VIII (FVIII) consumptions. The aim of our study was to assess the treatment variability of SHA patients without inhibitors and on prophylaxis regimen in Italy.

MATERIAL AND METHODS

Data reported in the National Registry of Congenital Coagulopathies (NRCC) were analysed to assess treatment distribution within SHA patients without inhibitors, focussing on FVIII consumption in 2017, associated with prophylaxis regimen. The analysis was stratified based on age groups and Italian regions to describe the variability of FVIII consumption in Italy.

RESULTS

In 2017, the Registry reported the therapeutic plans of 1068 SHA patients without inhibitors on prophylaxis. The mean (95% CI) individual consumption ranges from 123 127 IU (99 736-146 518) in the age group 0-6 years to 345 000 IU (336 000-354 000) in the age group >20 years. A significant FVIII consumption variability was identified within the adult population. Regions with less than 50 patients reported the higher variability in mean FVIII consumption per patient-year within the different age groups. Similar difference in FVIII consumption variability was reported also in the age groups comparing "low," "middle" and "high" patient volume regions.

DISCUSSION

A reliable estimation of FVIII consumption for patients' treatment is necessary to manage and plan the appropriate budget and keep treatment's costs affordable. However, without the implementation of a methodology aiming to assess the overall value produced by these FVIII consumptions, the scenario will keep driven by FVIII consumptions, its costs and the budget available. An effort by haemophilic community, haemophilia treatment centres and institutions is required to develop and share this cultural shift in improving haemophilia management and assessment.

Optimising prophylaxis in haemophilia A: The ups and downs of treatment

The classical goals of haemophilia A treatment are to prevent bleeds, minimise the risk of long-term complications associated with joint damage, and improve quality of life by maintaining appropriate factor VIII [FVIII] levels. The dose and frequency of FVIII replacement therapies required to reduce bleeds is now known to vary amongst individuals, and may change for the same individual over time, meaning that a standardised dose and regimen may not provide optimal protection to all patients. Here we review the evolving treatment landscape for haemophilia A, and discuss how an increased understanding of the pharmacology and pharmacokinetics underlying FVIII replacement and non-factor replacement therapies could improve patient outcomes. We also review the strengths and weaknesses of current treatments and explore the benefits of personalised therapy and review how this may best be achieved with current treatment options. The key points of our review are summarised in this accompanying short video.

Perspective - The case for zero bleeds and drug bioequivalence in the treatment of congenital hemophilia A in 2021

Not all patients with severe hemophilia A (HA) respond optimally to a given dose of a given product. Within-individual variance in cross-over studies makes each patient unique in the response to each standard half-life (SHL) factor VIII (FVIII) product in pharmacokinetic (PK) terms. This hampers the prediction of efficacy when a SHL FVIII product is employed. PK data showing that half-lives of SHL rFVIII are unsatisfactory to achieve zero bleeding in individual HA patients provide the rationale for switching from SHL to extended half-life (EHL) products. However, not all subjects receiving prophylaxis with EHL products achieve zero bleeding, the most cogent objective of personalized prophylaxis. Known determinants of FVIII half-life (age, von Willebrand factor [VWF] levels, blood group) cumulatively account for one third of the total inter-individual variation in FVIII clearance in subjects with severe HA. Investigations into precision, and accuracy of laboratory measurement to be employed; newer pathways for the clearance of both free-FVIII and VWF-bound FVIII, and adequately powered studies on omics and phenotypic heterogeneity, are likely to provide additional information on the remaining two thirds of inter-individual variation in FVIII clearance in HA. Variability in the clinical response has also been documented in patients when FVIII activity is mimicked by fixed subcutaneous doses of the bispecific antibody emicizumab. National registries that collect PK data of available FVIII products and ad hoc information on the individual response to emicizumab should be encouraged, to establish newer standards of care and ease personalized clinical decisions to achieve zero bleeding.

Factor VIII pharmacokinetics associates with genetic modifiers of VWF and FVIII clearance in an adult hemophilia A population

BACKGROUND

Factor VIII (FVIII) pharmacokinetics (PK) in adult hemophilia A populations are highly variable and have been previously determined to be influenced by von Willebrand factor:antigen (VWF:Ag), ABO blood group, and age. However, additional genetic determinants of FVIII PK are largely unknown.

OBJECTIVES

The contribution of VWF clearance, VWF-FVIII-binding activity, and genetic variants in VWF clearance receptors to FVIII PK in adult patients were assessed.

METHODS

FVIII PK assessment was performed in 44 adult subjects (age 18-61 years) with moderate or severe hemophilia A. VWF:Ag, VWF propeptide (VWFpp), VWFpp/VWF:Ag, and VWF:FVIII binding activity were measured. The VWF modifying loci CLEC4M, SCARA5, STAB2, and ABO, and the D'D3 FVIII-binding region of the VWF gene were genotyped.

RESULTS

VWF:Ag, VWFpp, and VWF:FVIIIB positively correlated with FVIII half-life and negatively correlated with FVIII clearance. VWFpp/VWF:Ag negatively correlated with FVIII half-life and positively correlated with FVIII clearance. The correlation between VWFpp/VWF:Ag and FVIII half-life was stronger for type non-O patients than for type O patients, suggesting that slower VWF clearance increases FVIII half-life. Patients heterozygous for the CLEC4M rs868875 variant had increased FVIII clearance when compared with individuals homozygous for the reference allele. The CLEC4M variable number of tandem repeat (VNTR) alleles were also associated with the rate of FVIII clearance. When compared with the quartile of patients with the fastest FVIII clearance, the quartile of patients with the slowest FVIII clearance had a decreased frequency of the CLEC4M 5-VNTR.

CONCLUSIONS

VWF-FVIII binding activity and genetic determinants of VWF clearance are important contributors to FVIII pharmacokinetics in adult patients.

Extended half-life factor VIII concentrates in adults with hemophilia A: Comparative pharmacokinetics of two products

BACKGROUND

The use of pharmacokinetic (PK) studies to help design personalized prophylaxis regimens for factor VIII (FVIII) concentrate in individuals with hemophilia A has been recognized for many years but only became practical for routine clinical use with the availability of web-accessible population PK applications based on Bayesian analysis.

OBJECTIVE

To compare PK variables using population PK studies done on 2 extended half-life recombinant FVIII concentrates in 23 individuals with hemophilia A after switching from one product to the other.

METHODS

We retrospectively analyzed PK parameters derived from the Web-Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-HEMO) application on 23 individuals with severe or moderately severe hemophilia A who were required to switch from recombinant FVIII Fc (Eloctate; Biogen, Cambridge, MA, USA) to recombinant antihemophilic factor PEGylated (Adynovate; Takeda Pharmaceutical Company, Osaka, Japan) between 2016 and 2017.

RESULTS

There were minor PK differences between Eloctate and Adynovate, but some parameters did reach statistical significance, namely in vivo recovery (mean, 2.73 IU/dL per IU/kg vs 2.41 IU/dL per IU/kg), clearance (mean, 0.163 mL/h vs 0.194 mL/h), and volume of distribution at steady state (mean, 42.5 ml/kg vs 49.8 mL/kg). Smaller nonsignificant trends toward higher values for Adynovate were seen in terminal half-life, area under the curve, and predicted times to 5% and 1% residual FVIII after infusion.

CONCLUSION

Population PK analysis revealed differences between the two extended half-life FVIII concentrates, reaching significance for in vivo recovery, clearance, and volume of distribution.

A Practical, One-Clinic Visit Protocol for Pharmacokinetic Profile Generation with the ADVATE myPKFiT Dosing Tool in Severe Hemophilia A Subjects

Standard pharmacokinetic (PK) assessments are demanding for persons with hemophilia A, requiring a 72-hour washout and 5 to 11 timed blood samples. A no-washout, single-clinic visit, sparse sampling population PK (PPK) protocol is an attractive alternative. Here, we compared PK parameters obtained with a traditional washout, 6-sampling time point PPK protocol with a no-washout, single-clinic visit, reverse 2-sampling time point PPK protocol in persons with severe hemophilia A (SHA) receiving ADVATE. A total of 39 inhibitor-negative males with SHA (factor VIII activity [FVIII:C] < 2%) were enrolled in a prospective sequential design PK study. Participants completed a washout, 6-sampling time point PPK protocol as well as a no-washout, reverse 2-sampling time point protocol, with samples taken during a single 3-hour clinic visit 24 hours post home infusion of FVIII and then 3 hours post infusion in clinic. FVIII:C levels were analyzed by one-stage and chromogenic assays; blood group and von Willebrand factor antigen (VWF:Ag) were determined; and PK parameters were analyzed using the ADVATE myPKFiT dosing tool. There was moderate to almost perfect agreement for the PK parameters obtained with the 2- and the 6- point PPK protocols using a one-stage FVIII:C assay and a substantial to almost perfect agreement using a chromogenic FVIII:C assay. Significant associations between specific PK parameters and blood group and VWF:Ag were observed. The no-washout, single-clinic visit, reverse 2-sampling time point PPK protocol can be used in the routine clinical setting since it demonstrates sufficient accuracy compared with the more demanding and less practical washout, 6-sampling time point PPK protocol in persons with SHA receiving ADVATE.

Comparison of the Pharmacokinetic Properties of Extended Half-Life and Recombinant Factor VIII Concentrates by In Silico Simulations

BACKGROUND

 The pharmacokinetic (PK) properties of extended half-life (EHL) factor VIII (FVIII) concentrates differ, leading to variation in the optimal dosing regimen for the individual patient. The aim of this study was to establish these PK differences for various EHL FVIII concentrates by in silico simulations.

METHODS

 FVIII level over time profiles of rFVIII-SC, BAY 81-8973, rFVIII-Fc, BAX 855, BAY 94-9027, and standard half-life (SHL) rFVIII concentrates were simulated for 1,000 severe hemophilia A patients during steady-state dosing of 40 IU/kg every 72 hours or dosing as advised in the summary of product characteristics (SmPC).

RESULTS

 Although the elimination half-life values were comparable for rFVIII-FC, BAX 855, and BAY 94-9027, a higher area under the curve (AUC; 2,779 IU/h/dL) for BAY 94-9027 was obtained. During steady-state dosing of 40 IU/kg every 72 hours, 58.5% (rFVIII-SC), 69.3% (BAY 81-8972), 89.0% (rFVIII-Fc), 83.9% (BAX 855), and 93.7% (BAY 94-9027) of the patients maintained a trough level of 1 IU/dL, compared with 56.0% for SHL rFVIII. Following dosing schemes described in the SmPC, between 51.0 and 65.4% or 23.2 and 31.1% of the patients maintained a target trough level of 1 IU/dL or 3 IU/dL, respectively.

CONCLUSION

 BAY 94-9027 showed the largest increase of AUC and best target attainment compared with SHL rFVIII, followed closely by BAX 855 and rFVIII-Fc. BAY 81-8973 and rFVIII-SC showed smaller PK improvements. Although our analyses increase insight into the PK of these FVIII concentrates, more studies evaluating the relation between factor levels and bleeding risk are needed.

Population Pharmacokinetics of Clotting Factor Concentrates and Desmopressin in Hemophilia

Hemophilia A and B are bleeding disorders caused by a deficiency of clotting factor VIII and IX, respectively. Patients with severe hemophilia (< 0.01 IU mL⁻¹) and some patients with moderate hemophilia (0.01–0.05 IU mL⁻¹) administer clotting factor concentrates prophylactically. Desmopressin (d-amino d-arginine vasopressin) can be applied in patients with non-severe hemophilia A. The aim of administration of factor concentrates or desmopressin is the prevention or cessation of bleeding. Despite weight-based dosing, it has been demonstrated that factor concentrates still exhibit considerable pharmacokinetic variability. Population pharmacokinetic analyses, in which this variability is quantified and explained, are increasingly performed in hemophilia research. These analyses can assist in the identification of important patient characteristics and can be applied to perform patient-tailored dosing. This review aims to present and discuss the population pharmacokinetic analyses that have been conducted to develop population pharmacokinetic models describing factor levels after administration of factor VIII or factor IX concentrates or d-amino d-arginine vasopressin. In total, 33 publications were retrieved from the literature. Two approaches were applied to perform population pharmacokinetic analyses, the standard two-stage approach and non-linear mixed-effect modeling. Using the standard two-stage approach, four population pharmacokinetic models were established describing factor VIII levels. In the remaining 29 analyses, the non-linear mixed-effect modeling approach was applied. NONMEM was the preferred software to establish population pharmacokinetic models. In total, 18 population pharmacokinetic analyses were conducted on the basis of data from a single product. From all available population pharmacokinetic analyses, 27 studies also included data from pediatric patients. In the majority of the population pharmacokinetic models, the population pharmacokinetic parameters were allometrically scaled using actual body weight. In this review, the available methods used for constructing the models, key features of these models, patient population characteristics, and established covariate relationships are described in detail.

Common Genetic Variants in ABO and CLEC4M Modulate the Pharmacokinetics of Recombinant FVIII in Severe Hemophilia A Patients

The pharmacokinetic (PK) response of severe hemophilia A (HA) patients to infused factor VIII (FVIII) shows substantial variability. Several environmental and genetic factors are associated with changes in FVIII plasma levels and infused FVIII PK. Based on the hypothesis that factors influencing endogenous FVIII can affect FVIII PK, the contribution of single-nucleotide variants (SNVs) in candidate genes was investigated in 51 severe HA patients. The effects of blood group, F8 variant type, von Willebrand factor antigen and activity levels, age, and weight were also explored. The myPKFiT device was used to estimate individual PK parameters, and SNVs and clinically reportable F8 variants were simultaneously analyzed in an Illumina MiSeq instrument, using the microfluidics-based Fluidigm Access Array system. The contribution of SNVs to FVIII half-life and clearance was addressed by robust regression modeling, taking into account other modulators. In line with previous studies, we provide robust evidence that age, body weight, and blood group, as well as SNVs in ABO and CLEC4M, participate in the variability of FVIII PK in HA patients. Main results: each copy of the rs7853989 (ABO) allele increases FVIII half-life by 1.4 hours (p = 0.0131) and decreases clearance by 0.5 mL/h/kg (p = 5.57E-03), whereas each additional rs868875 (CLEC4M) allele reduces FVIII half-life by 1.1 hours (p = 2.90E-05) and increases clearance by 0.3 mL/h/kg (p = 1.01E-03). These results contribute to advancing efforts to improve FVIII replacement therapies by adjusting to each patient's PK profile based on pharmacogenomic data. This personalized medicine will decrease the burden of treatment and maximize the benefits obtained.

Biological mechanisms underlying inter-individual variation in factor VIII clearance in haemophilia

Previous studies have highlighted marked inter‐individual variations in factor VIII (FVIII) clearance between patients with haemophilia (PWH). The half‐life of infused FVIII has been reported to vary from as little as 5.3 hours in some adult PWH, up to as long as 28.8 hours in other individuals. These differences in clearance kinetics have been consistently observed using a number of different plasma‐derived and recombinant FVIII products. Furthermore, recent studies have demonstrated that half‐life for extended half‐life (EHL‐) FVIII products also demonstrates significant inter‐patient variation. Since time spent with FVIII trough levels <1% has been shown to be associated with increased bleeding risk in PWH on prophylaxis therapy, this variability in FVIII clearance clearly has major clinical significance. Recent studies have provided significant novel insights into the cellular basis underlying FVIII clearance pathways. In addition, accumulating data have shown that endogenous plasma VWF levels, ABO blood group and age, all play important roles in regulating FVIII half‐life in PWH. Indeed, multiple regression analysis suggests that together these factors account for approximately 34% of the total inter‐individual variation in FVIII clearance observed between subjects with severe haemophilia A. In this review, we consider these and other putative modulators of FVIII half‐life, and discuss the biological mechanisms through which these factors impact upon FVIII clearance in vivo.

Kreuth V initiative: European consensus proposals for treatment of hemophilia using standard products, extended half-life coagulation factor concentrates and non-replacement therapies

This report contains the updated consensus recommendations for optimal hemophilia care produced in 2019 by three Working Groups (WG) on behalf of the European Directorate for Quality of Medicines and Healthcare in the frame of the Kreuth V Initiative. WG1 recommended access to prophylaxis for all patients, the achievement of plasma factor trough levels of at least 3-5% when extended half-life factor VIII (FVIII) and FIX products are used, a personalized treatment regimen, and a choice of chromogenic assays for treatment monitoring. It was also emphasized that innovative therapies should be supervised by hemophilia comprehensive care centers. WG2 recommended mandatory collection of postmarketing data to assure the long-term safety and efficacy of new hemophilia therapies, the establishment of national patient registries including the core data recommended by the European Medicines Agency and the International Society on Thrombosis and Haemostasis, with adequate support under public control, and greater collaboration to facilitate a comprehensive data evaluation throughout Europe. WG3 discussed methodological aspects of hemophilia care in the context of access decisions, particularly for innovative therapies, and recommended that clinical studies should be designed to provide the quality of evidence needed by regulatory authorities, HTA bodies and healthcare providers. The dialogue between all stakeholders in hemophilia care and patient organizations should be fostered to implement these recommendations.

Pharmacokinetic-tailored approach to hemophilia prophylaxis: Medical decision making and outcomes

BACKGROUND

Clinical application of population pharmacokinetics (popPK) is of increasing interest to patients with hemophilia, providers, and payers. Routine use of popPK profiles in factor replacement prophylaxis decision making has the potential to maintain or improve efficacy and reduce product consumption.

AIM

To investigate the feasibility of implementation and longitudinal assessment of pharmacokinetic (PK)-tailored prophylaxis in routine clinical practice for hemophilia A and to describe factors that influence decision making for prescribed hemophilia prophylaxis.

METHODS

This longitudinal, multicenter, prospective feasibility study of children and adults with hemophilia A without inhibitors used the Web Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo) to generate PK profiles. Assessments over 12 weeks captured data on prescribed prophylaxis, popPK tool use, provider decision making, and patient-reported outcomes.

RESULTS

Eighteen participants aged 6 to 39 years enrolled; half used extended half-life concentrates. Patient interest in their PK centered on general curiosity followed by a desire for participation in physical activity and decrease in infusion frequency. Providers used the WAPPS clinical calculator feature to simulate prophylaxis regimens under different dose, infusion, and trough conditions. Most targeted troughs were 1 to 3 IU/dL. The feasibility assessment demonstrated challenges with patient recruitment; however, the majority of participants successfully completed study assessments meeting feasibility targets.

CONCLUSION

A larger-scale study powered to evaluate the impact of PK-tailored prophylaxis on clinical and patient-reported outcomes is feasible with study design modifications to support increased recruitment rate. Shared decision making incorporating patient and provider goals is important and facilitated by regimen simulations with the clinical calculator.

Genetic determinants of VWF clearance and FVIII binding modify FVIII pharmacokinetics in pediatric hemophilia A patients

Factor VIII (FVIII) pharmacokinetic (PK) properties show high interpatient variability in hemophilia A patients. Although previous studies have determined that age, body mass index, von Willebrand factor antigen (VWF:Ag) levels, and ABO blood group status can influence FVIII PK, they do not account for all observed variability. In this study, we aim to describe the genetic determinants that modify the FVIII PK profile in a population of 43 pediatric hemophilia A patients. We observed that VWF:Ag and VWF propeptide (VWFpp)/VWF:Ag, but not VWFpp, were associated with FVIII half-life. VWFpp/VWF:Ag negatively correlated with FVIII half-life in patients with non-O blood type, but no correlation was observed for type O patients, suggesting that von Willebrand factor (VWF) half-life, as modified by the ABO blood group, is a strong regulator of FVIII PK. The FVIII-binding activity of VWF positively correlated with FVIII half-life, and the rare or low-frequency nonsynonymous VWF variants p.(Arg826Lys) and p.(Arg852Glu) were identified in patients with reduced VWF:FVIIIB but not VWF:Ag. Common variants at the VWF, CLEC4M, and STAB2 loci, which have been previously associated with plasma levels of VWF and FVIII, were associated with the FVIII PK profile. Together, these studies characterize the mechanistic basis by which VWF clearance and ABO glycosylation modify FVIII PK in a pediatric population. Moreover, this study is the first to identify non-VWF and non-ABO variants that modify FVIII PK in pediatric hemophilia A patients.

How I manage severe von Willebrand disease

Von Willebrand disease (VWD) is the most common inherited bleeding disorder. Most patients with mild and moderate VWD can be treated effectively with desmopressin. The management of severe VWD patients, mostly affected by type 2 and type 3 disease, can be challenging. In this article we review the current diagnosis and treatment of severe VWD patients. We will also discuss the management of severe VWD patients in specific situations, such as pregnancy, delivery, patients developing alloantibodies against von Willebrand factor and VWD patients with recurrent gastrointestinal bleeding. Moreover, we review emerging treatments that may be applied in future management of patients with severe VWD.

Regional variation and cost implications of prescribed extended half-life factor concentrates among U.S. Haemophilia Treatment Centres for patients with moderate and severe haemophilia

BACKGROUND

Extended half-life (EHL) factor VIII (FVIII) and IX (FIX) products are intended to decrease the burden of prophylaxis for patients with haemophilia A or B. Whether these newer concentrates have led to meaningful clinical practice change remains vague.

AIM

To characterize the longitudinal use of standard (SHL) and EHL factor concentrates at haemophilia treatment centres (HTCs), using the ATHNdataset, a US database of 138 ATHN-affiliated HTCs.

METHODS

Factor concentrate use among moderate and severe haemophilia A and B patients without inhibitors was analysed at three time points over 18 months.

RESULTS

Use of EHL concentrates rose from 10% of patients to 22% during this study. EHL FVIII prophylaxis is prescribed to the minority of patients, 28%; EHL FIX now predominates for prophylaxis, 52%. Rates of prescribed EHL products varied significantly by age group and HTC region. Median prescribed prophylaxis for SHL compared to EHL products was FVIII 6240 and 5200 and FIX 6968 and FIX 3900 IU/kg/y, respectively. On-demand EHL use has grown but has minimal contribution to overall usage (2%).

CONCLUSION

Haemophilia treatment centre region and patient age impact the rate of adoption of EHL products; however, EHL prescribing continues to rise nationally, particularly for EHL FIX. Careful attention to annual cost of prophylaxis is imperative as the decrease in median EHL prophylaxis consumption is not offset by the higher unit cost of these products. It is unclear how further growth in use of EHLs will be impacted by emerging non-factor replacement and gene therapies.

Dose tailoring of human cell line-derived recombinant factor VIII simoctocog alfa: Using a limited sampling strategy in patients with severe haemophilia A

AIMS

The use of factor VIII (FVIII) prophylaxis in haemophilia A is considered the standard of care, particularly in children. Despite adjustment of doses for body weight and/or age, a large pharmacokinetic (PK) variability between patients has been observed. PK-tailored prophylaxis may help clinicians adjust coagulation factor FVIII activity (FVIII:C) to the desired level, which may differ in individual patients. The objective was to develop a population PK model for simoctocog alfa based on pooled clinical trial data and to develop a Bayesian estimator to allow PK parameters in individual patients to be estimated using a reduced number of blood samples.

METHODS

PK data from 86 adults and 29 children/adolescents with severe haemophilia A were analysed. The FVIII data measured using 2 different assays (chromogenic and the 1-stage clotting assay) were fit to separate develop population PK models using nonlinear mixed-effect models. A Bayesian estimator was then developed to estimate the time above the threshold of 1%.

RESULTS

The PK data for chromogenic and the 1-stage clotting assays were both best described by a 2-compartment models. Simulations demonstrated good predictive capacity. The limited sampling strategy using blood sample at 3 and 24 hours allowed an accurate estimation of the time above the threshold of 1% FVIII:C (mean bias 0.01 and 0.11, mean precision 0.18 and 0.45 for 2 assay methods).

CONCLUSION

In this study, we demonstrated that a Bayesian approach can help to reduce the number of samples required to estimate the time above the threshold of 1% FVIII:C with good accuracy.

Pharmacokinetic-guided dosing of factor VIII concentrate in a morbidly obese severe haemophilia A patient undergoing orthopaedic surgery

A 58-year-old morbidly obese male (body mass index: 38 kg/m²) with severe haemophilia A underwent total knee replacement surgery. Perioperatively, factor VIII (FVIII) levels were measured daily and maximum a posteriori (MAP) Bayesian estimation was used to calculate the individual pharmacokinetic (PK) parameters and doses required to obtain prescribed FVIII target levels. In the MAP Bayesian procedure, a population PK model was used in which PK parameters were normalised using body weight. In this specific case, ideal body weight was used to scale the PK parameters instead of actual body weight. Except for the preoperative FVIII level, adequate FVIII levels were achieved during the 10-day perioperative period. During follow-up visits, the knee prosthesis was reported to function adequately.

Obesity in the global haemophilia population: prevalence, implications and expert opinions for weight management

Overweight and obesity may carry a significant disease burden for patients with haemophilia (PWH), who experience reduced mobility due to joint inflammation, muscle dysfunction and haemophilic arthropathy. This review aimed to define the prevalence and clinical impact of overweight/obesity in the global population of PWH. A detailed literature search pertaining to overweight/obesity in haemophilia in the last 15 years (2003-2018) was conducted, followed by a meta-analysis of epidemiological data. The estimated pooled prevalence of overweight/obesity in European and North American PWH was 31%. Excess weight in PWH is associated with a decreased range in motion of joints, accelerated loss of joint mobility and increase in chronic pain. Additionally, the cumulative disease burden of obesity and haemophilia may impact the requirement for joint surgery, occurrence of perioperative complications and the prevalence of anxiety and depression that associates with chronic illness. Best practice guidelines for obesity prevention and weight management, based on multidisciplinary expert perspectives, are considered for adult and paediatric PWH. Recommendations in the haemophilia context emphasize the importance of patient education and tailoring engagement in physical activity to avoid the risk of traumatic bleeding.