Primary prophylaxis in haemophilia care: Guideline update 2016

Considerations for shared decision management in previously untreated patients with hemophilia A or B

Recent advances in therapeutics are now providing a wide range of options for adults and children living with hemophilia. Although therapeutic choices are also increasing for the youngest individuals with severe disease, challenges remain about early management decisions, as supporting data are currently limited. Parents and healthcare professionals are tasked with helping children achieve an inclusive quality of life and maintain good joint health into adulthood. Primary prophylaxis is the gold standard to optimize outcomes and is recommended to start before 2 years of age. A range of topics need to be discussed with parents to aid their understanding of the decisions they can make and how these will affect the management of their child/children. For those with a family history of hemophilia, prenatal considerations include the possibility of genetic counseling, prenatal investigations, and planning for delivery, together with monitoring of the mother and neonate, as well as diagnosis of the newborn and treatment of any birth-associated bleeding. Subsequent considerations, which are also applicable to families where infant bleeding has resulted in a new diagnosis of sporadic hemophilia, involve explaining bleed recognition and treatment options, practical aspects of initiating/continuing prophylaxis, dealing with bleeds, and ongoing aspects of treatment, including possible inhibitor development. Over time, optimizing treatment efficacy, in which individualizing therapy around activities can play a role, and long-term considerations, including retaining joint health and tolerance maintenance, become increasingly important. The evolving treatment landscape is creating a need for continually updated guidance. Multidisciplinary teams and peers from patient organizations can help provide relevant information. Easily accessible, multidisciplinary comprehensive care remains a foundation to care. Equipping parents early with the knowledge to facilitate truly informed decision-making will help achieve the best possible longer-term health equity and quality of life for the child and family living with hemophilia.

Plain language summary

Points to be taken into account to help families make decisions to best care for children born with hemophilia Medical advances are providing a range of treatment options for adults and children with hemophilia. There is, however, relatively limited information about managing newborns with the condition. Doctors and nurses can help parents to understand the choices for infants born with hemophilia. We describe the various points doctors and nurses should ideally discuss with families to enable informed decision-making. We focus on infants who require early treatment to prevent spontaneous or traumatic bleeding (prophylaxis), which is recommended to start before 2 years of age. Families with a history of hemophilia may benefit from discussions before pregnancy, including how an affected child would be treated to protect against bleeds. When mothers are pregnant, doctors can explain investigations that can provide information about their unborn child, plan for the birth, and monitor mother and baby to minimize bleed risks at delivery. Testing will confirm whether the baby is affected by hemophilia. Not all infants with hemophilia will be born to families with a history of the condition. Identification of hemophilia for the first time in a family (which is 'sporadic hemophilia') occurs in previously undiagnosed infants who have bleeds requiring medical advice and possibly hospital treatment. Before any mothers and babies with hemophilia are discharged from hospital, doctors and nurses will explain to parents how to recognize bleeding and available treatment options can be discussed. Over time, ongoing discussions will help parents to make informed treatment decisions:• When and how to start, then continue, prophylaxis.• How to deal with bleeds (reinforcing previous discussions about bleed recognition and treatment) and other ongoing aspects of treatment. ○ For instance, children may develop neutralizing antibodies (inhibitors) to treatment they are receiving, requiring a change to the planned approach.• Ensuring treatment remains effective as their child grows, considering the varied needs and activities of their child.

The value of radiosynoviorthesis for treatment of chronic synovitis in hemophilic joint disease

Chronic synovitis is contributing to the development of arthropathy in hemophilia A and B. In most patients with severe and moderate hemophilia, during lifetime, joint damage progresses despite early prophylaxis and intense treatment with coagulation factor concentrates. Recurrent hemorrhages into the joints and subclinical bleeding lead to chronic inflammation of the synovium, neoangiogenesis and remodeling, sustaining a vicious circle of bleeding-remodeling-bleeding and progression of osteochondral damage. Imaging techniques including ultrasound and MRI are able to early visualize synovitis and osteochondral changes. Early detection and sustained therapy of synovitis are important preconditions to prevent further deterioration of joint status. Chronic synovitis requires intensified substitution of coagulation factors and concomitant analgetic, antiphlogistic and physical therapy. The value of early radiosynoviorthesis (RSO) as effective method to control ongoing synovitis is discussed here. RSO is recommended as first choice therapy in case of persistant chronic synovitis, recorded in both national and international guidelines.

Most subjectively affected joints in patients with haemophilia - what has changed after 20 years in Germany?

BACKGROUND

In patients with haemophilia (PwH), most frequently affected joints are the ankle, knee and elbow. Due to improved factor therapy in the last decades, these previous findings have to be verified in Germany.

AIM

The aim of this study is to detect the most affected joint, evaluate the significance of the source of pain and determine the point prevalence of back pain in Germany today.

PATIENTS AND METHODS

In a retrospective study, data of n = 300 patients with severe moderate and mild haemophilia were evaluated regarding the most affected joint, the most common source of pain, and the point prevalence of back pain. An anamnesis questionnaire and the German Pain Questionnaire were used for this assessment.

RESULTS

The most affected joint in German PwH is still the ankle (41%), followed by the knee (27%) and the elbow (11%). The most common source of pain is also the ankle joint (32%). Back pain was also identified as one of the most common sources of pain, which is comparable to the elbow (elbow:15%; back:13%). The point prevalence in PwH for back pain was significantly higher compared to the general German population (P = .031).

CONCLUSION

Our data showed that the ankle is still the most affected joint and the most common source of pain in Germany. These results also showed the relevance of back pain as a pain source. The evaluations also demonstrated the high point prevalence of back pain in PwH. Future therapies should also focus on the spine because joint changes affect posture.

Overcoming the challenges of treating hemophilia in resource-limited nations: a focus on medication access and adherence

BACKGROUND

Hemophilia is a high cost low volume disease. Resource limited nations (RLN) usually spend very little on health budget and most of it is spent in dealing with common ailments. Clotting products constitute more than 90% of the total cost of hemophilia care. The manner in which these products can be made accessible for persons with hemophilia (PWH) and how its continuous supply and distribution can be maintained and improved is described in this review.

AREAS COVERED

Number of PWH in the Resource Limited Nations (RLN); minimum amount of concentrate required to keep a PWH relatively free of bleeds; the different products available for management of PWH; means and ways to minimize and optimize the concentrate usage and purchase on a budget; nonfactor therapy; ways and means to improve the management and allow better quality concentrates in higher quantities for PWH in those countries; adherence as a challenge for RLN country and ways to manage them. The time covered is from 1980s till date. Pubmed was searched mainly for review articles with the key words hemophilia, RLN, concentrate access, alternative therapy. Cross references from these reviews as well as some of the abstracts from international conferences were read.

EXPERT OPINION

Developing a patient's society and a bleeding disorder registry are the two most important actions toward ensuring adequate treatment material for PWH in RLN. Government should allocate a budget for hemophilia care depending on the number of PWH diagnosed and future projection of increased numbers of PWH. Population based product requirement may not work initially as only 10-20% of PWH in such a country has been diagnosed hence initial requirement of concentrates should be directed to these patients. Meanwhile efforts should be made to diagnose new cases. Antenatal diagnosis centers should offer antenatal diagnosis and prevent birth of severe hemophilia children. Self sufficiency in plasma based concentrates should be planned and aimed. A national tendering committee can get a good price on the concentrates on global tendering with annual rate contracts (prevents outdating). Avoiding wastage by outdating of the products in large denomination vials will help. Hoarding concentrates in unreasonable amounts should be avoided through good supply chain management. Regular physiotherapy, proper use of optimum amounts of concentrate will reduce per PWH consumption of the factor concentrates. Plasma derived intermediate purity factors, first/second generation recombinant clotting factors are safe and relatively cheaper as well as effective. Also concentrates which are close to their expiry date (>3 < 6 months) are equally effective and cheap. With proper supply chain management such products can be included in the portfolio. Primary prophylaxis with low/ intermediate dose of the concentrates is a cost-effective way to manage the patients and this also reduces inhibitor development. Adherence to therapy is not yet an important issue for RLN countries but will become one in future. With advancement and improvement the country can access alternative non factor concentrates and other newer products.

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

OBJECTIVES

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

A tailored intervention for illness acceptance improves adherence and quality of life in adults with haemophilia using prophylaxis

INTRODUCTION

Adherence to prophylactic treatment (prophylaxis) in persons with haemophilia is challenging and has been reported at only ±50%. Acceptance problems are one of the main reasons for non-adherence in haemophilia. An evidence-based intervention was developed based on an acceptance and commitment therapy (ACT) approach.

AIM

To evaluate a tailored intervention focused on illness acceptance in adults with haemophilia who were prescribed prophylaxis.

METHODS

A pre-post study was executed in adults with haemophilia who were prescribed prophylaxis. A series of 8 2-hour group trainings were held, including 3-8 participants/series. Adherence (VERITAS-Pro, optimum 0), health-related quality of life (HRQoL, SF-36, optimum 100) and illness perception (BIPQ, optimum 0) were measured at start, after six months and 12 months and analysed using Wilcoxon signed-rank test.

RESULTS

Twenty-four patients (median age 47 years, range 27-74) were included. After 12 months, adherence improved in 68% of patients, quality of life in 48% and illness perception in 31%. Adherence (total score) improved from 35 to 25 (P<0.01). HRQoL showed clinically relevant improvement in domains of social-functioning (P = 0.04), role-emotional, physical-functioning, role-physical and bodily pain. Illness perception improved statistically significant on domains of affect (P = 0.01), concern (P = 0.01) and understanding (P = 0.04). Patients evaluated the training useful, an eye-opener, a personal enrichment and insightful.

CONCLUSION

The tailored group intervention resulted in significant improvement of adherence, quality of life and illness perception. Based on our current experience, we have implemented it in clinical practice and collaborate with the patient association to make it available for all Dutch people with haemophilia.

Impact of the HEAD-US Scoring System for Observing the Protective Effect of Prophylaxis in Hemophilia Patients: A Prospective, Multicenter, Observational Study

Objective:

This study aimed to observe the preventive effect of prophylactic treatment on joint health in people with hemophilia (PwH) and to investigate the importance of integration of ultrasonographic examination into clinical and radiological evaluation of the joints.

Materials and Methods:

This national, multicenter, prospective, observational study included male patients aged ≥6 years with the diagnosis of moderate or severe hemophilia A or B from 8 centers across Turkey between January 2017 and March 2019. Patients were followed for 1 year with 5 visits (baseline and 3^rd, 6^th, 9^th, and 12^th month visits). The Hemophilia Joint Health Score (HJHS) was used for physical examination of joints, the Pettersson scoring system was used for radiological assessment, point-of-care (POC) ultrasonography was used for bilateral examinations of joints, and the Hemophilia Early Arthropathy Detection with Ultrasound (HEAD-US) score was used for evaluation of ultrasonography results.

Results:

Seventy-three PwH, of whom 62 had hemophilia A and 11 had hemophilia B, were included and 24.7% had target joints at baseline. The HJHS and HEAD-US scores were significantly increased at the 12^th month in all patients. These scores were also higher in the hemophilia A subgroup than the hemophilia B subgroup. However, in the childhood group, the increment of scores was not significant. The HEAD-US total score was significantly correlated with both the HJHS total score and Pettersson total score at baseline and at the 12^th month.

Conclusion:

The HEAD-US and HJHS scoring systems are valuable tools during follow-up examinations of PwH and they complement each other. We suggest that POC ultrasonographic evaluation and the HEAD-US scoring system may be integrated into differential diagnosis of bleeding and long-term monitoring for joint health as a routine procedure.

Recombinant factor VIII Fc for the treatment of haemophilia A

Prophylaxis with factor VIII (FVIII) is the current therapeutic approach for people with haemophilia A. However, standard half-life (SHL) FVIII products must be injected frequently, imposing a substantial burden on the individual and making it difficult to tailor therapy according to patient need and lifestyle, which could impact adherence. Recombinant FVIII Fc fusion protein (rFVIIIFc; Elocta® , Sobi; Eloctate® , Sanofi) is a recombinant fusion protein that undergoes slower clearance from the body than SHL FVIII products. This pharmacokinetic property of rFVIIIFc allows prophylactic administration every 3-5 days, or once weekly in selected patients, with doses adjusted to patient needs and clinical outcomes. Higher FVIII levels can be achieved maintaining dosing frequency similar to that usually applied with SHL FVIII. This review provides a summary of recent data from the A-LONG, Kids A-LONG, ASPIRE and PUPs A-LONG studies and recently published real-world experience relevant to rFVIIIFc use in individualised regimens. The review also introduces ongoing studies of rFVIIIFc, including its use for induction of immune tolerance, and discusses some aspects to consider when switching patients to rFVIIIFc and managing ongoing treatment. In summary, rFVIIIFc is suitable for individualised prophylaxis regimens that can be tailored according to patient clinical needs and lifestyle.

Young adult outcomes of childhood prophylaxis for severe hemophilia A: results of the Joint Outcome Continuation Study

The Joint Outcome Study (JOS), a randomized controlled trial, demonstrated that children with severe hemophilia A (HA) initiating prophylactic factor VIII (FVIII) prior to age 2.5 years had reduced joint damage at age 6 years compared with those treated with episodic FVIII for bleeding. The Joint Outcome Continuation Study (JOS-C) evaluated early vs delayed prophylaxis effects on long-term joint health, following JOS participants to age 18 years in an observational, partially retrospective study. Index joint magnetic resonance imaging (MRI) scores of osteochondral (OC) damage (primary outcome), joint physical examination scores, and annualized rates of joint/other bleeding episodes (secondary outcomes) were collected. Thirty-seven of 65 JOS participants enrolled in JOS-C, including 15 randomized to prophylaxis at mean age 1.3 years ("early prophylaxis"); 18 initially randomized to episodic treatment, starting "delayed prophylaxis" at mean age 7.5 years; and 4 with high-titer inhibitors. At JOS-C exit, MRI OC damage was found in 77% of those on delayed and 35% of those on early prophylaxis for an odds ratio of OC damage, in the delayed vs early prophylaxis group, of 6.3 (95% confidence interval, 1.3, 29.9; P = .02). Annualized bleeding rates were higher with delayed prophylaxis (mean plus or minus standard deviation, 10.6 ± 6.6 vs 3.5 ± 2.1; P < .001), including when only comparing time periods on prophylaxis (6.2 ± 5.3 vs 3.3 ± 1.9; P < .05). In severe HA, early initiation of prophylaxis provided continued protection against joint damage throughout childhood compared with delayed initiation, but early prophylaxis was not sufficient to fully prevent damage. This trial was registered at www.clinicaltrials.gov as #NCT01000844.

A feasibility study on two tailored interventions to improve adherence in adults with haemophilia

INTRODUCTION

Haemophilia is a congenital bleeding disorder mainly affecting males. To prevent bleeding, patients need to perform regular intravenous injections (prophylaxis) throughout life. Non-adherence often occurs. Problems with acceptance or self-management appear to be the main reasons for non-adherence in haemophilia. The aim of this study was to test the feasibility and effects of two interventions focussed on acceptance (face-to-face) and self-management (online).

METHODS

Patients with severe haemophilia and acceptance or self-management problems were eligible. The face-to-face group intervention was based on Acceptance and Commitment Therapy (ACT) (8 sessions/6 months, target N = 8 participants). The online intervention was based on a successful online programme in rheumatoid arthritis (5-8 modules/2 months, target N = 8). Both interventions were designed according to the MRC framework in collaboration with the patient society and experts. We compared adherence (VERITAS-Pro, optimum 0), quality of life (SF-36, optimum 100) and illness perception (BIPQ, optimum 0) before start (T0) and after 2 months (T2). Feasibility criteria were as follows: completion of training by > 50% of participants and ability to collect at least 80% of outcome parameters.

RESULTS

The face-to-face intervention was feasible (89% enrolment and recruitment, 100% retention). One hundred percent of the outcome parameters was collected. Results were promising: although adherence (VERITAS-Pro) was stable (from 64 to 62 points), quality of life (SF-36) showed a clinically relevant improvement (> 5 points) in five of eight domains. Illness perception (BIPQ) showed a clinically relevant increase from 47 to 39 points. Patient evaluation was positive. The online intervention, however, was infeasible: enrolment was only 20% (6/30). Only three patients signed informed consent (recruitment 10%), and none completed more than one module (retention 0%). Consequently, the online intervention was terminated.

CONCLUSION

The face-to-face acceptance intervention was considered feasible with promising results. Unfortunately, the online intervention was infeasible and therefore terminated. These findings suggest that adapting effective interventions to other settings does not guarantee success, despite the use of established methodology and patient participation. Population differences (only male participants, congenital disease) could be an explanation for failure of the online intervention in haemophilia despite success in rheumatoid arthritis.

TRIAL REGISTRATION

NL55883.041.16.

Emerging benefits of Fc fusion technology in the context of recombinant factor VIII replacement therapy

Although the primary reason for recombinant factor VIII Fc fusion protein (rFVIIIFc) development was to reduce treatment burden associated with routine prophylaxis, new evidence suggests additional benefits of Fc fusion technology in the treatment of people with haemophilia A. Preclinical research has been utilized to characterize the potential immunomodulatory properties of rFVIIIFc, including an ability to reduce inflammation and induce tolerance to factor VIII. This has since been expanded into clinical research in immune tolerance induction (ITI) with rFVIIIFc, results of which suggest the potential for rapid tolerization in first‐time ITI patients and therapeutic benefit in patients undergoing rescue ITI. The potential for improved joint health through the anti‐inflammatory properties of rFVIIIFc has also been suggested. In addition, a new avenue of research into the role of rFVIIIFc in promoting bone health in patients with haemophilia A, potentially through reduced osteoclast formation, has yielded encouraging results that support further study. This review summarizes the existing preclinical and clinical studies of immunomodulation and tolerization with rFVIIIFc, as well as studies in joint and bone health, to elucidate the potential benefits of rFVIIIFc in haemophilia A beyond the extension of factor VIII half‐life.

Phosphatidylserine positive microparticles improve hemostasis in in-vitro hemophilia A plasma models

Circulating microparticles (MPs) are procoagulant due to the surface containing phosphatidylserine (PS), which facilitates coagulation. We investigated if MPs improve hemostasis in HA plasma models. MPs isolated from pooled normal human plasma were added to severe, moderate and mild HA plasma models (0%, 2.5%, 20% FVIII). The MPs’ effect on hemostasis was evaluated by calibrated automated thrombogram (CAT) and overall hemostasis potential (OHP) assays, while fibrin structure was imaged by standard confocal, stimulated emission depletion (STED) microscopy and scanning electron microscopy (SEM). MPs partially restored thrombin generation and fibrin formation in all HA plasma models. The procoagulant effect of MPs requires PS exposure, to a less extent of contact pathway activation, but not tissue factor exposure or in vitro stimulation of MPs. MPs partially normalized the fibrin structure, and using super-resolution STED, MPs attached to fibrin were clearly resolved. In summary, our results demonstrate that PS positive MPs could improve hemostasis in HA plasma models.

The Perspectives of Adolescents and Young Adults on Adherence to Prophylaxis in Hemophilia: A Qualitative Study

PURPOSE

Adolescents and young adults (AYAs) with severe hemophilia use prophylaxis that requires a high level of adherence. The present study aimed to explore the underlying reason for adherence and non-adherence to prophylaxis in hemophilia from the perspective of AYAs.

PATIENTS AND METHODS

A qualitative study in Dutch AYAs with hemophilia (14-25 years) using prophylaxis was executed. Focus group interviews and individual interviews were recorded, transcribed, coded and analyzed using an iterative process. Member checking in three respondents was used to validate the potential model.

RESULTS

A total of 21 interviews were performed. Parental support decreased when AYAs gained more treatment responsibilities, which resulted in a higher risk for non-adherence. AYAs were weighing their potential bleeding risk per activity based on the wish to do what they prefer while also wanting to simultaneously feel safe. When bleeding with low impact on their daily life occurred, or when bleeding remained absent, AYAs felt safe and the perceived need for prophylaxis decreased.

CONCLUSION

The level of treatment responsibility per AYA and estimated risks per activity were the two main underlying reasons for (non-)adherence.

CLINICAL IMPLICATIONS

We suggest using a conversation technique to discuss adherence, especially during bleeding assessment visits.

Economic impact model of delayed inhibitor development in patients with hemophilia a receiving emicizumab for the prevention of bleeding events

Aims: Cumulative exogenous factor VIII (FVIII) exposure is an important predictor of developing neutralizing antibodies (inhibitors) to FVIII in patients with persons with hemophilia A (PwHA). The aim of this study was to model the costs of emicizumab versus FVIII prophylaxis and total treatment costs for patients with severe HA.Materials and Methods: An Excel-based decision model was developed to calculate cumulative costs in PwHA over a 20-year time horizon from the US payer perspective. The model considered persons with severe HA beginning at age 12 months with no prior FVIII exposure and initiating prophylaxis with emicizumab or FVIII. PwHA could develop inhibitors on accumulation of 20 FVIII exposure days. PwHA with inhibitors replaced FVIII with bypassing agents until inhibitors resolved spontaneously, following immune tolerance induction (ITI), or at the end of the time horizon. The primary model outcome was the difference in emicizumab versus FVIII treatment costs in 2019 USD. Sensitivity analyses were performed to test the robustness of results.Results: Total incremental cost over 20 years was -$1,945,480 (emicizumab arm, $4,919,058; FVIII arm, $6,864,538). Prophylaxis costs (emicizumab arm, $4,096,105; FVIII arm, $6,290,919) comprised the majority of costs in both groups, followed by breakthrough bleed treatment for the FVIII arm ($342,652) and ITI costs for the emicizumab arm ($733,671). Higher costs in the FVIII group reflected earlier inhibitor development (FVIII, 4 months; emicizumab, 162 months) and switch to bypassing agents.Limitations: The model design reflects a simplified treatment pathway for patients with severe HA who initiate FVIII or emicizumab prophylaxis. In the absence of clinical data, a key conservative assumption of the model is that patients receiving emicizumab and FVIII prophylaxis have the same risk of developing inhibitors.Conclusions: This study suggests that prophylaxis with emicizumab results in cost savings compared to FVIII prophylaxis in HA.

Relationship between factor VIII activity, bleeds and individual characteristics in severe hemophilia A patients

Pharmacokinetic-based prophylaxis of replacement factor VIII (FVIII) products has been encouraged in recent years, but the relationship between exposure (factor VIII activity) and response (bleeding frequency) remains unclear. The aim of this study was to characterize the relationship between FVIII dose, plasma FVIII activity, and bleeding patterns and individual characteristics in severe hemophilia A patients. Pooled pharmacokinetic and bleeding data during prophylactic treatment with BAY 81-8973 (octocog alfa) were obtained from the three LEOPOLD trials. The population pharmacokinetics of FVIII activity and longitudinal bleeding frequency, as well as bleeding severity, were described using non-linear mixed effects modeling in NONMEM. In total, 183 patients [median age 22 years (range, 1-61); weight 60 kg (11-124)] contributed with 1,535 plasma FVIII activity observations, 633 bleeds and 11 patient/study characteristics [median observation period 12 months (3.1-13.1)]. A parametric repeated time-to-categorical bleed model, guided by plasma FVIII activity from a 2-compartment population pharmacokinetic model, described the time to the occurrence of bleeds and their severity. Bleeding probability decreased with time of study, and a bleed was not found to affect the time of the next bleed. Several covariate effects were identified, including the bleeding history in the 12-month pre-study period increasing the bleeding hazard. However, unexplained inter-patient variability in the phenotypic bleeding pattern remained large (111%CV). Further studies to translate the model into a tool for dose individualization that considers the individual bleeding risk are required. Research was based on a post-hoc analysis of the LEOPOLD studies registered at clinicaltrials.gov identifiers: 01029340, 01233258 and 01311648.

Favorable pharmacokinetics in hemophilia B for nonacog beta pegol versus recombinant factor IX-Fc fusion protein: A randomized trial

BACKGROUND AND OBJECTIVE

Nonacog beta pegol (N9-GP) and recombinant factor IX-Fc fusion protein (rFIXFc) are extended half-life rFIX compounds. We report the first single-dose pharmacokinetic trial of N9-GP and rFIXFc.

PATIENTS/METHODS

Paradigm 7 was a multicenter, open-label, randomized, crossover trial in previously treated (>150 exposure days) adults with congenital hemophilia B (FIX activity ≤2%). Patients received single intravenous injections (50 IU/kg) of N9-GP and rFIXFc with at least 21 days between doses. Plasma FIX activity, predose, and at serial time points up to 240 hours postdose, was measured using validated one-stage clotting assays (SynthAFax for N9-GP; Actin FSL for rFIXFc) and a chromogenic assay (ROX factor IX) with normal human plasma as calibrator. The primary endpoint was area under the FIX activity-time curve from 0 to infinity, dose-normalized to 50 IU/kg (AUC0-inf,norm).

RESULTS

Fifteen patients received study treatment. Based on FIX activity results from the one-stage clotting assays, estimated AUC0-inf,norm was significantly greater for N9-GP than rFIXFc (ratio: 4.39; P < 0.0001, based on a two-sided test on 5% significance level). In addition, N9-GP had a longer terminal half-life, two times higher incremental recovery at 30 minutes and maximum FIX activity (dose-normalized to 50 IU/kg) and six times higher FIX activity at 168 hours than rFIXFc. These findings were largely comparable with the chromogenic assay data and are consistent with published data for each compound.

CONCLUSIONS

In this comparison, N9-GP demonstrated favorable pharmacokinetic characteristics versus rFIXFc, helping clinicians to understand differences between N9-GP and rFIXFc.

REGISTRATION

This trial is registered with clinicaltrials.gov (NCT03075670) and the European Clinical Trials Database (EudraCT: 2016-001149-25).

Pharmacokinetic Studies of Factor VIII in Chinese Boys with Severe Hemophilia A: A Single-Center Study

Background:

Although much attention has been paid to the pharmacokinetics (PKs) of different factor VIII (FVIII) concentrates in persons with hemophilia A (HA), limited information is available in young boys with severe HA. In this study, we aimed to assess the PK parameters of FVIII products in boys with severe HA in China.

Methods:

A total of 36 boys (plasma-derived [pd]-FVIII, n = 15; recombinant [r] FVIII, n = 21) were enrolled between January 2015 and May 2016 in Beijing Children's Hospital. PK characteristics of FVIII products were studied according to a reduced 4-sampling time point design (1 h, 9 h, 24 h, and 48 h postinfusion).

Results:

The mean FVIII half-life (t_1/2) was 10.99 ± 3.45 h (range 5.52–20.02 h), the mean in vivo recovery (IVR) was 2.01 ± 0.42 IU/dl per IU/kg (range 1.24–3.02 IU/dl per IU/kg) and mean clearance (CL) of FVIII is 4.34 ± 1.58 ml·kg⁻¹·h⁻¹ (range 2.29–7.90 ml·kg⁻¹·h⁻¹). We also analyzed the influence of several parameters that potentially modulate FVIII PK. The age was closely associated with FVIII half-life (R²= 0.32, P < 0.01). The t_1/2 of FVIII increased by 0.59 h per year. Besides age, von Willebrand factor antigen (VWF:Ag) also was associated with FVIII half-life (R²= 0.52, P < 0.01). Patients with blood Group O had a shorter FVIII half-life than patients with non-O blood group (9.40 ± 0.68 h vs. 12.3 ± 0.79 h, t = 2.70, P = 0.01). The FVIII IVR correlated with age (R²= 0.21, P < 0.01) and VWF:Ag level (R²= 0.28, P < 0.01). CL rates were faster in young patients and in those with low-VWF:Ag levels. CL rates of FVIII are higher in blood Group O versus non-blood Group O persons (5.02 ± 0.38 vs. 4.00 ± 0.32 ml·kg⁻¹·h⁻¹, t = 2.53, P = 0.02).

Conclusions:

Chinese boys with severe HA have similar PK values to other ethnic groups and large differences in FVIII PK between individual patients. Age, blood group, and VWF:Ag levels are important determining factors for FVIII CL.

Navigating Speed Bumps on the Innovation Highway in Hemophilia Therapeutics

The unprecedented emergence of novel therapeutics for both hemophilia A and B during the last half decade has been accompanied by the promise of even more extraordinary progress in ameliorative and curative strategies for both disorders. Paradoxically, the speed of innovation has created new dilemmas for persons with hemophilia and their physicians with respect to optimizing individual choices from the expanding menu of standard and novel therapies and approaches to symptom or risk reduction, and ultimately, to normalizing the hemophilia phenotype. Among the most disruptive new approaches, challenges remain in the form of the adverse reactions that have been observed with nonfactor therapies, as well as in the uncertain long-term safety profile of potentially curative gene therapy. Together, these challenges have generated uncertainty as to how to adopt novel therapies and treatment strategies across a diverse patient population, creating speed bumps on the hemophilia innovation highway. It is from this perspective that this article discusses the current state of gene therapy and bleeding prophylaxis for hemophilia A and B, as well as prevention and treatment of the factor VIII inhibitor phenotype in hemophilia A. It further posits that these speed bumps may provide important clues to the mechanistic understanding of both symptom manifestation and resilience within the hemophilia phenotype, as well as opportunities to reconsider and reconfigure the current paradigms for symptom prediction and individualized therapeutic decision making.

GlycoPEGylated recombinant factor IX for hemophilia B in context

Decisions over hemophilia treatment selection and switching involve balancing many clinical and patient-related factors. The current standard of care for patients with hemophilia B is prophylaxis with plasma-derived or recombinant factor IX (rFIX) concentrates. However, several extended half-life (EHL) rFIX products have recently been developed to improve treatment convenience and clinical outcomes for these patients. Nonacog beta pegol, an rFIX product that combines the FIX protein with a 40 kDa polyethylene glycol moiety, has been evaluated in 115 previously treated patients with hemophilia B (including 25 children) in the paradigm clinical trial program. FIX activity levels and pharmacokinetics were monitored throughout these trials and showed that nonacog beta pegol offers significant pharmacological improvements over standard FIX products. Once-weekly prophylaxis with nonacog beta pegol 40 IU/kg resulted in fewer bleeds in all patients (median annualized bleeding rate of 1.0 across all ages), resolved 90% of target joints, and improved health-related quality of life. No patients developed FIX inhibitors, and there were no thromboembolic events or unexpected safety concerns. Nonacog beta pegol was also safe and effective in the perioperative setting. These findings show that nonacog beta pegol is highly effective, while also offering more convenient dosing than standard FIX products. Nonacog beta pegol represents a significant advance in the current context of treatment for hemophilia B, offering effective management across several treatment modalities and settings, and potentially easing the treatment burden for patients of all ages. Meanwhile, the development of novel treatment strategies, such as gene therapy, anti-tissue factor pathway inhibitor antibodies, and RNA interference therapy, may provide patients with additional therapeutic options, which would require reassessment of the role of EHL products in the future.

Long-term outcomes from prophylactic or episodic treatment of haemophilia A: A systematic review

INTRODUCTION

Evaluating treatment success in patients with haemophilia A (HA) remains a vigorous debate, especially concerning the interpretation of results from clinical and observational research. The benefits of short-term prophylaxis are well established, but long-term outcomes, particularly related to humanistic and economic burden, are not as well understood.

AIM

We conducted a systematic literature review to evaluate the association of episodic or prophylactic bleed control with long-term clinical, humanistic and economic outcomes.

METHODS

Studies published in English between 1 January 2006 and 15 December 2016 were included. Participants had HA (with or without inhibitors), received prophylactic or episodic treatment and had at least 4 years of treatment or follow-up. Results were analysed qualitatively with descriptive findings.

RESULTS

A total of 2091 records were screened, resulting in 19 studies from 20 publications for inclusion. Most studies included children (84%), were limited to patients with severe disease (74%) and were conducted in Europe or North America (89%). Ten studies (53%) included patients with inhibitors. Median study follow-up ranged from 5 to 19 years. Long-term bleeding and haemarthrosis outcomes were consistently better for patients receiving prophylaxis, who also required fewer hospitalizations or surgeries. Health-related quality of life, functionality and productivity were generally more favourable in patients receiving prophylaxis. Quantitative comparisons were not feasible due to the lack of consistency in endpoint collection and reporting among studies.

CONCLUSION

This systematic review confirmed that the benefits of prophylactic treatment on short-term outcomes translate to broader long-term clinical, humanistic and economic benefits. Better harmonization of data collection and outcome assessments across both registries and clinical studies is needed to allow for effective comparisons across studies and across data sources.

Prophylactic versus on-demand treatments for hemophilia: advantages and drawbacks

INTRODUCTION

Early long-term prophylaxis is the standard of care to prevent joint bleeding and chronic arthropathy in patients with severe hemophilia. Areas covered: Despite the obvious prophylaxis advantages upon the clinical outcomes, there are still several drawbacks to be addressed for the optimal patients' compliance. Frequency of treatment due to short half-life of conventional FVIII and FIX concentrates, difficult venous access, adherence to the prescribed therapy and costs may represent significant critical issues. The development of inhibitors also makes replacement therapy ineffective, preventing patients from receiving long-term prophylaxis. This paper will review these drawbacks and the tools to overcome these limitations, mainly thanks to the use of extended half-life products and the development of novel non-conventional therapeutic approaches. Expert commentary: The use of extended half-life products may help in reducing the burden of the frequent intravenous administration and in better tailoring an individualized prophylaxis. The development of novel therapeutic approaches, like the bi-specific antibody mimicking the coagulation function of FVIII or inhibition of anticoagulant proteins may facilitate prophylaxis treatment not only in patients with inhibitors, but also in severe hemophilia patients without inhibitors. Exciting opportunities are emerging for improving prophylaxis in hemophilia.