Factor VIII prophylaxis for adult patients with severe haemophilia A: results of a US survey of attitudes and practices

[Treatment of haemophilia in Austria]

This guideline is intended to provide practical guidance for the diagnosis and treatment of haemophilia in Austria. Few randomized controlled interventional trials are available addressing the treatment of haemophilia, therefore recommendations are usually based on low level of evidence and represent expert consensus.This guideline is based on the WFH guideline, published in 2020, and adapted according to the national circumstances and experience.It includes recommendations and suggestions for diagnosis and follow-up visits and pharmacological therapies for treatment and prophylaxis. Further topics comprise special aspects in children and adults with severe haemophilia, outcome measurement, and management of trauma, special bleedings and interventions, including dental procedures, inhibitors, management of haemophilia carriers, and psychosocial aspects.

Characteristics of BAY 2599023 in the Current Treatment Landscape of Hemophilia A Gene Therapy

Hemophilia A, a single gene disorder leading to deficient Factor VIII (FVIII), is a suitable candidate for gene therapy. The aspiration is for single administration of a genetic therapy that would allow the production of endogenous FVIII sufficient to restore hemostasis and other biological processes. This would potentially result in reliable protection from bleeding and its associated physical and emotional impacts. Gene therapy offers the possibility of a clinically relevant improvement in disease phenotype and transformational improvement in quality of life, including an opportunity to engage in physical activities more confidently. Gene therapy products for hemophilia A in advanced clinical development use adeno-associated viral (AAV) vectors and a codon-optimized B-domain deleted FVIII transgene. However, the different AAV-based gene therapies have distinct design features, such as choice of vector capsid, enhancer and promoter regions, FVIII transgene sequence and manufacturing processes. These, in turn, impact patient eligibility, safety and efficacy. Ideally, gene therapy technology for hemophilia A should offer bleed protection, durable FVIII expression, broad eligibility and limited response variability between patients, and long-term safety. However, several limitations and challenges must be overcome. Here, we introduce the characteristics of the BAY 2599023 (AAVhu37.hFVIIIco, DTX 201) gene therapy product, including the low prevalence in the general population of anti-AAV-hu37 antibodies, as well as other gene therapy AAV products and approaches. We will examine how these can potentially meet the challenges of gene therapy, with the ultimate aim of improving the lives of patients with hemophilia A.

Surgery for chronic arthropathy in people with haemophilia

BACKGROUND

Chronic arthropathy is a potentially debilitating complication for people with haemophilia - a genetic, X-linked, recessive bleeding disorder, characterised by the absence or deficiency of a clotting factor protein. Staging classifications, such as the Arnold-Hilgartner classification for haemophilic arthropathy of the knee, radiologically reflect the extent of knee joint destruction with underlying chronic synovitis. Management of this highly morbid disease process involves intensive prophylactic measures, and chemical or radioisotope synovectomy in its early stages. However, failure of non-surgical therapy in people with progression of chronic arthropathy often prompts surgical management, including synovectomy, joint debridement, arthrodesis, and arthroplasty, depending on the type of joint and extent of the damage. To date, management of people with mild to moderate chronic arthropathy from haemophilia remains controversial; there is no agreed standard treatment. Thus, the benefits and disadvantages of non-surgical and surgical management of mild to moderate chronic arthropathy in people with haemophilia needs to be systematically reviewed.  OBJECTIVES: To assess the efficacy and safety of surgery for mild to moderate chronic arthropathy in people with haemophilia A or B.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Coagulopathies Trials Register, CENTRAL, MEDLINE, Embase, CINAHL, and two trial registers to August 2022. We also handsearched relevant journals and conference abstract books.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and quasi-RCTs comparing surgery and non-surgical interventions, for any joint with chronic arthropathy, in people with haemophilia, who were at least 12 years old.

DATA COLLECTION AND ANALYSIS

The review authors did not identify any trials to include in this review.

MAIN RESULTS

The review authors did not identify any trials to include in this review.

AUTHORS' CONCLUSIONS

The review authors did not identify any trials to include in this review. Due to a lack of research in this particular area, we plan to update the literature search every two years, and will update review if any new evidence is reported. There is a need for a well-designed RCT that assesses the safety and efficacy of surgical versus non-surgical interventions for chronic arthropathy in people with haemophilia.

Bioengineering hemophilia A-specific microvascular grafts for delivery of full-length factor VIII into the bloodstream

Hemophilia A (HA) is a bleeding disorder caused by mutations in the F8 gene encoding coagulation factor VIII (FVIII). Current treatments are based on regular infusions of FVIII concentrates throughout a patient's life. Alternatively, viral gene therapies that directly deliver F8 in vivo have shown preliminary successes. However, hurdles remain, including lack of infection specificity and the inability to deliver the full-length version of F8 due to restricted viral cargo sizes. Here, we developed an alternative nonviral ex vivo gene-therapy approach that enables the overexpression of full-length F8 in patients' endothelial cells (ECs). We first generated HA patient-specific induced pluripotent stem cells (HA-iPSCs) from urine epithelial cells and genetically modified them using a piggyBac DNA transposon system to insert multiple copies of full-length F8. We subsequently differentiated the modified HA-iPSCs into competent ECs with high efficiency, and demonstrated that the cells (termed HA-FLF8-iECs) were capable of producing high levels of FVIII. Importantly, following subcutaneous implantation into immunodeficient hemophilic (SCID-f8ko) mice, we demonstrated that HA-FLF8-iECs were able to self-assemble into vascular networks, and that the newly formed microvessels had the capacity to deliver functional FVIII directly into the bloodstream of the mice, effectively correcting the clotting deficiency. Moreover, our implant maintains cellular confinement, which reduces potential safety concerns and allows effective monitoring and reversibility. We envision that this proof-of-concept study could become the basis for a novel autologous ex vivo gene-therapy approach to treat HA.

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.

Pro-coagulant haemostatic factors for the prevention and treatment of bleeding in people without haemophilia

BACKGROUND

Some hospital patients may be at risk of or may present with major bleeding. Abnormalities of clotting (coagulation) are often recorded in these people, and the traditional management has been with transfusions of blood components, either to prevent bleeding (prophylactic) or to treat bleeding (therapeutic). There is growing interest in the use of targeted therapies with specific pro-coagulant haemostatic (causing bleeding to stop and to keep blood within a damaged blood vessel) factor concentrates in place of plasma.

OBJECTIVES

To assess the effects and safety of pro-coagulant haemostatic factors and factor concentrates in the prevention and treatment of bleeding in people without haemophilia.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (2018, issue 3), MEDLINE (from 1948), Embase (from 1974), CINAHL (from 1938), PubMed (publications in process to 18 April 2018), PROSPERO, Transfusion Evidence Library (from 1950), LILACS (from 1980), IndMED (from 1985), KoreaMed (from 1934), Web of Science Conference Proceedings Citation Index (from 1990) and ongoing trial databases to 18 April 2018.

SELECTION CRITERIA

We included RCTs that compared intravenous administration of a pro-coagulant haemostatic factor concentrate, either with placebo, current best or standard treatment, or another pro-coagulant haemostatic factor concentrate for prevention or treatment of bleeding. There was no restriction on the types of participants. We excluded studies of desmopressin, tranexamic acid and aminocaproic acid and use of pro-coagulant haemostatic factors for vitamin K over-anticoagulation.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodological procedures.

MAIN RESULTS

We identified 31 RCTs with 2392 participants and 22 ongoing trials. There were 13 therapeutic RCTs that randomised 1057 participants (range from 20 to 249 participants) and 18 prophylactic trials that randomised 1335 participants (range 20 to 479 participants). The pro-coagulant haemostatic factor concentrate was fibrinogen in 23 trials, Factor XIII in seven trials and pro-thrombin complex concentrates (PCC) in one trial.Seventeen trials had industrial funding or support, eight studies either did not declare their funding or were unclear about their source of funding and six studies declared non-industrial funding sources.Certainty in the evidence and included study biasOur certainty in the evidence, using GRADE criteria, ranged from very low to high across all outcomes. We assessed most outcomes as being of low certainty. Risks of bias were a concern in many of the RCTs; randomisation methodology was unclear in 15 RCTs, with allocation concealment unclear in 14 RCTs and at high risk of bias in five RCTs. The blinding status of outcome assessors was unclear in 13 RCTs and at high risk of bias in five RCTs, although most outcomes in these trials were objective and not prone to observer bias. Study personnel were often unblinded or insufficient information was available to assess their level of blinding (five RCTs were at unclear risk and seven at high risk of bias).Primary outcomesAll-cause mortality was reported by 21 RCTs, arterial thromboembolic events by 22 RCTs, and venous thromboembolic events by 21 RCTs.Fibrinogen concentrate: prophylactic trials with inactive comparator (nine RCTs)The trials had heterogeneous clinical settings and outcome time points, so we did not pool the data. Compared to placebo, there was no evidence that prophylactic fibrinogen concentrate reduced all-cause mortality (4 RCTs; 248 participants). Compared to inactive comparators there was low- to moderate-quality evidence that prophylactic fibrinogen concentrate did not increase the risk of arterial or venous thromboembolic complications (7 RCTs; 398 participants).Fibrinogen concentrate: prophylactic trials with active comparator (two RCTs)There was no mortality or incidence of thromboembolic events in these two RCTs (with 57 participants).Fibrinogen concentrate: therapeutic trials with inactive comparator (eight RCTs)The trials had heterogeneous surgical settings and outcome time points, so we pooled data for subgroups only. Compared to an inactive comparator, there was no evidence (quality ranging from low to high) that fibrinogen concentrate reduced all-cause mortality in actively bleeding participants (7 RCTs; 724 participants). Compared to inactive comparators there was no evidence that the use of fibrinogen concentrate in active bleeding increased arterial (7 RCTs; 607 participants) or venous (6 RCTs; 562 participants) thromboembolic events.Fibrinogen concentrate: therapeutic trials with active comparator (four RCTs)We did not pool the outcome data, as they were not measured at comparable time points. Compared to other active pro-coagulant agents, there was no evidence (very low to moderate quality) that fibrinogen concentrate reduced all-cause mortality in actively bleeding participants (4 RCTs; 220 participants). There was no evidence that fibrinogen concentrate increased the risk of arterial (3 RCTs; 126 participants) or venous (4 RCTs; 220 participants) thromboembolic events.FactorXIII: Prophylactic trials with inactive comparator (six trials)The trials were heterogeneous in their surgical settings and time points for outcome analysis, so we pooled data for subgroups only. Compared to an inactive comparator, there was no evidence that prophylactic Factor XIII reduced all-cause mortality (5 RCTs; 414 participants). There was no evidence (very low to low quality) of a difference in the arterial or venous event rate between Factor XIII and inactive comparators (4 trials; 354 participants).FactorXIII: therapeutic trials with inactive comparator (one trial)There was no mortality or incidence of thromboembolic events in this trial.Prothrombin complex concentrate (PCC): prophylactic trials with inactive comparator (one trial)There was no evidence (moderate quality) that PCC reduced all-cause mortality (1 trial; 78 participants). No thromboembolic complications were reported in this trial.

AUTHORS' CONCLUSIONS

The paucity of good-quality comparable evidence precludes the drawing of conclusions for clinical practice. Further research is required to determine the risk-to-benefit ratio of these interventions. The sample sizes of future RCTs would need to be greatly increased to detect a reduction in mortality or thromboembolic events between treatment arms. To improve consistency in outcome reporting, the development of core outcome sets is essential and may help address a number of the limitations identified in this review.

Pharmacokinetics and the transition to extended half-life factor concentrates: communication from the SSC of the ISTH

Extended half-life proteins (EHL) are increasingly used in clinical practice, but there is no standardized approach to sampling, interpretation and implementation of pharmacokinetics (PK) data to maximize treatment benefit. The goal of EHL treatment is to attain a trough level sufficient to protect against spontaneous bleeds and reduce infusion frequency and limitations on individual activity and lifestyle. Performing classical PK assessments requires multiple blood samples, which is burdensome for patients and providers. Herein we review a population pharmacokinetic (popPK) approach to estimate individual PK parameters to transition patients from standard half-life (SHL) to EHL concentrates. We propose that a minimum of two to four post-infusion samples is sufficient to estimate individual PK profiles, with sufficient certainty to maintain factor levels above 1% and achieve bleed-free lifestyles. We also survey current PK use in patients transitioning to EHL, review key PK parameters and popPK models, and recommend an approach to using PK in patients initiating or switching to EHL.

Prophylaktische Faktorsubstitution bei schwerer Hämophilie A

Prophylaxe kann bei Erwachsenen mit schwerer Hämophilie A klinisch notwendig sein. Ziel war es, die prophylaktische Faktor-VIII-Substitution bei erwachsenen Patienten mit Hämophilie in Deutschland ökonomisch zu bewerten. Patienten, Methoden: Für die Analysen wurde ein Entscheidungsmodell erstellt: Zeithorizont ein Jahr; Perspektive gesetzliche Krankenkassen; Referenzpatient (RP) und zwei Patientenprofile. Die Berech-nungen basieren auf Daten aus einer struktu-rierten Literatursuche, -analyse und einer Pharmakovigilanzstudie mit Patienten zu Therapiewechsel On-demand/Prophylaxe (OD/Proph). Ergebnisse: RP: 45 Jahre, 20 Blutungen p.a. OD, 16 vermiedene Blutungen mit 8,5 I.U./kg/d Proph, Zusatzkosten 141 113 Euro p.a.; Profil 1: 50 Jahre, 55 Blutungen p.a. OD, Faktorverbrauch pro Blutung 20 I.U./kg höher als bei R P, 39 vermiedene Blutungen mit 8,5 I.U./kg/d Proph, Zusatzkosten 19 134 Euro p.a.; Profil 2: 60 Jahre, 35 Blutungen p.a. OD, Faktorverbrauch pro Blutung 40–80 I.U./kg höher als bei R P, 34 vermiedene Blutungen mit 11 I.U./kg/d Proph, Einsparung 660 Euro p.a. Schlussfolgerung: In der indivi-duellen Situation kann eine prophylaktische Faktorsubstitution bei erwachsenen Patienten auch ökonomisch sinnvoll sein. Um künftig diesen Effekt umfassend zu bewerten, werden longitudinale Daten aus dem Versorgungsalltag inklusive klinischer Outcomes, Lebensqua-lität und Adhärenz benötigt.

Predicting dose sparing benefit and bleeding risk of pharmacokinetic-based personalized prophylactic dosing of factor VIII products

BACKGROUND

Previously published factor VIII (FVIII) pharmacokinetic (PK)-based dosing approaches employ fixed infusion interval with a wide dose range that may lead to increased risk of bleeding, excessive doses or decreased health-related quality of life.

AIM

The objectives of the study includes (i) personalizing infusion interval in lieu of fixed infusion, (ii) constraining dose within the range of 10-50 IU/kg and (iii) characterizing bleeding risk of PK-based dosing in comparison with empiric standard doses.

METHODS

Patient demographics and PK parameters for conventional FVIII products were obtained from published literatures. Subject-specific PK parameters were derived from FVIII activities vs time data generated through simulation.

RESULTS

Our data indicated approximately 4%, 38%, 37% and 20% of the subjects can be dosed with infusion interval of every 24, 48, 72 and 96 hours, respectively, for maintaining a target 1 IU/dL FVIII level within the dose range of 10-50 IU/kg. Maintaining an alternative trough value of 3 or 5 IU/dL requires more frequent infusion. The predicted median probability of bleeding risk per year was 35.7% (range, 11%-49%) for PK-based dosing maintaining 1 IU/dL. Predicted median bleeding risk was 37.9% (0%-74%), 32.8% (0%-72%) and 26.7% (0%-70%) for standard dosing of 20, 30 and 50 IU/kg, respectively. PK-based dosing resulted in a dose sparing benefit compared to standard dose of 30 or 50 IU/kg three times per week.

CONCLUSION

The results of the study demonstrate the feasibility of individualizing infusion interval, restricting FVIII dose, trough and peak concentration within an acceptable range.

Treatment adherence in hemophilia

Prophylactic clotting-factor regimens reduce the occurrence of bleeding episodes and maintain joint health in individuals with moderate and severe hemophilia. However, these outcomes are only achieved with adherence to prescribed prophylaxis regimens. There are several types of barriers to adherence related to key patient, condition, treatment, health-care system, and/or socioeconomic variables. Notably, health-care professionals may not prescribe prophylaxis if they perceive that a patient will be nonadherent. Prophylactic treatment strategies should be developed with the patient and family, focused on individualized treatment goals. Personalized strategies are needed to reinforce the importance of and encourage confidence in administering the regular infusions required for prophylactic therapy. These strategies may include verbal and written information delivered by health-care professionals, peers, and inter-active media. The advent of extended half-life clotting factors requiring less frequent infusion may improve adherence.

Adherence to treatment regimen and bleeding rates in a prospective cohort of youth and young adults on low-dose daily prophylaxis for severe hemophilia A

BACKGROUND

When availability and/or affordability of anti-hemophilic factor concentrates are limited, optimal prophylaxis regimens in severe hemophilia A (HA) remain to be determined. In selected situations, low-dose daily prophylaxis (LDDP) may be an effective and economical option. The goal of our study was to evaluate if subjects on a LDDP regimen could achieve adherence and good clinical outcome.

METHODS

Seventeen subjects (age between 15.2 and 28.4) on LDDP suffering from severe/moderate HA were followed prospectively for 2 to 3 years as part of a health-related quality of life (HRQoL) study. Bleeding and treatments data were collected using electronic diaries and validated every three months. The SF-36 questionnaire was administered at the beginning of the study and then every 6 months until the end of the study.

RESULTS

The subjects (mean age 22.0, median 21.9, standard deviation 4.06), were all from a single centre and on LDDP for at least 12 months as part of their routine care before entering the study. Fifteen subjects were prescribed a daily dose of 500 IU factor VIII (FVIII) and 2 subjects received 1000 IU FVIII per day, resulting into a median dose of 7.1 IU/kg/day (ranging from 4 to 13 IU/kg/day) and of 2591 IU/kg/year. Median adherence (the percentage of the prescribed daily dose received) was 84 % (mean 80 %, range 57 % to 94 %) throughout the study. Seventy-six bleeds in the 6 index joints and 51 other types of bleeds were observed throughout the study. The median annualized bleeding rate in joints (ABRjoints) was 0.7 and the median annualized bleeding rate for all bleeds (ABRall) was 1.6. The Physical Component and Mental Component Summary scores of SF-36, and the Hemophilia Joint Health Score were not significantly different over the course of the study (respective medians of 49.8, 52.4 and 16.0 at entry; vs. 52.5, 51.5 and 16.0 upon exit).

CONCLUSIONS

This prospective longitudinal study in youth and young adults shows that LDDP may be associated with low ABRs, adequate adherence and HRQoL comparable to previously reported.

New and Emerging Agents for the Treatment of Hemophilia: Focus on Extended Half-Life Recombinant Clotting Proteins

Hemophilia A and B are X-linked disorders caused by deficient or defective clotting factor VIII (FVIII) or IX factor (FIX) proteins, and characterized by spontaneous or traumatic bleeding into joints and muscles. Previous use of plasma and plasma-derived clotting factors that lacked appropriate viral inactivation steps in manufacturing led to significant morbidity associated with transfusion-transmitted HIV and hepatitis C virus (HCV). The development of recombinant proteins revolutionized their treatment, and, with no new HIV or HCV infection via clotting proteins for nearly 30 years, greatly improved their lifespan, which now approaches that of the general population, and with the same risks for aging complications. Novel long-acting factor proteins are being licensed to extend FVIII and FIX half-life, thereby reducing infusion frequency and potentially bleed frequency and associated morbidity. Further, novel therapeutics which take advantage of new technologies, including siRNA, monoclonal antibody, and small peptide inhibition technologies, have the potential to simplify treatment and improve outcomes for those with inhibitors.

[Treatment of haemophilia in Austria]

This guideline which is endorsed by the Austrian Society of Haemophilia, the Austrian Society of Paediatrics, and the Austrian Society of Haematology & Medical Oncology is intended to give a clear and practical guidance for diagnosing and treating haemophilia in Austria. In the treatment of haemophilia there are few controlled interventional trials, and recommendations usually have a rather low level of evidence.The main basis for this paper are the new international guidelines by the World Federation of Hemophilia, published in 2013. These were adapted according to the local situation and experience.Covered topics are diagnostics, control visits, pharmacological treatment options, prophylaxis and treatment in children and adults, possible problems arising in haemophilia carriers and special aspects like home therapy, options for venous catheters, management of various traumas, bleedings and interventions, including dental procedures, and last not least inhibitors and their treatment.

National needs assessment of patients treated at the United States Federally-Funded Hemophilia Treatment Centers

AIM

The National Hemophilia Program Coordinating Center, with the U.S. Regional Hemophilia Network conducted a national needs assessment of U.S. Hemophilia Treatment Center (HTC) patients. The objectives were to determine: (i) To what extent do patients report that they receive needed services and education; (ii) How well do the services provided meet their needs; and (iii) What are the patients' perspectives about their care.

METHODS

A survey was mailed to active patients of 129 HTCs. Respondents completed the anonymous surveys on line or returned them by mail. Questions focused on management and information, access and barriers to care, coping, resources, and transition.

RESULTS

Of 24 308 questionnaires mailed, 4004 (16.5%) were returned. Most respondents reported very few gaps in needed services or information and reported that services and information met their needs. Over 90% agreed or strongly agreed that care was patient-centred and rated HTC care as important or very important. Identified gaps included dietary advice, genetic testing, information on ageing, sexual health and basic needs resources. Minority respondents reported more barriers.

CONCLUSION

This survey is the largest assessment of the HTC population. Respondents reported that the services and information provided by the HTCs met their needs. Quality improvement opportunities include transition and services related to ageing and sexual health. Further investigation of barriers to care for minorities is underway. Results will help develop national priorities to better serve all patients in the US. HTCs.

Benefits of prophylaxis versus on-demand treatment in adolescents and adults with severe haemophilia A: the POTTER study

Rigorous evidence is lacking on long-term outcomes of factor VIII (FVIII) prophylaxis initiated in adolescent or adult patients with severe haemophilia A. The prospective, open-label Prophylaxis versus On-demand Therapy Through Economic Report (POTTER) study (ClinicalTrials.gov NCT01159587) compared long-term late secondary prophylaxis (recombinant FVIII-FS 20-30 IU/kg thrice weekly) with on-demand treatment in patients aged 12 to 55 years with severe haemophilia A. The annual number of joint bleeding episodes (primary endpoint), total bleeding episodes, orthopaedic and radiologic (Pettersson) scores, health-related quality of life (HRQoL), pharmacoeconomic impact, and safety were evaluated over a > 5-year period (2004-2010). Fifty-eight patients were enrolled at 11 centres in Italy; 53 (27 prophylaxis, 26 on demand) were evaluated and stratified into 2 age subgroups (12-25 and 26-55 years). Patients receiving prophylaxis experienced a significantly lower number of joint bleeding episodes vs the on-demand group (annualised bleeding rate, 1.97 vs 16.80 and 2.46 vs 16.71 in younger and older patients, respectively; p=0.0043). Results were similar for total bleeding episodes. Prophylaxis was associated with significantly fewer target joints (p< 0.001), better orthopaedic (p=0.0019) and Pettersson (p=0.0177) scores, better HRQoL, and fewer days of everyday activities lost (p< 0.0001) but required significantly higher FVIII product consumption. The POTTER study is the first prospective, controlled trial documenting long-term benefits of late secondary prophylaxis in adolescents and adults with severe haemophilia A. The benefits of reduced bleeding frequency, improved joint status, and HRQoL may offset the higher FVIII consumption and costs.

Prophylaxis in older Canadian adults with hemophilia A: lessons and more questions

BACKGROUND

Although prophylaxis is a standard of care for young children in developed countries, known to reduce the severity of hemophilic arthropathy, older adults with existing arthropathy have not traditionally used prophylaxis. Recent studies have shown that adults with hemophilia A are increasingly adopting prophylaxis but the characteristics of this treatment in older adults are not well understood. This multicenter observational study was conducted to describe how secondary/tertiary prophylaxis is being used in older adults (≥40 years of age) in comparison to younger adults with severe hemophilia A.

METHODS

Eligible adult (≥18 years of age) Canadian males with baseline FVIII:C ≤2% from the participating centres were observed over a 2 year period.

RESULTS

Of the 220 adult severe hemophilia patients enrolled, 70% (155/220) used prophylaxis during the observational period. Only 27% (60/220) are older adults with very few >60 years of age. A lower proportion of older adults use prophylaxis compared to younger adults (58% vs. 75%, p = 0.016), with most patients in both groups using continuous prophylaxis (92 and 94% respectively). When considering all treatment modalities together, younger subjects use more factor concentrate than older subjects (2437 u/kg/year vs. 1702 u/kg/year, p = 0.027); however, older subjects on prophylaxis use 3447 u/kg/year and had an ABR of 12 while those on demand use 560 u/kg/year and had an ABR of 13.

CONCLUSION

A significant number of older adults use secondary/tertiary continuous prophylaxis in Canada, accounting for a significant fraction of factor concentrate utilization.

Understanding patient preferences and willingness to pay for hemophilia therapies

BACKGROUND

Despite clearly improved clinical outcomes for prophylaxis compared to on-demand therapy, on average only 56% of patients diagnosed with severe hemophilia receive prophylactic factor replacement therapy in the US. Prophylaxis rates generally drop as patients transition from childhood to adulthood, partly due to patients becoming less adherent when they reach adulthood. Assessment of patient preferences is important because these are likely to translate into increased treatment satisfaction and adherence. In this study, we assessed preferences and willingness to pay (WTP) for on-demand, prophylaxis, and longer acting prophylaxis therapies in a sample of US hemophilia patients.

METHODS

Adult US hemophilia patients and caregivers (N=79) completed a discrete-choice survey that presented a series of trade-off questions, each including a pair of hypothetical treatment profiles. Using a mixed logit model for analysis, we compared the relative importance of five treatment characteristics: 1) out-of-pocket treatment costs (paid by patients), 2) factor dose adjustment, 3) treatment side effects, 4) availability of premixed factor, and 5) treatment effectiveness and dosing frequency. Based on these attribute estimates, we calculated patients' WTP.

RESULTS

Out-of-pocket treatment costs (P<0.001), side effects (P<0.001), and treatment effectiveness and dosing frequency (P<0.001) were found to be statistically significant in the model. Patients were willing to pay US $410 (95% confidence interval: $164-$656) out of pocket per month for thrice-weekly prophylaxis therapy compared to on-demand therapy and $360 (95% confidence interval: $145-$575) for a switch from thrice-weekly to once-weekly prophylaxis therapy.

CONCLUSION

Improvements in treatment effectiveness and dosing frequency, treatment side effects, and out-of-pocket costs per month were the greatest determinants of hemophilia treatment choice and WTP. The positive preferences and WTP for longer acting prophylactic therapies suggest that the uptake is likely to increase adherence, improving treatment outcomes. These preferences should also inform the Food and Drug Administration's assessment of new longer acting hemophilia therapies.

Controlled, cross-sectional MRI evaluation of joint status in severe haemophilia A patients treated with prophylaxis vs. on demand

In patients with haemophilia A, factor VIII (FVIII) prophylaxis reduces bleeding frequency and joint damage compared with on-demand therapy. To assess the effect of prophylaxis initiation age, magnetic resonance imaging (MRI) was used to evaluate bone and cartilage damage in patients with severe haemophilia A. In this cross-sectional, multinational investigation, patients aged 12-35 years were assigned to 1 of 5 groups: primary prophylaxis started at age <2 years (group 1); secondary prophylaxis started at age 2 to <6 years (group 2), 6 to <12 years (group 3), or 12-18 years (group 4); or on-demand treatment (group 5). Joint status at ankles and knees was assessed using Compatible Additive MRI scoring (maximum and mean ankle; maximum and mean of all 4 joints) and Gilbert scores in the per-protocol population (n = 118). All prophylaxis groups had better MRI joint scores than the on-demand group. MRI scores generally increased with current patient age and later start of prophylaxis. Ankles were the most affected joints. In group 1 patients currently aged 27-35 years, the median of maximum ankle scores was 0.0; corresponding values in groups 4 and 5 were 17.0 and 18.0, respectively [medians of mean index joint scores: 0.0 (group 1), 8.1 (group 2) and 13.8 (group 4)]. Gilbert scores revealed outcomes less pronounced than MRI scores. MRI scores identified pathologic joint status with high sensitivity. Prophylaxis groups had lower annualized joint bleeds and MRI scores vs. the on-demand group. Primary prophylaxis demonstrated protective effects against joint deterioration compared with secondary prophylaxis.

Haemophilia Experiences, Results and Opportunities (HERO) study: treatment-related characteristics of the population

The HERO (Haemophilia Experiences, Results and Opportunities) quantitative surveys collected information on characteristics and perceptions of adult persons with haemophilia (PWH) and parents of children with haemophilia. The aim of this article is to describe the perceptions of PWH and parents on psychosocial aspects related to treatment. Two online surveys (one for PWH, one for parents) were conducted in 10 countries. Among 675 PWH respondents, 77% reported having responsibility for their own care; 72% of 561 parent respondents had the main responsibility for their son. PWH were most commonly treated on demand (45% of 648 adults using factor concentrate), with 32% on regular prophylaxis and 23% treated on demand with short-term prophylaxis (e.g. for sports/physiotherapy). Children were most often treated with prophylaxis (65% of 549 children using factor concentrate), with 26% treated on demand and 8% treated on demand with short-term prophylaxis. Factor was generally used as instructed at home. Some respondents (41% PWH; 30% parents) had difficulties/concerns with factor availability/affordability. PWH reported more bleeds in the last 12 months than parents reporting their son's bleeds (mean 17.8 vs. 8.7). Both PWH and parents generally perceived that overall, their (their son's) haemophilia was well controlled. Results differed by country. The HERO study captured new, patient-based data regarding many facets of life relevant to PWH, including treatment. The information conveyed in this article largely represents new insights regarding perceptions of treatment and provides initial benchmark statistics for further research.

Prophylaxis in adult patients with severe haemophilia A

Primary prophylaxis is the standard of care for children and adolescents with severe haemophilia; however, its role in adults is less well defined. To establish to which extent prophylaxis is currently being used in adults with severe haemophilia A, we conducted a systematic review of the literature by searching MEDLINE using the terms "prophylaxis", "adult", "severe" and "haemophilia A". Evidence-based guidelines and national studies relating to the use of prophylaxis in adults with severe haemophilia A were identified and reviewed. One published evidence-based guideline and three published studies fulfilled our inclusion criteria. A combined analysis of published data suggests that almost 45% of adult patients with severe haemophilia A are being treated with prophylaxis. Withdrawal of prophylaxis is attempted relatively infrequently; however, when attempted, around 27% of adolescents and adults with severe haemophilia do not experience an increase in bleeding tendency over a specific treatment period. Prophylaxis (primary and secondary) is an important part of haemophilia treatment that should be granted to all patients depending on their clinical presentation. Further studies are needed to better define this treatment strategy in adults.

Adherence to clotting factors among persons with hemophilia A or B

OBJECTIVE

Evaluate adherence to clotting factor treatment and associated outcomes for patients with hemophilia using an integrated delivery database.

METHODS

This was a retrospective, observational study tracking patients between 2006 and 2011. Patients with diagnosis codes for hemophilia were identified. Bleeding and complication rates were annualized over the study period. Medication adherence was assessed using prescription claims for clotting factors by examining sequential time periods of 180 days for each patient's continuous enrollment. Adherence within the time period was calculated using the 'days supply' field divided by 180 days. Under the assumption that severe patients should be treated prophylactically, patients were considered adherent within the time period if the ratio of 'days supply' to observed days was 60% or greater.

RESULTS

A total of 207 patients (74.9 and 25.1% hemophilia A and B, respectively) met the inclusion/exclusion criteria. There were 101 (48.8%) mild, 32 (15.5%) moderate, and 74 (35.7%) severe patients with hemophilia. The percentage of time periods where adherence to clotting factors was 60% or greater was 14% (SD = 28%) for mild disease, 21% (SD = 32%) for moderate disease, and 51% (SD = 36%) for severe disease. Among patients with severe disease, 27 (36.5%) were adherent ≤ 30% of time periods, 22 (29.7%) adherent 31-70% of the time periods, and 25 (33.8%) were adherent ≥ 71% of time periods. Joint bleeding episodes and hospitalizations were uncommon events among the three groups.

CONCLUSIONS

Among patients with severe disease, the majority (66.2%) were adherent <70% of the time.

Assessment of the impact of treatment on quality of life of patients with haemophilia A at different ages: insights from two clinical trials on turoctocog alfa

Haemophilia and its treatment interfere with patients' life, so health-related quality of life (HRQoL) should be assessed when evaluating treatments. This study investigated the HRQoL of patients with haemophilia A treated prophylactically with a new recombinant factor VIII. Two phase 3 trials investigated turoctocog alfa in patients with severe haemophilia A: one in children, one in adults and adolescents. HRQoL was a secondary endpoint assessed by the HAEMO-QOL age-specific, self-administered questionnaires. Parent-completed versions were also included for parents of children and adolescents. All HAEMO-QOL questionnaires allow the calculation of domain-specific and total scores ranging from 0 to 100, lower scores indicating better HRQoL. Mean change in all scores was described for 25 children aged 4-7 years, 21 children aged 8-12 years, 18 adolescents aged 13-18 years and 129 adults, overall, and according to the treatment regimen received prior to the study (on-demand; prophylaxis; mixed). Mean changes in HAEMO-QOL total score were 1.4 for children aged 4-7 years, -2.6 for children aged 8-12 years, -5.8 for adolescents and -1.6 for adults. In parent-completed versions, mean changes in total score were -6.0 for children aged 4-7 years, -4.7 for children aged 8-12 years, and -10.0 for adolescents. Patients receiving on-demand treatment before the trial showed greater improvement in HRQoL scores than patients already on prophylaxis. HRQoL of patients remained fairly stable over the course of the trials. However, improvements were observed for adolescents. Switching to prophylaxis was identified as a potential driver of improvement of HRQoL in patients with haemophilia A.

Factor VIII therapy for hemophilia A: current and future issues

Hemophilia A is a congenital, recessive, X-linked bleeding disorder that is managed with infusions of plasma-derived or recombinant factor (F) VIII. The primary considerations in FVIII replacement therapy today are the: 1) immunogenicity of FVIII concentrates, 2) role of longer-acting FVIII products, 3) prophylactic use of FVIII in children and adults with severe hemophilia A, and 4) affordability and availability of FVIII products. Improving patient outcomes by increasing the use of FVIII prophylaxis, preventing or eliminating FVIII inhibitors, and expanding access to FVIII concentrates in developing countries are the major challenges confronting clinicians who care for patients with hemophilia A.

Advancing personalized care in hemophilia A: ten years' experience with an advanced category antihemophilic factor prepared using a plasma/albumin-free method

Detailed analysis of data from studies of recombinant antihemophilic factor produced using a plasma/albumin-free method (rAHF-PFM) in previously treated patients showed a substantial level of interpatient variation in pharmacokinetics (PKs), factor VIII dosing, and annualized bleed rate (ABR), suggesting that individual patient characteristics contributed to outcome. For example, plasma half-life (t_1/2), recovery, and clearance appeared to differ between patients aged <6 years and 10–65 years. Prophylaxis resulted in lower ABRs than episodic treatment in both age groups; better adherence to the prophylactic regimen resulted in a lower ABR in patients aged 10–65 years. The weekly frequency of dosing and adherence to dosing were both significantly and inversely related to the rate of bleeding (young children, P<0.0001 for both all bleeds and joint bleeds; older patients, P<0.0001 for all bleeds and P<0.05 for joint bleeds), as was adherence to dosing frequency (P<0.0001 for all comparisons). A post-marketing randomized study of prophylaxis demonstrated that a PK-guided dosing regimen, based on an individual patient’s rAHF-PFM PK (infusion interval, estimated t_1/2, and recovery), was as effective as standard prophylaxis and that both prophylactic regimens were superior to episodic treatment with respect to ABR and quality of life measures. Thus, compared with standard prophylaxis, the PK-guided regimen achieved comparable efficacy with fewer weekly infusions. A two-compartment population PK model describes the PK data across the entire age range and forms the basis for future PK-guided therapy with rAHF-PFM. The model confirmed a shorter t_1/2 and faster clearance of rAHF-PFM in children <6 years of age versus patients ≥10 years and predicted similar PK parameters with either a full or reduced blood sampling schedule, offering the potential for the use of PK-guided, individualized treatment in the routine clinical care setting.

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

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

Current prescription of prophylactic factor infusions and perceived adherence for children and adolescents with haemophilia: a survey of haemophilia healthcare professionals in the United States

The primary goal of prophylaxis in patients with severe haemophilia is to convert the phenotype from severe to moderate and to prevent the development of chronic arthropathy. Prior studies have demonstrated that prophylaxis decreases episodes of joint bleeds and chronic arthropathy. Effectiveness depends on prescription of prophylaxis and adherence to the prescribed regimen. The aim of this study was to determine if prescription of prophylaxis for children with haemophilia and perceptions of adherence to prophylaxis have changed since publication of the Joint Outcome Study (JOS). A questionnaire was sent, in electronic and written formats, to health professionals who provide care to children with haemophilia at US haemophilia treatment centres (HTCs). The response rate was 56 of 128 (44%) of the targeted HTCs. There were a few missing data and denominators are provided. All responses agreed with the results of the JOS and 30/55 (55%) reported the JOS increased their prescription of prophylaxis. Nineteen of 56 (34%) physicians or HTC staff reported that they had not prescribed prophylaxis within the last year due to concerns about adherence, and 19/56 (34%) reported they had stopped prophylaxis due to concerns about adherence within the last year. Predicted adherence decreased with increasing age. Prescription of prophylaxis appears to be increasing since publication of the JOS. Strategies to improve adherence may increase the likelihood of physician prescription of prophylaxis and make prophylaxis easier to implement for individual patients, thereby improving the clinical outcome of children and adults with haemophilia.

Rationale for a randomized controlled trial comparing two prophylaxis regimens in adults with severe hemophilia A: the Hemophilia Adult Prophylaxis Trial

A major goal of comprehensive hemophilia care is to prevent occurrence of bleeds by prophylaxis or regular preventive factor, one or more times weekly. Although prophylaxis is effective in reducing bleeding and joint damage in children, whether it is necessary to continue into adulthood is not known. The purpose of this article is to describe a Phase III randomized controlled trial to evaluate prophylaxis comparing two dose regimens in adults with severe hemophilia A. I hypothesize that adults with mature cartilage and joints are less susceptible to joint bleeds and joint damage, and that once-weekly recombinant factor VIII prophylaxis, with up to two rescue doses per week, is as effective as thrice-weekly prophylaxis in reducing bleeding frequency, but less costly and more acceptable, with higher quality of life. The ultimate goal of this project is to determine whether once-weekly prophylaxis is any worse than thrice-weekly prophylaxis in reducing joint bleeding frequency, while potentially utilizing less factor, at lower cost, leading to a better quality of life. This is an innovative concept, as it challenges the current paradigm of thrice-weekly prophylaxis in adults, which is based on dosing in children. Furthermore, this trial will assess interdose thrombin generation, a novel tissue factor-based assay of hemostasis, to determine if individualized thrombin generation can predict more individualized prophylaxis dosing, which would be practice changing.

Hemophilia-Specific Quality of Life Index (Haemo-QoL and Haem-A-QoL questionnaires) of children and adults: result of a single center from Turkey

The aim of this study is to describe the health status, health care received, and their impact on the quality of life in patients with hemophilia. Patients with severe factor VIII or IX deficiency without inhibitors or other chronic disease were enrolled. Turkish version of the Hemophilia-Specific Quality of Life Index (Haemo-QoL) questionnaire was administered to the pediatric patients aged 4 to 16 years and Haem-A-QoL to the adult patients. Joints were evaluated according to the World Federation of Hemophilia (WFH) orthopedic joint scores.Thirty-nine children/adolescents and 31 adult patients were enrolled. Mean Haemo-QoL scores were 39.6 +/- 15.0 for the children and mean Haem-A-QoL 47.4 +/- 14.1 for the adult patients, respectively. Internal consistency reliability was generally sufficient. Total Cronbach's alpha coefficient was >.70 (range .77-.96) in all the age groups. Mean total WFH orthopedic joint scores were 1.83 +/- 2.7, 4.9 +/- 4.96, and 6.94 +/- 6.15 in 4-7, 8-12, and 13-16-year-old groups, respectively. They were more impaired in the adult patients (16.23 +/-14.12). These results show that the Turkish version of the Haemo-QoL and Haem-A-QoL are reliable instruments to measure the quality of life in the pediatric and adult patients with severe hemophilia. When compared to the Haemo-QoL scores of an international multicenter West European study of children, quality of life in the Turkish patients were more impaired in the subscales of physical health, feeling, view, school and sport, and treatment as well as more impaired WFH joint scores. The authors recommend primary factor prophylaxis and encouraging the patients to learn home treatment to improve joint scores and quality of life.