Cost of care of haemophilia with inhibitors

Efficacy, safety and cost of emicizumab prophylaxis in haemophilia A patients with inhibitors: A nationwide observational study in Taiwan

INTRODUCTION

Emicizumab mimicking the cofactor function of activated factor VIII (FVIII) restores haemostasis.

METHODS

This nationwide observational study aimed to retrospectively investigate efficacy, safety, and cost in 1 year before and up to 3 years after emicizumab prophylaxis for haemophilia A (HA) patients with FVIII inhibitors.

RESULTS AND DISCUSSION

A total of 39 severe HA patients with a median age of 23.0 years were enrolled. The median historical peak FVIII inhibitor titre was 174.2 BU/mL with an interquartile range of 56.5-578.8 BU/mL. The median annualized bleeding rate reduced from 24 to 0 events in the first year after emicizumab prophylaxis (p < .01) and sustained in the second and third years. The median annualized joint bleeding rate reduced to 0 and maintained up to 3 years (p < .01). Twenty-seven patients (69.2%) had target joints before emicizumab prophylaxis and only seven patients (17.9%) of them had target joints after prophylaxis. Medical costs, including cost of haemostatic therapy, frequency of outpatient department visits, emergency room visits and hospital admission, were significantly reduced after emicizumab prophylaxis (p < .01). FVIII inhibitor titre decreased after emicizumab prophylaxis. Overall, three (7.7%) patients experienced 202 grade 1 drug-related adverse events after emicizumab prophylaxis. No serious adverse events were reported during emicizumab prophylaxis period. The adherence to emicizumab prophylaxis was 100% up to 3 years.

CONCLUSIONS

HA patients with FVIII inhibitors treated with emicizumab prophylaxis resulted in a significant reduction in treated bleeds and associated costs. No new safety events were observed.

Simoctocog alfa (Nuwiq®) in previously untreated patients with severe haemophilia A-Final efficacy and safety results from the NuProtect study

INTRODUCTION

Simoctocog alfa (Nuwiq®) is a 4th generation recombinant FVIII with proven efficacy for the prevention and treatment of bleeding episodes (BEs) in previously treated patients with severe haemophilia A. The NuProtect study assessed the immunogenicity, efficacy and safety of simoctocog alfa in 108 previously untreated patients (PUPs). The incidence of high-titre inhibitors was 16.2% and no patients with non-null F8 mutations developed inhibitors.

AIM

To report the efficacy and safety results from the NuProtect study.

METHODS

PUPs received simoctocog alfa for prophylaxis, treatment of BEs, or as surgical prophylaxis. The efficacy of prophylaxis (during inhibitor-free periods) was assessed using annualised bleeding rates (ABRs). The efficacy in treating BEs and in surgical prophylaxis was assessed using a 4-point scale. Adverse events were recorded throughout the study.

RESULTS

Of 108 PUPs treated with simoctocog alfa, 103 received at least one prophylactic dose and 50 received continuous prophylaxis for at least 24 weeks. In patients on continuous prophylaxis, the median ABR was 0 (mean 0.5) for spontaneous BEs and 2.5 (mean 3.6) for all BEs. In 85 patients who had BEs, efficacy of BE treatment was excellent or good for 92.9% (747/804) of rated BEs; 92.3% of BEs were treated with 1 or 2 infusions. The efficacy of surgical prophylaxis was excellent or good for 94.7% (18/19) of rated procedures. There were no safety concerns and no thromboembolic events.

CONCLUSION

Simoctocog alfa was efficacious and well tolerated as prophylaxis, surgical prophylaxis and for the treatment of BEs in PUPs with severe haemophilia A.

Plasma-derived FVIII/VWF complex shows higher protection against inhibitors than isolated FVIII after infusion in haemophilic patients: A translational study

Introduction

Presence of von Willebrand factor (VWF) in FVIII concentrates offers protection against neutralizing inhibitors in haemophilia A (HA). Whether this protection is more evident in plasma‐derived (pd) FVIII/VWF or recombinant (r) FVIII concentrates remains controversial.

Aim

We investigated the protection exerted by VWF against FVIII inhibitors in an in vivo mouse model of HA exposed to pdFVIII/VWF or to various rFVIII concentrates.

Methods

Haemophilia A mice received the different FVIII concentrates after administration of vehicle or an inhibitory IgG purified from a commercial pool of HA plasma with inhibitors and FVIII:C recoveries were measured. Furthermore, using a novel clinically oriented ex vivo approach, Bethesda inhibitory activities (BU) of a commercial pool of HA plasma with inhibitors were assessed using normal plasma, or plasma from severe HA patients, without inhibitors, after treatment with the same concentrates.

Results

in vivo studies showed that pdFVIII/VWF offers markedly higher protection against inhibitors when compared with any of the FVIII products without VWF. More importantly, in the ex vivo studies, plasma from patients treated with pdFVIII/VWF showed higher protection against inhibitors (P values ranging .05‐.001) in comparison with that observed in plasma from patients who received FVIII products without VWF, regardless of the type of product evaluated.

Conclusion

Data indicate that FVIII+VWF complexes assembled in the circulation after rFVIII infusion are not equivalent to the naturally formed complex in pdFVIII/VWF. Therefore, rFVIII infused into HA patients with inhibitors would be less protected by VWF than the FVIII in pdFVIII/VWF concentrates.

Immune Tolerance Induction (ITI) with a pdFVIII/VWF Concentrate (octanate) in 100 Patients in the Observational ITI (ObsITI) Study

Background  Immune tolerance induction (ITI) with repeated factor VIII (FVIII) administration is the only strategy proven to eradicate inhibitors. The observational ITI study is evaluating ITI with a range of FVIII products.

Methods  This subgroup analysis reports prospective interim data for patients treated with a plasma-derived, von Willebrand factor-stabilized FVIII concentrate (pdFVIII/VWF, octanate). Complete success (CS) of ITI required achievement of three criteria: inhibitor titer < 0.6 BU/mL; FVIII recovery ≥ 66%; FVIII half-life ≥6 hours. Partial success (PS) required achievement of two criteria and partial response (PR) one. ITI success was defined as CS or PS. Data were analyzed for patients who achieved CS, had 36 months' observation, or failed ITI.

Results  One-hundred prospectively enrolled patients were included in the analysis; 91 had poor prognosis factors for ITI success. The mean (standard deviation) daily ITI dose was 116.4 (61.1) IU FVIII/kg in 14 low responders (< 5 BU/mL) and 173.7 (112.0) IU FVIII/kg in 86 high responders (≥ 5 BU/mL). Inhibitor titers < 0.6 BU/mL were achieved in 71% of patients in a median of 4.01 months, accompanied by a 93% reduction in bleeding rate. ITI success was achieved by 70% of patients and 56 of 72 (78%) primary (first-line) ITI patients. PR was achieved by 5 patients; ITI failed in 25 patients. PS and CS were achieved in a median of 5.55 and 11.25 months, respectively.

Conclusions  ITI with pdFVIII/VWF led to rapid eradication of FVIII inhibitors, normalization of FVIII pharmacokinetics in the majority of patients, and a significant reduction in bleeding rates.

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

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

Simoctocog Alfa (Nuwiq) in Previously Untreated Patients with Severe Haemophilia A: Final Results of the NuProtect Study

Introduction  FVIII inhibitor development is the most serious contemporary treatment complication in haemophilia A, particularly in previously untreated patients (PUPs). No inhibitors developed in clinical trials in previously treated patients treated with simoctocog alfa (Nuwiq), a fourth-generation recombinant FVIII produced in a human cell line.

Methods  The NuProtect study investigated the immunogenicity of simoctocog alfa in PUPs. NuProtect was a prospective, multinational, open-label, non-controlled, phase III study. PUPs with severe haemophilia A (FVIII:C <1%) of any age and ethnicity were treated with simoctocog alfa for 100 exposure days or a maximum of 5 years. Patients were true PUPs without prior exposure to FVIII concentrates or blood components. Inhibitor titres were measured with the Nijmegen-modified Bethesda assay; cut-off for positivity was 0.6 BU mL ⁻¹ (≥0.6 to <5 low-titre, ≥5 high titre).

Results  A total of 108 PUPs with a median age at first treatment of 12.0 months (interquartile range: 8.0–23.5) were treated with simoctocog alfa. F8 mutation type was known for 102 patients (94.4%) of whom 90 (88.2%) had null F8 mutations and 12 (11.8%) had non-null mutations. Of 105 PUPs evaluable for inhibitor development, 28 (26.7%) developed inhibitors; 17 high titre (16.2%) and 11 low titre (10.5%). No PUPs with non-null F8 mutations developed inhibitors.

Conclusion  In the NuProtect study, the rate of inhibitor development in PUPs with severe haemophilia A treated with simoctocog alfa was lower than the rate reported for hamster-cell-derived recombinant factor VIII products in other recent clinical trials. No inhibitors were reported in PUPs with non-null F8 mutations.

Characterisation of healthcare utilisation and cost of haemophilia care in real-life: A 4-year follow-up study in Finland

INTRODUCTION

Characterisation of outcomes and costs of haemophilia care in common practice settings is essential for evaluation of new treatment options and for developing clinical practices. In Finland, haemophilia care is mostly centralised to University Hospitals, but treatment practices and costs in adult patients have not been systematically evaluated.

AIM

This study was designed to characterise healthcare resource utilisation and treatment costs of adult inhibitor-negative haemophilia patients managed in Finnish University Hospitals.

METHODS

The study was based on a nationwide cohort, which consists of all adult haemophilia A (HA; n = 120) and B (HB; n = 35) patients treated in University Hospitals from 2012 to 2016. Patient characteristics and data on healthcare utilisation and factor replacement use were collected from medical records. Direct costs of care were evaluated based on wholesale drug prices and healthcare service utilisation with standard unit costs.

RESULTS

Most of HA (79%, n = 96) and HB (84%, n = 31) patients received factor replacement therapy. The median annual bleeding rate (ABR) was low, at 0.8 for HA and 0.5 for HB, also among the patients with on-demand therapy. Over 94% (n = 149) of the patients had outpatient visits during the follow-up period. The mean total annual costs of treatment ranged from €2520 to €176,330. The highest individual cost was factor replacement therapy.

CONCLUSION

The outcomes of centralising the management of care to University Hospital Treatment Centres show low ABR and lower treatment costs compared with earlier reports from other high-income European populations. Management strategies, including choosing the right therapy between prophylaxis and on-demand, has been successful in Finland.

The evolving landscape of gene therapy for congenital haemophilia: An unprecedented, problematic but promising opportunity for worldwide clinical studies

With liver-directed gene therapy, congenital haemophilia has the potential to progress from an incurable to a phenotypically curable condition. However, the proportion of haemophilia population likely to benefit from gene therapy remains to be established. Achieving a phenotypic curative goal is presently hampered by: 1) availability of effective treatments (e.g. extended half-life products, non-factor therapies) that address major unmet needs in haemophilia; 2) key differences between hope and reality that patients undergoing gene therapy face (e.g. unknown risks and long-term follow-up, durability of the therapeutic effect, possibility of re-administering the vector), 3) lack of expertise of health care professionals (HCP) in managing/monitoring unexpected side effects in patients, and 4) lack of expertise of HCP in advising payers on key issues for cost-effectiveness analyses of gene therapy (e.g., eligibility criteria, predictability of response, unknown risks, long-term complications). There is also uncertainty about the possibility to absorb the cost of the "one-time, one-dose cure" by payers that are used to different payment models. An active partnership between regulators, payers, patients and health care professionals is key to identify patient sub-populations that might benefit the most from gene therapy, and to align the interests of patients (needing effective disease correction and improved quality of life) and pharma companies (reluctant to lose the profitability of lifelong repeated treatments). Educational programs will provide the healthcare chain with information on the strategy that is expected to transform morbidity and mortality patterns and how it should be regarded as part of the future therapeutic options in haemophilia.

Mixing-based inhibitor screening in haemophilia A: challenges in interpretation

: Inhibitor development in haemophilia A patients is a dreaded complication of factor VIII (FVIII) replacement therapy. With increasing use of FVIII replacement therapy, there is an imperative need for cost-effective and standardized screening. To evaluate the efficacy of mixing-based inhibitor screening (MBIS) in the detection of FVIII inhibitors and to assess the best cut-off values for MBIS. Forty inhibitor positive and 40 inhibitor negative haemophilia A patients, diagnosed by standard criteria, with detailed clinical, haematological and on-demand treatment records were included. MBIS was evaluated in all 80 cases and a classical Bethesda assay and Nijmegen modification of Bethesda assay (NBA) were used as gold standards for inhibitor diagnosis. Classical Bethesda assay missed eight cases, most with low titres, which were confirmed by NBA. A systematic analysis of cut-offs for MBIS using a receiver operating characteristic curve fixed the cut-off at more than 5 s. MBIS detected 36 out of 40 inhibitor positive haemophilia A patients with a sensitivity, specificity, PPV and NPV of 90.0, 95, 94.7, 90.5%, respectively, whereas at the conventional cut-off of more than 10 s, MBIS detected only 25 of 40 cases with a low sensitivity of 62.5%. The likelihood ratio of a positive test was 11. The false-negative haemophilia A patients had low titres from 1.6 to 4.2 BU/ml. MBIS at a cut-off of 5 s can be considered as an effective screening test in low-resource situations. In clinical situations and in cases with clinical evidence of inhibitors we recommend that a direct NBA should be done.

Paradigm shift for the treatment of hereditary haemophilia: Towards precision medicine

Patients with haemophilia A (HA) or B (HB) experience spontaneous limb- or life-threatening bleedings which are prevented by regular prophylactic intravenous infusions of the deficient coagulation factor (FVIII or FIX). Prophylaxis with subcutaneous long-acting non-factor products that improve in vivo thrombin generation is now under intensive investigation (concizumab, fitusiran) or successfully employed (emicizumab) in haemophilia patients. Both haemophilia patients with/without inhibitors take advantage of non-factor products employed alone. In those who also need bypassing agents (or FVIII concentrates) for breakthrough bleeds, thromboembolic events and/or thrombotic microangiopathy may occur. By enhancing thrombin generation, prothrombotic mutations co-segregating with FVIII/FIX gene mutations may trigger thrombotic episodes in HA patients carrying acquired thrombogenic factors (e.g. venous catheters). A thorough knowledge of individual needs increasingly contributed to improve comprehensive care and personalize treatments in haemophilia. Integrating genomics, lifestyle and environmental data is expected to be key to: 1) identify which haemophilia patients are less likely to benefit from a given intervention; 2) define optimal dosing and scheduling of bypassing agents (or FVIII) to employ in combination with non-factor products; 3) establish tests to monitor in vivo thrombin generation; 4) improve communication and deliver results to individuals. As individual outcomes will be improved and the risk of adverse events minimized, non-factor products will come into wider use within the haemophilia community, and patients will hopefully have no more risks of breakthrough bleeds. The risks of a normal life for a "former haemophilia patient" is likely to change the treatment landscape and the structure of haemophilia Centers.

Efficacy and safety of simoctocog alfa (Nuwiq®) in patients with severe hemophilia A: a review of clinical trial data from the GENA program

Simoctocog alfa (human-cl rhFVIII, Nuwiq®) is a 4th generation recombinant FVIII (rFVIII), without chemical modification or fusion with any other protein/fragment. Nuwiq® is produced in a human embryonic kidney cell line (HEK293F), which ensures human-specific post-translational protein processing. Nuwiq® was evaluated in seven prospective clinical studies in 201 adult and pediatric previously treated patients (PTPs) with severe hemophilia A. The NuProtect study in 110 previously untreated patients (PUPs) is ongoing. The mean half-life of Nuwiq® was 15.1–17.1 h in PTP studies with adults and adolescents, and 12.5 h in children aged 2–12 years. Clinical trials in PTPs demonstrated the efficacy and safety of Nuwiq® in the prevention and treatment of bleeds and as surgical prophylaxis. In the NuPreviq study of pharmacokinetic (PK)-guided personalized prophylaxis in 66 adult PTPs, 83% of patients had no spontaneous bleeds during 6 months of personalized prophylaxis and 57% were treated ⩽2 per week. No FVIII inhibitors were detected in PTPs after treatment with 43,267 injections and >80 million IU of Nuwiq®. Interim data for 66 PUPs with ⩾20 exposure days to Nuwiq® in NuProtect demonstrated a low cumulative high-titer inhibitor rate of 12.8% [actual incidence 12.1% (8/66)] and convincing efficacy and safety.

Prevalence of factor VIII inhibitors among Afghan patients with hemophilia A: a first report

: Prevalence of inhibitors in Afghan hemophilia patients has not been reported previously. Our aim was to determine the prevalence of factor VIII inhibitors among hemophilia A patients from the Kabul province of Afghanistan to identify and characterize the pattern of inhibitor formation. Clinical information and blood samples were collected from three hemophilia centers in Kabul, Afghanistan. Plasma samples were obtained from 62 patients with severe (80.5%) and 15 patients with moderate hemophilia A (19.5%) in this cross-sectional study design. All the patients were receiving on-demand treatment. The Nijmegen modification of the Bethesda assay was used to detect inhibitors. Multiplex PCR, inverse-PCR, Multiplex ligation-dependent probe amplification and direct sequencing were performed for genotyping. Inhibitor activity was detected in one out of 15 (6.7%) patients with moderate hemophilia and in six out of 62 (9.7%) with severe disease. Apart from the intron 22 inversion, five different mutations including one missense, two large and two small deletions were detected. This is the first report showing that the prevalence of inhibitors in Afghan hemophilia A patients is much lower than in other populations.

Clinicopathological parameters influencing inhibitor development in patients with hemophilia A receiving on-demand therapy

BACKGROUND

Development of inhibitors to transfused factor VIII in patients with hemophilia A continues to be a challenge for professionals involved in hemophilia care. The majority of patients in India receive 'on-demand' rather than prophylactic therapy. The present study was done to assess the prevalence of factor VIII inhibitors in patients with hemophilia A (PWHA) receiving 'on-demand' therapy in a North Indian population and to study the clinicopathological parameters influencing the development of inhibitors.

METHODS

The study group comprised of 300 PWHA. Detailed clinical parameters, treatment history, bleeding profile including family history were recorded. Diagnosis of hemophilia A was confirmed by relevant coagulation tests. Inhibitors were screened using mixing based studies followed by quantification by Bethesda assay and Nijmegen modified Bethesda assay. Samples were collected from five cities in North India where a free supply of factor VIII was available and effectively used in three of these cities.

RESULTS

In the 300 PWHA, disease phenotype was severe in 219 (73%), moderate in 62 (20.67%) and mild in 19 (6.34%), based on the factor VIII bioassay. Inhibitor prevalence was 9.6% (n = 29) and seen only in the severe phenotype. Inhibitor titers ranged from 0.8 to 108.8 BU/ml. A total of 12 PWHA had low and 17 had high titers. Correlation of various clinicopathological parameters in inhibitor-positive versus negative PWHA showed significant correlation with age at onset of disease, severity of disease, age at first exposure to treatment, annual factor intake (IU/kg/year), intense treatment episodes and bleeding manifestations like central nervous system bleed and hematuria. The total study sample had blood group B in 33.34% PWHA, followed by O (27.34%), A (24.34%) and AB (15%), however, in inhibitor-positive samples, significant inhibitor formation was associated with the ABO subtype A (19/29, 65.51%).

CONCLUSIONS

Factor VIII inhibitor prevalence in PWHA receiving 'on-demand' therapy was 9.6%. Clinicopathological correlates of inhibitor development in such PWHA have been analyzed in this novel study.

Polymorphisms in the TGF-β1 (rs1982037) and IL-2 (rs2069762, rs4833248) genes are not associated with inhibitor development in Iranian patients with hemophilia A

Objectives Development of neutralizing antibodies against factor VIII is the major complication in hemophilia care which makes replacement therapies ineffective. The reports showed that inflammatory cytokines play an important role in inhibitor production. In the present study, the relationship between inhibitor development and the polymorphisms of two cytokine genes was studied in severe hemophiliac patients from Iran. Methods In this case-control study, three polymorphisms of immune regulatory genes [TGF-β (rs1982037) and IL-2 (rs2069762, rs4833248)] were analyzed in 100 Iranian hemophilia A patients divided into 55 inhibitor positive and 45 inhibitor negative patients using Tetra primer ARMS PCR, and DNA sequencing. Results The analysis of polymorphisms in the TGF-β and IL-2 genes showed no association between the genotypes and the production of inhibitors (p > 0.05). Also, comparison of allele frequencies for TGF-β and IL-2 genes between two groups indicated no significant differences associated with the development of FVIII inhibitors (p > 0.05). Discussion In contrast with some reports involving the correlation between polymorphisms of the TGF-β1 and IL-2 genes and inhibitor development in the world, no statistically significant differences in analysis of the alleles and genotypes for TGF-β and IL-2 genes were found between the inhibitor and non-inhibitor Iranian patients. Thus, other genetic markers influencing the immune response to replacement therapy in patients with hemophilia should be identified. Conclusions Regarding our results in molecular predisposition for inhibitor development, further studies of effective genetic markers are required as a prerequisite for the development of novel immunogenic therapeutic approaches in the future.

Cost-utility of a six-month programmed sports therapy (PST) in patients with haemophilia

INTRODUCTION

Recurrent musculoskeletal haemorrhages in people with haemophilia (PwH) lead to restrictions in the locomotor system and, as a result, in physical performance, too. Due to its physical and psychological benefits, sport is increasingly re-commended for haemophilic patients. Evidence on the cost-effectiveness of sports therapy is still lacking.

AIM

The aim of this study was to determine the cost-effectiveness of a 6-month programmed sports therapy (PST).

METHODS

The cost-effectiveness of the 6-month PST was assessed from a societal perspective alongside a RCT using cost-utility analysis. The analysis included 50 PwH with moderate-to-severe haemophilia A and B and a training period over 6 months. The health-related quality of life was measured with the EuroQoL-domain questionnaire. Resource utilization was assessed by questionnaire before and after the intervention. A cost-effectiveness acceptability curve was constructed, and sensitivity analyses were performed.

RESULTS

During the 6-month study period, mean adjusted total healthcare costs were lower (mean difference: -22 805 EUR; 95%-CI: -73 944-48 463; P = .59) and the number of QALYs was higher in the intervention group (mean difference: 0.3733; 95%-CI: 0.0014-0.0573; P = .04). The probability of an incremental cost-effectiveness ratio <50 000 EUR per QALY was 71%. The performed sensitivity analysis confirmed these results.

CONCLUSION

Results showed that the PST is effective in terms of a significant gain of QALYs. Furthermore, results weakly indicate the potential of the PST to reduce healthcare costs. Future studies should expand the observation period to have a closer look at the influence of PST on lifetime costs.

Modern Treatments of Haemophilia: Review of Cost-Effectiveness Analyses and Future Directions

BACKGROUND

Cost is currently one of the most important aspects in haemophilia care. Factor concentrates absorb more than 90% of healthcare direct costs of haemophilia care, and the debate regarding the high cost of haemophilia treatments and their different use across different countries is increasing.

OBJECTIVE

The objective of this study was to review cost-effectiveness analyses conducted on treatment options in haemophilia, focusing on their results and their strengths and limitations; to highlight the possible issues associated with economic evaluations of new treatment options.

METHODS

Electronic searches in PubMed and EMBASE were performed to retrieve papers published between November 2015 and September 2017 to update the previous review of economic evaluations of haemophilia treatments by Drummond et al. Reference lists of included articles and reviews were examined for relevant studies, which were assessed for their quality and their empirical results.

RESULTS

Twenty-six relevant economic analyses were identified; 15 (57.7%) were conducted in patients with haemophilia with inhibitors while 11 (42.3%) involved patients without inhibitors. There were methodological variations among the included studies, and differences in the treatment schemes make a comparative assessment of interventions for patients with haemophilia difficult. Only immune tolerance induction showed consistent results in its cost-saving profile compared with the treatment with bypassing agents.

CONCLUSIONS

Economic evaluations of haemophilia treatments are increasing, but the identification of general cost-effectiveness trends is still difficult in these studies. We are now facing a new era in haemophilia management with a soaring need for high-quality economic evaluations, performed through proactive collaboration between clinical experts, budget holders and health economists.

Lonoctocog alfa (rVIII-SingleChain) for the treatment of haemophilia A

INTRODUCTION

The administration of factor VIII (FVIII) concentrates on-demand or on long-term prophylaxis is the effective and safe standard of care of patients with hemophilia A (HA). Development of neutralizing antibodies against exogenous FVIII and the short half-life of the current available products remain major challenges. There is currently a great interest towards newer FVIII products with the goal of reducing the inhibitor risk and increasing the half-life. Area covered: In this review, the authors describe the efficacy and safety of rVIII-SingleChain (Lonoctocog alfa), the first and only single chain recombinant FVIII (rFVIII) molecule developed for the prevention and treatment of bleeding episodes in HA patients. The pre-clinical and clinical studies of rVIII-SingleChain as well as the results of the AFFINITY trial program in previously treated patients both adults and pediatric are presented and discussed. Expert opinion: The results from PTP studies document the efficacy and safety profile of the rVIII-SingleChain. However, even if rFVIII-SingleChain presents advantageous pharmacokinetic features compared to conventional rFVIII, it should not be considered as an EHL-FVIII while its immunogenicity is currently being studied in PUPs. The slightly better PK profile of rFVIII-SingleChain could however allow a small number of selected patients to be treated with a less intensive regimen.

Prospective surveillance study of haemophilia A patients switching from moroctocog alfa or other factor VIII products to moroctocog alfa albumin-free cell culture (AF-CC) in usual care settings

This prospective, open-label, postauthorisation safety surveillance study assessed clinically significant inhibitor development in patients with severe haemophilia A transitioning from moroctocog alfa or other factor VIII (FVIII) replacement products to reformulated moroctocog alfa (AF-CC). Males aged12 years with severe haemophilia A (FVIII:C) < 1 IU/dl), > 150 exposure days (EDs) to recombinant or plasma-derived FVIII products, and no detectable inhibitor at screening were enrolled. Primary end point was the incidence of clinically significant FVIII inhibitor development. Secondary end points included annualised bleeding rate (ABR), less-than-expected therapeutic effect (LETE), and FVIII recovery. Patients were assigned to one of two cohorts based on whether they were transitioning to moroctocog alfa (AF-CC) from moroctocog alfa (cohort 1; n=146) or from another recombinant or plasma-derived FVIII product (cohort 2; n=62). Mean number of EDs on study was 94 (range, 1–139). Six positive FVIII inhibitor results, as determined by local laboratories, were reported in four patients; none were confirmed by a central laboratory, no inhibitor-related clinical manifestations were reported, and all anti-FVIII antibody assays were negative. Median ABRs were 23.4 and 3.4 in patients categorised at baseline as following on-demand and prophylactic regimens, respectively; 86.5 % of bleeding episodes resolved after one infusion. LETE incidence was 0.06 % and 0.19 % in the on-demand and prophylaxis settings, respectively. FVIII recovery remained constant throughout the study. No new safety concerns were identified. This study found no increased risk of clinically significant FVIII inhibitor development in patients transitioning from moroctocog alfa or other FVIII replacement products to moroctocog alfa (AF-CC).

Analyses of the FranceCoag cohort support differences in immunogenicity among one plasma-derived and two recombinant factor VIII brands in boys with severe hemophilia A

Around one third of boys with severe hemophilia A develop inhibitors (neutralizing antibodies) against their therapeutic factor VIII product. This adverse effect may result in more life-threatening bleeding, disability, impaired quality of life, and costly care. We compared the incidence of inhibitors in boys treated with the three factor VIII products most used in France: one plasma-derived (Factane) and two recombinant products (Advate and Kogenate Bayer). A previously untreated cohort of patients was created in 1994 to investigate risk factors for inhibitor development. We selected boys with severe hemophilia A (factor VIII <1 IU/dL) first treated with one of the three factor VIII products studied. Details of product infusions, inhibitor assays and main fixed and time-varying inhibitor risk factors were recorded for the first 75 exposure days. Three outcomes (all inhibitors, high-titer inhibitors and subsequently treated inhibitors) were analyzed by univariate and multivariate Cox models. We studied 395 boys first treated between 2001 and 2016 (131, 137, and 127 with Factane, Advate, and Kogenate Bayer, respectively). Clinically significant inhibitors were diagnosed in 121 patients (70 high-titer). The incidence of high-titer inhibitors was significantly associated with the factor VIII product received (P=0.005): the cumulative incidence at 75 exposure days was 12.7% (95% CI: 7.7-20.6) with Factane, 20.4% (95% CI: 14.0-29.1) with Advate, and 31.6% (95% CI: 23.5-41.7) with Kogenate Bayer. The low inhibitor incidence observed with Factane is concordant with recent findings from the SIPPET randomized trial. These consistent results from observational and experimental studies should lead to improved care for previously untreated patients and cost savings for healthcare systems worldwide.

Treatment and Prevention of Bleeds in Haemophilia Patients with Inhibitors to Factor VIII/IX

The development of alloantibodies neutralising therapeutically administered factor (F) VIII/IX (inhibitors) is currently the most severe complication of the treatment of haemophilia. When persistent and at a high titre, inhibitors preclude the standard replacement treatment with FVIII/FIX concentrates, making patients’ management challenging. Indeed, the efficacy of bypassing agents, i.e., activated prothrombin complex concentrates (aPCC) and recombinant activated factor VII (rFVIIa), needed to overcome the haemostatic interference of the inhibitor, is not comparable to that of factor concentrates. In addition, the therapeutical response is unpredictable, with a relevant inter-individual and even intra-individual variability, and no laboratory assay is validated to monitor the efficacy and safety of the treatment. As a result, inhibitor patients have a worse joint status and quality of life compared to inhibitor-free subjects and the eradication of the inhibitor by immune tolerance induction is the preeminent therapeutic goal, particularly in children. However, over the last decades, treatment with bypassing agents has been optimised, allowing home treatment and the individualisation of regimens aimed at improving clinical outcomes. In this respect, a growing body of evidence supports the efficacy of prophylaxis with both bypassing agents in reducing bleeding rates and improving the quality of life, although the impact on long-term outcomes (in particular on preventing/reducing joint deterioration) is still unknown. This review offers an update on the current knowledge and practice of the use of bypassing agents in haemophiliacs with inhibitors, as well as on debated issues and unmet needs in this challenging setting.

The prevalence of factor VIII and IX inhibitors among Saudi patients with hemophilia: Results from the Saudi national hemophilia screening program

Hemophilia A and B are X-linked diseases that predominantly affect male patients. Patients can develop coagulation factor inhibitors, which exponentially increases the treatment cost. However, the prevalence of factor VIII and IX inhibitors in Saudi Arabia is unclear.This study aimed to determine the Saudi prevalence of factor VIII and IX inhibitors.This 4-year, 7-center, cross-sectional study evaluated the Saudi prevalences of hemophilia A and B. We collected the patients' clinical data, evaluated their disease, and tested for factor inhibitors.We included 202 patients with hemophilia (median age at diagnosis: 0.13 years, range: birth-34.8 years). The patients included 198 male patients (98%), 148 patients with hemophilia A (73.3%), and 54 patients with hemophilia B (26.7%). The patients exhibited severe factor VIII activity (<1%; 121 patients; 5.2%), moderate activity (1-5%; 7 patients; 4.9%), and mild activity (14 patients; 9.9%). Among the patients with care-related data, most patients were treated for episodic bleeding (76.8%) or received prophylaxis (22.6%); 1 patient received both treatments. Among the patients with source-related data, the factor replacements were derived from plasma (48.4%), recombinant concentrates (22.9%), both sources (14.6%), or fresh frozen plasma (14.1%). Factor VIII inhibitors were observed in 43 (29.3%) of the 147 patients, and only 1 of the 54 patients developed factor IX inhibitors. Most patients who developed inhibitors had severe hemophilia (40/44; 90.9%), and inhibitors were also common among patients who received recombinant products (14/43; 32.6%).The Saudi prevalence of factor inhibitors was similar to those among other ethnic populations.

2017 Clinical trials update: Innovations in hemophilia therapy

A surge in therapeutic clinical trials over recent years is paving the way for transformative treatment options for patients with hemophilia. The introduction of recombinant factor concentrates in the early 1990s facilitated the use of prophylactic replacement as standard care for hemophilia rather than on-demand treatment. This has revolutionized health outcomes for hemophilia patients, enabling participation in physical activities and reducing debilitating, chronic joint damage. Challenges of prophylactic factor infusion include the frequency of infusions needed to maintain factor levels greater than 1%, patient adherence, reliable intravenous access, and development of neutralizing alloantibodies ("inhibitors"). Novel therapeutics seek to improve upon current factor concentrates by several different mechanisms: (1) extending the half-life of circulating exogenous factor protein, (2) replacing the gene necessary for production of endogenous factor protein, (3) employing bispecific antibody technology to mimic the coagulation function of factor VIII, (4) disrupting anticoagulant proteins, such as tissue factor pathway inhibitor (TFPI) or antithrombin (AT3) with antibodies, aptamers, or RNA interference technology. Emerging treatment options may reduce the frequency of (extended half-life products) or eliminate (gene therapy) the need for scheduled factor concentrate infusions, or provide a subcutaneous administration option (bispecific antibody, AT3, and TFPI targeting therapies). In addition, the nonfactor replacement strategies provide a promising treatment option for patients with inhibitors, presently the greatest unmet medical need in hemophilia. This review highlights current and recently completed clinical trials that are driving a paradigm shift in our approach to hemophilia care for patients with and without inhibitors. Am. J. Hematol. 91:1252-1260, 2016. © 2016 Wiley Periodicals, Inc.

Economic analysis of not running tenders for recombinant Factor VIII procurement: a simplified analysis to estimate an otherwise unknown pharmacoeconomic index

Background

Two approaches to the procurement of recombinant Factor VIII products are used by health systems: (A) the most common approach where acquisition tenders are not carried out; (B) the approach tested in the UK in which procurement is based on tenders. The respective cost-effectiveness is not known.

Objective

To estimate the incremental cost-effectiveness ratio (ICER) for the comparison A vs B.

Methods

The analysis evaluated: (i) Factor VIII cost with/without tenders; (ii) inhibitor development caused by switching between products; (iii) clinical and economic consequences of inhibitors. Information on these items was obtained from a literature search. Because of the scarce evidence available on some items, our analysis considered the 'most favourable' scenario-that is, some extreme though reasonable assumptions were adopted that were intentionally biased towards improving the ICER of the no-tender option.

Results and discussion

We estimated an ICER for A vs B of £486 409 (€657 139; £1=€1.351) per quality-adjusted life year (QALY). Since pharmacoeconomic thresholds are ∼£30 000 per QALY, our results indicate that the cost-effectiveness of acquisition strategies that avoid tenders is prohibitive. Because of the simplified nature of our analysis, this estimate is preliminary.

Conclusions

The 'true' ICER of A vs B remains unknown, but its value is likely to be even worse than the unfavourable ICER of £486 409 (€657 139) per QALY.

Increased inhibitor incidence in severe haemophilia A since 1990 attributable to more low titre inhibitors

Many studies have reported an increased incidence of inhibitors in previously untreated patients (PUPs) with severe haemophilia A after the introduction of recombinant products. It was the objective of this study to investigate whether the inhibitor incidence has increased between 1990 and 2009 in an unselected cohort of PUPs with severe haemophilia A (FVIII< 1 %). Patients were consecutively recruited from 31 haemophilia treatment centres in 16 countries and followed until 50 exposure days or until inhibitor development. Inhibitor development was studied in five-year birth cohorts comparing cumulative incidences. Furthermore the risk for inhibitor development per five-year birth cohort was studied using multivariable Cox regression, adjusting for potential genetic and treatment-related confounders. A total of 926 PUPs were included with a total cumulative inhibitor incidence of 27.5 %. The inhibitor incidence increased from 19.5 % in 1990-1994 (lowest) to 30.9 % in 2000-2004 (highest; p-value 0.011). Low titre inhibitor incidence increased from 3.1 % in 1990-1994 to 10.5 % in 2005-2009 (p-value 0.009). High titre inhibitor incidences remained stable over time. After 2000, risk of all inhibitor development was increased with adjusted hazard ratios 1.96 (95 % CI 1.06-2.83) in 2000-2004 and 2.34 (1.42-4.92) in 2005-2009. Screening for inhibitors was intensified over this 20-year study period from a median of 1.9 to 2.9 tests/year before 2000 to 2.7 to 4.3 tests/year after 2000. In conclusion, the cumulative inhibitor incidence has significantly increased between 1990 and 2009. The high titre inhibitor incidence has remained stable.

Costs and utilization of treatment in patients with hemophilia

Background

Although hemophilia has a potentially high economic impact, there are no published estimates of healthcare costs for this disease in Portugal. The aim of this study was to evaluate costs of treatment and hospital utilization among patients with hemophilia A and B, with and without inhibitors, over a 3-year period in a Portuguese Comprehensive Care Hemophilia Centre. This is the first study on the financial impact of healthcare costs in patients with hemophilia in Portugal.

Methods

This retrospective, observational study identified patients diagnosed with hemophilia A and B using medical and pharmacy electronic medical records and data from Centro Hospitalar São João, between January 2011 and December 2013. Patients with inhibitors were all high responders (>5 Bethesda Units [BU]). Severity was classified as mild, moderate or severe based on clotting factor levels. Two main outcomes were measured: (1) cost associated with hospital pharmacy claims (clotting factor) and (2) number of hospital visits/hospitalization.

Results

A cohort of 103 patients were identified: 72 (69.9 %) with hemophilia A and 31 (30.1 %) with hemophilia B. Among these, five individuals were classified as patients with inhibitors (four with hemophilia A and one with hemophilia B). From the cohort of hemophilia A patients, 36 individuals (35.0 %) were identified as having severe disease; 20 (19.4 %) moderate; and 16 (15.5 %) mild. In the cohort of hemophilia B patients, 14 (13.6 %) were identified as having severe disease; 14 (13.6 %) moderate; and three (2.9 %) mild. The total mean aggregate cost per year (including clotting factor and hospital utilization) for patients with severe hemophilia B was €112,469, compared with €793 for mild hemophilia A. Clotting factor concentrate amounted for 90 % of total cost in severe cases and hospital utilization was also higher in these cases.

Conclusions

Hemophilia treatment is expensive, particularly for patients with severe disease and especially if they develop inhibitors to replacement clotting factors. In our study, severe hemophilia is associated with greater annual total costs in both types of hemophilia (A = €77,587 and B = € 112,469). Patients with inhibitors have costs 3.3 times higher than patients without inhibitors. Age was not associated with significantly greater total costs (clotting factor and hospital visits/hospitalizations).

Comparison of bypassing agents in bleeding reduction in treatment of bleeding episodes in patients with haemophilia and inhibitors

CONTEXT

Mild-to-moderate bleeding disorders in haemophilia are primarily treated via recombinant activated factor VII a (rFVIIa) or activated prothrombin complex concentrate (aPCC). However, the efficacy of each bypassing agents may vary and none of them is universally effective.

EVIDENCE ACQUISITION

After reviewing the databases of PubMed, Scopus, MD Consult, Ovid, Trip database, Google Scholar, ProQuest and the Cochrane Library, finally, 17 papers published from 2000 to 2013 were extracted. We used as a random effect model in meta-analysis. Comprehensive meta-analysis (CMA) software was used for calculating and estimating the mean of bleeding reduction and performing meta-analysis.

RESULTS

The mean of bleeding reduction in aPCC and rFVIIa were 71.2% with CI 95% (lower limit 86.8% and upper limit 82%) and 72.3% with CI 95% (lower limit 57.6% and upper limit 83.4%), respectively.

CONCLUSIONS

Although differences between the two products were very close to each other, they reported similar effects on joint bleeds. Further clinical studies should be performed by incorporating a standardized measurement in comparative efficacy of aPCC and rFVIIa.

Factor VIII alloantibody inhibitors: cost analysis of immune tolerance induction vs. prophylaxis and on-demand with bypass treatment

Development of inhibitors (alloantibodies to exogenous factor VIII) is the most significant treatment complication in patients with haemophilia A. The only proven way to eradicate inhibitors is through immune tolerance induction (ITI), while bypassing agents are typically employed to treat or prevent bleeds in patients with high titre inhibitors. Costs of these approaches have not been well studied. The aim of this study was to compare lifetime costs of treating patients with severe haemophilia A with inhibitors using on-demand or prophylaxis treatment with bypassing agents and ITI. A decision-analytic model was developed to compare the treatment costs and outcomes. Quantitation of the reduction in bleeding events for patients on prophylaxis and after eradication of inhibitors when on ITI and relapse of inhibitors was derived from published studies. Costs were obtained from standard US costing sources and are reported in 2014 US dollars. Costs and outcomes were discounted 3% per annum. Lifetime costs of treating patients with inhibitors are lower for ITI vs. on-demand or prophylaxis. Patients are also projected to live longer, have greater quality-adjusted life-years, and have fewer bleeding events than patients treated on-demand. Treating patients via ITI to eradicate inhibitors may result in lower lifetime costs and greater life-years and quality-adjusted life-years than treating with bypassing agents.

Haemophilia A: pharmacoeconomic review of prophylaxis treatment versus on-demand

OBJECTIVES

Haemophilia A is a congenital disorder of coagulation that mainly affects males and causes a considerable use of resources, especially when hemophilic patients are treated with prophylaxis. The aim of the present review was to discuss and appraise the methodological aspects and results of published economic evaluations of haemophilia A treatments in the last decade.

METHODS

The literature search, performed by consulting four engines, covered studies published between 2002 and 2014. Full economic evaluations published in English language were identified and included in the review. A quality assessment of the studies was also carried out based on Drummond's checklist.

RESULTS

After careful evaluations of the identified records, 5 studies were reviewed. Primary and secondary prophylaxis resulted cost-effective compared to on-demand therapy: the ICER of primary prophylaxis ranged from € 40.236 to € 59.315/QALY gained, while the ICER of secondary prophylaxis was € 40.229/QALY gained. Furthermore, 60% were high quality and 40% were medium quality studies.

CONCLUSIONS

The review underlines the cost-effectiveness of prophylaxis versus on-demand treatment and the different methodological approaches applied. Further economic evaluations are required with models that reflect the clinical reality and consumption of resources in each country.

Current management of the hemophilic child: a demanding interlocutor. Quality of life and adequate cost-efficacy analysis

Hemophilias are the most known inherited bleeding disorders. The challenges in the management of hemophilic children are different from those in adults: prophylaxis regimen removed the hallmark of crippling disease with lifelong disabilities; individualized regimens are being implemented in order to overcome venous access problems. Presently, at least in high-income countries, advances in treatment of hemophilia resulted in continuous improvement of the patients' quality of life and life expectancy. Inhibitors remain the most severe complication of hemophilia therapy. The treatment' compliance is the key to achieve a successful management. The patient, his family, the medical and psychological team are the players of a comprehensive care system. The current management of hemophilic children is the example of huge resource investments enabling long-term benefits in particular quality of life as a primary objective of the healthcare process.

Recombinant factor VIII products and inhibitor development in previously untreated boys with severe hemophilia A

Six recombinant factor VIII (rFVIII) products have been marketed worldwide. In 2013, the Research of Determinants of Inhibitor Development (RODIN) study group reported an unexpectedly high risk of inhibitor development with a second-generation full-length rFVIII (Product D) in previously untreated patients (PUPs) with severe hemophilia A (HA). In 1994, French public health authorities established a prospective cohort to monitor hemophilia treatment safety. A PUP subgroup was designed to investigate inhibitor risk factors. We analyzed this subcohort in view of the RODIN findings. After excluding 50 patients who participated in the RODIN study, the primary analysis focused on 303 boys with severe HA first treated with a rFVIII product. A clinically significant inhibitor was detected in 114 boys (37.6%). The inhibitor incidence was higher with Product D vs the most widely used rFVIII product (adjusted hazard ratio [aHR], 1.55; 95% confidence interval [CI], 0.97-2.49). Similar results were found for high-titer inhibitors and in 10 sensitivity analyses. No heterogeneity was observed between RODIN and our results. Combined aHRs were 1.58 (95% CI, 1.17-2.14) for all inhibitors and 1.70 (95% CI, 1.15-2.52) for high-titer inhibitors. Our results confirm the higher immunogenicity of Product D vs other rFVIII products in PUPs with severe HA.

Immune tolerance induction for treating inhibitors in people with congenital haemophilia A or B

BACKGROUND

The occurrence of factor inhibitory antibodies, or inhibitors, is a significant complication in the care of individuals with congenital haemophilia A or B. Currently, immune tolerance induction is the only known intervention to successfully eradicate inhibitors. However, ideal dosing regimens, and the comparative safety and efficacy of different immune tolerance induction regimens have not yet been established.

OBJECTIVES

The objective of this review was to assess the effects of immune tolerance induction (different protocols of this therapy versus each other, or versus only bypassing agents) for treating inhibitors in people with congenital haemophilia A or B.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Coagulopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched: MEDLINE (from 1946 to 15 July 2013); Embase (from 1980 to 15 July 2013) via the OVID platform; CINAHL (from conception to 15 July 2013); and ClinicalTrials.gov (most recent search: 15 July 2013). We also searched the reference lists of relevant articles and reviews.

SELECTION CRITERIA

Randomised controlled trials comparing either different immune tolerance induction regimens or immune tolerance induction versus only bypassing therapy for the eradication of factor inhibitory antibodies in patients with congenital haemophilia A or B.

DATA COLLECTION AND ANALYSIS

Two review authors independently completed data collection, extraction and assessment of the risk of bias of trials.

MAIN RESULTS

One methodologically sound randomised controlled trial met the inclusion criteria and was included in the review. One further randomised controlled trial has been recently stopped, but it has not yet been reported.The included multinational trial randomised 115 paediatric participants with severe haemophilia A and high-responding inhibitors, for whom this was the first attempt at immune tolerance induction, to receive either a low dose (50 IU/kg of factor VIII concentrate three times per week) or a high dose (200 IU/kg of factor VIII daily). Although, there was no statistically significant difference in the success of immune tolerance induction between treatment arms, the confidence intervals were too wide to infer no effect: 24 out of 58 participants (46.6%) in the low-dose group and 22 out of 57 (38.6%) in the high-dose group experiencing full tolerance, risk ratio 1.07 (95% CI 0.68 to 1.68) (moderate quality evidence). The rate of infection was not statistically different between groups, but again confidence intervals were too wide. Of those patients who had a central venous catheter device, 19 out of 47 participants (40.4%) in the low-dose arm had 69 infections, and 22 out of 52 participants (42.3%) in the high-dose arm had 55 infections, risk ratio 0.96 (95% CI 0.60 to 1.53) (moderate quality evidence). However, participants in the low-dose immune tolerance induction group experienced significantly more bleeding episodes (50 out of 58 participants (86.2%) experienced one or more bleeding events) than those in the high-dose group (36 out of 57 participants (63.1%) experienced one or more bleeding events), risk ratio 1.36 (95% CI 1.09 to 1.71) (low quality evidence). One factor VIII reaction, one incidence of trauma and 13 incidences of needing to insert or remove the catheter were reported as trial-related serious adverse events; however, the treatment group where these events occurred was not specified. No incidence of nephrotic syndrome was reported.

AUTHORS' CONCLUSIONS

We did not find any randomised controlled trial-based comparison of immune tolerance induction with alternate treatment schemes (i.e. bypassing agents for bleeding only). In a single randomised trial, there were no significant differences in the immune tolerance induction success rate between different dosing regimens, which may have been due to imprecision of the estimate. There is low-quality evidence to suggest that high-dose immune tolerance induction may induce tolerance more quickly which is associated with fewer bleeding complications. The choice of immune tolerance induction regimen should be considered individually for each case, until further research provides additional evidence.

Factor VIII gene (F8) mutation and risk of inhibitor development in nonsevere hemophilia A

The inhibitor incidence in nonsevere hemophilia A patients with certain F8 mutations approaches the inhibitor incidence in severe patients. These findings are highly relevant for clinical practice, as they facilitate identification of high-risk patients based on F8 genotype.

Management of patients with long-term inhibitors: is immune tolerance an underestimated life-long solution?

Immune tolerance induction (ITI) is recognized as the first choice treatment in haemophilic patients with inhibitors, with the aim of restoring safe and effective standard factor VIII replacement and, particularly, prophylaxis in children. For the latter, literature data and clinical practice support the optimal cost utility ratio of ITI. Indeed, the high success rate, the low incidence of inhibitor recurrence after successful ITI and the possibility of preventing joint deterioration, enable one to predict a considerable long-term reduction of costs in the majority of treated patients. Therefore, in spite of high costs and open issues about optimal regimens, ITI is actually attempted in virtually all children with inhibitors. Few patients with long-standing inhibitors presently undergo ITI, particularly in the case of severe bleeding tendency. In this setting, uncertainties concerning management are amplified by the paucity of literature data and psychological reluctance by both patients and treaters due to the perceived poor prognosis and the demanding treatment (also in terms of costs). However, clinical data suggest that the role of age at ITI start and of time interval from inhibitor diagnosis, as predictors of ITI outcome, should be considered in a larger framework of proposed and more established prognostic factors. Moreover, optimising ITI management, particularly with respect to inhibitor titre at ITI start and avoidance of adverse events or interruption of treatment, may also contribute to improve outcomes. Although the economic constraints of the present era significantly affect resources for such a high-cost treatment, the individual cost-utility ratio (bleeding tendency and risk of fatal bleeding, arthropathy and need for orthopaedic surgery, comorbidities, quality of life) should be assessed carefully to determine whether ITI is a suitable option and thus not preclude adults from the opportunity of inhibitor eradication.

Factor VIII inhibitors in hemophilia A: rationale and latest evidence

Factor VIII (FVIII) replacement therapy is the foundation of treatment in hemophilia A and is effective unless a patient develops an alloantibody (inhibitor) against exogenous FVIII. Inhibitor development is currently the most significant treatment complication seen in patients with hemophilia and is associated with considerable morbidity and a decreased quality of life. The development of an inhibitor is the result of a complex interaction between a patient's immune system and genetic and environmental risk factors. The mainstay of treatment is the eradication of the inhibitor through immune tolerance. This review summarizes the current evidence regarding inhibitor risk factors, eradication, and hemostatic bypassing agents.

Economic burden of high-responding inhibitors in patients with hemophilia A in Taiwan

PURPOSE

Hemophilia A (HA) is the most common X-linked inherited bleeding disorder. In some patients with HA, particularly those with severe HA, replacement therapy results in the production of high-responding clotting factor VIII inhibitors. The economic burden of this complication is the highest reported for a chronic disease. Our aim was to investigate the direct medical expenditure burden of high-responding inhibitors in patients with HA.

MATERIALS AND METHODS

A retrospective study was conducted using the National Health Insurance Research Database, utilizing data covering the period of 2004-2007.

RESULTS

In total, 638 males with HA¸ including 37 patients with high-responding inhibitors were evaluated. Over 99% of the annual median medical expenditure was attributable to the cost of clotting factor concentrates (CFCs) in patients with high-responding inhibitors. The annual median expenditure related to CFCs of the total medical care and outpatient care were US$170611 and US$141982, respectively, and were 4.6- and 4.3-fold higher in these patients during the study period, respectively. In patients with high-responding inhibitors, the median hospitalization expenditure and daily hospitalization cost with or without surgical procedures were 3.0- and 2.4-fold higher, respectively, and 4.3 and 5.6-fold higher, respectively.

CONCLUSION

Our data reveal higher medical expenditures burden for patients with HA and high-responding inhibitors in Taiwan. Future research is encouraged to evaluate the impact of this burden on patient quality of life.

Candidate diseases for prenatal gene therapy

Prenatal gene therapy aims to deliver genes to cells and tissues early in prenatal life, allowing correction of a genetic defect, before irreparable tissue damage has occurred. In contrast to postnatal gene therapy, prenatal application may target genes to a large population of stem cells, and the smaller fetal size allows a higher vector to target cell ratio to be achieved. Early gestation delivery may allow the development of immune tolerance to the transgenic protein, which would facilitate postnatal repeat vector administration if needed. Moreover, early delivery would avoid anti-vector immune responses which are often acquired in postnatal life. The NIH Recombinant DNA Advisory Committee considered that a candidate disease for prenatal gene therapy should pose serious morbidity and mortality risks to the fetus or neonate, and not have any effective postnatal treatment. Prenatal gene therapy would therefore be appropriate for life-threatening disorders, in which prenatal gene delivery maintains a clear advantage over cell transplantation or postnatal gene therapy. If deemed safer and more efficacious, prenatal gene therapy may be applicable for nonlethal conditions if adult gene transfer is unlikely to be of benefit. Many candidate diseases will be inherited congenital disorders such as thalassaemia or lysosomal storage disorders. However, obstetric conditions such as fetal growth restriction may also be treated using a targeted gene therapy approach. In each disease, the condition must be diagnosed prenatally, either via antenatal screening and prenatal diagnosis, for example, in the case of hemophilias, or by ultrasound assessment of the fetus, for example, congenital diaphragmatic hernia. In this chapter, we describe some examples of the candidate diseases and discuss how a prenatal gene therapy approach might work.

The first recombinant human coagulation factor VIII of human origin: human cell line and manufacturing characteristics

INTRODUCTION

Since the early 1990s, recombinant human clotting factor VIII (rhFVIII) produced in hamster cells has been available for haemophilia A treatment. However, the post-translational modifications of these proteins are not identical to those of native human FVIII, which may lead to immunogenic reactions and the development of inhibitors against rhFVIII. For the first time, rhFVIII produced in a human host cell line is available.

AIM

We describe here the establishment of the first human production cell line for rhFVIII and the manufacturing process of this novel product.

METHODS AND RESULTS

A human cell line expressing rhFVIII was derived from human embryonic kidney (HEK) 293 F cells transfected with an FVIII expression plasmid. No virus or virus-like particles could be detected following extensive testing. The stringently controlled production process is completely free from added materials of animal or human origin. Multistep purification employing a combination of filtration and chromatography steps ensures the efficient removal of impurities. Solvent/detergent treatment and a 20 nm pore size nanofiltration step, used for the first time in rhFVIII manufacturing, efficiently eliminate any hypothetically present viruses. In contrast to hamster cell-derived products, this rhFVIII product does not contain hamster-like epitopes, which might be expected to be immunogenic.

CONCLUSIONS

HEK 293 F cells, whose parental cell line HEK 293 has been used by researchers for decades, are a suitable production cell line for rhFVIII and will help avoid immunogenic epitopes. A modern manufacturing process has been developed to ensure the highest level of purity and pathogen safety.