Current options and new developments in the treatment of haemophilia

Intra-articular injection of tranexamic acid in patients with haemophilia arthritis: retrospective controlled study in total knee arthroplasty

PURPOSE

Total knee arthroplasty is the main method for the treatment of advanced haemophilic knee arthritis. Due to the particularity of hemophilia, the blood management plan is the focus of the perioperative period for haemophilia patients. This study aimed to investigate the clinical effect and safety of intra-articular injection of tranexamic acid in patients with haemophilia.

METHODS

This is a retrospective study. According to whether tranexamic acid is used or not, patients are divided into tranexamic acid group (n=30) and non-tranexamic acid group (n=29). Total blood loss, intraoperative blood loss, complete blood count, total amount of coagulation factor VIII (FVIII) usage, coagulation biomarkers, inflammatory biomarkers, knee range of motion, knee joint function, pain status, complication rate, and patient satisfaction were assessed and compared at a mean follow-up of 16 months.

RESULTS

Injecting tranexamic acid into the knee joint cavity can effectively reduce the hidden blood loss and total blood loss (P<0.001), and reduce the patient's early postoperative inflammation biomarkers, pain status, and limb swelling. Therefore, the patient can obtain a better range of motion following total knee arthroplasty. In the long run, in terms of joint function and surgical satisfaction, there are no statistically significant differences. In addition, there are no statistically significant differences between the two groups of patients in terms of the total amount of FVIII usage, length of stay, and hospitalization expenses.

CONCLUSION

In patients with haemophilia, intra-articular injection of tranexamic acid during total knee arthroplasty can effectively reduce postoperative blood loss, early postoperative inflammation levels, pain and limb swelling, and enable patients to receive higher-quality rehabilitation exercises to get better joint function. Previous studies on TKA in haemophilic patients have already demonstrated the efficacy of intra-articular injections of TXA in reducing postoperative blood loss. Our study confirms this efficacy.

The frequency of complications in a cohort of patients diagnosed with hemophilia A and hemophilia B receiving prophylactic treatment in Colombia: A retrospective noninterventional study

INTRODUCTION

Hemophilia A and B are disorders associated with the deficit of coagulation factors VIII and IX.

OBJECTIVE

Was to determine the incidence of complications in a cohort of patients diagnosed with moderate and severe hemophilia A or B under treatment in a specialized institution.

METHODS

A retrospective study of a cohort of patients with replacement therapy for hemophilia A or B, evaluating treatment and complications between January/2012 and July/2019. Sociodemographic, clinical and disease management-related variables were extracted from the medical records. Time to inhibitor development and rate associated with bleeding and hospitalizations were evaluated.

RESULTS

A total of 159 male patients were identified with hemophilia A (n = 140; 88.1%) and B (n = 19; 11.9%) with a mean follow-up of 5.9±2.3 years. The mean age was 23.6±16.1 years, hemophilia was reported as severe in 125 patients in hemophilia A (89.3%) and 13 patients in hemophilia B (68.4%). Primary prophylaxis was registered in 17.0% of patients, 44.7% secondary, and 38.3% tertiary, with recombinant factors (n = 84; 52.8%) followed by plasma derived factors (n = 75; 47.2%). The incidence of inhibitor development was 0.3 per 100 patients/year, with mean time to event of 509 days. The incidence of bleeding was 192 per 100 patients/year, especially at the joint (n = 99; 62.3%) and muscle (n = 25; 15.7%) level. The incidence of hospitalization was 3.7 per 100 patients/year.

CONCLUSIONS

The most common complication was joint bleeding which was expected in this type of patients. Low proportion of patients developed factor inhibitors during the follow up.

Costs and management of patients with hemophilia A in France: the Hemraude study

OBJECTIVE

The Hemraude study was conducted to describe the profile of patients with HA, disease management, and economic burden in a collective perspective.

METHODS

This retrospective study was conducted using the French administrative healthcare claims database SNIIRAM/SNDS. Male patients treated for hemophilia A with a long-term illness (ALD) status or invalidity were included in the study between January 1, 2016 and December 31, 2017. Patients were classified in six treatment groups: no treatment, on-demand FVIII, prophylactic FVIII, FVIII in immune tolerance induction (ITI) protocol, on-demand bypassing agents, and prophylactic bypassing agents. Patients treated with FVIII in ITI protocol and those treated with bypassing agents are deemed to have developed inhibitors. HA patients were compared to a control population without coagulation disorder and matched (ratio 1:3) on age and sex.

RESULTS

A total of 4172 patients were included in the analysis, aged on average 35.2 years, 5.3% had HIV infection, and 8.8% had hepatitis B or C. In 2017, half of the patients received no treatment for HA, 46.7% were treated with FVIII (25% on demand, 20.6% with prophylaxis, and 1.1% ITI), 1.5% with bypassing agents. Patients treated with prophylactic treatments, either inhibitor or non-inhibitor, were less likely to be hospitalized for severe bleeding compared to patients receiving on-demand treatments. The average annual costs for HA management per patient were 72,209.60 €. The highest costs were observed in patients treated with FVIII in ITI protocol and those receiving prophylactic bypassing agents.

CONCLUSION

Direct costs of HA treatments for HA may be very high especially in the small percentage of patients developing inhibitors or treated with ITI protocol.

Hemophilia A Gene Therapy: Current and Next-Generation Approaches

INTRODUCTION

: Hemophilia comprises a group of X-linked hemorrhagic disorders that result from a deficiency of coagulation factors. The disorder affects mainly males and leads to chronic pain, joint deformity, reduced mobility, and increased mortality. Current therapies require frequent administration of replacement clotting factors, but the emergence of alloantibodies (inhibitors) diminishes their efficacy. New therapies are being developed to produce the deficient clotting factors and prevent the emergence of inhibitors.

AREAS COVERED

: This article provides an update on the characteristics and disease pathophysiology of hemophilia A, as well as current treatments, with a special focus on ongoing clinical trials related to gene replacement therapies.

EXPERT OPINION

: Gene replacement therapies provide safe, durable, and stable transgene expression while avoiding the challenges of clotting factor replacement therapies in patients with hemophilia. Improving the specificity of the viral construct and decreasing the therapeutic dose are critical toward minimizing cellular stress, induction of the unfolded protein response, and the resulting loss of protein production in liver cells. Next-generation gene therapies incorporating chimeric DNA sequences in the transgene can increase clotting factor synthesis and secretion, and advance the efficacy, safety, and durability of gene replacement therapy for hemophilia A as well as other blood clotting disorders.

Platelet-targeted hyperfunctional FIX gene therapy for hemophilia B mice even with preexisting anti-FIX immunity

Gene therapy may lead to a cure for hemophilia B (HB) if it is successful. Data from clinical trials using adeno-associated virus (AAV)-mediated liver-targeted FIX gene therapy are very encouraging. However, this protocol can be applied only to adults who do not have liver disease or anti-AAV antibodies, which occur in 30% to 50% of individuals. Thus, developing a protocol that can be applied to all HB patients is desired. Our previous studies have demonstrated that lentivirus-mediated platelet-specific FIX (2bF9) gene therapy can rescue bleeding diathesis and induce immune tolerance in FIXnull mice, but FIX expression was only ∼2% to 3% in whole blood. To improve the efficacy, we used a codon-optimized hyperfunctional FIX-Padua (2bCoF9R338L) to replace the 2bF9 cassette, resulting in 70% to 122% (35.08-60.77 mU/108 platelets) activity levels in 2bCoF9R338L-transduced FIXnull mice. Importantly, sustained hyperfunctional platelet-FIX expression was achieved in all 2bCoF9R338L-transduced highly immunized recipients with activity levels of 18.00 ± 9.11 and 9.36 ± 12.23 mU/108 platelets in the groups treated with 11 Gy and 6.6 Gy, respectively. The anti-FIX antibody titers declined with time, and immune tolerance was established after 2bCoF9R338L gene therapy. We found that incorporating the proteasome inhibitor bortezomib into preconditioning can help eliminate anti-FIX antibodies. The bleeding phenotype in 2bCoF9R338L-transduced recipients was completely rescued in a tail bleeding test and a needle-induced knee joint injury model once inhibitors dropped to undetectable. The hemostatic efficacy in 2bCoF9R338L-transduced recipients was further confirmed by ROTEM and thrombin generation assay (TGA). Together, our studies suggest that 2bCoF9R338L gene therapy can be a promising protocol for all HB patients, including patients with inhibitors.

Cementless total hip arthroplasty in haemophilia patients through direct anterior approach

INTRODUCTION

Total hip arthroplasty (THA) has become the treatment of choice for patients with severe haemophilic arthropathy of the hip. However, the intraoperative and postoperative complications, including blood loss and infection, are significant concerns. Direct Anterior Approach (DAA) might be beneficial in THA of patients with haemophilia.

AIM

The present study was conducted to assess outcomes of THA using DAA in patients with haemophilia.

METHODS

We retrospectively reviewed our joint replacement database. From January 2010 to December 2015, we had 12 patients with haemophilia who underwent 14 THAs by DAA and followed for an average of 69 months.

RESULTS

All patients were male with a mean age of 36 ± 7 years at the time of THA. The mean Harris Hip Score improved from 46 preoperatively to 89 at the final follow-up visit. One dislocation and one infection occurred. Only one patient with simultaneous bilateral THA needed a transfusion. All components were radiologically well fixed at the final follow-up visit except one acetabular loosening that needed revision. All patients were satisfied with the outcome of the surgery at the final follow-up visit.

CONCLUSION

In this study, it was observed that complications of cementless THA using DAA in haemophilia patients with hip arthropathy are comparable to other surgical approaches. However, the complication of bleeding in this approach might be less.

Reflections on the Importance of Cost of Illness Analysis in Rare Diseases: A Proposal

In the field of rare diseases (RDs), the evidence standard is often lower than that required by health technology assessment (HTA) and payer authorities. In this commentary, we propose that appropriate economic evaluation for rare disease treatments should be initially informed by cost-of-illness (COI) studies conducted using a societal perspective. Such an approach contributes to improving countries' understanding of RDs in their entirety as societal and not merely clinical, or product-specific issues. In order to exemplify how the disease burden's distribution has changed over the last fifteen years, key COI studies for Hemophilia, Fragile X Syndrome, Cystic Fibrosis, and Juvenile Idiopathic Arthritis are examined. Evidence shows that, besides methodological variability and cross-country differences, the disease burden's share represented by direct costs generally grows over time as novel treatments become available. Hence, to support effective decision-making processes, it seems necessary to assess the re-allocation of the burden produced by new medicinal products, and this approach requires identifying cost drivers through COI studies with robust design and standardized methodology.

An overview of patients with haemophilia A in China: Epidemiology, disease severity and treatment strategies

INTRODUCTION

Haemophilia A (HA) is a rare X chromosome-linked bleeding disorder resulting in missing or defective clotting factor VIII (FVIII) and causes large disease burden.

AIM

As a member of World Federation of Hemophilia, China seeks to understand the current epidemiology, disease profile and treatment landscape of patients with HA through the Hemophilia Treatment Center Collaboration Network of China (HTCCNC).

METHODS

The HTCCNC enabled data collection on patients with HA from 166 member hospitals (2007-2019) across China. The distribution of patients across 31 divisions was summarized using a heat map. Patient demographics, disease severity and clinical and treatment information were summarized using descriptive statistics.

RESULTS

HTCCNC identified 17,779 patients with HA during 2007-2019. Patients were predominantly male (99.99%), and 28.3% had a known family history of haemophilia. Among patients with lab-measured disease severity (N = 13,116), 6,519 had severe HA (49.7%), 4,788 had moderate HA (36.5%), and 1,809 had mild HA (13.8%). Among patients with information on the delays, delays in diagnosis and in treatment initiation were observed in 1,437 (28.8%) and 1,750 (39.2%) patients, respectively. On average, those patients had an 8.4 years gap between the first bleed and HA diagnosis and a delay of 8.6 years from the first bleed to treatment initiation. Additionally, 44.33% of patients relied solely on episodic treatments, and 16.2% received any prophylaxis treatments.

CONCLUSIONS

Using data from the largest haemophilia registry in China, this study indicated that delayed diagnosis and treatment, together with low utilization of prophylaxis, are key challenges for patients with HA.

Gene therapy for haemophilia

BACKGROUND

Haemophilia is a genetic disorder characterized by spontaneous or provoked, often uncontrolled, bleeding into joints, muscles and other soft tissues. Current methods of treatment are expensive, challenging and involve regular administration of clotting factors. Gene therapy for haemophilia is a curative treatment modality currently under investigation. This is an update of a published Cochrane Review.

OBJECTIVES

To evaluate the safety and efficacy of gene therapy for treating people with haemophilia A or B.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis & Genetic Disorders Group's Coagulopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews. Date of last search: 17 April 2020.

SELECTION CRITERIA

Eligible trials include randomised or quasi-randomised clinical trials, including controlled clinical trials comparing gene therapy (with or without standard treatment) with standard treatment (factor replacement) or other 'curative' treatment such as stem cell transplantation for individuals with haemophilia A or B of all ages who do not have inhibitors to factor VIII or IX.

DATA COLLECTION AND ANALYSIS

No trials of gene therapy for haemophilia matching the inclusion criteria were identified.

MAIN RESULTS

No trials of gene therapy for haemophilia matching the inclusion criteria were identified.

AUTHORS' CONCLUSIONS

No randomised or quasi-randomised clinical trials of gene therapy for haemophilia were identified. Thus, we are unable to determine the safety and efficacy of gene therapy for haemophilia. Gene therapy for haemophilia is still in clinical investigation and there is a need for well-designed clinical trials to assess the long-term feasibility, success and risks of gene therapy for people with haemophilia.

Platelet-inspired therapeutics: current status, limitations, clinical implications, and future potential

Recent research has been successful in demonstrating the importance of the addition of platelets to the field of cell-mediated therapeutics, by making use of different platelet forms to design modalities able to positively impact a wide range of diseases. A key obstacle hindering the success of conventional therapeutic interventions is their inability to produce targeted treatment, resulting in a number of systemic side effects and a longer duration for the onset of action to occur. An additional challenge facing current popular therapeutic interventions is biocompatibility of the system, resulting in the decline of patient compliance to treatment. In an attempt to address these challenges, the past few decades have been witness to the discovery and innovation of precision therapy, in order to achieve targeted treatment for an array of conditions, thereby superseding alternative mechanisms of treatment. Platelet-mediated therapeutics, as well as employing platelets as drug delivery vehicles, are key components in advancing precision therapy within research and in clinical settings. This novel approach is designed with the objective that the platelets retain their original structure and functions within the body, thereby mitigating biocompatibility challenges. In this article, we review the current significant impact that the addition of platelet-inspired systems has made on the field of therapeutics; explore certain limitations of each system, together with ideas on how to overcome them; and discuss the clinical implications and future potential of platelet-inspired therapeutics. Graphical abstract.

Hemophilia A ameliorated in mice by CRISPR-based in vivo genome editing of human Factor VIII

Hemophilia A is a monogenic disease with a blood clotting factor VIII (FVIII) deficiency caused by mutation in the factor VIII (F8) gene. Current and emerging treatments such as FVIII protein injection and gene therapies via AAV-delivered F8 transgene in an episome are costly and nonpermanent. Here, we describe a CRISPR/Cas9-based in vivo genome editing method, combined with non-homologous end joining, enabling permanent chromosomal integration of a modified human B domain deleted-F8 (BDD-F8) at the albumin (Alb) locus in liver cells. To test the approach in mice, C57BL/6 mice received tail vein injections of two vectors, AAV8-SaCas9-gRNA, targeting Alb intron 13, and AAV8-BDD-F8. This resulted in BDD-F8 insertion at the Alb locus and FVIII protein expression in the liver of vector-, but not vehicle-, treated mice. Using this approach in hemophilic mice, BDD-F8 was expressed in liver cells as functional human FVIII, leading to increased plasma levels of FVIII and restoration of blood clotting properties in a dose-dependent manor for at least 7 months, with no detectable liver toxicity or meaningful off-target effects. Based on these findings, our BDD-F8 genome editing approach may offer an efficacious, long-term and safe treatment for patients with hemophilia A.

Gene Therapy for Hemophilia: Progress to Date

Hemophilia is a congenital bleeding disorder that affects nearly half a million individuals worldwide. Joint bleeding and other co-morbidities are a significant source of debilitation for this population. Current therapies are effective but must be given lifelong at regular intervals, are costly, and are available to only about 25% of the hemophilia population living in resource-rich countries. Gene therapy for hemophilia has been in development for three decades and is now entering pivotal-stage clinical trials. While many different technology platforms exist for gene therapy, all current clinical trials for hemophilia employ adeno-associated vector (AAV)-based cell transduction. This small viral particle is capable of packaging modified F8 or F9 transgenes, can be generated robustly from cell lines, and transduces several relatively end-differentiated target tissues such as the liver with high efficiency. While pre-existing neutralizing antibodies to the AAV capsid are recognized to limit current therapy, other challenges have been identified in human studies that were not seen in preclinical studies. Both liver transaminase elevations and immune-mediated loss of transgene expression have been observed in clinical trials. Toll-like receptors, cytotoxic T cells, and other components of the immune response have been implicated in the loss of factor expression, but a full understanding of the immune response awaits clarification. Despite these challenges, many patients enrolled in gene therapy trials have attained long-term expression of factors VIII and IX. This emerging technology now represents a cure for the severe bleeding and joint damage associated with hemophilia.

Hemophilia Burden of Disease: A Systematic Review of the Cost-Utility Literature for Hemophilia

BACKGROUND

Prophylaxis with clotting factor replacement products is recommended by the Medical and Scientific Advisory Council of the National Hemophilia Foundation as the optimal therapy for the prevention of bleeding episodes in individuals with severe hemophilia A or B (< 1 IU per dL endogenous factor VIII or factor IX activity, respectively). Prophylaxis is associated with an improved health-related quality of life and has been shown to be cost-effective compared with on-demand therapy. However, the overall cost of treatment remains high, particularly among patients with a greater propensity to bleed. The overall value of hemophilia treatments and their associated benefits, measured in quality-adjusted life-years (QALYs), and dollar costs compared with other interventions can be evaluated through the use of cost-utility analyses (CUAs). Previous CUA studies in hemophilia have focused primarily on patients with more severe forms of hemophilia and on prophylaxis compared with on-demand treatment. However, to our knowledge, no studies to date have utilized QALYs as a standardized outcome measure to systematically evaluate the relative cost-effectiveness of current hemophilia treatment options.

OBJECTIVE

To systematically review the CUA literature of hemophilia treatments and demonstrate the challenges in producing cost-utility evidence compared with other rare diseases.

METHODS

We conducted a systematic literature review using the Tufts Medical Center Cost-Effectiveness Analysis Registry and the National Health Service Economic Evaluation Database for English-language CUAs published from 2000 through 2015 with the search terms hemophilia, haemophilia, factor VIII, or factor IX. Two trained reviewers independently reviewed every study to extract relevant data. Incremental cost-effectiveness ratios were converted to 2014 U.S. dollars using exchange rates for currency conversion and the Consumer Price Index to adjust for inflation.

RESULTS

Our search yielded 52 studies, 11 of which met our inclusion criteria. The cost-effectiveness of hemophilia treatments varied widely based on variations in the study designs, including differences in time horizon, discount rates, and medical interventions.

CONCLUSIONS

We found the cost-effectiveness of hemophilia treatments to be broadly comparable to that of other orphan drugs. Improved standardization of future CUA studies will be important for further evaluation of the cost-effectiveness of hemophilia treatments.

DISCLOSURES

This research was funded by Biogen, which provided an unrestricted research grant to the Center for the Evaluation of Value and Risk in Health at Tufts Medical Center. Biogen and Sobi reviewed and provided feedback on the manuscript. The authors had full editorial control of the manuscript and provided final approval of all content. The authors report no conflict of interest regarding the material discussed in this article. Neumann and Chambers are employed at the Center for the Evaluation of Value and Risk in Health at Tufts Medical Center. Thorat was an employee of Center for Evaluation Value and Risk in Health, Tufts Medical Center when the analyses were carried out. Chambers has participated on advisory boards for Sanofi and Astellas Pharma.

Platelet-Targeted Gene Therapy for Hemophilia

Gene therapy is an attractive approach for disease treatment. Since platelets are abundant cells circulating in blood with the distinctive abilities of storage and delivery and fundamental roles in hemostasis and immunity, they could be a unique target for gene therapy of diseases. Recent studies have demonstrated that ectopic expression of factor VIII (FVIII) in platelets under control of the platelet-specific promoter results in FVIII storage together with its carrier protein von Willebrand factor (VWF) in α-granules and the phenotypic correction of hemophilia A. Importantly, the storage and sequestration of FVIII in platelets appears to effectively restore hemostasis even in the presence of functional-blocking inhibitory antibodies. This review summarizes studies on platelet-specific gene therapy of hemophilia A as well as hemophilia B.

Gene therapy for haemophilia

BACKGROUND

Haemophilia is a genetic disorder characterized by spontaneous or provoked, often uncontrolled, bleeding into joints, muscles and other soft tissues. Current methods of treatment are expensive, challenging and involve regular administration of clotting factors. Gene therapy has recently been prompted as a curative treatment modality. This is an update of a published Cochrane Review.

OBJECTIVES

To evaluate the safety and efficacy of gene therapy for treating people with haemophilia A or B.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis & Genetic Disorders Group's Coagulopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Date of last search: 18 August 2016.

SELECTION CRITERIA

Eligible trials include randomised or quasi-randomised clinical trials, including controlled clinical trials comparing gene therapy (with or without standard treatment) with standard treatment (factor replacement) or other 'curative' treatment such as stem cell transplantation for individuals with haemophilia A or B of all ages who do not have inhibitors to factor VIII or IX.

DATA COLLECTION AND ANALYSIS

No trials of gene therapy for haemophilia were found.

MAIN RESULTS

No trials of gene therapy for haemophilia were identified.

AUTHORS' CONCLUSIONS

No randomised or quasi-randomised clinical trials of gene therapy for haemophilia were identified. Thus, we are unable to determine the safety and efficacy of gene therapy for haemophilia. Gene therapy for haemophilia is still in its nascent stages and there is a need for well-designed clinical trials to assess the long-term feasibility, success and risks of gene therapy for people with haemophilia.

COST-UTILITY ANALYSIS OF PRIMARY PROPHYLAXIS, COMPARED WITH ON-DEMAND TREATMENT, FOR PATIENTS WITH SEVERE HEMOPHILIA TYPE A IN COLOMBIA

Objectives: This article presents a cost-utility analysis from the Colombian health system perspective comparing primary prophylaxis to on-demand treatment using exogenous clotting factor VIII (FVIII) for patients with severe hemophilia type A.

Methods: We developed a Markov model to estimate expected costs and outcomes (measured as quality-adjusted life-years, QALYs) for each strategy. Transition probabilities were estimated using published studies; utility weights were obtained from a sample of Colombian patients with hemophilia and costs were gathered using local data. Both deterministic and probabilistic sensitivity analysis were performed to assess the robustness of results.

Results: The additional cost per QALY gained of primary prophylaxis compared with on-demand treatment was 105,081,022 Colombian pesos (COP) (55,204 USD), and thus not considered cost-effective according to a threshold of up to three times the current Colombian gross domestic product (GDP) per-capita. When primary prophylaxis was provided throughout life using recombinant FVIII (rFVIII), which is much costlier than FVIII, the additional cost per QALY gained reached 174,159,553 COP (91,494 USD).

Conclusions: using a decision rule of up to three times the Colombian GDP per capita, primary prophylaxis (with either FVIII or rFVIII) would not be considered as cost-effective in this country. However, a final decision on providing or preventing patients from primary prophylaxis as a gold standard of care for severe hemophilia type A should also consider broader criteria than the incremental cost-effectiveness ratio results itself. Only a price reduction of exogenous FVIII of 50 percent or more would make primary prophylaxis cost-effective in this context.

Long-term liver-related morbidity and mortality related to chronic hepatitis C virus infection in Swedish patients with inherited bleeding disorders

INTRODUCTION

Hepatitis C virus (HCV) infection is common in patients with inherited bleeding disorders treated with clotting factor concentrates prior to the introduction of viral inactivation of these products. The long-term consequences of hepatitis C infection in Swedish patients are not fully understood.

AIM

To examine the impact of HCV infection on liver-related morbidity and mortality in Swedish patients with inherited bleeding disorders.

METHODS

We retrospectively collected data on 183 patients with inherited bleeding disorders infected with HCV who attended the Coagulation Unit at Karolinska University Hospital, Sweden. Data regarding end-stage liver disease (ESLD), defined as presence of ascites, encephalopathy, variceal bleeding, hepatocellular carcinoma or liver-related death, were collected from the patient records and the national registers.

RESULTS

The median follow-up time was 35.9 years (IQR 29.0-41.2). A total of 41% had achieved sustained virological response (SVR) after treatment. In total, 14.2% developed ESLD at the median age of 52.6 years (IQR 46.5-64.7). Nineteen (35.8%) of all deaths were due to liver-related causes. Co-infection with human immunodeficiency virus (HIV), older age at time of infection and severe form of bleeding disorder was associated with higher risk of developing ESLD, while SVR was a strong protective factor.

CONCLUSIONS

This study demonstrated that liver-related morbidity and mortality was significant in patients with bleeding disorders and HCV infection in Sweden. Patients with HCV-infection should be candidates for treatment with the new highly effective antiviral drugs, since SVR proved to be a strong protective factor.

The immunogenicity of platelet-derived FVIII in hemophilia A mice with or without preexisting anti-FVIII immunity

Evidence shows that factor VIII (FVIII) ectopically expressed in platelets (2bF8) is therapeutic in FVIII(null) mice even with anti-FVIII inhibitory antibodies (inhibitors). If current efforts to generate platelets in vitro succeed, genetically manipulated platelets containing FVIII may be used therapeutically in hemophilia A patients with inhibitors. One important concern is the immunogenicity of platelet-derived FVIII. To address this concern, we infused 2bF8 transgenic (2bF8(Tg)) platelets into naïve FVIII(null) mice weekly for 8 weeks. No anti-FVIII antibodies were detected in the infused animals during the study course. We then explored whether platelet-derived FVIII is immunogenic in FVIII(null) mice with inhibitors. The 2bF8(Tg) platelets were transfused into rhF8-primed FVIII(null) mice, resulting in no augmentation of anti-FVIII antibodies. To investigate whether preconditioning affects the immune response, animals were sublethally irradiated and subsequently transfused with 2bF8(Tg) platelets. No anti-FVIII antibodies were detected in the recipients after platelet infusions. Following further challenge with rhF8, the inhibitor titer in this group was significantly lower than in naïve FVIII(null) mice utilizing the same immunization protocol. Thus, our data demonstrate that infusion of platelets containing FVIII triggers neither primary nor memory anti-FVIII immune response in FVIII(null) mice and that sublethal irradiation plus 2bF8(Tg) platelet infusion suppresses anti-FVIII immune response in FVIII(null) mice.

Gene therapy for haemophilia

BACKGROUND

Haemophilia is a genetic disorder which is characterized by spontaneous or provoked, often uncontrolled, bleeding into joints, muscles and other soft tissues. Current methods of treatment are expensive, challenging and involve regular administration of clotting factors. Gene therapy has recently been prompted as a curative treatment modality.

OBJECTIVES

To evaluate the safety and efficacy of gene therapy for treating people with haemophilia A or B.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis & Genetic Disorders Group's Coagulopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Date of last search: 06 November 2014.

SELECTION CRITERIA

Eligible trials included randomised or quasi-randomised clinical trials, including controlled clinical trials comparing gene therapy (with or without standard treatment) with standard treatment (factor replacement) or other 'curative' treatment such as stem cell transplantation individuals with haemophilia A or B of all ages who do not have inhibitors to factor VIII or IX.

DATA COLLECTION AND ANALYSIS

No trials of gene therapy for haemophilia were found.

MAIN RESULTS

No trials of gene therapy for haemophilia were identified.

AUTHORS' CONCLUSIONS

No randomised or quasi-randomised clinical trials of gene therapy for haemophilia were identified. Thus, we are unable to determine the effects of gene therapy for haemophilia. Gene therapy for haemophilia is still in its nascent stages and there is a need for well-designed clinical trials to assess the long-term feasibility, success and risks of gene therapy for people with haemophilia.

Platelet gene therapy corrects the hemophilic phenotype in immunocompromised hemophilia A mice transplanted with genetically manipulated human cord blood stem cells

Our previous studies have demonstrated that platelet FVIII (2bF8) gene therapy can improve hemostasis in hemophilia A mice, even in the presence of inhibitory antibodies, but none of our studies has targeted human cells. Here, we evaluated the feasibility for lentivirus (LV)-mediated human platelet gene therapy of hemophilia A. Human platelet FVIII expression was introduced by 2bF8LV-mediated transduction of human cord blood (hCB) CD34(+) cells followed by xenotransplantation into immunocompromised NSG mice or NSG mice in an FVIII(null) background (NSGF8KO). Platelet FVIII was detected in all recipients that received 2bF8LV-transduced hCB cells as long as human platelet chimerism persisted. All NSGF8KO recipients (n = 7) that received 2bF8LV-transduced hCB cells survived tail clipping if animals had greater than 2% of platelets derived from 2bF8LV-transduced hCB cells, whereas 5 of 7 survived when human platelets were 0.3% to 2%. Whole blood clotting time analysis confirmed that hemostasis was improved in NSGF8KO mice that received 2bF8LV-transduced hCB cells. We demonstrate, for the first time, the feasibility of 2bF8LV gene delivery to human hematopoietic stem cells to introduce FVIII expression in human platelets and that human platelet-derived FVIII can improve hemostasis in hemophilia A.

Difficult encounters with a hemophilic patient: the inner perspective of physicians

This study aimed at exploring the hematologists' internal representation of a difficult encounter with a hemophilic patient, using a written open format. Narrations were analyzed with Interpretative Phenomenological Analysis. Three main issues were identified, each with sub-issues: (1) Inside the relationship: to tell or not to tell, the balance between a normal life and a deviant medical condition, the guilt; (2) The borders of the professional role: professional values, the "do-it-all" doctor; and (3) The existential confrontation. This study reveals the deep involvement of physicians with their patients, at a professional level and, strongly, at a personal level. The experience of being so deeply involved should be considered in the continuing medical programs for physicians dealing with hemophilia.

Preclinical efficacy and safety of rVIII-SingleChain (CSL627), a novel recombinant single-chain factor VIII

INTRODUCTION

The preclinical efficacy and safety of rVIII-SingleChain (CSL627), a novel recombinant single-chain factor VIII, was assessed in a series of animal studies.

MATERIALS AND METHODS

In the tail-clip bleeding model, hemophilia A mice were injected with escalating doses (1-150 IU/kg) of rVIII-SingleChain, B-domain deleted (BDD) rFVIII (ReFacto AF(®)), or full-length rFVIII products (Advate(®), Helixate(®)). Total blood loss and the percentage of animals in which hemostasis occurred were assessed in this observer-blinded, randomized study. In a second non-randomized study in hemophilia A mice, thromboelastographic analysis, thrombin generation, and activated partial thromboplastin time assays were performed. General safety and toxicity were assessed in three animal species, including determination of the prothrombotic potential of rVIII-SingleChain in a rabbit venous thrombosis model.

RESULTS

Under acute bleeding conditions, the effect of rVIII-SingleChain on total blood loss and hemostasis was indistinguishable from BDD and full-length rFVIII. rVIII-SingleChain and full-length rFVIII (both 20 IU/kg) corrected thromboelastographic parameters, activated partial thromboplastin time, and thrombin generation to a similar degree in hemophilia A mice. In a thrombosis model, the effect of rVIII-SingleChain on thrombus incidence was non-significant and comparable to BDD rFVIII at doses up to 500 IU/kg. Treatment with rVIII-SingleChain did not cause anaphylactic reaction or local intolerance in safety and toxicity studies, and demonstrated an excellent overall safety profile.

CONCLUSIONS

rVIII-SingleChain showed convincing hemostatic efficacy and excellent tolerability in animal studies, warranting continued investigation in human Phase I/III trials (AFFINITY).

New developments in the treatment of pediatric hemophilia and bleeding disorders

PURPOSE OF REVIEW

Disorders of hemostasis such as hemophilia, von Willebrand disease (VWD), and other clotting protein deficiencies lead to significant morbidity in the pediatric population. Because of the limitations of current treatment options, novel therapies are being developed, many of which are reviewed here.

RECENT FINDINGS

Several new observations about the nature of clotting protein physiology have been made recently, creating novel perspectives on the treatment options. This review will mostly focus on the current therapy as well as new progress in hemophilia care (particularly strategies to prolong half-life of clotting factor replacements, the management of inhibitors, gene therapy, and novel therapeutic approaches), and briefly mention some progress in VWD and fibrinogen deficiency therapies.

SUMMARY

New therapeutic developments have the potential to dramatically decrease morbidity and improve the quality of life of children with bleeding disorders.

The history and evolution of the clinical effectiveness of haemophilia type a treatment: a systematic review

First evidence of cases of haemophilia dates from ancient Egypt, but it was when Queen Victoria from England in the 19th century transmitted this illness to her descendants, when it became known as the "royal disease". Last decades of the 20th century account for major discoveries that improved the life expectancy and quality of life of these patients. The history and evolution of haemophilia healthcare counts ups and downs. The introduction of prophylactic schemes during the 1970s have proved to be more effective that the classic on-demand replacement of clotting factors, nevertheless many patients managed with frequent plasma transfusions or derived products became infected with the Human Immunodeficiency Virus (HIV) and Hepatitis C virus during the 1980s and 1990s. Recombinant factor VIII inception has decreased the risk of blood borne infections and restored back longer life expectancies. Main concerns for haemophilia healthcare are shifting from the pure clinical aspects to the economic considerations of long-term replacement therapy. Nowadays researchers' attention has been placed on the future costs and cost-effectiveness of costly long-term treatment. Equity considerations are relevant as well, and alternative options for less affluent countries are under the scope of further research. The aim of this review was to assess the evidence of different treatment options for haemophilia type A over the past four decades, focusing on the most important technological advances that have influenced the natural course of this "royal disease".

Factor VIII inhibitors: von Willebrand factor makes a difference in vitro and in vivo

BACKGROUND

The important association between von Willebrand factor (VWF) and factor VIII (FVIII) has been investigated for decades, but the effect of VWF on the reactivity of FVIII inhibitory antibodies, referred to as inhibitors, is still controversial.

OBJECTIVE

To investigate the interaction among VWF, FVIII and FVIII inhibitory antibodies.

METHODS

Three sources of inhibitors were used for in vitro studies, including the plasma from immunized VWF(null) FVIII(null) mice, purified plasma IgG from human inhibitor patients, or human monoclonal antibody from inhibitor patients' B-cell clones. Inhibitors were incubated with recombinant human FVIII (rhFVIII) either with or without VWF. The remaining FVIII activity was determined by chromogenic assay and inhibitor titers were determined. For in vivo studies, inhibitors and rhFVIII were infused into FVIII(null) or VWF(null) FVIII(null) mice followed by a tail clip survival test.

RESULTS

VWF has a dose-dependent protective effect on FVIII, limiting inhibitor inactivation of FVIII in both mouse and human samples. A preformed complex of VWF with FVIII provides more effective protection from inhibitors than competitive binding of antibodies and VWF to FVIII. The protective effect of VWF against FVIII inactivation by inhibitors was further confirmed in vivo by infusing inhibitors and FVIII into FVIII(null) or VWF(null) FVIII(null) mice followed by a tail clip survival test.

CONCLUSION

Our results demonstrate that VWF exerts a protective effect, reducing inhibitor inactivation of FVIII, both in vitro and in vivo.