Hemophilia Therapy Research Articles

Acceptability of prenatal diagnosis and prenatal treatment of haemophilia using cell and gene therapies within US haemophilia community.

The overall burden of disease in persons with haemophilia continues to be high despite the latest advancements in therapeutics. Clinical trials testing prenatal treatments for several genetic disordersare underway or are recruiting subjects, attesting to the much-needed change in paradigm of how patients with monogenic disorders can be treated. Here we investigate the overall attitude towards prenatal diagnosis, preferences on types of prenatal therapies for haemophilia, the level of 'acceptable' risk tolerated, and which social and moral pressures or disease personal experiences may predict willingness of individuals to consider foetal therapy in a future pregnancy. A multidisciplinary team designed the survey, and the study was carried out using REDCap, and publicized through the National Haemophilia Foundation. Subjects ≥18 years of age were eligible to participate in the study. We assessed participants' attitudes towards prenatal therapy and their level of 'acceptable' risk towards the procedure and therapy. The survey was completed by 67 adults, the majority females. Respondents were willing to undergo prenatal diagnosis, and their main concerns related to the well-being of the pregnant woman and the foetus regarding lasting therapeutic efficacy, side effects of the therapy, and procedural risks, but they were likely to accept a wide range of prenatal therapeutic options, particularly if the foetal therapy proved to be long-lasting and safe. These data demonstrate the willingness of persons with haemophilia, and the haemophilia community, to explore new treatment options beyond the currently offered approaches.

A child diagnosed with severe hemophilia A presenting with nephrotic syndrome: a case report

BackgroundNephrotic syndrome occurring as a complication of immune tolerance therapy for inhibitors in hemophilia B is well recognized. It is also known to occur in association with factor borne infections, especially hepatitis C. This is the first case report of nephrotic syndrome occurring in a child receiving prophylactic factor VIII in the absence of inhibitors of hepatitis infection. However, the pathophysiology of this phenomenon is poorly understood.Case presentationA 7-year Sri Lankan boy diagnosed with severe hemophilia A on weekly factor VIII prophylaxis was diagnosed with three episodes of nephrotic syndrome, a condition in which there is leakage of plasma protein into urine. He had three episodes of nephrotic syndrome, all of which responded well to 60 mg/m2 daily dose of oral steroids, achieving remission within 2 weeks of starting daily prednisolone. He has not developed inhibitors for factor VIII. His hepatitis screening remained negative.ConclusionsThere is a possible link between factor therapy for hemophilia A and nephrotic syndrome, which can be a T-cell-mediated immune response. This case also highlights the importance of monitoring for renal involvement in patients treated with factor replacement.

Factor VIII trafficking to CD4+ T cells shapes its immunogenicity and requires several types of antigen-presenting cells

AbstractDespite >80 years of clinical experience with coagulation factor VIII (FVIII) inhibitors, surprisingly little is known about the in vivo mechanism of this most serious complication of replacement therapy for hemophilia A. These neutralizing antidrug alloantibodies arise in ∼30% of patients. Inhibitor formation is T-cell dependent, but events leading up to helper T-cell activation have been elusive because of, in part, the complex anatomy and cellular makeup of the spleen. Here, we show that FVIII antigen presentation to CD4+ T cells critically depends on a select set of several anatomically distinct antigen-presenting cells, whereby marginal zone B cells and marginal zone and marginal metallophilic macrophages but not red pulp macrophages (RPMFs) participate in shuttling FVIII to the white pulp in which conventional dendritic cells (DCs) prime helper T cells, which then differentiate into follicular helper T (Tfh) cells. Toll-like receptor 9 stimulation accelerated Tfh cell responses and germinal center and inhibitor formation, whereas systemic administration of FVIII alone in hemophilia A mice increased frequencies of monocyte-derived and plasmacytoid DCs. Moreover, FVIII enhanced T-cell proliferation to another protein antigen (ovalbumin), and inflammatory signaling–deficient mice were less likely to develop inhibitors, indicating that FVIII may have intrinsic immunostimulatory properties. Ovalbumin, which, unlike FVIII, is absorbed into the RPMF compartment, fails to elicit T-cell proliferative and antibody responses when administered at the same dose as FVIII. Altogether, we propose that an antigen trafficking pattern that results in efficient in vivo delivery to DCs and inflammatory signaling, shape the immunogenicity of FVIII.

Plasma Clearance of Coagulation Factor VIII and Extension of Its Half-Life for the Therapy of Hemophilia A: A Critical Review of the Current State of Research and Practice.

Factor VIII (FVIII) is an important component of blood coagulation as its congenital deficiency results in life-threatening bleeding. Current prophylactic therapy of the disease (hemophilia A) is based on 3-4 intravenous infusions of therapeutic FVIII per week. This poses a burden on patients, demanding reduction of infusion frequency by using FVIII with extended plasma half-life (EHL). Development of these products requires understanding FVIII plasma clearance mechanisms. This paper overviews (i) an up-to-date state of the research in this field and (ii) current EHL FVIII products, including recently approved efanesoctocog alfa, for which the plasma half-life exceeds a biochemical barrier posed by von Willebrand factor, complexed with FVIII in plasma, which results in ~1 per week infusion frequency. We focus on the EHL FVIII products' structure and function, in particular related to the known discrepancy in results of one-stage clotting (OC) and chromogenic substrate (CS) assays used to assign the products' potency, dosing, and for clinical monitoring in plasma. We suggest a possible root cause of these assays' discrepancy that is also pertinent to EHL factor IX variants used to treat hemophilia B. Finally, we discuss approaches in designing future EHL FVIII variants, including those to be used for hemophilia A gene therapy.

Hemophilia therapy in Italy: what the near future promises.

In Italy have materialized changes pertaining to the striking progress for replacement and non-replacement therapies in patients with hemophilia A and B. This editorial looks at further progress that is expected to occur in Italy as elsewhere with the approval of two gene therapies for the hemophilias, as well as the forthcoming approval and availability of a new factor VIII product with a very extended plasma half-life that can be administered no more frequently than once weekly.

The effectiveness and value of gene therapy for hemophilia: A Summary from the Institute for Clinical and Economic Review's California Technology Assessment Forum.

DISCLOSURES: Dr Tice and Mr Sarker received ICER grants during the conduct of the study. Dr Moradi, Ms Herce-Hagiwara, Dr Faghim, Dr Agboola, Dr Rind, and Dr Pearson reports grants from Arnold Ventures, grants from Blue Cross Blue Shield of MA, grants from California Healthcare Foundation, grants from The Commonwealth Fund, grants from The Peterson Center on Healthcare, during the conduct of the study; other from Aetna, other from America's Health Insurance Plans, other from Anthem, other from AbbVie, other from Alnylam, other from AstraZeneca, other from Biogen, other from Blue Shield of CA, other from Cambia Health Services, other from CVS, other from Editas, other from Express Scripts, other from Genentech/Roche, other from GlaxoSmithKline, other from Harvard Pilgrim, other from Health Care Service Corporation, other from Health Partners, other from Johnson & Johnson (Janssen), other from Kaiser Permanente, other from LEO Pharma, other from Mallinckrodt, other from Merck, other from Novartis, other from National Pharmaceutical Council, other from Premera, other from Prime Therapeutics, other from Regeneron, other from Sanofi, other from Spark Therapeutics, other from United Healthcare, other from HealthFirst, other from Pfizer, other from Boehringer-Ingelheim, other from uniQure, other from Evolve Pharmacy Solutions, other from Humana, other from Sun Life, outside the submitted work.

FDA Approval of Gene Therapy for Hemophilia B: The Dawn of a New Era in Hemophilia Care

FDA Approval of Gene Therapy for Hemophilia B: The Dawn of a New Era in Hemophilia Care

Altered cleavage of human factor VIII at the B-domain and acidic region 3 interface enhances expression after gene therapy in hemophilia A mice

BackgroundVariants of human factor VIII (hFVIII) have been developed to further understand the structure and function of hFVIII and improve gene-based therapeutics. We have previously characterized several hFVIII variants of the furin cleavage site (1645-1648) with improved secretion. We have also identified a second cleavage site in the acidic region 3 (a3) (1657-1658) that becomes the primary hFVIII intracellular cleavage position in the absence of the furin site. We tested a hypothesis that modification of this site may confer additional functional advantages to hFVIII. ObjectivesThe aim of this study was to conduct the biochemical and functional characterization of hFVIII variants of the furin cleavage site, the a3 cleavage site, or in combination, both in vitro and in vivo after AAV mediated gene therapy. MethodsRecombinant hFVIII variants of the furin cleavage site (hFVIII-Δ3), the a3 cleavage site (hFVIII-S1657P/D1658E [SP/DE]), or in combination (hFVIII-Δ3-SP/DE) were purified and characterized in vitro and in vivo. ResultsRecombinant hFVIII-Δ3, hFVIII-SP/DE, and hFVIII-Δ3-SP/DE variants all had comparable specific activity to B-domain deleted (BDD) hFVIII. Hemophilia A mice tolerant to hFVIII did not develop immune responses to hFVIII after protein challenge with these variants or after adeno-associated virus (AAV) delivery. Following AAV delivery, hFVIII-Δ3-SP/DE resulted in expression levels that were 2- to 5-fold higher than those with hFVIII-BDD in hemophilia A mice. ConclusionThe novel hFVIII-Δ3-SP/DE variant of the furin and a3 cleavage sites significantly improved secretion compared with hFVIII-BDD. This key feature of the Δ3-SP/DE variant provides a unique strategy that can be combined with other approaches to further improve factor VIII expression to achieve superior efficacy in AAV-based gene therapy for hemophilia A.

The Unbearable Cost of Drug Development

The Unbearable Cost of Drug Development

Gene Therapy for Hemophilia A: A Mixed Methods Study of Patient Preferences and Shared Decision-Making.

As gene therapies for hemophilia are incorporated into clinical practice, shared decision-making (SDM) is recommended for implementation. SDM tools may facilitate informed decision-making for gene therapy and other novel therapies. To inform the development of SDM tools for hemophilia gene therapy. Men with severe hemophilia were recruited from the National Hemophilia Foundation (NHF) Community Voices in Research (CVR). Semi-structured interviews were completed, and the interviews were transcribed verbatim for quantitative and qualitative analysis. Twenty-five men with severe hemophilia A participated. All participants reported treatment with prophylaxis, nine (36%) on continuous prophylaxis with clotting factor, one (4%) on intermittent prophylaxis with clotting factor, and 15 (60%) on continuous prophylaxis with emicizumab. Ten (40%) indicated that they are excited about gene therapy, 12 (48%) indicated that they are hopeful about gene therapy, one (4%) indicated that they are worried or scared about gene therapy, and one (4%) indicated that they do not have strong feelings about gene therapy. Participants reported engaging Hemophilia Treatment Center, family, and the hemophilia community in their decision-making process. The most reported information needs are efficacy, safety, cost/insurance, mechanism of action, and follow-up. In addition, key information themes that emerged were patient testimonials, hard data and statistics, and comparison to other products. Twenty-two (88%) indicated that a SDM tool would be useful when discussing gene therapy with their hemophilia team. Two indicated that they do their own research, and the tool would not add anything. One needed more information to provide an answer. These data highlight the utility of a SDM tool for hemophilia gene therapy and key information needs. Data including comparison to other treatments should be provided along with patient testimonials in a transparent format. Patients will engage the Hemophilia Treatment Center, family, and community members in the decision-making process.

RNAi for the Treatment of People with Hemophilia: Current Evidence and Patient Selection.

Severe hemophilia is associated with spontaneous, prolonged and recurrent bleeding. Inadequate prevention and treatment of bleeding can lead to serious morbidity and mortality. Due to the limitations of intravenous clotting factor replacement, including the risk of inhibitory antibodies, innovative novel therapies have been developed that have dramatically changed the landscape of hemophilia therapy. Ribonucleic acid interference (RNAi) has brought the opportunity for multiple strategies to manipulate the hemostatic system and ameliorate the bleeding phenotype in severe bleeding disorders. Fitusiran is a RNAi therapeutic that inhibits the expression of the natural anticoagulant serpin antithrombin. Reduction in antithrombin is known to cause thrombosis if coagulation parameters are otherwise normal and can rebalance hemostasis in severe hemophilia. Reports from late stage clinical trials of fitusiran in hemophilia A and B participants, with and without inhibitory antibodies to exogenous clotting factor, have demonstrated efficacy in preventing bleeding events showing promise for a future "universal" prophylactic treatment of individuals with moderate-severe hemophilia.

Expectation and loss when gene therapy for haemophilia is not an option: An exigency sub-study.

Qualitative studies have explored why people with haemophilia (PwH) might consider or forgo gene therapy, the impact it has had on those who have received it, and what support might be needed throughout the process. No studies have yet examined what withdrawal prior to transfection might mean for PwH and their families. To understand the experiences of PwH and their families of withdrawal from gene therapy and to understand what support mechanisms might be required. Qualitative interviews were conducted with people with severe haemophilia who consented to take part in a gene therapy study in the UK but either withdrew or were withdrawn before transfection. Nine PwH and a family member were invited to this sub-study. Eight participants were recruited: six PwH (five haemophilia A and one haemophilia B) and two family members. Four participants were excluded from a study after consenting but before transfection, having failed to meet all the inclusion criteria; two withdrew after consenting but before transfection due to concerns including duration of factor expression and the time commitment involved in follow-up. The mean age of participants was 40.5 years (range 25-63 years). Two major themes emerged during the interviews: Expectation and loss. PwH have many expectations about the difference gene therapy can make to their lives. Studies show that these expectations may not be fully realised. For those who have either withdrawn or been withdrawn from gene therapy, any expectations they had may now be unachievable. The nature of these expectations and the loss expressed by the participants indicate that support needs to be provided to help them and their families manage it.

Low-dose immune tolerance induction therapy in severe hemophilia a children in China: Starting earlier resulted in better inhibitor eradication outcomes

BackgroundShorter interval-time from inhibitor detection to starting immune tolerance induction (ITI) might predict better ITI outcomes for severe Hemophilia A (SHA) patients with high-risk-inhibitors. However, the prediction-impact of interval-time for these patients on low-dose ITI strategy remained unclear. ObjectivesTo explore the relationship between interval-time and low-dose ITI outcomes in Chinese SHA children with high-risk-inhibitors. MethodsThis was a single-center, retrospective study on SHA children with high-risk-inhibitors (each with immediate pre-ITI inhibitor titer>10 Bethesda Units/mL) undergoing low-dose ITI strategy for ≥24 months. ITI outcomes and their predictive factors were evaluated at the 24th month treatment for each patient. The predictive ability of interval-time on ITI success was determined using receiver operating characteristic (ROC) curve. ResultsAmong 47 patients investigated, 34 (72.3 %) achieved success. Independent predictor for ITI-outcome on multivariate analysis included the interval-time (p = 0.007) and peak inhibitor-titer (p = 0.011). Shorter interval-time predicted ITI success [cut-off value = 22.3 months, area under ROC-curve (AUC) = 0.701] and early-ITI success within 12 month (cut-off value = 9.4 months AUC = 0.704). Linear regression analysis suggested each month interval-time delay delayed success by 0.1552 month. Unlike the interval-time, peak inhibitor-titer had no success-predictive value in high-peak inhibitor-titer patients on ITI with immunosuppressants. ConclusionsInterval-time represented a strong predictive value for outcomes in our low-dose ITI strategy for SHA patients with high-risk-inhibitors. Shorter interval-time was associated with higher success rate and earlier success achievement. The respective interval-time cut-off values were 22.3 months for ITI success and 9.4 months for early-success.

Non-factor therapies for haemophilia A and B management

Non-factor therapies for haemophilia A and B management

Gene Therapy with Etranacogene Dezaparvovec for Hemophilia B

BackgroundModerate-to-severe hemophilia B is treated with lifelong, continuous coagulation factor IX replacement to prevent bleeding. Gene therapy for hemophilia B aims to establish sustained factor IX activity, thereby protecting against bleeding without burdensome factor IX replacement.MethodsIn this open-label, phase 3 study, after a lead-in period (≥6 months) of factor IX prophylaxis, we administered one infusion of adeno-associated virus 5 (AAV5) vector expressing the Padua factor IX variant (etranacogene dezaparvovec; 2×1013 genome copies per kilogram of body weight) to 54 men with hemophilia B (factor IX activity ≤2% of the normal value) regardless of preexisting AAV5 neutralizing antibodies. The primary end point was the annualized bleeding rate, evaluated in a noninferiority analysis comparing the rate during months 7 through 18 after etranacogene dezaparvovec treatment with the rate during the lead-in period. Noninferiority of etranacogene dezaparvovec was defined as an upper limit of the two-sided 95% Wald confidence interval of the annualized bleeding rate ratio that was less than the noninferiority margin of 1.8. Superiority, additional efficacy measures, and safety were also assessed.ResultsThe annualized bleeding rate decreased from 4.19 (95% confidence interval [CI], 3.22 to 5.45) during the lead-in period to 1.51 (95% CI, 0.81 to 2.82) during months 7 through 18 after treatment, for a rate ratio of 0.36 (95% Wald CI, 0.20 to 0.64; P<0.001), demonstrating noninferiority and superiority of etranacogene dezaparvovec as compared with factor IX prophylaxis. Factor IX activity had increased from baseline by a least-squares mean of 36.2 percentage points (95% CI, 31.4 to 41.0) at 6 months and 34.3 percentage points (95% CI, 29.5 to 39.1) at 18 months after treatment, and usage of factor IX concentrate decreased by a mean of 248,825 IU per year per participant in the post-treatment period (P<0.001 for all three comparisons). Benefits and safety were observed in participants with predose AAV5 neutralizing antibody titers of less than 700. No treatment-related serious adverse events occurred.ConclusionsEtranacogene dezaparvovec gene therapy was superior to prophylactic factor IX with respect to the annualized bleeding rate, and it had a favorable safety profile. (Funded by uniQure and CSL Behring; HOPE-B ClinicalTrials.gov number, NCT03569891.)

Une thérapie très attendue… et un prix exorbitant !

After many years of development, a gene therapy for haemophilia B has demonstrated effectiveness and durability, at least over a time span of three years. It has just been approved (as Hemgenix®) by the FDA in the USA and by the EMA in the EU. However, the multimillion price tag of this treatment is a serious problem for healthcare systems and for patients, and raises a number of thorny issues about marketing practices of the pharmaceutical industry.

Suppression of anti-drug antibody formation against coagulation factor VIII by oral delivery of anti-CD3 monoclonal antibody in hemophilia A mice

Active tolerance to ingested dietary antigens forms the basis for oral immunotherapy to food allergens or autoimmune self-antigens. Alternatively, oral administration of anti-CD3 monoclonal antibody can be effective in modulating systemic immune responses without T cell depletion. Here we assessed the efficacy of full length and the F(ab’)2 fragment of oral anti-CD3 to prevent anti-drug antibody (ADA) formation to clotting factor VIII (FVIII) protein replacement therapy in hemophilia A mice. A short course of low dose oral anti-CD3 F(ab’)2 reduced the production of neutralizing ADAs, and suppression was significantly enhanced when oral anti-CD3 was timed concurrently with FVIII administration. Tolerance was accompanied by the early induction of FoxP3+LAP-, FoxP3+LAP+, and FoxP3-LAP+ populations of CD4+ T cells in the spleen and mesenteric lymph nodes. FoxP3+LAP+ Tregs expressing CD69, CTLA-4, and PD1 persisted in spleens of treated mice, but did not produce IL-10. Finally, we attempted to combine the anti-CD3 approach with oral intake of FVIII antigen (using our previously established method of using lettuce plant cells transgenic for FVIII antigen fused to cholera toxin B (CTB) subunit, which suppresses ADAs in part through induction of IL-10 producing FoxP3-LAP+ Treg). However, combining these two approaches failed to improve suppression of ADAs. We conclude that oral anti-CD3 treatment is a promising approach to prevention of ADA formation in systemic protein replacement therapy, albeit via mechanisms distinct from and not synergistic with oral intake of bioencapsulated antigen.

Hemgenix - A Gene Therapy for Hemophilia B

Etranacogene dezaparvovec-drlb (Hemgenix – CSL Behring), an adeno-associated virus vector-based gene therapy, has been approved by the FDA for treatment of hemophilia B in adults who currently receive factor IX prophylaxis therapy or have had life-threatening or repeated, serious, spontaneous bleeding episodes.

Big stride in gene therapy for hemophilia B in China.

Big stride in gene therapy for hemophilia B in China.

Angiology and hemostasis : what's new in 2022

In this article, we have selected four topics that particularly caught our attention during the year 2022, and which are related to anticoagulation, its bleeding complications, and hemophilia. Thus, we discuss the issue of the treatment with rivaroxaban of atrial fibrillation associated with rheumatic valvulopathy, which has been studied in a randomized trial, the intensity of thromboprophylaxis in COVID outpatients and inpatients, and the bleeding risk of anticoagulation in patients with cerebral tumors. Finally, recent data on gene therapy in severe hemophilia A, an upcoming treatment, are discussed.