Gene Therapy For Hemophilia Research Articles

Clinical immunogenicity outcomes from GENEr8-1, a phase 3 study of valoctocogene roxaparvovec, an AAV5-vectored gene therapy for hemophilia A

Gene transfer therapies utilizing adeno-associated virus (AAV) vectors involve a complex drug design with multiple components that may impact immunogenicity. Valoctocogene roxaparvovec is an AAV serotype 5 (AAV5)-vectored gene therapy for treatment of hemophilia A that encodes a B-domain–deleted human factor VIII (FVIII) protein controlled by a hepatocyte-selective promoter. Following previous results from the first-in-human phase 1/2 clinical trial, we assessed AAV5 capsid– and transgene-derived FVIII-specific immune responses with 2 years of follow-up data from GENEr8-1, a phase 3, single-arm, open-label study in 134 adult men with severe hemophilia A. No FVIII inhibitors were detected following administration of valoctocogene roxaparvovec. Immune responses were predominantly directed toward the AAV5 capsid, with all participants developing durable anti-AAV5 antibodies. Cellular immune responses specific for the AAV5 capsid were detected in most participants by interferon-ᵧ enzyme-linked immunosorbent spot assay 2 weeks following dose administration and declined or reverted to negative over the first 52 weeks. These responses were weakly correlated with alanine aminotransferase elevations and showed no association with changes in FVIII activity. FVIII-specific cellular immune responses were less frequent and more sporadic compared with those specific for AAV5 and showed no association with safety or efficacy parameters.

Three-year outcomes of valoctocogene roxaparvovec gene therapy for hemophilia A

BackgroundValoctocogene roxaparvovec transfers a human factor (F)VIII coding sequence into hepatocytes of people with severe hemophilia A to provide bleeding protection. ObjectivesTo present 3-year efficacy and safety in the multicenter, open-label, single-arm, phase 3 GENEr8-1 trial. MethodsGENEr8-1 enrolled 134 adult males with severe hemophilia A who were receiving FVIII prophylaxis. Efficacy endpoints included annualized bleeding rate, annualized FVIII utilization, FVIII activity (chromogenic substrate assay; imputed as 1 IU/dL at baseline and 0 IU/dL after discontinuation), and the Haemophilia-Specific Quality of Life Questionnaire for Adults. Safety was assessed by adverse events (AEs). ResultsAt week 156, 131 of 134 participants remained in the study; overall, 17 of 134 resumed prophylaxis. Mean annualized bleeding rate for treated bleeds decreased from 4.8 (SD, 6.5) bleeds/y at baseline to 0.8 (SD, 2.3; P < .0001) bleeds/y after prophylaxis (prophylaxis cessation to last follow-up) and 0.97 (SD, 3.48) bleeds/y during year 3. Annualized FVIII utilization decreased 96.8% from baseline after prophylaxis and 94.2% during year 3. At week 156, mean and median FVIII activity were 18.4 (SD, 30.8) and 8.3 IU/dL, respectively. FVIII activity decrease was lower between years 2 and 3 than between years 1 and 2. At the end of year 3, clinically meaningful improvements in the Haemophilia-Specific Quality of Life Questionnaire for Adults Total Score were observed (mean change from baseline, 6.6; 95% CI, 4.24-8.87; P < .0001). Mild alanine aminotransferase elevations remained the most common AE during year 3 (23.7% of participants). A serious AE of B-cell acute lymphoblastic leukemia was considered unrelated to treatment. ConclusionHemostatic efficacy was maintained, and safety remained unchanged from previous years.

Gene Therapy in Hemophilia A: Achievements, Challenges, and Perspectives.

Strides in advancements of care of persons with hemophilia include development of long-acting factor replacement therapies, novel substitution and hemostatic rebalancing agents, and most recently approved gene therapy. Several decades of preclinical and clinical trials have led to development of adeno-associated viral (AAV) vector-mediated gene transfer for endogenous production of factor VIII (FVIII) in hemophilia A (HA). Only one gene therapy product for HA (valoctocogene roxaparvovec) has been approved by regulatory authorities. Results of valoctocogene roxaparvovec trial show significant improvement in bleeding rates and use of factor replacement therapy; however, sustainability and duration of response show variability with overall decline in FVIII expression over time. Further challenges include untoward adverse effects involving liver toxicity requiring immunosuppression and development of neutralizing antibodies to AAV vector rendering future doses ineffective. Real-life applicability of gene therapy for HA will require appropriate patient screening, infrastructure setup, long-term monitoring including data collection of patient-reported outcomes and innovative payment schemes. This review article highlights the success and development of HA gene therapy trials, challenges including adverse outcomes and variability of response, and perspectives on approach to gene therapy including shared decision-making and need for future strategies to overcome the several unmet needs.

Hepatitis after gene therapy, what are the possible causes?

Hepatitis is a common adverse event following gene therapy for haemophilia, often associated with a loss of transgene expression. Investigating the potential causes and implications of this is crucial for the overall success of treatment. Gene therapy trials using adeno-associated virus (AAV) vectors have demonstrated promising results marked by increases in factor FVIII and FIX levels and reductions in episodes of bleeding. However, hepatocellular injury characterised by elevations in alanine aminotransferases (ALT) has been noted. This liver injury is typically transient and asymptomatic, posing challenges in determining its clinical significance. Proposed causes encompass immune-mediated responses, notably T cell cytotoxicity in response to the AAV vector, direct liver injury from the viral capsid or transcribed protein via the unfolded protein response and pre-existing liver conditions. Liver biopsy data conducted years post-gene therapy infusion has shown sinusoidal infiltration without significant inflammation. The overall safety profile of gene therapy remains favourable with no evidence drug-induced liver injury (DILI) based on Hy's Law criteria. Essential pre-therapy monitoring and identifying patients at high risk of liver injury should involve liver function tests and non-invasive fibroscans, while novel blood-based biomarkers are under exploration. Further research is required to comprehend the mechanisms underlying transaminitis, loss of transgene expression and long-term effects on the liver, providing insights for optimising gene therapy for haemophilia.

Which patients should be considered for gene therapy.

Gene therapy for haemophilia, utilizing adeno-associated viral vectors (AAVs) and coagulation factor genes, have demonstrated promising results, leading to recent approvals and introduction of the first gene therapy products into clinical practice. For successful and safe use, there are predefined inclusion and exclusion criteria, and the treatment process and associated risks should be thoroughly understood and long-term safety and efficacy carefully evaluated during follow up. As gene therapy becomes more accessible outside of clinical study centers, continuous evaluation of patient eligibility for subsequent AAV-based treatments becomes essential. Thorough evaluation of factors such as liver condition, anti-AAV status, and medical history ensures that gene therapy maximizing benefits while minimizing risks. Apart from fulfilling the established inclusion and exclusion criteria, the success of gene therapy is greatly influenced by the motivation and willingness of patients to accept temporary constraints, such as regular laboratory monitoring, potential use of immunosuppressants, and thorough documentation. Furthermore, various patient-related factors play a significant role in the management and outcomes of gene therapy, making a comprehensive evaluation essential. With the accumulation of more data, there is potential for the expansion of certain inclusion criteria, which may allow for a larger number of eligible patients to benefit from gene therapy. Empowering patients through shared decision-making enables them to thoroughly consider the therapy's potential benefits and risks.

Monitoring for liver cancer post-gene therapy-How much and how often?

Hepatocellular carcinoma (HCC) has long been recognized as a complication in people with chronic liver disease, particularly those with cirrhosis. Two gene therapies for haemophilia A and B recently approved in Europe and the US utilize adeno-associated virus (AAV) vectors designed to target hepatocytes. A number of other AAV gene therapies are undergoing clinical investigation for both liver and extrahepatic diseases, many of which likely transduce hepatocytes as well. Although AAV vectors predominantly persist in episomal forms, concerns about insertional mutagenesis have arisen due to findings in pre-clinical models and in a small subset of human HCC cases featuring wild-type AAV integrations in proximity to potential oncogenes. Despite the absence of any causative link between AAV vector therapy and HCC in approved extrahepatic gene therapies or haemophilia gene therapy trials, the package inserts for the recently approved haemophilia gene therapies advise HCC screening in subsets of individuals with additional risk factors. In this review, we discuss HCC risk factors, compare various screening modalities, discuss optimal screening intervals, and consider when to initiate and possibly discontinue screening. At this early point in the evolution of gene therapy, we lack sufficient data to make evidence-based recommendations on HCC screening. While AAV vectors may eventually be shown to be unassociated with risk of HCC, we presently favour a cautious approach that entails regular surveillance until such time as it is hopefully proven to be unnecessary.

Current and emerging gene therapies for haemophilia A and B.

After decades of stumbling clinical development, the first gene therapies for haemophilia A and B have been commercialized and have normalized factor (F)VIII and factor (F)IX levels in some individuals in the long term. Several other clinical programs testing adeno-associated viral (AAV) vector gene therapy are at various stages of clinical testing. Multiyear follow-up in phase 1/2 and 3 studies showed long-term and sometimes curative but widely variable and unpredictable efficacy. Liver toxicities, mostly low-grade, occur in the 1st year in at least some individuals in all haemophilia A and B trials and are poorly understood. Wide variability and unpredictability of outcome and slow decline of FVIII levels are a major disadvantage because immune responses to AAV vectors preclude repeat dosing, which otherwise could improve suboptimal or restore declining expression, while overexpression may predispose to thrombosis. Long-term safety outcomes will need lifelong monitoring because AAV vectors infused at high doses integrate into chromosomes at rates that raise questions about potential oncogenicity and necessitate vigilance. Alternative gene transfer systems employing gene editing and/or non-viral vectors are under development and promise to overcome some limitations of the current state of the art for both haemophilia A and B. AAV gene therapies for haemophilia have now become new treatment options but not universal cures. AAV is a powerful but imperfect gene transfer platform. Biobetter FVIII transgenes may help solve some problems plaguing gene therapy for haemophilia A. Addressing variability and unpredictability of efficacy, and delivery of gene therapy to ineligible patient subgroups may require different gene transfer systems, most of which are not ready for clinical translation yet but bring innovations needed to overcome the current limitations of gene therapy.

Correction to: Efficacy and Safety of Adeno-Associated Virus-Based Clinical Gene Therapy for Hemophilia: A Systematic Review and Meta-Analysis, by Han et al. Hum Gene Ther 2024;35(3-4):93-103; doi: 10.1089/hum.2023.208.

Correction to: Efficacy and Safety of Adeno-Associated Virus-Based Clinical Gene Therapy for Hemophilia: A Systematic Review and Meta-Analysis, by Han et al. Hum Gene Ther 2024;35(3-4):93-103; doi: 10.1089/hum.2023.208.

Cost-Effectiveness Analysis of Etranacogene Dezaparvovec Versus Extended Half-Life Prophylaxis for Moderate-to-Severe Haemophilia B in Germany.

Haemophilia B is a rare genetic disease that is caused by a deficiency of coagulation factor IX (FIX) in the blood and leads to internal and external bleeding. Under the current standard of care, haemophilia is treated either prophylactically or on-demand via intravenous infusions of FIX. These treatment strategies impose a high burden on patients and health care systems as haemophilia B requires lifelong treatment, and FIX is costly. Etranacogene dezaparvovec (ED) is a gene therapy for haemophilia B that has been recently approved by the United States Food and Drug Administration and has received a recommendation for conditional marketing authorization by the European Medicines Agency. We aimed to examine the cost-effectiveness of ED versus extended half-life FIX (EHL-FIX) prophylaxis for moderate-to-severe haemophilia B from a German health care payer perspective. A microsimulation model was implemented in R. The model used data from the ED phase 3 clinical trial publication and further secondary data sources to simulate and compare patients receiving ED or EHL-FIX prophylaxis over a lifetime horizon, with the potential for ED patients to switch treatment to EHL-FIX prophylaxis when the effectiveness of ED waned. Primary outcomes of this analysis included discounted total costs, discounted quality-adjusted life years (QALYs), incremental cost-effectiveness, and the incremental net monetary benefit. The annual discount rate for costs and effects was 3%. Uncertainty was examined via probabilistic analysis and additional univariate sensitivity analyses. Probabilistic analysis indicated that patients treated with ED instead of EHL-FIX prophylaxis gained 0.50 QALYs and experienced cost savings of EUR 1,179,829 at a price of EUR 1,500,000 per ED treatment. ED was the dominant treatment strategy. At a willingness to pay of EUR 50,000/QALY, the incremental net monetary benefit amounted to EUR 1,204,840. Depending on the price, ED can save costs and improve health outcomes of haemophilia patients compared with EHL-FIX prophylaxis, making it a potentially cost-effective alternative. These results are uncertain due to a lack of evidence regarding the long-term effectiveness of ED.

Next-generation strategies to improve safety and efficacy of adeno-associated virus-based gene therapy for hemophilia: lessons from clinical trials in other gene therapies.

Three major directions for the global progress of adeno-associated virus (AAV) vectors for gene therapies (GT) are analyzed: a) engineering vectors to increase transgene expression; b) aligning interests of the health system with costs and challenges for pharmaceutical industry; c) refining patient eligibility criteria, and endpoints definition. Currently employed AAV vectors may cause toxicity and adverse events. Furthermore, studies in animals do not fully predict risks and clinical benefits of AAV-based GT, and animal models reflecting the heterogeneity of certain clinical settings (e.g., congestive heart failure) are poorly available for improving AAV-based GT. Finally, antisense and gene editing approaches will soon complement gene augmentation strategies for the stable solution of unsolved issues of AAV-based GT. While minimizing toxicity, next-generation AAV vectors should decrease the viral load needed to achieve therapeutic efficacy; be functional in a restricted cellular subset; avoid transgene expression in unwanted cells (e.g., hepatocytes), and escape immune oversight in AAV-based GT. The role of stress-induced apoptosis in the loss of transgene expression in GT should be also explored. Aligning interests and obligations of pharmaceutical industry with those of the health system is critical for AAV-based GT success. Costs and challenges for pharmaceutical industry include a) removing impurities from AAV; b) validating tests to measure treatment efficacy, c) promoting training programs to standardize vector genomes delivery, d) collecting long-term follow-up data, and e) maintaining sustainability and cost-effectiveness of AAV-based GT. In rare disorders with small patient numbers (e.g., hemophilia), clearcut outcomes are mandatory as endpoints of unequivocal efficacy data.

Fidanacogene Elaparvovec (Beqvez)

&#x0D; CADTH recommends that Beqvez be reimbursed by public drug plans for the treatment of adults with moderately severe to severe hemophilia B (congenital factor IX deficiency) who are negative for neutralizing antibodies to variant adeno-associated virus (AAV) serotype Rh74 , if certain conditions are met.&#x0D; Beqvez should only be covered to treat adult patients (aged 18 years or older) with circulating coagulation factor IX (FIX:C) activity of 2% or less and bleeding that requires ongoing prophylactic treatment. Beqvez should not be covered if the patient has FIX inhibitors or has previously received gene therapy for hemophilia B.&#x0D; Beqvez should only be reimbursed if prescribed by specialists who have expertise in treating hemophilia B and if the cost of Beqvez is reduced. Beqvez is a 1-time therapy.&#x0D;

Etranacogene dezaparvovec gene therapy for haemophilia B (HOPE-B): 24-month post-hoc efficacy and safety data from a single-arm, multicentre, phase 3 trial

Etranacogene dezaparvovec, the first gene therapy approved for haemophilia B treatment, was shown to be superior to treatment with continuous prophylactic factor IX in terms of bleeding protection 18 months after gene therapy in a phase 3 trial. We report post-hoc 24-month efficacy and safety data from this trial to evaluate the longer-term effects of etranacogene dezaparvovec in individuals with haemophilia B. The phase 3 HOPE-B trial enrolled males aged 18 years or older with inherited haemophilia B, classified as severe (plasma factor IX activity level <1%) or moderately severe (plasma factor IX activity level ≥1% and ≤2%), with a severe bleeding phenotype and who were on stable continuous factor IX prophylaxis. Participants were treated with a single infusion of etranacogene dezaparvovec (2 × 1013 genome copies per kg of bodyweight). The primary endpoint, reported previously, was non-inferiority of the annualised bleeding rate (ABR) during the 52 weeks following stable factor IX expression (defined as months 7-18 after treatment) versus an at least 6-month lead-in period in which participants received their usual continuous factor IX prophylaxis, and is updated here up to month 24. Additional, post-hoc efficacy analyses, including adjusted ABR, factor IX activity, participants within factor IX ranges, and factor IX use, and safety analyses were performed at 24 months after gene therapy. Data were analysed in the full analysis set, which comprised the 54 patients who received at least a partial dose of gene therapy. The trial is ongoing and is registered with ClinicalTrials.gov, number NCT03569891. The study began on June 27, 2018, and participants were treated between January, 2019, and March, 2020; the date of data cutoff was April 21, 2022. 54 adult males (40 White, two Asian, one Black or African American, 11 other or missing) received a single intravenous infusion of etranacogene dezaparvovec and were followed for a median of 26·51 months (IQR 24·54-27·99), after a lead-in period of 7·13 months (6·51-7·82). In the updated analysis comparing months 7-24 after gene therapy to the lead-in period, mean adjusted ABR significantly reduced from 4·18 to 1·51 (p=0·0002) for all bleeds and from 3·65 to 0·99 (p=0·0001) for factor IX-treated bleeds. During each 6-month period after gene therapy, at least 67% of participants experienced no bleeding (36 of 54 during months 0-6 and stable thereafter), compared with 14 (26%) of 54 during the lead-in period. 24 months after gene therapy, 1 (2%) participant had one-stage factor IX activity less than 5%, whereas 18 (33%) had factor IX activity more than 40% (non-haemophilia range), with mean factor IX activity stable and sustained at 36·7% (SD 19·0%). 52 (96%) of 54 participants expressed endogenous factor IX, remaining free of factor IX prophylaxis at month 24. No new safety concerns were identified and no treatment-related serious adverse events or treatment-related deaths occurred. The most common treatment-related adverse events were an increase in alanine aminotransferase (nine [17%] of 54 patients), headache (eight [15%]), influenza-like illness (seven [13%]), and an increase in aspartate aminotransferase (five [9%]). By providing durable disease correction throughout the 24 months after gene therapy, etranacogene dezaparvovec provides a safe and effective therapeutic option for patients with severe or moderately severe haemophilia B. uniQure and CSL Behring.

AAV mediated gene therapy for haemophilia B: From the early attempts to modern trials

Early gene therapy clinical trials for the treatment of Haemophilia B have been instrumental to our global understanding of gene therapy and have significantly contributed to the rapid expansion of the field. The use of adeno-associated viruses (AAVs) as vectors for gene transfer has successfully led to therapeutic expression of coagulation factor IX (FIX) in severe haemophilia B patients. Expression of FIX has remained stable following a single administration of vector for up to 8 years at levels that are clinically relevant to reduce the incidence of spontaneous bleeds and have permitted a significant change in the disease management with reduction or elimination of the need for coagulation factor concentrates. These trials have also shed light on several concerns around AAV-mediated gene transfer such as the high prevalence of pre-existing immunity against the vector capsid as well as the elevation of liver transaminases that is associated with a loss of FIX transgene expression in some patients. However, this field is advancing very rapidly with the development of increasingly more efficient strategies to overcome some of these obstacles and importantly raise the possibility of a functional cure, which has been long sought after. This review overviews the evolution of gene therapy for haemophilia B over the last two decades.

Efficacy and Safety of Adeno-Associated Virus-Based Clinical Gene Therapy for Hemophilia: A Systematic Review and Meta-Analysis.

Clinical trials of adeno-associated virus (AAV)-based gene therapy have made remarkable progress in recent years. We aimed to perform a systematic review and meta-analysis of the literature to assess the efficacy and safety of AAV-based gene therapy for hemophilia. We systematically searched the Web of Science, Embase, PubMed, and the Cochrane Database of Systematic Reviews databases, for clinical trials involving patients diagnosed with hemophilia and treated with AAV-mediated gene therapy. Data on the annualized bleeding rate (ABR), annualized infusion rate (AIR), the incidence of treatment-related adverse events (TRAEs), severe adverse events (SAEs), and alanine aminotransferase (ALT) elevation were extracted as our outcomes. A total of 12 articles from 11 clinical trials were selected from 868 articles for meta-analysis. Pooled analyses showed that AAV-based gene therapy in hemophilia patients reduced the number of bleeding events and the number of factor infusion events by an approximate average of 7 per year and 103 per year, respectively. Eighty percent, 18%, and 63% of hemophilia patients had elevated TRAE, SAE, and ALT levels, respectively. Moreover, subgroup analysis found a significant reduction in ABR and AIR 2-3 years after the therapy. Additional findings that were not pooled including coagulation factor activity are presented in the accompanying tables. Our analysis supported the efficacy and safety of AAV-mediated gene therapy for hemophilia, providing evidence for its application as a therapeutic option for widespread clinical use in hemophilia patients in the future.

Gene Therapy for Genetic Syndromes: Understanding the Current State to Guide Future Care.

Gene therapy holds promise as a life-changing option for individuals with genetic variants that give rise to disease. FDA-approved gene therapies for Spinal Muscular Atrophy (SMA), cerebral adrenoleukodystrophy, β-Thalassemia, hemophilia A/B, retinal dystrophy, and Duchenne Muscular Dystrophy have generated buzz around the ability to change the course of genetic syndromes. However, this excitement risks over-expansion into areas of genetic disease that may not fit the current state of gene therapy. While in situ (targeted to an area) and ex vivo (removal of cells, delivery, and administration of cells) approaches show promise, they have a limited target ability. Broader in vivo gene therapy trials have shown various continued challenges, including immune response, use of immune suppressants correlating to secondary infections, unknown outcomes of overexpression, and challenges in driving tissue-specific corrections. Viral delivery systems can be associated with adverse outcomes such as hepatotoxicity and lethality if uncontrolled. In some cases, these risks are far outweighed by the potentially lethal syndromes for which these systems are being developed. Therefore, it is critical to evaluate the field of genetic diseases to perform cost-benefit analyses for gene therapy. In this work, we present the current state while setting forth tools and resources to guide informed directions to avoid foreseeable issues in gene therapy that could prevent the field from continued success.

Challenges and Emerging Strategies in ATMPs

Advanced therapy medicinal products (ATMPs) are a significant innovation in medicine, categorized by the European Medicines Agency into four types: gene therapy medicines, somatic cell therapy medicines, tissue-engineered medicines and combined ATMPs. They hold potential for treating various conditions, including rare diseases, degenerative diseases like Parkinson’s and Alzheimer’s and cancers. The global market for ATMPs was valued at US$9.28 billion in 2023 and is projected to reach US$22.80 billion by 2032, growing at a compound annual growth rate of 10.50%. Gene and cell therapies are advancing rapidly, with over 1,700 approved clinical trials worldwide. Notable successes include Glybera for lipoprotein lipase deficiency and Roctavian for haemophilia. Despite limited current approvals, many gene therapies are expected to gain market approval soon. Challenges include stringent regulatory requirements, safety and ethical concerns. For example, Glybera faced multiple rejections before approval due to safety issues. Current clinical studies are exploring immune-based therapies like CAR-T, cytotoxic T lymphocytes, natural killer cells and mesenchymal stromal cells. CAR-T cell therapies, such as Yescarta and Kymriah, have shown promise in treating B-cell lymphoma. However, high development and manufacturing costs limit accessibility, exemplified by Hemgenix, a gene therapy for haemophilia B priced at US$3.5 million. Increased ATMP sales have spurred investor interest in R&amp;D, leading to advancements in technology and manufacturing processes. Despite challenges, the future is promising with more academic and commercial ATMP clinical trials. There are now 32 approved gene therapies globally. To attract industries, the focus should shift from rare to common diseases, and alternative reimbursement models could help manage high costs. A trained workforce and public involvement are crucial for the successful delivery of ATMPs.

A multi-stakeholder collaborative approach to awareness, education and support needed in the haemophilia gene therapy patient journey – a report on insights from a European patient advisory board

Abstract Gene therapy presents a potentially transformational approach to haemophilia management. The patient journey for gene therapy is unlike that for other haemophilia treatments, and its one-time, irreversible nature has led to broad agreement that informed shared decision-making is essential. Understanding the educational and support needs of people with haemophilia (PwH) who may consider or undergo gene therapy in the future is key to enabling this. A one-day patient advisory board was conducted with the aim of gaining insights on what education and support would enable PwH to have appropriate conversations with health care practitioners (HCPs) about gene therapy and participate in informed shared decision-making. The participants were 11 age-diverse men with severe haemophilia A or B, including six who had received gene therapy in phase 1-3 clinical trials. Two were members of a national patient organisation or a patient organisation leader. Participants agreed that informed shared decision-making was essential for gene therapy, but most felt the choice to have gene therapy would be limited by healthcare budgets and access arrangements. They identified key education needed by PwH to enable true informed decision-making, best delivered through a collaborative approach by patient organisations and HCPs. Eligibility criteria should be more widely shared within the community as part of general education around gene therapy. Gene therapy should be presented as one of a range of treatment options; understanding its risks, uncertainties and benefits is key to managing expectations and minimising treatment remorse. Awareness of how different factor levels impact bleeding tendency and frequency would be helpful, as success of gene therapy cannot be determined by factor activity alone. Other key educational needs included follow-up commitments, the role and potential side effects of corticosteroids or other immunosuppressants, impact on sense of identity, mental health, family planning, and managing bleeds after gene therapy. Teach-back could help ensure appropriate levels of understanding; psychological support could aid managing expectations. Peer-to-peer learning delivered across a variety of platforms, to share experiences of gene therapy and contextualise more ‘formal’ gene therapy education, was considered invaluable.

Different Gene Therapies Fortreatment of Hemophilia A

According to US Center for Disease Control and Prevention, there are 12 per 100000 males born with hemophilia A in US, and there are 400 male babies born with hemophilia A per year. Hemophilia A is type of disease that is inherited with X-linked recessive that have mutation in Factor VII gene. Recently, there are types of gene therapies success in hepatic vivo gene transferring. In this review, this paper will discuss three types of gene therapies for hemophilia A which are Zinc Finger Nucleases (ZFNs) and Transcription Activator Factors (TALENs) and CRISPER Cas9. ZFNs using the zinc finger DNA binding array in conjunction with FoKI cleavage nucleases domain to target and cleave to trigger the DNA repairing. In TALENs researchers induced pluripotent stem cells (iPSCs) derived by TALENickases to target the FVIII site. The latest research is using CRISPR Cas9 as a gene editing method to treat hemophilia A. The researchers used this method to repair the mutated gene so that the FVIII factor could be expressed normally. The paper also explains the current methods and process of delivery in gene therapy and shows the pros and cons of each. In conclusion, this paper express our prospects for future research about gene therapies.

Advances and challenges with gene therapy for haemophilia

Summary:&#x0D; Haemophilia rare inherited bleeding disorder caused by deficiency in clotting factor that affects around 6,000 people in the UK. Patients with haemophilia require regular prophylactic infusions of the deficient clotting factor intravenously, which causes a large burden on patients and their families. Gene therapy holds promise as a potential cure for Haemophilia. This article critically evaluates the existing evidence for gene therapy in Haemophilia.&#x0D; Relevance:&#x0D; There are several gene therapies in development for inherited conditions such as Haemophilia. Valoctocogene Roxaparvovec, a gene therapy for Haemophilia, is currently being assessed by regulatory authorities worldwide. Medical students and practicing physicians must be aware of the current evidence base for gene therapy for Haemophilia as well as the limitations thereof to help patients make informed decisions on whether gene therapy is a suitable treatment option for them. &#x0D; Take Home Messages:&#x0D; The current evidence shows that gene therapy is likely to be effective in increasing clotting factor levels and reducing bleeds for at least 3 years. However, long-term data is limited, and therefore, the durability of the treatment is unknown. Additionally, there is limited evidence on the safety and efficacy of gene therapy in patients with pre-existing antibodies to the viral vector, patients with inhibitors to the clotting factor, and children.

Gene therapy for haemophilia A and B, from basic principles to clinical implementation: An illustrated review.

With recent approval of the first two gene therapies for haemophilia A and B, educational materials about AAV-based gene therapy are needed by the haemophilia community for a better understanding of this novel therapeutic approach and helping healthcare providers and patients making personalized choices amongst an increasing array of therapeutic options. To provide a comprehensive summary of the whole process of AAV-based gene therapy from basic principles to clinical implementation through an illustrated review. The authors, with expertise in and knowledge about gene therapy for haemophilia A and B, reviewed relevant articles from PubMed database and translated them into illustrations. The review is divided into eight illustrated sections providing an overview of gene therapy for haemophilia A and B from haemophilia basics and current treatment landscape, principles of the AAV-based liver-directed gene therapy, through exploring the efficacy and safety results of published phase III clinical trials, current and future challenges, to implementation in clinical practice, including the hub and spoke models and the patient journey. This illustrated review educates healthcare professionals on AAV-based gene therapy for haemophilia A and B enabling them to further educate their peers and their patients.