The 1st WFH Gene Therapy Round Table: Understanding the landscape and challenges of gene therapy for haemophilia around the world

Development of the World Federation of Hemophilia Shared Decision-Making Tool

INTRODUCTION

The use of shared decision-making (SDM) in clinical settings is becoming more prevalent. The evolving and increasingly complex treatment landscape of haemophilia management has augmented the need and desire for SDM between patients and their healthcare team. SDM tools have been used in other chronic conditions and can be an effective form of education for patients and clinicians.

AIM

The World Federation of Hemophilia (WFH) partnered with people with haemophilia (PWH), patient advocacy groups, and healthcare practitioners to form an expert working group to develop an educational tool for PWH and their caregivers. The primary objectives included educating PWH on the available prophylactic treatments and facilitating discussion between PWH and their healthcare team.

METHODS

The tool was proposed and developed by the expert working group, workshopped at conference round tables, and evaluated in two focus groups.

RESULTS

The interactive WFH SDM Tool guides users through the SDM treatment journey and provides an opportunity for reflection on current disease impact and treatment preferences, educational fact sheets and videos, and a comparison between treatment classes. Two forms of the SDM Tool are available: an online platform with a summary page that may be printed and shared and a printable workbook. All evidence in the tool is based on the prescribing information or phase III clinical trial publications. The Tool will be updated twice each year.

CONCLUSION

The WFH SDM Tool is the first available resource that translates published guidance on SDM in haemophilia into a practical, user-friendly tool aimed at facilitating patient-centred treatment decisions.

Knowledge and attitudes toward gene therapy of a cohort of Italian patients with hemophilia

BACKGROUND

Gene therapy (GT) has recently become a new therapeutic option for hemophilia A and B. However, patient levels of knowledge and attitudes toward it are poorly understood. A general lack of knowledge and education has been highlighted in previous studies. To date, no studies focused on patient attitudes toward GT, priorities, concerns, and information needs, nor how these factors might influence their willingness to accept it.

OBJECTIVES

To evaluate knowledge and attitudes toward GT of an Italian cohort of patients with hemophilia.

METHODS

A questionnaire was administered to patients with hemophilia A and B to evaluate: (1) clinical data; (2) GT knowledge; (3) willingness to accept GT, perceived benefits and concerns, and information needs.

RESULTS

Eighty-five patients participated in the study; 64 with severe hemophilia A and 4 with severe hemophilia B. Participants appeared to know only general information on GT, but little about its detailed functioning. The avoidance of frequent infusions and the reduction of bleeding episodes seem to be the most relevant expected benefits. The possibility of failing or losing effectiveness of GT over time was the main concern. Regarding willingness to undergo GT, 54.4% of respondents gave a negative response, mainly due to fear that treatment will lose effectiveness over time, fear of side effects, and lack of GT knowledge. Greater knowledge increased the acceptability of this disruptive therapy among patients with severe hemophilia.

CONCLUSION

Overall, Italian patients with hemophilia showed poor knowledge of GT. However, it seems that greater knowledge was associated with a greater willingness to have GT.

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

INTRODUCTION

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.

AIM

To provide a comprehensive summary of the whole process of AAV-based gene therapy from basic principles to clinical implementation through an illustrated review.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Perspectives and perception of haemophilia gene therapy by French patients

INTRODUCTION AND AIM

A national survey was initiated by representatives of French patients with haemophilia (AFH) and the French reference centre for haemophilia, in order to appreciate the awareness and knowledge of these patients regarding haemophilia gene therapy (HGT) and understand better their position about this innovative treatment that will soon become available.

RESULTS

Of 143 answers received, 137 could be analysed, representing about 3.5% of patients with severe or moderate haemophilia over 16year-old. They were 80.3% with haemophilia A and 19.7 % with haemophilia B, with a severe form of the disease for 80.3 % of them. Curiosity for HGT was formulated by 64.2% of the participants, 33.6 % being interested by this approach as soon as it will be available and 38.7 % preferring to wait until more patients have been treated. Only 3.6 % of the participants would never consider receiving HGT. The level of awareness and knowledge was estimated to be limited by 39.5 % of the patients. More than 60 % of them declared having never or almost never discussed HGT with the team of their haemophilia centre. Before deciding to get HGT, 54.4 % of the participants considered that it will be very important to compare it with their current treatment and 53.7 % would like to be better informed by their care providers.

CONCLUSIONS

These results highlight the need for training and education for patients, but also for professionals at haemophilia centres, about HGT and the shared decision-making process. Objective, unbiased and transparent information must be available for patients about this very promising therapy which nonetheless carries more uncertainty and unknowns compared to other haemophilia treatments.

The ethics of gene therapy for hemophilia: a narrative review

Gene therapy is expected to become a promising treatment, and potentially even a cure, for hemophilia. After several years of research, the first gene therapy product has been granted conditional market authorization by the European Union in August 2022. The recent progress in the field also has implications on the ethical aspects of hemophilia gene therapy. Reviews conducted in the 2000s mainly identified questions on the ethics of conducting early-phase clinical trials. However, since then, the knowledge on safety and efficacy has improved, and the field has moved toward clinical application, a phase that has its own ethical aspects. Therefore, we conducted a narrative review to take stock of the ethical aspects of hemophilia gene therapy. Based on our analysis of the literature, we identified 3 ethical themes. The theme Living up to expectations describes the existing hopes for gene therapy and the unlikelihood of the currently approved product becoming a permanent cure. In the theme Psychosocial impacts, we discuss the fear that gene therapy will impact the identity of people with hemophilia and their need for psychosocial support. The theme Costs and access discusses the expected cost-effectiveness of gene therapy and its implications on accessibility worldwide. We conclude that it may be necessary to change the narratives surrounding gene therapy, from describing it as a cure to describing it as one of the many treatments that temporarily relieve symptoms and that there is a need to reevaluate the desirability of gene therapy for hemophilia, given the availability of other treatments.

How to translate and implement the current science of gene therapy into haemophilia care?

Gene-based therapy opens an entirely new paradigm in managing people with haemophilia (PWH), offering them the possibility of a functional cure by enabling continuous expression of factor VIII (FVIII) or factor IX (FIX) after transfer of a functional gene designed to replace the PWH's own defective gene. In recent years, significant advances in gene therapy have been made, resulting in clotting factor activity attaining near-normal levels, as reflected by 'zero bleeding rates' in previously severely inflicted patients following a single administration of adeno-associated viral (AAV) vectors. While this new approach represents a major advancement, there are still several issues that must be resolved before applying this technology in clinical practice. First, awareness, communication, and education about the therapeutic potential and modalities of gene therapy must be further strengthened. To this end, objective, unbiased, transparent, and regularly updated information must be shared, in an appropriate way and understandable language with the support of patients' organizations. Second, healthcare providers should adopt a patient-centred approach, as the 'one size fits all' approach is inappropriate when considering gene therapy. Instead, a holistic patient view taking into account their physical and mental dimensions, along with unexpressed expectations and preferences, is mandatory. Third, the consent procedure must be improved, ensuring that patients' interests are maximally protected. Finally, gene therapy is likely to be first delivered in a few centres, with the highest expertise and experience in this domain. Thus, patients should be managed based on a hub-and-spoke model, taking into account that the key to gene therapy's success lies in an optimal communication and collaboration both within and between haemophilia centres sharing their experiences in the frame of international registries. This review describes recent progress and explains outstanding hurdles that must be tackled to ease the implementation of this paradigm-changing new therapy.

Gene therapy preferences and informed decision-making: Results from a National Hemophilia Foundation Community Voices in research survey

INTRODUCTION

To inform education and treatment discussions, it is important to understand how persons with haemophilia prefer to learn about and discuss new therapies and to identify variables that influence decision-making.

AIM

The aim of this study was to evaluate preferences and variables which influence decision-making related to gene therapy and other novel haemophilia therapies.

METHODS

An online survey was sent to men with severe haemophilia enrolled in the National Hemophilia Foundation Community Voices in Research online platform for patient-powered research.

RESULTS

One hundred four men completed the survey including 33% Hispanics, 96 who had had not gene therapy and 71/96 (74%) who were on prophylaxis. Ninety-five percent were somewhat or very familiar with gene therapy. Men with haemophilia obtain information about new therapies from several sources, most commonly their haemophilia treatment team, patient advocacy groups and self-study. Participants identified safety and efficacy as well as other educational needs to inform decision-making. Of those without prior gene therapy, 73% indicated a high likelihood of considering gene therapy. Hispanic ethnicity and government-issued insurance were associated with a higher likelihood of considering gene therapy as a treatment option.

CONCLUSION

Haemophilia Treatment Centers and patient advocacy groups must be able to educate persons with haemophilia about aspects of novel therapies which are important to the individual, especially short- and long-term safety and efficacy. Further research is needed to determine how patient activation and health literacy influence decision-making and how to achieve equitable access and valid informed consent for novel therapies.

Gene therapy in haemophilia: literature review and regional perspectives for Turkey

Haemophilia is an X-linked lifelong congenital bleeding disorder that is caused by insufficient levels of factor VIII (FVIII; haemophilia A) or factor IX (FIX; haemophilia B) and characterized by spontaneous and trauma-related bleeding episodes. The cornerstone of the treatment, factor replacement, constitutes several difficulties, including frequent injections due to the short half-life of recombinant factors, intravenous administration and the risk of inhibitor development. While extended half-life factors and subcutaneous novel molecules enhanced the quality of life, initial successes with gene therapy offer a significant hope for cure. Although adeno-associated viral (AAV)-based gene therapy is one of the most emerging approaches for treatment of haemophilia, there are still challenges in vector immunogenicity, potency and efficacy, genotoxicity and persistence. As the approval for the first gene therapy product is coming closer, eligibility criteria for patient selection, multidisciplinary approach for optimal delivery and follow-up and development of new pricing policies and reimbursement models should be concerned. Therefore, this review addresses the unmet needs of current haemophilia treatment and explains the rationale and principles of gene therapy. Limitations and challenges are discussed from a global and national perspective and recommendations are provided to adopt the gene therapies faster and more sufficient for the haemophilia patients in developing countries like Turkey.

Gene therapy access: Global challenges, opportunities, and views from Brazil, South Africa, and India

Gene and cell therapies for a variety of life-limiting illnesses are under investigation, and a small number of commercial products have successfully obtained regulatory approval. The cost of treatment is high, and clinical studies evaluating safety and efficacy are performed predominately in high-income countries. We reviewed the current status of gene and cell therapies in low- and middle-income countries and highlighted the need and current barriers to access. The state of product development in Brazil, South Africa, and India is discussed, including lessons learned from American Society of Gene and Cell Therapy (ASGCT)-sponsored virtual symposia in each of these countries.

Gene therapy - are we ready now?

Introduction

Haemophilia therapy has evolved from rudimentary transfusion‐based approaches to an unprecedented level of innovation with glimmers of functional cure brought by gene therapy. After decades of misfires, gene therapy has normalized factor (F)VIII and factor (F)IX levels in some individuals in the long term. Several clinical programmes testing adeno‐associated viral (AAV) vector gene therapy are approaching completion with imminent regulatory approvals.

Discussion

Phase 3 studies along with multiyear follow‐up in earlier phase investigations raised questions about efficacy as well as short‐ and long‐term safety, prompting a reappraisal of AAV vector gene therapy. Liver toxicities, albeit mostly low‐grade, occur in the first year in at least some individuals in all haemophilia A and B trials and are poorly understood. Extreme variability and unpredictability of outcome, as well as a slow decline in factor expression (seemingly unique to FVIII gene therapy), are vexing because immune responses to AAV vectors preclude repeat dosing, which could increase suboptimal or restore declining expression, while overexpression may result in phenotoxicity. The long‐term safety will need lifelong monitoring because AAV vectors, contrary to conventional wisdom, integrate into chromosomes at the rate that calls for vigilance.

Conclusions

AAV transduction and transgene expression engage the host immune system, cellular DNA processing, transcription and translation machineries in ways that have been only cursorily studied in the clinic. Delineating those mechanisms will be key to finding mitigants and solutions to the remaining problems, and including individuals who cannot avail of gene therapy at this time.

Haemophilia gene therapy-Update on new country initiatives

INTRODUCTION

Gene therapy is emerging as a potential cure for haemophilia. Gene therapy is a one-time treatment that can elevate factor levels for many years and minimize or eliminate the need for clotting factor concentrate (CFC) replacement therapy. However, there is a paucity of reports on gene therapy efforts in countries outside of North America or Europe, especially in low-and-middle-income countries (LMIC). All indications are that gene therapy will be one of standard care treatments for haemophilia in the future. Still, it may not be accessible to many countries due to various barriers and challenges. At the same time, each country may formulate solutions that may be used globally.

AIM

To summarize the approaches taken to establish haemophilia gene therapy in Japan, China, India, South Africa, and Brazil, and to describe the US-initiated multi-LMIC haemophilia gene therapy development program to include Peru, Vietnam, Thailand, Nepal, and Sri Lanka.

METHODS

A review of related published information or as accessible by each country's author.

RESULTS

Different starting conditions, differing input and level of support from the multitude of stakeholders, and strong leadership have led to various approaches for facilitating research and developing needed infrastructure and regulatory and financing models. Gene therapy programs are at various stages of development and include both adeno-associated viral and lentiviral vectors.

CONCLUSION

Global partnerships and collaboration, exchange of knowledge and experience, and alignment of processes across borders will promote further progress towards global access to gene therapy for haemophilia.

Transcutaneous ultrasound mediated gene delivery into canine livers achieves therapeutic levels of FVIII expression

Nonviral UMGD can achieve therapeutic levels of FVIII gene expression in a large animal model.

UMGD targeting liver is safe without evidence of any lasting damage.

A safe, effective, and inclusive gene therapy will significantly benefit a large population of patients with hemophilia. We used a minimally invasive transcutaneous ultrasound-mediated gene delivery (UMGD) strategy combined with microbubbles (MBs) to enhance gene transfer into 4 canine livers. A mixture of high-expressing, liver-specific human factor VIII (hFVIII) plasmid and MBs was injected into the hepatic vein via balloon catheter under fluoroscopy guidance with simultaneous transcutaneous UMGD treatment targeting a specific liver lobe. Therapeutic levels of hFVIII expression were achieved in all 4 dogs, and hFVIII levels were maintained at a detectable level in 3 dogs throughout the 60-day experimental period. Plasmid copy numbers correlated with hFVIII antigen levels, and plasmid-derived messenger RNA (mRNA) was detected in treated livers. Liver transaminase levels and histology analysis indicated minimal liver damage and a rapid recovery after treatment. These results indicate that liver-targeted transcutaneous UMGD is promising as a clinically feasible therapy for hemophilia A and other diseases.

The experiences of people with haemophilia and their families of gene therapy in a clinical trial setting: regaining control, the Exigency study

BACKGROUND

Gene therapy has the potential to change the life experience of people with haemophilia and family members. Few studies have sought to explore the impact of gene therapy on both individuals and families. The aim of this study was to capture real-life experiences of gene therapy in People with haemophilia and their families.

RESULTS

Sixteen participants with severe haemophilia (11 haemophilia A, five haemophilia B), mean age 41.4 years (range 23-75 years), took part in a single qualitative interview; ten were accompanied by a family member. Mean time since transfection was 3.56 years (range 1-10 years). Participants saw their involvement in gene therapy as a positive experience, freeing them from the personal burden of haemophilia and furthering treatment options for the wider haemophilia community. However, participants reported being unprepared for the side effects of immunosuppression. Some also reported feeling unsupported and having little control over what was happening as their factor levels became the focus of the process.

CONCLUSION

The results suggest that strategies need to be put into place to enable PwH fully to understand the process of gene therapy, and thereby make an informed choice as to whether it is a treatment they might wish for themselves. These include early and ongoing education, increased provision of psychosocial support and ongoing qualitative research.

The Hemophilia Gene Therapy Patient Journey: Questions and Answers for Shared Decision-Making

PURPOSE

The anticipated emergence of hemophilia gene therapy will present people with hemophilia (PWH) and treating clinicians with increasingly complex treatment options. It will be critical that PWH and their families be empowered to participate fully in decision-making through transparent communication and the development of targeted educational resources.

METHODS

The Council of Hemophilia Community (CHC) convened across a series of roundtable meetings to define the patient journey for hemophilia gene therapy, and to develop a question-and-answer style resource to guide discussion between healthcare professionals (HCPs) and their patients. Patient groups were also consulted during the development of this tool.

RESULTS

The CHC defined 5 key stages in the hemophilia gene therapy patient journey: pre-gene therapy (information-seeking and decision-making), treatment initiation, short- and long-term post-gene therapy follow-up. PWH will have different questions and concerns at each stage of their journey, which should be discussed with their HCP to aid decision-making. The resulting patient journey infographic and Q&A resource (see Supplementary Materials) has been developed for HCPs and PWH to provide a novel and practical roadmap of key issues and considerations throughout all stages.

CONCLUSION

These resources support a collaborative, patient-centric, shared decision-making approach to inform treatment decision discussions between HCPs and PWH. The value of such discussions will be influenced by the language adopted; health literacy is a particularly important consideration, and these discussions should be accessible and tailored to PWH. HCPs and PWH can benefit from awareness of the common questions and uncertainties as they progress together along the patient journey. While the contents of this article are specific to hemophilia gene therapy, the concepts developed here could be adapted to aid patients in other disease states.

Beliefs and Values About Gene Therapy and In-Utero Gene Editing in Patients with Hemophilia and Their Relatives

AIM

Hemophilia is an inherited disease for which current treatment is noncurative. While gene therapy and gene editing are being researched, we do not know how the hemophilia community perceives them. Herein, we explore the beliefs and values regarding these new therapies in patients with hemophilia and their relatives.

METHODS

This qualitative study used phone-based semi-structured interviews on 21 adult English-speaking patients with hemophilia A or B and their parents across the United States during March to July 2019. The study was advertised through different chapters of the Hemophilia Foundation. The interview guide included questions about participants' prior experience with hemophilia, and included two case scenarios about the use of gene therapy and in utero gene editing, after which participants were asked about their opinions, beliefs, and values on each scenario. We used a grounded theory approach and identified the main themes using an inductive process.

RESULTS

We interviewed 21 participants-12 patients and 9 mothers. Most of them had or were related to a patient with severe disease. The main themes discussed were related to efficacy, safety and financial concerns and insurance coverage for both gene therapy and in utero gene editing. Patients and their parents had expected outcomes in terms of durability of therapy and impact on emotional health and lifestyle changes in the long term. Gene therapy was more accepted among patients with severe and uncontrolled disease. In-utero gene editing was not completely accepted because of safety and ethical issues.

CONCLUSION

Patients with severe hemophilia perceive gene therapy as a potential cure, while gene editing was more controversial. Patients still have questions that remain to be answered regarding safety and efficacy that should be assessed with long-term follow up studies.

Post-authorization pharmacovigilance for hemophilia in Europe and the USA: Independence and transparency are keys

The regulatory process is currently designed to ensure drug safety during the pre-marketing process. Due to limitations of the pivotal studies owing to their short duration and small number of highly selected cases, some adverse drug reactions (ADRs) are not detected, particularly the rarest and those which appear a long time after exposure. Thus it is essential to foster pharmacovigilance run totally independently from marketing authorization holders in order to attain transparent surveillance. This challenge is relevant for hemophilia drugs, after recent advances offered innovative replacement and non-replacement medicines that warrant monitoring due to the occurrence of predicted but also unexpected and rare ADRs. This article contains an overview of pharmacovigilance systems in the European Union and USA, describing the main ADRs related to traditional and recently available hemophilia medications and suggests how to involve stakeholders other than marketing authorization holders for an independent and transparent pharmacovigilance targeted to detect not only early ADRs but also those emerging post-marketing.

Market access of gene therapies across Europe, USA, and Canada: challenges, trends, and solutions

This review can inform gene therapy developers on challenges that can be encountered when seeking market access. Moreover, it provides an overview of trends among challenges and potential solutions.

The German Hemophilia Registry: Growing with Its Tasks

Hemophilia is a rare heredity bleeding disorder that requires treatment for life. While few therapeutic options were available in the past, multiple recent breakthroughs have fundamentally altered and diversified hemophilia therapy, with even more new therapeutic options forthcoming. These changes are mirrored by significant regulatory and legal changes, which have redefined the role of hemophilia registries in the European Union (EU). This dual paradigm shift poses new regulatory, scientific but also structural requirements for hemophilia registries. The aim of this manuscript is to enumerate these significant challenges and to demonstrate their incorporation into the redesign of the German Hemophilia Registry (Deutsches Hämophilieregister, dhr). To identify the spectrum of hemophilia therapies and the degree of regulatory changes, a horizon screening was performed. Consequently, a core dataset for the dhr was defined by harmonization with regulatory guidelines as well as other hemophilia registries and by heeding the needs of different stakeholders (patients, clinicians, regulators, and scientists). Based on this information, a new registry structure was established, which is optimized for capturing data on new and established hemophilia therapies in a changing therapeutic and regulatory landscape.

Hemophilia gene therapy-New country initiatives

Gene therapy is an opportunity for haemophilia patients to receive a one-time treatment and have lasting factor levels for years or decades instead of dependence on repeated administration within short intervals and on sustained supply of drug. Great strides have been made in the development of gene therapy for haemophilia in the last decade. Adeno-associated virus (AAV) vector-mediated gene transfer in haemophilia A and B has entered the phase III trial stage. Gene transfer by lentiviral vector or gene editing technologies using factor VIII (FVIII) or IX (FIX) genes are now entering clinical evaluation. It is expected that the first FVIII and FIX gene therapy products will soon be approved and distributed in major markets. Global access to gene therapy is a critical goal. This review presents new and ongoing efforts towards this goal in countries other than North America and Europe. In Japan, researchers, regulators and funders have established a promising gene therapy development platform for multiple diseases including haemophilia. Decades of scientific and clinical research in haemophilia gene therapy in China have led to a recently registered clinical trial of AAV-mediated gene therapy for haemophilia B. Other countries are in earlier phases of building gene therapy programmes or participate in international trials. A phase 2 feasibility trial of AAV-mediated FIX gene therapy in low- and middle-income countries aims to demonstrate that gene therapy could become available in resource-constrained socio-economic settings. The different strategies for establishing gene therapy provide opportunities for closing the global gap in haemophilia care.

In vivo enrichment of genetically manipulated platelets for murine hemophilia B gene therapy

Our previous studies have demonstrated that platelet-targeted factor IX (FIX) gene therapy can introduce sustained platelet-FIX expression in hemophilia B (FIX^null ) mice. In this study, we aimed to enhance platelet-FIX expression in FIX^null mice with O⁶ -methylguanine-DNA-methyltransferase (MGMT)-mediated in vivo drug selection of transduced cells under nonmyeloablative preconditioning. We constructed a novel lentiviral vector (2bF9/MGMT lentivirus vector), which harbors dual genes, the FIX gene driven by the αIIb promoter (2bF9) and the MGMT P140K gene under the murine stem cell virus promoter. Platelet-FIX expression in FIX^null mice was introduced by 2bF9/MGMT-mediated hematopoietic stem cell transduction and transplantation. The 2bF9/MGMT-transduced cells were effectively enriched after drug selection by O⁶ -benzylguanine/1,3-bis-2-chloroethyl-1-nitrosourea. There were a 2.9-fold higher FIX antigen and a 3.7-fold higher FIX activity in platelets, respectively, posttreatment compared with pretreatment. When a 6-hr tail bleeding test was used to grade the bleeding phenotype, the clotting time in treated animals was 2.6 ± 0.5 hr. In contrast, none of the FIX^null control mice were able to clot within 6 hr. Notably, none of the recipients developed anti-FIX antibodies after gene therapy. One of four recipients developed a low titer of inhibitors when challenged with rhF9 together with adjuvant. In contrast, all FIX^null controls developed inhibitors after the same challenge. Anti-FIX immunoglobulin G were barely detectable in recipients (1.08 ± 0.54 µg/ml), an 875-fold lower level than in the FIX^null controls. Our data demonstrate that using the MGMT-mediated drug selection system in 2bF9 gene therapy can significantly enhance therapeutic platelet-FIX expression, resulting in sustained phenotypic correction and immune tolerance in FIX^null mice.

Delivering on the promise of gene therapy for haemophilia

The promise of gene therapy is a single treatment ('one and done') that leads to steady-state expression of endogenous factor VIII or factor IX sufficient to achieve a functional cure (free of recurrent haemophilic bleeding) if not normalized haemostasis. The elimination of the need for continued prophylaxis, or factor replacement following trauma or prior to surgery would lead to annual cost savings. Such optimized health and well-being would be reaching a level of health equity that was unimaginable several decades ago. 'Before anything else, preparation is the key to success'-Alexander Graham Bell. This quote from the famous inventor, scientist and engineer highlights that, although we currently stand on the threshold of this achievement, delivering on this promise will require broad-based multistakeholder preparation (scientists, manufacturers, federal regulators, health technology assessors, persons with haemophilia, national advocacy groups and multidisciplinary healthcare teams) with a focused emphasis on education, approval of safe and effective therapies, removal of barriers to access and excellence in clinical delivery.

Uncertainty in an era of transformative therapy for haemophilia: Addressing the unknowns

Haemophilia is at the dawn of a new era in therapeutic management, one that can generate greater protection from bleeding and a functional cure in some individuals. Prior advances in protein engineering and monoclonal antibody technology have facilitated therapeutic options to maintain decreased risk of bleeding and less burdensome treatment. The use of gene transfer, first proposed in 1971 for monogenic diseases, is emerging as an effective long-term treatment for a variety of diseases. Transfer of functional factor VIII (FVIII) and factor IX (FIX) genes has witnessed a series of advances and setbacks since the first non-clinical experiments in animals were initiated nearly 30 years ago. More recently, multiyear therapeutic levels of FVIII and FIX activity have been achieved in human clinical trials, translated into meaningful clinical benefit and a functional cure. While clinical progress has been definitive, many questions remain unanswered as prelicensure phase 3 clinical trials are underway. These unanswered questions translate into a state of uncertainty about the known unknowns and unknown unknowns intrinsic to any new therapeutic platform. Accepting this modality as a means to functionally cure haemophilia also means accepting the uncertainty regarding the biology of viral vector-mediated gene transfer, which remains inadequately understood. Gene therapy is a far more complex biological 'drug' than small molecule and protein drugs, where manufacturing processes and the drugs themselves are now well characterized. Extent of community acceptance of uncertainty and acknowledgement of the need for an uncompromising drive for answers to the unknowns will characterize the introduction of this first generation of gene therapy for haemophilia to the wider patient population in both resource-rich and resource-poor countries.

Hemophilia gene therapy knowledge and perceptions: Results of an international survey

BACKGROUND

Hemophilia gene therapy is a rapidly evolving therapeutic approach in which a number of programs are approaching clinical development completion.

OBJECTIVE

The aim of this study was to evaluate knowledge and perceptions of a variety of health care practitioners and scientists about gene therapy for hemophilia.

METHODS

This survey study was conducted February 1 to 18, 2019. Survey participants were members of the ISTH, European Hemophilia Consortium, European Hematology Association, or European Association for Hemophilia and Allied Disorders with valid email contacts. The online survey consisted of 36 questions covering demographic information, perceptions and knowledge of gene therapy for hemophilia, and educational preferences. Survey results were summarized using descriptive statistics.

RESULTS

Of the 5117 survey recipients, 201 responded from 55 countries (4% response rate). Most respondents (66%) were physicians, and 59% were physicians directly involved in the care of people with hemophilia. Among physician respondents directly involved in hemophilia care, 35% lacked the ability to explain the science of adeno-associated viral gene therapy for hemophilia, and 40% indicated limited ability or lack of comfort answering patient questions about gene therapy for hemophilia based on clinical trial results to date. Overall, 75% of survey respondents answered 10 single-answer knowledge questions correctly, 13% incorrectly, and 12% were unsure of the correct answers.

CONCLUSIONS

This survey highlighted knowledge gaps and educational needs related to gene therapy for hemophilia and, along with other inputs, has informed the development of "Gene Therapy in Hemophilia: An ISTH Education Initiative."

A Molecular Revolution in the Treatment of Hemophilia

For decades, the monogenetic bleeding disorders hemophilia A and B (coagulation factor VIII and IX deficiency) have been treated with systemic protein replacement therapy. Now, diverse molecular medicines, ranging from antibody to gene to RNA therapy, are transforming treatment. Traditional replacement therapy requires twice to thrice weekly intravenous infusions of factor. While extended half-life products may reduce the frequency of injections, patients continue to face a lifelong burden of the therapy, suboptimal protection from bleeding and joint damage, and potential development of neutralizing anti-drug antibodies (inhibitors) that require less efficacious bypassing agents and further reduce quality of life. Novel non-replacement and gene therapies aim to address these remaining issues. A recently approved factor VIII-mimetic antibody accomplishes hemostatic correction in patients both with and without inhibitors. Antibodies against tissue factor pathway inhibitor (TFPI) and antithrombin-specific small interfering RNA (siRNA) target natural anticoagulant pathways to rebalance hemostasis. Adeno-associated virus (AAV) gene therapy provides lasting clotting factor replacement and can also be used to induce immune tolerance. Multiple gene-editing techniques are under clinical or preclinical investigation. Here, we provide a comprehensive overview of these approaches, explain how they differ from standard therapies, and predict how the hemophilia treatment landscape will be reshaped.

Towards a global multidisciplinary consensus framework on haemophilia gene therapy: Report of the 2nd World Federation of Haemophilia Gene Therapy Round Table

INTRODUCTION

With approval of gene therapy for haemophilia likely in the near future, policy frameworks are needed to guide the path forward for this disruptive and novel therapeutic advance.

AIM

The WFH has initiated a series of multi-stakeholder Gene Therapy Round Tables (GTRT) to better understand where guidance is needed and develop initial consensus statements to inform policy.

METHODS

The first day of the 2nd GTRT was devoted to didactic presentations on models of access to gene therapy, payment and health technology assessment considerations, regulatory issues and the generation of evidence on safety and durable efficacy of gene therapy products. On the second day, participants were tasked with developing and voting on consensus statements that reflected the information presented and multi-stakeholder views expressed during discussions in the 1st and 2nd WFH GTRTs. The statements covered global access to gene therapy for all people with haemophilia (PWH), collection of long-term safety and efficacy data, ensuring gene therapy is available for all subgroups of PWH including those who have been largely excluded from clinical trials and characterizing acceptable and ideal factor expression levels for gene therapy products.

RESULTS

The first 3 statements achieved consensus (at least 80% agreement) by this group of experts. The statement on identifying an ideal and an acceptable factor level expression elicited a lively discussion but failed to achieve consensus by this group.

CONCLUSIONS

This issue of ideal and acceptable factor level expression and other unresolved issues will be brought to the 3rd WFH GTRT in 2020.