Hemophilia gene therapy: first, do no harm

What is a cure through gene therapy? An analysis and evaluation of the use of "cure"

The development of gene therapy has always come with the expectation that it will offer a cure for various disorders, of which hemophilia is a paradigm example. However, although the term is used regularly, it is unclear what exactly is meant with "cure". Therefore, the aim of this paper is to analyse how the concept of cure is used in practice and evaluate which of the interpretations is most suitable in discussions surrounding gene therapy. We analysed how cure is used in four different medical fields where the concept raises discussion. We show that cure can be used in three different ways: cure as normalization of the body, cure as obtaining a normal life, or cure as a change in identity. We argue that since cure is a practical term, its interpretation should be context-specific and the various uses can exist simultaneously, as long as their use is suitable to the function the notion of cure plays in each of the settings. We end by highlighting three different settings in the domain of hemophilia gene therapy in which the term cure is used and explore the function(s) it serves in each setting. We conclude that in the clinical application of gene therapy, it could be better to abandon the term cure, whereas more modest and specified definitions of cure are required in the context of health resource allocation decisions and decisions on research funding.

Investigation of SEN virus prevalence in hemophilia patients

Background

Hemophilia and transfusion-dependent patients are at high risk of a wide range of blood-borne agents. Among these, SEN virus (SENV) stands out as a significant concern due to its association with transfusion-induced non-A to non-E hepatitis. This study, therefore, aimed to investigate the prevalence of this virus in hemophilia patients, focusing on potential complications and risk factors.

Method

This was a cross-sectional study conducted in a hemophilia center in the east of Iran. Blood samples were taken from patients and healthy people, and demographic and clinical information was collected. The sera samples were then subjected to DNA extraction. PCR-based methods detected SENV and its genotype, and then phylogenetic analysis was performed. The collected data were analyzed and interpreted by SPSS22 software.

Results

The mean age of patients and the healthy group was 26.18 ± 14.97 and 41.69 ± 14.05, respectively. Among the patient and healthy groups, 94.5 % and 36.4 % were male, and the rest were female, respectively. Most of the participants in the patient group had hemophilia type A (85.5 %), then type B (7.3 %), VWD type (3.6 %), and F and plt type (1.8 %) were in the next categories. SENV-DNA was detected in 58.2 % of patients and 20 % of healthy groups (P-value: 0.00). Among these, H and D genotypes were found in 35 % and 23.7 % of patients and 12.7 % and 7.3 % of healthy groups, respectively. The prevalence of the virus was significantly related to minor elevation of AST and was higher in hemophilia type A (63.8 %) and severe type of disease (63.2 %).

Conclusion

This study underscore the significant prevalence of the SENV virus in hemophilia patients, a particularly noteworthy finding compared to the healthy population. With the limited information available about this virus, our findings highlight the importance of continuous monitoring and follow-up of high-risk groups in relation to blood-borne pathogens, providing reassurance about the ongoing efforts in the field.

Sleeping Beauty mRNA-LNP enables stable rAAV transgene expression in mouse and NHP hepatocytes and improves vector potency

Recombinant adeno-associated virus (rAAV) vector gene delivery systems have demonstrated great promise in clinical trials but continue to face durability and dose-related challenges. Unlike rAAV gene therapy, integrating gene addition approaches can provide curative expression in mitotically active cells and pediatric populations. We explored a novel in vivo delivery approach based on an engineered transposase, Sleeping Beauty (SB100X), delivered as an mRNA within a lipid nanoparticle (LNP), in combination with an rAAV-delivered transposable transgene. This combinatorial approach achieved correction of ornithine transcarbamylase deficiency in the neonatal Spfash mouse model following a single delivery to dividing hepatocytes in the newborn liver. Correction remained stable into adulthood, while a conventional rAAV approach resulted in a return to the disease state. In non-human primates, integration by transposition, mediated by this technology, improved gene expression 10-fold over conventional rAAV-mediated gene transfer while requiring 5-fold less vector. Additionally, integration site analysis confirmed a random profile while specifically targeting TA dinucleotides across the genome. Together, these findings demonstrate that transposable elements can improve rAAV-delivered therapies by lowering the vector dose requirement and associated toxicity while expanding target cell types.

Assessment of joint health in patients receiving prophylaxis for haemophilia A: a cross-sectional survey in five European countries

OBJECTIVES

To evaluate joint health, pain and health-related quality of life (HRQoL) in patients with moderate/severe haemophilia A in Europe.

DESIGN

Multinational, cross-sectional survey, with retrospective data collection. Data were taken from the Adelphi Real World Haemophilia Disease Specific Programme Wave II, using surveys completed by physicians and patients between February 2020 and May 2021.

SETTING

Haematologists/haemato-oncologists and their patients in France, Germany, Italy, Spain and the UK.

PARTICIPANTS

Males aged ≥18 years with moderate or severe haemophilia A (baseline clotting factor level ≤5%), without existing inhibitors and currently receiving prophylaxis. Patients were grouped into those with or without haemophilia-affected joints (HAJs) based on bleeding, radiographic, surgical, mobility and joint pain data.

PRIMARY OUTCOME MEASURE

Characterisation of humanistic and clinical outcomes in patients with or without HAJs.

RESULTS

A total of 120 physicians provided data for 351 eligible patients; 209 (59.5%) patients had HAJs and 142 (40.5%) had no HAJs. Pain/discomfort was significantly different (p=0.01) and reported more frequently in the HAJ (85.7%) vs non-HAJ group (53.3%). Pain medication use was significantly higher in the HAJ versus non-HAJ group (73.2% vs 60.6%; p=0.01). Up to half of the patients with HAJs had synovitis (49.8%) or arthropathy (48.4%), and one-third had undergone joint surgery (35.4%). Overall health status was significantly worse in the HAJ versus non-HAJ group (mean (SD) EuroQol Visual Analogue Scale score: 65.5 (19.3) vs 81.1 (14.6); p=0.01).

CONCLUSIONS

In this multinational real-world study, nearly two-thirds of adults with moderate/severe haemophilia A without inhibitors experienced HAJs despite prophylaxis. Individuals with HAJs had higher rates of pain and pain medication use, and lower HRQoL compared with those without HAJs. These data indicate that HAJs represent a clinically relevant burden and early identification/monitoring and management of affected joints should be an important consideration to help prevent long-term joint morbidity.

Benefits and risks of non-factor therapies: Redefining haemophilia treatment goals in the era of new technologies

INTRODUCTION

Over the last decades progress in haemophilia treatment has been remarkable and prophylaxis with clotting factor concentrates in haemophilia A and B has been established as the standard of care in individuals with haemophilia and a severe bleeding phenotype. Besides clotting factor products with prolonged half-life non-factor therapies were developed which enable prophylaxis via subcutaneous administration. Factor VIIIa mimetics like emicizumab facilitate the coagulation pathway and are used in routine clinical practice for indivdiduals with haemophilia A. Rebalancing therapeutic agents like fitusiran, concizumab, marstacimab and serpin PC block the anticoagulant pathway and clinical trials using these products in individuals with haemophilia A and B are ongoing.

AIM AND METHODS

A narrative review to asess the benefits and risks of non-factor therapies taking in to account re-defined haemophilia treatment goals.

RESULTS

Prophylaxis for prevention of bleeds using non-factor products by subcutaneous administration is effective and results in reductions of bleeding episodes in individuals with haemophilia A or B with and without inhibitors. The treatment with emicizumab showed tolerable safety both in clinical trials and long-term real-world observations with few thrombotic events. In some clinical trials with rebalancing therapies (fitusiran and concizumab) thrombotic events occurred. Monitoring of the haemostatic function of novel therapies especially with concomitant haemostatic treatment is not yet established.

CONCLUSION

With the advent of novel therapeutic agents including factor concentrates with ultra-long half-life and improved FVIIIa mimetics aimed at raising the bar of protection into the non-hemophilic range redefinition of haemophilia treatment goals is eagerly needed.

Current and emerging gene therapies for haemophilia A and B

INTRODUCTION

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.

DISCUSSION

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.

CONCLUSIONS

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.

Recent advances in various adeno-associated viruses (AAVs) as gene therapy agents in hepatocellular carcinoma

Primary liver cancer, which is scientifically referred to as hepatocellular carcinoma (HCC), is a significant concern in the field of global health. It has been demonstrated that conventional chemotherapy, chemo-hormonal therapy, and conformal radiotherapy are ineffective against HCC. New therapeutic approaches are thus urgently required. Identifying single or multiple mutations in genes associated with invasion, metastasis, apoptosis, and growth regulation has resulted in a more comprehensive comprehension of the molecular genetic underpinnings of malignant transformation, tumor advancement, and host interaction. This enhanced comprehension has notably propelled the development of novel therapeutic agents. Therefore, gene therapy (GT) holds great promise for addressing the urgent need for innovative treatments in HCC. However, the complexity of HCC demands precise and effective therapeutic approaches. The adeno-associated virus (AAV) distinctive life cycle and ability to persistently infect dividing and nondividing cells have rendered it an alluring vector. Another appealing characteristic of the wild-type virus is its evident absence of pathogenicity. As a result, AAV, a vector that lacks an envelope and can be modified to transport DNA to specific cells, has garnered considerable interest in the scientific community, particularly in experimental therapeutic strategies that are still in the clinical stage. AAV vectors emerge as promising tools for HCC therapy due to their non-immunogenic nature, efficient cell entry, and prolonged gene expression. While AAV-mediated GT demonstrates promise across diverse diseases, the current absence of ongoing clinical trials targeting HCC underscores untapped potential in this context. Furthermore, gene transfer through hepatic AAV vectors is frequently facilitated by GT research, which has been propelled by several congenital anomalies affecting the liver. Notwithstanding the enthusiasm associated with this notion, recent discoveries that expose the integration of the AAV vector genome at double-strand breaks give rise to apprehensions regarding their enduring safety and effectiveness. This review explores the potential of AAV vectors as versatile tools for targeted GT in HCC. In summation, we encapsulate the multifaceted exploration of AAV vectors in HCC GT, underlining their transformative potential within the landscape of oncology and human health.

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.

Exploration of the Noncoding Genome for Human-Specific Therapeutic Targets-Recent Insights at Molecular and Cellular Level

While it is well known that 98-99% of the human genome does not encode proteins, but are nevertheless transcriptionally active and give rise to a broad spectrum of noncoding RNAs [ncRNAs] with complex regulatory and structural functions, specific functions have so far been assigned to only a tiny fraction of all known transcripts. On the other hand, the striking observation of an overwhelmingly growing fraction of ncRNAs, in contrast to an only modest increase in the number of protein-coding genes, during evolution from simple organisms to humans, strongly suggests critical but so far essentially unexplored roles of the noncoding genome for human health and disease pathogenesis. Research into the vast realm of the noncoding genome during the past decades thus lead to a profoundly enhanced appreciation of the multi-level complexity of the human genome. Here, we address a few of the many huge remaining knowledge gaps and consider some newly emerging questions and concepts of research. We attempt to provide an up-to-date assessment of recent insights obtained by molecular and cell biological methods, and by the application of systems biology approaches. Specifically, we discuss current data regarding two topics of high current interest: (1) By which mechanisms could evolutionary recent ncRNAs with critical regulatory functions in a broad spectrum of cell types (neural, immune, cardiovascular) constitute novel therapeutic targets in human diseases? (2) Since noncoding genome evolution is causally linked to brain evolution, and given the profound interactions between brain and immune system, could human-specific brain-expressed ncRNAs play a direct or indirect (immune-mediated) role in human diseases? Synergistic with remarkable recent progress regarding delivery, efficacy, and safety of nucleic acid-based therapies, the ongoing large-scale exploration of the noncoding genome for human-specific therapeutic targets is encouraging to proceed with the development and clinical evaluation of novel therapeutic pathways suggested by these research fields.