Communicating the promise for ocular gene therapies: challenges and recommendations

A multinational survey of potential participant perspectives on ocular gene therapy

Amidst rapid advancements in ocular gene therapy, understanding patient perspectives is crucial for shaping future treatment choices and research directions. This international cross-sectional survey evaluated knowledge, attitudes, and perceptions of ocular genetic therapies among potential recipients with inherited retinal diseases (IRDs). Survey instruments included the Attitudes to Gene Therapy-Eye (AGT-Eye), EQ-5D-5L, National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25), and Patient Attitudes to Clinical Trials (PACT-22) instruments. This study included 496 participant responses (89% adults with IRDs; 11% parents/guardians/carers) from 35 countries, with most from the United States of America (USA; 69%) and the United Kingdom (11%). Most participants (90%) indicated they would likely accept gene therapy if it was available, despite only 45% agreeing that they had good knowledge of gene therapy. The main sources of information were research registries (60% of participants) and the internet (61%). Compared to data from our recently published Australian national survey of people with IRDs (n = 694), USA respondents had higher knowledge of gene therapy outcomes, and Australian respondents indicated a higher perceived value of gene therapy treatments. Addressing knowledge gaps regarding outcomes and financial implications will be central to ensuring informed consent, promoting shared decision-making, and the eventual clinical adoption of genetic therapies.

Short Communication: Lived experience perspectives on genetic testing for a rare eye disease

This qualitative study explored the motivators and barriers for genetic testing for individuals with aniridia. Semi-structured interviews were conducted with 8 participants. The main findings highlighted the complex and interrelated factors involved in the decision-making process, including family planning, learning about the specific pathogenic variant of the disease and having access to genetic testing. Benefits and potential risks of genetic testing for aniridia were also discussed. For participants, gaining knowledge about their condition was perceived as a benefit, while administrative issues and concerns around privacy were identified as risks. Increased access to quality information about genetic testing and to the service and associated resources are needed to better support people living with aniridia.

Prostaglandin-based rAAV-mediated glaucoma gene therapy in Brown Norway rats

Prostaglandin analogs are first-line treatments for open angle glaucoma and while effective at lowering intraocular pressure, they are undermined by patient non-compliance, causing atrophy of the optic nerve and severe visual impairment. Herein, we evaluate the safety and efficacy of a recombinant adeno-associated viral vector-mediated gene therapy aimed at permanently lowering intraocular pressure through de novo biosynthesis of prostaglandin F2α within the anterior chamber. This study demonstrated a dose dependent reduction in intraocular pressure in normotensive Brown Norway rats maintained over 12-months. Crucially, therapy could be temporarily halted through off-type riboswitch activation, reverting intraocular pressure to normal. Longitudinal multimodal imaging, electrophysiology, and post-mortem histology revealed the therapy was well tolerated at low and medium doses, with no major adverse effects to anterior chamber health, offering a promising alternative to current treatment strategies leading to clinically relevant reductions in intraocular pressure without the need for adherence to a daily treatment regimen.

Early-Phase Clinical Trials of Bio-Artificial Organ Technology: A Systematic Review of Ethical Issues

Regenerative medicine has emerged as a novel alternative solution to organ failure which circumvents the issue of organ shortage. In preclinical research settings bio-artificial organs are being developed. It is anticipated that eventually it will be possible to launch first-in-human transplantation trials to test safety and efficacy in human recipients. In early-phase transplantation trials, however, research participants could be exposed to serious risks, such as toxicity, infections and tumorigenesis. So far, there is no ethical guidance for the safe and responsible design and conduct of early-phase clinical trials of bio-artificial organs. Therefore, research ethics review committees will need to look to related adjacent fields of research, including for example cell-based therapy, for guidance. In this systematic review, we examined the literature on early-phase clinical trials in these adjacent fields and undertook a thematic analysis of relevant ethical points to consider for early-phase clinical trials of transplantable bio-artificial organs. Six themes were identified: cell source, risk-benefit assessment, patient selection, trial design, informed consent, and oversight and accountability. Further empirical research is needed to provide insight in patient perspectives, as this may serve as valuable input in determining the conditions for ethically responsible and acceptable early clinical development of bio-artificial organs.

Experiences of genetic testing among individuals with retinitis pigmentosa

BACKGROUND

Retinitis pigmentosa (RP) is a genetically heterogeneous retinal dystrophy which results in progressive vision loss. There is scant literature on the experiences of genetic testing in patients with RP.

MATERIALS AND METHODS

Patients with a clinical diagnosis of RP who received genetic testing at the Wills Eye Ocular Genetics clinic between 2016 and 2020 were recruited. Telephone interviews were conducted using a semi-structured guide designed to elicit participant experiences with genetic testing. A thematic analysis was performed to describe patterns in participant responses.

RESULTS

Twelve patients participated. Seven participants identified as female and five as male, with ages ranging from 22 to 70. Ten patients had positive genetic test results, while two had negative genetic testing. Reported motivations for genetic testing included qualification for clinical trials (58% of total participants), determination of etiology or usal gene (50%), reproductive concerns (50%), and prognostic outlook (50%). Most participants (75%) expressed satisfaction about their decision to pursue genetic testing. Participants with both positive and negative genetic testing reported persistent uncertainty regarding their prognosis for visual decline (50%). Genetic confirmation of disease leads to initiation of safety and vision-protecting health behaviors (42%).

CONCLUSION

Patients with RP are generally satisfied with their testing experience, despite approaching testing with a wide range of motivations and expectations. Future research can leverage this methodology to identify targets for improvement in pre- and post-test education and counselling.

Lessons learned from research on choroideremia

Having devoted over 35 years of my professional life to various projects on choroideremia (CHM), I began to reflect on the many lessons that I learned along the way. One of the most important is: we should pay careful attention to possible, unintended psychological harm in clinical research. This lesson was learned early and then reinforced when I engaged CHM patients in an investigator-sponsored Phase IB clinical trial of ocular gene therapy for choroideremia. My second lesson came from the trial itself in that preliminary data may not be sufficient to predict the risks to patients in a clinical trial. In the significant push to begin a gene therapy trial for CHM patients, writing grants, recruiting personnel, interacting with regulatory authorities, acquiring research equipment to test outcome measures, I missed a third lesson. There is significant bias when the principal investigator of an investigator-sponsored clinical trial is also the treating physician in the trial. Ideally, those two roles should be kept separate. Finally, having completed the clinical trial, I learned that gene replacement with an AAV vector may not be the only genetic therapy for CHM; an antisense oligonucleotide therapy may be possible in select cases.

Access to genetic testing for rare diseases: Existing gaps in public-facing information

Genetic testing plays an increasingly important role in the diagnosis and potential treatment of inherited and rare conditions, such as aniridia-a disease that leads to abnormal eye development, as well as in health research on these conditions. As genetic testing is increasingly sought for accurate and early diagnosis of rare genetic disorders and in the context of direct-to-consumer genomics, it is critical to examine the public-facing information about access to these services and reimbursement policies. We conducted a targeted policy and public-facing resource search. Our analysis of resources available for the patient community revealed that there is very little practical guidance available about access and reimbursement for genetic testing for rare diseases. Greater clarity in public-facing resources about genetic testing would be beneficial to the patient community as it would promote informed choices about the procedure, mitigate potential harms associated with lack of information and enable patient engagement in their own health care.

Application of protection motivation theory to clinical trial enrolment for pediatric chronic conditions

BACKGROUND

Parents of children living with chronic but manageable conditions hope for improved therapies or cures, including Advanced Therapy Medicinal Products (ATMPs). Multiple pediatric clinical trials for ATMPs are underway, but the risk profile of ATMPs for chronic conditions is largely unknown and likely different than for terminal pediatric illnesses. Applying Protection Motivation Theory modified to the context of pediatric ATMP clinical trial enrollment, our study analyses information needs of parents of children living with chronic manageable conditions: Type 1 Diabetes (T1D) or Inherited Retinal Diseases (IRD).

METHODS

We conducted semi-structured interviews with 15 parents of children living with T1D and 14 parents of children living with an IRD about: a) family background and the diagnostic experience; b) awareness of gene and stem cell therapy research and clinical trials for T1D and IRD; c) information sources on trials and responses to that information; d) attitudes to trial participation, including internationally; e) understanding of trial purpose and process; and f) any experiences with trial participation. We then discussed a pediatric ATMP clinical trial information sheet, which we developed with experts. We applied directed qualitative content analysis, based on PMT, to examine the information preferences of parents in deciding whether to enrol their children in stem cell or gene therapy clinical trials.

RESULTS

Parents balanced trial risks against their child's ability to cope with the chronic condition. The better the child's ability to cope with vision impairment or insulin management, the less likely parents were to assume trial risks. Conversely, if the child struggled with his/her vision loss, parents were more likely to be interested in trial participation, but only if the risks were low and likelihood for potential benefit was high.

CONCLUSIONS

Fear of adverse events as part of threat appraisal was the predominant consideration for parents in considering whether to enroll their child living with a manageable, chronic condition in a pediatric clinical trial of an ATMP. This consideration outweighed potential benefits and severity of their child's condition. Parents called for available safety data and fulsome communication processes that would enable them to make informed decisions about clinical trial enrolment on behalf of their children.

Participant perspectives on a phase I/II ocular gene therapy trial (NCT02077361)

Background: To learn from the experiences of potential clinical trial participants, participants in a Phase 1 ocular gene therapy trial, and their partners to improve communications and trial conduct. Materials and methods: Primary and secondary qualitative analysis of semi-structured interviews of potential participants (n = 20), clinical trial participants (n = 2) and their partners (n = 2) in a gene therapy clinical trial for choroideremia (NCT02077361). Analysis included: 1) thematic analysis of transcribed entrance and exit semi-structured interviews with trial participants and their partners; and 2) secondary qualitative analysis of interviews with potential trial participants, conducted prior to the initiation of the clinical trial. Results: Participants and partners who had received information during the consent process had a better understanding of the risks and benefits of participation in a Phase 1 gene therapy clinical trial than potential trial participants. However, participants and partners reported deficiencies in communication throughout the trial. Results highlight additional opportunities for trial staff to reinforce initial information about the trial, communicate logistical information and individual outcome data, and express appreciation for participation. Conclusions: Our study enabled clinical trial participants to describe their experiences in a clinical trial for a novel gene therapy. We provide practical recommendations to future clinical trial staff on communications and conduct participant perspectives. Communications strategies should address changing information needs over the course of the trial, express appreciation for participation and enable feedback from participants and their supporting family members, friends, or caregivers.

Compound pathogenic mutation in the USH2A gene in Chinese RP families detected by whole‑exome sequencing

Retinitis pigmentosa (RP) is a common form of inherited retinal degeneration that causes progressive loss of vision or adult blindness, characterized by the impairment of rod and cone photoreceptors. At present, mutations in >60 pathogenic genes have been confirmed to cause RP. The predominant modes of inheritance are autosomal dominant, autosomal recessive and X‑linked. In addition, other modes of inheritance, including digenic or mitochondrial inheritance, have been reported. In previous decades, with the development of sequencing techniques, significant advances in identifying novel RP pathogenic genes and screening mutations have been made. In the present study, whole‑exome sequencing was performed on samples from two Chinese pedigrees diagnosed with RP. A compound heterozygous mutation in the gene usherin 2A (USH2A; c.6,485+5G>A/c.11,156G>A) and a heterozygous X‑linked mutation in the gene retinitis pigmentosa 2 (RP2) ARL3 GTPase‑activating protein (RP2; c.358C>T) were identified by Sanger sequencing and co‑segregation analysis, of which the pathogenic mutation (c.6,485+5G>A) in USH2A has not been previously reported among Chinese patients. The findings of the present study may expand on current knowledge of RP among the Chinese population, providing essential assistance in the molecular diagnosis and screening of RP, and promoting further investigation of the pathogenesis of RP.

The ethics of genome editing in the clinic: A dose of realism for healthcare leaders

Genome editing technologies promise therapeutic advances for genetic diseases. We discuss the ethical and societal issues raised by these technologies, including their use in preclinical research, their potential to address mutations in somatic cells, and their potential to make germ line alterations that may be passed to subsequent generations. We call for a proportionate response from health leaders based on a realistic assessment of benefits, risks, and timelines for clinical translation.

L'éthique de la modification du génome en clinique : une dose de réalisme pour les leaders en santé

Les technologies de modification du génome promettent des avancées dans le traitement des maladies génétiques. Les auteurs abordent les enjeux éthiques et sociaux que soulèvent ces technologies, y compris leur utilisation dans des recherches précliniques, leur potentiel à résoudre les mutations somatiques et leur potentiel à modifier les lignées germinales qui peuvent être transmises aux prochaines générations. Ils demandent une réponse modérée de la part des leaders en santé, reposant sur une évaluation réaliste des avantages, des risques et des délais d'application clinique.

Single stranded adeno-associated virus achieves efficient gene transfer to anterior segment in the mouse eye

Adeno-associated viruses (AAVs) are used extensively as a gene delivery vehicle for retinal gene therapy, yet its ability to target the anterior segment of the eye, critical to unlocking therapeutic opportunities, is less characterized. Previously, self-complimentary (sc) AAV was shown to be necessary for transduction of the cornea and trabecular meshwork (TM), limiting the size of the gene transfer cassette, likely due to a block in second strand synthesis thought to be required for functional transduction. Here, we evaluated several AAV capsids in a single stranded (ss) genome conformation for their ability to overcome the need for scAAV for targeting corneal endothelium and TM. AAV2, 8, and a recently synthetically developed AAV called Anc80L65 were evaluated in vitro and in vivo by intracameral injection in mice. Results show that although scAAV2 demonstrated superior infectivity in vitro including Human Trabecular meshwork (HTM) immortalized cell lines; Anc80L65 transduced following a single intracameral injection efficiently all components of the mouse anterior segment, including the TM, corneal stroma, and endothelial cells. These results suggest that Anc80L65 is able to overcome the requirement for scAAV genomes to enable TM and corneal targeting, expanding the potential experimental and therapeutic use of AAV gene transfer in the anterior segment of the eye.

Identification of a rhodopsin gene mutation in a large family with autosomal dominant retinitis pigmentosa

Retinitis pigmentosa (RP) is a genetically highly heterogeneous retinal disease and one of the leading causes of blindness in the world. Next-generation sequencing technology has enormous potential for determining the genetic etiology of RP. We sought to identify the underlying genetic defect in a 35-year-old male from an autosomal-dominant RP family with 14 affected individuals. By capturing next-generation sequencing (CNGS) of 144 genes associated with retinal diseases, we identified eight novel DNA variants; however, none of them cosegregated for all the members of the family. Further analysis of the CNGS data led to identification of a recurrent missense mutation (c.403C > T, p.R135W) in the rhodopsin (RHO) gene, which cosegregated with all affected individuals in the family and was not observed in any of the unaffected family members. The p.R135W mutation has a reference single nucleotide polymorphism (SNP) ID (rs104893775), and it appears to be responsible for the disease in this large family. This study highlights the importance of examining NGS data with reference SNP IDs. Thus, our study is important for data analysis of NGS-based clinical genetic diagnoses.