The Impact of Inherited Retinal Diseases in the United States of America (US) and Canada from a Cost-of-Illness Perspective

The Visual Impairment of Inherited Retinal Diseases in Portugal as per the National Table of Disabilities

Purpose

To evaluate the visual impairment of patients with inherited retinal diseases (IRDs), as per the national table of disabilities (TNI).

Design

Retrospective, single-center cohort study.

Participants

Patients with a clinical diagnosis of IRD were recruited at a referral center in Portugal.

Methods

Demographics and clinical data were collected from each individual patient file. The estimated visual disability coefficient was calculated through the evaluation of 7 graduated categories: orbital or eyelid deformities, low vision, visual field change, loss of bi-foveolar fixation, oculomotor palsy, photophobia, and chronic conjunctivitis. The TNI provides minimum and maximum disability values for numerous conditions within each category, which were summed to calculate an overall summary disability coefficient for each patient.

Main Outcome Measures

Demographic/clinical and estimated minimum and maximum visual disability coefficient according to the TNI for each patient.

Results

This study included 253 patients from 214 families, aged 3 to 80 years, with a mean age of 39.8 ± 20.0 years. The mean estimated minimum and maximum visual disability coefficients as per the TNI were 0.6 ± 0.4 and 0.7 ± 0.4, respectively. The low vision was the single most frequent contributor category (21.7%) present in the calculation of visual impairment. Low vision and visual field changes were the most frequent double combination (18.2%), and the addition of loss of bi-foveolar fixation was the most frequent triple combination (8.3%).

Conclusions

This study found that IRD patients had a significant visual disability, with the majority having a disability coefficient ≥0.6, which would qualify them for a "multipurpose disability medical certificate."

Financial Disclosures

The authors have no proprietary or commercial interest in any materials discussed in this article.

The socioeconomic epidemiology of inherited retinal diseases in Portugal

BACKGROUND

Inherited retinal diseases (IRDs) are a group of rare degenerative disorders of the retina that can lead to blindness from birth to late middle age. Knowing the target population and its resources is essential to better plan support measures. The aim of this study was to evaluate the socioeconomic characteristics of regions in Portugal where IRD patients reside to inform the planning of vision aid and rehabilitation intervention measures.

RESULTS

This study included 1082 patients from 973 families, aged 3 to 92 years, with a mean age of 44.8 ± 18.1 years. Patients living with an IRD were identified in 190 of the 308 municipalities. According to this study, the estimated IRD prevalence in Portugal was 10.4 per 100,000 inhabitants, and by municipalities, it ranged from 0 to 131.2 per 100,000 inhabitants. Overall, regions with a higher prevalence of IRD have a lower population density (r=-0.371, p < 0.001), a higher illiteracy rate (r = 0.404, p < 0.001) and an overall older population (r = 0.475, p < 0.001). Additionally, there is a lower proportion of doctor per capita (r = 0.350, p < 0.001), higher social security pensions beneficiaries (r = 0.439, p < 0.001), worse water quality for human consumption (r=-0.194, p = 0.008), fewer audiences at the cinema (r=-0.315, p < 0.001) and lower proportion of foreign guests in tourist accommodations (r=-0.287, p < 0.001).

CONCLUSION

The number of identified patients with IRD varied between regions. Using data from national statistics (PORDATA), we observed differences in socioeconomic characteristics between regions. Multiple targeted aid strategies can be developed to ensure that all IRD patients are granted full clinical and socioeconomic support.

Whole genome sequencing for inherited retinal diseases in the Korean National Project of Bio Big Data

PURPOSE

This study aimed to analyze the genetic results of inherited retinal diseases (IRDs) and evaluate the diagnostic usefulness of whole genome sequencing (WGS) in the Korean National Project of Bio Big Data.

METHODS

As part of the Korean National Project of Bio Big Data, WGS was performed on 32 individuals with IRDs with no identified pathogenic variants through whole or targeted exome sequencing.

RESULTS

Individuals with retinitis pigmentosa (n = 23), cone dystrophy (n = 2), cone-rod dystrophy (n = 2), familial exudative vitreoretinopathy (n = 2), pigmented paravenous chorioretinal atrophy (n = 1), North Carolina macular dystrophy (n = 1), and bull's-eye macular dystrophy (n = 1) were included. WGS revealed genetic mutations in the IQCB1, PRPF31, USH2A, and GUCY2D genes in five cases (15.6%). Two large structural variations and an intronic variant were newly detected in three cases. Two individuals had biallelic missense mutations that were not identified in previous exome sequencing.

CONCLUSION

With WGS, the causative variants in 15.6% of unsolved IRDs from the Korean National Project of Bio Big Data were identified. Further research with a larger cohort might unveil the diagnostic usefulness of WGS in IRDs and other diseases.

Inherited retinal dystrophies and orphan designations in the European Union

Inherited Retinal Dystrophies (IRD) are diverse rare diseases that affect the retina and lead to visual impairment or blindness. Research in this field is ongoing, with over 60 EU orphan medicinal products designated in this therapeutic area by the Committee for Orphan Medicinal Products (COMP) at the European Medicines Agency (EMA). Up to now, COMP has used traditional disease terms, like retinitis pigmentosa, for orphan designation regardless of the product's mechanism of action. The COMP reviewed the designation approach for IRDs taking into account all previous Orphan Designations (OD) experience in IRDs, the most relevant up to date scientific literature and input from patients and clinical experts. Following the review, the COMP decided that there should be three options available for orphan designation concerning the condition: i) an amended set of OD groups for therapies that might be used in a broad spectrum of conditions, ii) a gene-specific designation for targeted therapies, and iii) an occasional term for products that do not fit in the above two categories. The change in the approach to orphan designation in IRDs caters for different scenarios to allow an optimum approach for future OD applications including the option of a gene-specific designation. By applying this new approach, the COMP increases the regulatory clarity, efficiency, and predictability for sponsors, aligns EU regulatory tools with the latest scientific and medical developments in the field of IRDs, and ensures that all potentially treatable patients will be included in the scope of an OD.

Cell-cell interaction in the pathogenesis of inherited retinal diseases

The retina is part of the central nervous system specialized for vision. Inherited retinal diseases (IRD) are a group of clinically and genetically heterogenous disorders that lead to progressive vision impairment or blindness. Although each disorder is rare, IRD accumulatively cause blindness in up to 5.5 million individuals worldwide. Currently, the pathophysiological mechanisms of IRD are not fully understood and there are limited treatment options available. Most IRD are caused by degeneration of light-sensitive photoreceptors. Genetic mutations that abrogate the structure and/or function of photoreceptors lead to visual impairment followed by blindness caused by loss of photoreceptors. In healthy retina, photoreceptors structurally and functionally interact with retinal pigment epithelium (RPE) and Müller glia (MG) to maintain retinal homeostasis. Multiple IRD with photoreceptor degeneration as a major phenotype are caused by mutations of RPE- and/or MG-associated genes. Recent studies also reveal compromised MG and RPE caused by mutations in ubiquitously expressed ciliary genes. Therefore, photoreceptor degeneration could be a direct consequence of gene mutations and/or could be secondary to the dysfunction of their interaction partners in the retina. This review summarizes the mechanisms of photoreceptor-RPE/MG interaction in supporting retinal functions and discusses how the disruption of these processes could lead to photoreceptor degeneration, with an aim to provide a unique perspective of IRD pathogenesis and treatment paradigm. We will first describe the biology of retina and IRD and then discuss the interaction between photoreceptors and MG/RPE as well as their implications in disease pathogenesis. Finally, we will summarize the recent advances in IRD therapeutics targeting MG and/or RPE.

Cost-of-illness studies of inherited retinal diseases: a systematic review

BACKGROUND

While health care and societal costs are routinely modelled for most diseases, there is a paucity of comprehensive data and cost-of-illness (COI) studies for inherited retinal diseases (IRDs). This lack of data can lead to underfunding or misallocation of resources. A comprehensive understanding of the COI of IRDs would assist governmental and healthcare leaders in determining optimal resource allocation, prioritizing funding for research, treatment, and support services for these patients.

METHODS

Following PRISMA guidelines, a literature search was conducted using Medline, EMBASE and Cochrane databases, from database inception up to 30 Jun 2023, to identify COI studies related to IRD. Original studies in English, primarily including patients with IRDs, and whose main study objective was the estimation of the costs of IRDs and had sufficiently detailed methodology to assess study quality were eligible for inclusion. To enable comparison across countries and studies, all annual costs were standardized to US dollars, adjusted for inflation to reflect their current value and recalculated on a "per patient" basis wherever possible. The review protocol was registered in PROSPERO (registration number CRD42023452986).

RESULTS

A total of nine studies were included in the final stage of systematic review and they consistently demonstrated a significant disease burden associated with IRDs. In Singapore, the mean total cost per patient was roughly US$6926/year. In Japan, the mean total cost per patient was US$20,833/year. In the UK, the mean total cost per patient with IRD ranged from US$21,658 to US$36,549/year. In contrast, in the US, the mean total per-patient costs for IRDs ranged from about US$33,017 to US$186,051 per year. In Canada, these mean total per-patient costs varied between US$16,470 and US$275,045/year. Non-health costs constituted the overwhelming majority of costs as compared to healthcare costs; 87-98% of the total costs were due to non-health costs, which could be attributed to diminished quality of life, poverty, and increased informal caregiving needs for affected individuals.

CONCLUSION

IRDs impose a disproportionate societal burden outside health systems. It is vital for continued funding into IRD research, and governments should incorporate societal costs in the evaluation of cost-effectiveness for forthcoming IRD interventions, including genomic testing and targeted therapies.

Genetic Testing Experiences of People Living with Inherited Retinal Degenerations: Results of a Global Survey

INTRODUCTION

Obtaining a genetic diagnosis via genetic testing (GT) is a fundamental step in determining the eligibility of a patient to be enrolled in emerging clinical trials and research studies. Besides, the knowledge of genetic outcome allows patients to plan for significant life choices. However, critical barriers exist to an equitable access to genetic services globally. The objective of this study was to explore patient experiences while seeking genomic services for inherited retinal degenerations (IRDs).

METHODS

An online survey was designed based on a focus group conducted by Retina International and including people affected by IRDs and their families living in different regions around the world. The survey was then circulated to 43 Retina International member organisations globally via email newsletters and social networks. The survey involved questions in relation to the accessibility, affordability, and timeliness of genomic services for IRDs as well as patient perceived awareness of genomic services for IRDs among healthcare professionals.

RESULTS

A total of 410 respondents (IRD patients and caregivers) from over 30 countries across all continents responded to the survey. A considerable number of the patients had to go through a long and arduous journey to access GT and counselling services, wherein 40% had to visit more than 5 physicians, 27% had to visit more than 5 clinics, and 57% had to wait for more than 3 years before obtaining a genetic diagnosis. Furthermore, 46% of respondents reported not receiving genetic counselling prior to undergoing GT, and 39% reported not receiving genetic counselling after undergoing GT. Over 3/4th of the participants reported that they did not have to pay for their genomic services for IRDs. Thirty-seven percent of the respondents reported that their eye care professionals (ECPs) were either not aware of GT, remained neutral, or did not encourage them to undergo GT.

CONCLUSION

Patients with IRDs do not have equitable access to best practice GT and counselling services. Greater awareness and training regarding IRDs and the benefits of GT and genetic counselling for patients and families are needed among ECPs. A best practice model on access to genomic services for IRDs is required.

Reduced cone photoreceptor function and subtle systemic manifestations in two siblings with loss of SCLT1

BACKGROUND

The sodium channel and clathrin linker 1 gene (SCLT1) has been involved in the pathogenesis of various ciliopathy disorders such as Bardet-Biedl syndrome, orofaciodigital syndrome type IX, and Senior-Løken syndrome. Detailed exams are warranted to outline all clinical features. Here, we present a family with a milder phenotype of SCLT1-related disease.

MATERIAL AND METHODS

Comprehensive eye examination including fundus images, OCT, color vision, visual fields and electroretinography were performed. Affected individuals were assessed by a pediatrician and a medical geneticist for systemic features of ciliopathy. Investigations included echocardiography, abdominal ultrasonography, blood work-up for diabetes, liver and kidney function. Genetic testing included NGS retinal dystrophy panel, segregation analysis and transcriptome sequencing.

RESULTS

Two male children, age 10 and 8 years, were affected with attention deficit hyperactivity disorder (ADHD), obesity and mild photophobia. The ophthalmic exam revealed reduced best-corrected visual acuity (BCVA), strabismus, hyperopia, astigmatism and moderate red-green defects. Milder changes suggesting photoreceptors disease were found on retinal imaging. Electroretinogram confirmed cone photoreceptors dysfunction. Genetic testing revealed a homozygous likely pathogenic, splice-site variant in SCLT1 gene NM_144643.3: c.1439 + 1del in the proband and in the affected brother. The unaffected parents were heterozygous for the SCLT1 variant. Transcriptome sequencing showed retention of intron 16 in the proband.

CONCLUSIONS

In this report, we highlight the importance of further extensive diagnostics in patients with unexplained reduced vision, strabismus, refractive errors and ADHD spectrum disorders. SCLT1-related retinal degeneration is very rare and isolated reduced function of cone photoreceptors has not previously been observed.

Toward low-cost gene therapy: mRNA-based therapeutics for treatment of inherited retinal diseases

Inherited retinal diseases (IRDs) stem from genetic mutations that result in vision impairment. Gene therapy shows promising therapeutic potential, exemplified by the encouraging initial results with voretigene neparvovec. Nevertheless, the associated costs impede widespread access, particularly in low-to-middle income countries. The primary challenge remains: how can we make these therapies globally affordable? Leveraging advancements in mRNA therapies might offer a more economically viable alternative. Furthermore, transitioning to nonviral delivery systems could provide a dual benefit of reduced costs and increased scalability. Relevant stakeholders must collaboratively devise and implement a research agenda to realize the potential of mRNA strategies in equitable access to treatments to prevent vision loss.

Perspectives of carriers of X-linked retinal diseases on genetic testing and gene therapy: A global survey

Female carriers of X-linked inherited retinal diseases (IRDs) are burdened with potentially passing their disease-causing variant to future generations, as well as exhibiting signs of retinal disease themselves. This study aimed to investigate carriers' experiences of genetic testing, emotions relating to having affected children, and their knowledge regarding genetic testing and gene therapy. An online survey was advertised to self-identified carriers worldwide. Two hundred and twenty-eight carriers completed the survey with mean age of 51 years (SD ± 15.0). A majority of respondents resided in the United States of America (51%), Australia (19%), and the United Kingdom (14%). Most carriers identified with feelings of guilt (70%), concern (91%), and anxiety (88%) for their child. Female carriers who had given birth to children had significantly greater gene therapy knowledge compared to carriers who had not (p < 0.05). Respondents agreed that their eyecare provider and general practitioner helped them understand their condition (63%), however, few carriers reported receiving psychological counselling (9%) or family planning advice (5%). Most respondents (78%) agreed that gene therapy should be available to carriers. This study emphasises the importance of providing appropriate counselling to female carriers and illustrates the motivation of many to participate in emerging treatment options, such as gene therapy.

Rationale and protocol paper for the Asia Pacific Network for inherited eye diseases

PURPOSE

There are major gaps in our knowledge of hereditary ocular conditions in the Asia-Pacific population, which comprises approximately 60% of the world's population. Therefore, a concerted regional effort is urgently needed to close this critical knowledge gap and apply precision medicine technology to improve the quality of lives of these patients in the Asia-Pacific region.

DESIGN

Multi-national, multi-center collaborative network.

METHODS

The Research Standing Committee of the Asia-Pacific Academy of Ophthalmology and the Asia-Pacific Society of Eye Genetics fostered this research collaboration, which brings together renowned institutions and experts for inherited eye diseases in the Asia-Pacific region. The immediate priority of the network will be inherited retinal diseases (IRDs), where there is a lack of detailed characterization of these conditions and in the number of established registries.

RESULTS

The network comprises 55 members from 35 centers, spanning 12 countries and regions, including Australia, China, India, Indonesia, Japan, South Korea, Malaysia, Nepal, Philippines, Singapore, Taiwan, and Thailand. The steering committee comprises ophthalmologists with experience in consortia for eye diseases in the Asia-Pacific region, leading ophthalmologists and vision scientists in the field of IRDs internationally, and ophthalmic geneticists.

CONCLUSIONS

The Asia Pacific Inherited Eye Disease (APIED) network aims to (1) improve genotyping capabilities and expertise to increase early and accurate genetic diagnosis of IRDs, (2) harmonise deep phenotyping practices and utilization of ontological terms, and (3) establish high-quality, multi-user, federated disease registries that will facilitate patient care, genetic counseling, and research of IRDs regionally and internationally.

Gene Therapy for Inherited Retinal Diseases: From Laboratory Bench to Patient Bedside and Beyond

This comprehensive review provides a thorough examination of inherited retinal diseases (IRDs), encompassing their classification, genetic underpinnings, and the promising landscape of gene therapy trials. IRDs, a diverse group of genetic conditions causing vision loss through photoreceptor cell death, are explored through various angles, including inheritance patterns, gene involvement, and associated systemic disorders. The focal point is gene therapy, which offers hope for halting or even reversing the progression of IRDs. The review highlights ongoing clinical trials spanning retinal cell replacement, neuroprotection, pharmacological interventions, and optogenetics. While these therapies hold tremendous potential, they face challenges like timing optimization, standardized assessment criteria, inflammation management, vector refinement, and raising awareness among vision scientists. Additionally, translating gene therapy success into widespread adoption and addressing cost-effectiveness are crucial challenges to address. Continued research and clinical trials are essential to fully harness gene therapy's potential in treating IRDs and enhancing the lives of affected individuals.

The economic burden of inherited retinal disease in Singapore: a prevalence-based cost-of-illness study

OBJECTIVE

To assess the economic impact of inherited retinal disease (IRD) among Singaporeans.

METHODS

IRD prevalence was calculated using population-based data. Focused surveys were conducted for sequentially enrolled IRD patients from a tertiary hospital. The IRD cohort was compared to the age- and gender-matched general population. Economic costs were expanded to the national IRD population to estimate productivity and healthcare costs.

RESULTS

National IRD caseload was 5202 cases (95% CI, 1734-11273). IRD patients (n = 95) had similar employment rates to the general population (67.4% vs. 70.7%; p = 0.479). Annual income was lower among IRD patients than the general population (SGD 19,500 vs. 27,161; p < 0.0001). Employed IRD patients had lower median income than the general population (SGD 39,000 vs. 52,650; p < 0.0001). Per capita cost of IRD was SGD 9382, with a national burden of SGD 48.8 million per year. Male gender (beta of SGD 6543, p = 0.003) and earlier onset (beta of SGD 150/year, p = 0.009) predicted productivity loss. Treatment of the most economically impacted 10% of IRD patients with an effective IRD therapy required initial treatment cost of less than SGD 250,000 (USD 188,000) for cost savings to be achieved within 20 years.

CONCLUSIONS

Employment rates among Singaporean IRD patients were the same as the general population, but patient income was significantly lower. Economic losses were driven in part by male patients with early age of onset. Direct healthcare costs contributed relatively little to the financial burden.

Impact of inherited retinal diseases on Canadian patients and families: a mixed-methods study

OBJECTIVE

To understand the physical, psychosocial, and practical challenges faced by Canadian patients with inherited retinal diseases (IRDs) and their families.

DESIGN

Mixed methods.

PARTICIPANTS

A total of 408 Canadians living with or caring for someone with an IRD (mean age = 51.4 ± 16.7 years) completed an online survey. Twenty cohort respondents participated in additional telephone interviews.

METHODS

The online survey was comprised of questions concerning demographics, self-reported vision, genetic testing, information preferences, health care experiences, treatment goals, and disease impact on daily life. Recruitment occurred through Fighting Blindness Canada's community database. Survey dissemination also occurred via social media and not-for-profit stakeholder outreach. Subsequent to survey completion, a subset of respondents participated in semistructured telephone interviews to further elucidate illness experience.

RESULTS

Respondents identified having 1 of more than 14 IRDs, with 72% specifying retinitis pigmentosa. Sixty-eight percent reported being legally blind, and more than 85% self-reported moderate to low vision or worse. IRDs impacted daily functioning, with 53% of respondents indicating that they affected employment or education. Psychological challenges were evident, with more than 70% worried about coping with daily life and more than 60% indicating fear and stress. Qualitative data described hopelessness around suitable work, loss of independence, and challenges with social interaction. Sixty-five percent reported a negative impact on family life. Many had not accessed social support services because of a lack of perceived need, awareness, or availability.

CONCLUSION

Canadian patients with IRDs report moderate to severe visual impairment, and both patients and their families describe an impact on psychosocial well-being and functioning during daily activities. Vision rehabilitation with a psychosocial approach is necessary, alongside facilitating access to emerging treatments.

Stem cell therapy for inherited retinal diseases: a systematic review and meta-analysis

PURPOSE

Stem cell therapy is a promising therapeutic approach for inherited retinal diseases (IRDs). This study aims to quantitatively examine the effectiveness and safety of stem cell therapy for patients with IRDs, including retinitis pigmentosa and Stargardt disease (STGD).

METHODS

We searched PubMed, EMBASE, Web of Science, Cochrane Library databases, and the ClinicalTrials.gov website. The latest retrieval time was August 20, 2023. The primary outcomes were rates and mean difference (MD) of best-corrected visual acuity (BCVA) improvement. Subgroup analyses were conducted according to administration routes and stem cell types. This study was registered with PROSPERO (CRD42022349271).

RESULTS

Twenty-one prospective studies, involving 496 eyes (404 RP and 92 STGD) of 382 patients (306 RP and 76 STGD), were included in this study. For RP, the rate of BCVA improvement was 49% and 30% at 6 months and 12 months, respectively, and the BCVA was significantly improved in the operative eyes at 6 months post-treatment (MD = - 0.12 logMAR, 95% CI .17 to - 0.06 logMAR; P < 0.001), while there was no significant difference at 12 months post-treatment (MD = -0.06 logMAR; 95% CI - 0.13 to 0.01 logMAR; P = 0.10). For STGD, the rate of BCVA improvement was 60% and 55% at 6 months and 12 months, respectively, and the BCVA was significantly improved in the operative eyes at 6 months (MD = - 0.14 logMAR, 95% CI - 0.22 to - 0.07 logMAR; P = 0.0002) and 12 months (MD = - 0.17 logMAR, 95% CI - 0.29 to - 0.04 logMAR; P = 0.01). Subgroup analyses showed suprachoroidal space injection of stem cells may be more efficient for RP. Eleven treated-related ocular adverse events from three studies and no related systemic adverse events were reported.

CONCLUSIONS

This study suggests stem cell therapy may be effective and safe for patients with RP or STGD. The long-term vision improvement may be limited for RP patients. Suprachoroidal space injection of stem cells may be a promising administration route for RP patients. Limited by the low grade of evidence, large sample size randomized clinical trials are required in the future.

CRB1-Associated Retinal Dystrophy Patients Have Expanded Lewis Glycoantigen-Positive T Cells

Purpose

Eye inflammation may occur in patients with inherited retinal dystrophies (IRDs) and is seen frequently in IRDs associated with mutations in the CRB1 gene. The purpose of this study was to determine the types of inflammatory cells involved in IRDs, by deep profiling the composition of peripheral blood mononuclear cells of patients with a CRB1-associated IRD.

Methods

This study included 33 patients with an IRD with confirmed CRB1 mutations and 32 healthy controls. A 43-parameter flow cytometry analysis was performed on peripheral blood mononuclear cells isolated from venous blood. FlowSOM and manual Boolean combination gating were used to identify and quantify immune cell subsets.

Results

Comparing patients with controls revealed a significant increase in patients in the abundance of circulating CD4+ T cells and CD8+ T cells that express sialyl Lewis X antigen. Furthermore, we detected a decrease in plasmacytoid dendritic cells and an IgA+CD24+CD38+ transitional B-cell subset in patients with an IRD.

Conclusions

Patients with a CRB1-associated IRD show marked changes in blood leukocyte composition, affecting lymphocyte and dendritic cell populations. These results implicate inflammatory pathways in the disease manifestations of IRDs.

Oxidative Stress: A Suitable Therapeutic Target for Optic Nerve Diseases?

Optic nerve disorders encompass a wide spectrum of conditions characterized by the loss of retinal ganglion cells (RGCs) and subsequent degeneration of the optic nerve. The etiology of these disorders can vary significantly, but emerging research highlights the crucial role of oxidative stress, an imbalance in the redox status characterized by an excess of reactive oxygen species (ROS), in driving cell death through apoptosis, autophagy, and inflammation. This review provides an overview of ROS-related processes underlying four extensively studied optic nerve diseases: glaucoma, Leber's hereditary optic neuropathy (LHON), anterior ischemic optic neuropathy (AION), and optic neuritis (ON). Furthermore, we present preclinical findings on antioxidants, with the objective of evaluating the potential therapeutic benefits of targeting oxidative stress in the treatment of optic neuropathies.

The health care and societal costs of inherited retinal diseases in Australia: a microsimulation modelling study

OBJECTIVES

To estimate the health care and societal costs of inherited retinal diseases (IRDs) in Australia.

DESIGN, SETTING, PARTICIPANTS

Microsimulation modelling study based on primary data - collected in interviews of people with IRDs who had ophthalmic or genetic consultations at the Children's Hospital at Westmead or the Save Sight Institute (both Sydney) during 1 January 2019 - 31 December 2020, and of their carers and spouses - and linked Medicare Benefits Schedule (MBS) and Pharmaceutical Benefits Schedule (PBS) data.

MAIN OUTCOME MEASURES

Annual and lifetime costs for people with IRDs and for their carers and spouses, grouped by payer (Australian government, state governments, individuals, private health insurance) and type (health care costs; societal costs: social support, National Disability Insurance Scheme (NDIS), income and taxation, costs associated with caring for family members with IRDs); estimated annual national cost of IRDs.

RESULTS

Ninety-four people (74 adults, 20 people under 18 years; 55 girls and women [59%]) and 30 carers completed study surveys (participation rate: adults, 66%; children, 66%; carers, 63%). Total estimated lifetime cost was $5.2 million per person with an IRD, of which 87% were societal and 13% health care costs. The three highest cost items were lost income for people with IRDs ($1.4 million), lost income for their carers and spouses ($1.1 million), and social spending by the Australian government (excluding NDIS expenses: $1.0 million). Annual costs were twice as high for people who were legally blind as for those with less impaired vision ($83 910 v $41 357 per person). The estimated total annual cost of IRDs in Australia was $781 million to $1.56 billion.

CONCLUSION

As the societal costs associated with IRDs are much larger than the health care costs, both contributors should be considered when assessing the cost-effectiveness of interventions for people with IRDs. The increasing loss of income across life reflects the impact of IRDs on employment and career opportunities.

Lipid nanoparticle-mediated delivery of mRNA into the mouse and human retina and other ocular tissues

Purpose

Lipid nanoparticles (LNPs) show promise in their ability to introduce mRNA to drive protein expression in specific cell types of the mammalian eye. Here, we examined the ability of mRNA encapsulated in lipid nanoparticles (LNPs) with two distinct formulations to drive gene expression in mouse and human retina and other ocular tissues.

Methods

We introduced mRNA carrying LNPs into two biological systems. Intravitreal injections were tested to deliver LNPs into the mouse eye. Human retinal pigment epithelium (RPE) and retinal explants were used to assess mRNA expression in human tissue. We analyzed specificity of expression using histology, immunofluorescence, and imaging.

Results

In mice, mRNAs encoding GFP and ciliary neurotrophic factor (CNTF) were specifically expressed by Müller glia and retinal pigment epithelium (RPE). Acute inflammatory changes measured by microglia distribution (Iba-1) or interleukin-6 (IL-6) expression were not observed 6 hours post-injection. Human RPE also expressed high levels of GFP. Human retinal explants expressed GFP in cells with apical and basal processes consistent with Müller glia and in perivascular cells consistent with macrophages.

Conclusions

We demonstrated the ability to reliably transfect subpopulations of retinal cells in mice eye tissues in vivo and in human ocular tissues. Of significance, intravitreal injections were sufficient to transfect the RPE in mice. To our knowledge we demonstrate delivery of mRNA using LNPs in human ocular tissues for the first time.

Quality of Life and Economic Impacts of Retinitis Pigmentosa on Japanese Patients: A Non-interventional Cross-sectional Study

INTRODUCTION

Retinitis pigmentosa (RP) is an inherited progressive disease, characterized by a loss of photoreceptors, and is the second leading cause of visual impairment in Japan. RP is currently incurable and can result in complete blindness, with affected patients typically experiencing a gradual loss of light sensitivity, visual field, and visual acuity. Identification of any unmet medical needs of patients with this condition requires an understanding of the impacts of RP; in this study, we surveyed Japanese patients with RP to investigate the quality of life and economic impacts of visual impairment.

METHODS

This non-interventional, cross-sectional study surveyed Japanese patients with RP. Economic impact was measured using an original questionnaire that assessed out-of-pocket cost (e.g., vision aids and medical services), salary gap with the general public, and the cost of depression and anxiety. Worker productivity was assessed using the Work Productivity and Activity Impairment Questionnaire (WPAI). Quality of life was evaluated using the Health Utilities Index Mark 3 (HUI3), the National Eye Institute Visual Function Questionnaire-25 (VFQ-25), and the 5-level EQ-5D version (EQ-5D-5L). The primary outcome was direct and indirect costs of visual impairment or blindness during the lifetime of patients with RP.

RESULTS

Among 122 surveyed patients with RP, the estimated annual cost per patient was 218,520 yen (2176 USD), and the estimated lifetime cost per patient was 18,523,909 yen (184,501 USD). Additional robustness testing increased the estimated annual cost and lifetime cost per patient to 783,176 yen (7801 USD) and 66,389,827 yen (661,253 USD), respectively. In working patients, work productivity loss was 26.2% per person and impairment of daily activities was 31.6% per person. The mean VFQ-25, HUI3, and EQ-5D-5L scores were 42.0, 0.393, and 0.833, respectively.

CONCLUSION

RP imposed a heavy economic burden and negative quality of life impacts in Japanese patients.

Disparities in Inherited Retinal Degenerations

To review disparities in the field of inherited retinal degenerations to establish foundations for future discussions oriented toward finding possible solutions. A narrative overview of the literature. Despite collective efforts towards democratization of genetic testing and investigation, genetic databases containing primarily European populations are heavily relied upon. Access to specialized care and other resources is also still not available to all. Recognizing and addressing disparities and inequities within the field of inherited retinal degenerations will improve our care of these patients and our knowledge of their conditions.

The State of Patient-Reported Outcome Measures for Pediatric Patients with Inherited Retinal Disease

Patient-reported outcome measures (PROMs) are questionnaires that assess health outcomes meaningful to the patient. PROMs have multiple applications, such as supporting clinicians’ decision-making for patient care, understanding the impact of disease on patient functioning, and evaluating the efficacy of therapeutics. Though PROMs were developed for various eye conditions, no PROM was tailored to pediatric patients with inherited retinal disease (IRD). Hence, a literature search was conducted using MEDLINE and Embase to identify PROMs potentially relevant to this patient population. This review evaluated selected pediatric PROMs against the US Food and Drug Administration (FDA) guidelines and found restricted use in the context of IRD. As there is a need for PROMs tailored to pediatric patients with IRD, we provide a perspective on applying the International Society for Pharmacoeconomics and Outcomes Research and FDA standards on the development of PROMs specific to IRD.

Inherited retinal diseases refer to a group of genetic conditions that affect the eye’s light-sensing cells and lead to vision loss. When a patient undergoes an eye assessment, the measures used are technical (e.g., visual acuity, visual field) and do not routinely address the patient’s experience. It is increasingly evident that the technical tools used do not really reflect how patients’ vision affects their daily lives. Questionnaires designed to assess how a condition impacts a daily activity are referred to as patient-reported outcome measures. The perspective of the impact of a condition on daily activities differs between adults and children. These tools are being created to evaluate health outcomes important to the patient on the basis of their condition and age. This is especially important when determining the value of therapies from the patient perspective. To date, no such questionnaire has been designed for pediatric patients with inherited retinal disease, an important cause of blindness. We explored the literature to evaluate existing pediatric vision tools and found that those could not be used to fill this gap. Given that we found a need to develop questionnaires tailored to pediatric patients with IRD, we also provide insight into how such a tool can be created for this population.

Cancers: What Are the Costs in Relation to Disability-Adjusted Life Years? A Systematic Review and Meta-Analysis

Cancers currently represent a leading cause of morbidity and mortality, and precisely estimating their burden is crucial for evidence-based decision-making. This study aimed at understanding the average costs of cancer-related disability-adjusted life years (DALYs) and highlighting possible differences in economic estimates obtained with diverse approaches. We searched four scientific databases to identify all the primary literature simultaneously investigating cancer-related costs and DALYs. In view of the different methodologies, studies were divided into two groups: those estimating costs starting from DALYs, and those independently performing cost and DALY analyses. The latter were pooled to compute costs per disease-related DALY: meta-analytic syntheses were performed for total costs and indirect costs, and in relation to the corresponding gross domestic product (GDP) per capita. The quality of included studies was assessed through the Quality of Health Economic Studies instrument. Seven studies were selected. Total and indirect pooled costs per DALY were, respectively, USD 9150 (95% CI: 5560-15,050) and USD 3890 (95% CI: 2570-5880). Moreover, the cost per cancer-related DALY has been found to be, on average, 32% (95% CI: 24-42%) of the corresponding countries' GDP per capita. Costs calculated a priori from DALYs may lead to results widely different from those obtained after data retrieval and model building. Further research is needed to better estimate the economic burden of cancer in terms of costs and DALYs.

Gene-Based Therapeutics for Inherited Retinal Diseases

Inherited retinal diseases (IRDs) are a heterogenous group of orphan eye diseases that typically result from monogenic mutations and are considered attractive targets for gene-based therapeutics. Following the approval of an IRD gene replacement therapy for Leber's congenital amaurosis due to RPE65 mutations, there has been an intensive international research effort to identify the optimal gene therapy approaches for a range of IRDs and many are now undergoing clinical trials. In this review we explore therapeutic challenges posed by IRDs and review current and future approaches that may be applicable to different subsets of IRD mutations. Emphasis is placed on five distinct approaches to gene-based therapy that have potential to treat the full spectrum of IRDs: 1) gene replacement using adeno-associated virus (AAV) and nonviral delivery vectors, 2) genome editing via the CRISPR/Cas9 system, 3) RNA editing by endogenous and exogenous ADAR, 4) mRNA targeting with antisense oligonucleotides for gene knockdown and splicing modification, and 5) optogenetic approaches that aim to replace the function of native retinal photoreceptors by engineering other retinal cell types to become capable of phototransduction.

Zebrafish models of inherited retinal dystrophies

Inherited retinal degenerations (IRDs) cause permanent vision impairment or vision loss due to the death of rod and cone photoreceptors. Animal models of IRDs have been instrumental in providing knowledge of the pathological mechanisms that cause photoreceptor death and in developing successful approaches that could slow or prevent vision loss. Zebrafish models of IRDs represent an ideal model system to study IRDs in a cone-rich retina and to test strategies that exploit the natural ability to regenerate damaged neurons. This review highlights those zebrafish mutants and transgenic lines that exhibit adult-onset retinal degeneration and serve as models of retinitis pigmentosa, cone-rod dystrophy, and ciliopathies.