Immunomodulatory Effects of Hydroxychloroquine and Chloroquine in Viral Infections and Their Potential Application in Retinal Gene Therapy

Effective treatment of retinal diseases with adeno-associated virus (AAV)-mediated gene therapy is highly dependent on the proportion of successfully transduced cells. However, due to inflammatory reactions at high vector doses, adjunctive treatment may be necessary to enhance the therapeutic outcome. Hydroxychloroquine and chloroquine are anti-malarial drugs that have been successfully used in the treatment of autoimmune diseases. Evidence suggests that at high concentrations, hydroxychloroquine and chloroquine can impact viral infection and replication by increasing endosomal and lysosomal pH. This effect has led to investigations into the potential benefits of these drugs in the treatment of viral infections, including human immunodeficiency virus and severe acute respiratory syndrome coronavirus-2. However, at lower concentrations, hydroxychloroquine and chloroquine appear to exert immunomodulatory effects by inhibiting nucleic acid sensors, including toll-like receptor 9 and cyclic GMP-AMP synthase. This dose-dependent effect on their mechanism of action supports observations of increased viral infections associated with lower drug doses. In this review, we explore the immunomodulatory activity of hydroxychloroquine and chloroquine, their impact on viral infections, and their potential to improve the efficacy and safety of retinal gene therapy by reducing AAV-induced immune responses. The safety and practicalities of delivering hydroxychloroquine into the retina will also be discussed.

Gene Therapy Targeting the Inner Retina Rescues the Retinal Phenotype in a Mouse Model of CLN3 Batten Disease

The neuronal ceroid lipofuscinoses (NCLs), often referred to as Batten disease, are inherited lysosomal storage disorders that represent the most common neurodegeneration during childhood. Symptoms include seizures, vision loss, motor and cognitive decline, and premature death. The development of brain-directed treatments for NCLs has made noteworthy progress in recent years. Clinical trials are currently ongoing or planned for different forms of the disease. Despite these promising advances, it is unlikely that therapeutic interventions targeting the brain will prevent loss of vision in patients as retinal cells remain untreated and will continue to degenerate. Here, we demonstrate that Cln3^Δex7/8 mice, a mouse model of CLN3 Batten disease with juvenile onset, suffer from a decline in inner retinal function resulting from the death of rod bipolar cells, interneurons vital for signal transmission from photoreceptors to ganglion cells in the retina. We also show that this ocular phenotype can be treated by adeno-associated virus (AAV)-mediated expression of CLN3 in cells of the inner retina, leading to significant survival of bipolar cells and preserved retinal function. In contrast, the treatment of photoreceptors, which are lost in patients at late disease stages, was not therapeutic in Cln3^Δex7/8 mice, underlining the notion that CLN3 disease is primarily a disease of the inner retina with secondary changes in the outer retina. These data indicate that bipolar cells play a central role in this disease and identify this cell type as an important target for ocular AAV-based gene therapies for CLN3 disease.

Evolving consensus on managing vitreo-retina and uvea practice in post-COVID-19 pandemic era

The COVID-19 pandemic has brought new challenges to the health care community. Many of the super-speciality practices are planning to re-open after the lockdown is lifted. However there is lot of apprehension in everyone's mind about conforming practices that would safeguard the patients, ophthalmologists, healthcare workers as well as taking adequate care of the equipment to minimize the damage. The aim of this article is to develop preferred practice patterns, by developing a consensus amongst the lead experts, that would help the institutes as well as individual vitreo-retina and uveitis experts to restart their practices with confidence. As the situation remains volatile, we would like to mention that these suggestions are evolving and likely to change as our understanding and experience gets better. Further, the suggestions are for routine patients as COVID-19 positive patients may be managed in designated hospitals as per local protocols. Also these suggestions have to be implemented keeping in compliance with local rules and regulations.

Future Vision 2020 and Beyond-5 Critical Trends in Eye Research

Ophthalmology has been at the forefront of many innovations in basic science and clinical research. The randomized prospective multicenter clinical trial, comparative clinical trials, the bench to beside development of diagnostic and therapeutic devices, the powerful combination of biostatistics and epidemiology, gene therapy, cell-based therapy, stem cell therapy, regenerative medicine, artificial intelligence, and the development of personalized molecular medicine continue to propel us forward. This article summarizes several critical trends in eye research.Innovative translational research continues to bring new solutions to blinding retinal diseases. The discovery of the genetic code presaged a day when the development of molecular tools and understanding of the basis of disease would lead not only to disease management but potentially lifelong cure. After decades of investigation, gene therapy is now a reality for a single autosomal recessive bi-allelic disease, Lebers Congenital Amaurosis. Its success has paved the way for a myriad of conditions once thought to be untreatable. In parallel, the progress to utilize pluripotential stem cells, immunomodulation, computational biology, and continued investigation into the fundamental mechanisms of cell and molecular biology is breathtaking in its rapidity. The next decade is likely to be the most exciting in the history of medicine. It will be essential that research progresses in a meticulously thoughtful, ethical, and collaborative process that safeguards the trust of our work and that of the society we serve.Presented as the International Award Lecture, Asia-Pacific Vitreoretinal Society meeting, November 2019, Shanghai China.

Suprachoroidal Delivery of Viral and Nonviral Gene Therapy for Retinal Diseases

Retinal gene therapy is a rapidly growing field with numerous clinical trials underway, and route of delivery is a critical contributor to its success. Subretinal administration, which involves pars plana vitrectomy in the operating room, offers targeted delivery to retinal-pigment epithelium cells and photoreceptors. Due to the immune-privileged nature of the subretinal space, the risk of an immune reaction against viral capsid antigens is minimized, an advantage of subretinal administration in patients with preexisting neutralizing antibodies. Intravitreal administration, with fewer procedure-related complications, is challenged by potential immune response and incomplete vector penetration through the internal limiting membrane. However, novel vectors, optimized by "directed evolution" may address these issues. Nonsurgical in-office suprachoroidal gene delivery offers the potential for greater surface-area coverage of the posterior segment compared to focal subretinal injection, and is not hindered by the internal limiting membrane. However, the vector must pass through multiple layers to reach the targeted retinal layers, and there is a risk of immune response. This review highlights recent developments, challenges, and future opportunities associated with viral and nonviral suprachoroidal gene delivery for the treatment of chorioretinal diseases. While ocular tolerability and short-term effectiveness of suprachoroidal gene delivery have been demonstrated in preclinical models, durability of gene expression, long-term safety, potential systemic exposure, and effective delivery to the macula require further exploration. Although the safety and efficacy of suprachoroidal gene delivery are yet to be proven in clinical trials, further optimization could facilitate nonsurgical in-office suprachoroidal gene therapy.

Severe vaso-occlusive lupus retinopathy in the early stage of a pediatric patient with systemic lupus erythematosus: a case report

INTRODUCTION

Systemic lupus erythematosus (SLE) is a multisystem, chronic, autoimmune disease which can affect any organ system including the eye. About one-third of the patients can be diagnosed with SLE-related eye involvement which is usually indicative of disease activity. Retinopathy is one of the most vision-threatening complications that can be associated with the disease.

PATIENT CONCERNS

An 11-year-old girl was hospitalized with complains of repeated swelling and pain in her extremities for 1 month, chest pain for 24 days, rash for 5 days and proteinuria for 1 day. On the morning of her fourth day in hospital, she suddenly complained of sudden, painless vision loss in the left eye. The ophthalmologist found that she had obstruction of central retinal vein and artery with diffuse retinal hemorrhages and macular edema.

DIAGNOSIS

The patient was diagnosed with systemic lupus erythematosus, lupus nephritis, and lupus retinopathy through her clinical manifestations and laboratory tests.

INTERVENTIONS

After diagnosis, she received steroid therapy, retinal laser photocoagulation, and intravitreal injection of dexamethasone (OZURDEX, Allergan Pharmaceuticals, Dublin, Ireland) early in her course.

OUTCOMES

At the latest follow-up, her vision improved partially. However, she still has the possibility of subsequent neovascular glaucoma and bleeding in the future.

CONCLUSIONS

An early diagnosis and the prompt therapeutic measures are necessary to prevent sight-threatening consequences, especially in pediatric patients with SLE.

CRISPR Interference-Potential Application in Retinal Disease

The treatment of dominantly inherited retinal diseases requires silencing of the pathogenic allele. RNA interference to suppress gene expression suffers from wide-spread off-target effects, while CRISPR-mediated gene disruption creates permanent changes in the genome. CRISPR interference uses a catalytically inactive 'dead' Cas9 directed by a guide RNA to block transcription of chosen genes without disrupting the DNA. It is highly specific and potentially reversible, increasing its safety profile as a therapy. Pre-clinical studies have demonstrated the versatility of CRISPR interference for gene silencing both in vivo and in ex vivo modification of iPSCs for transplantation. Applying CRISPR interference techniques for the treatment of autosomal dominant inherited retinal diseases is promising but there are few in vivo studies to date. This review details how CRISPR interference might be used to treat retinal diseases and addresses potential challenges for clinical translation.

Noble Metals and Soft Bio-Inspired Nanoparticles in Retinal Diseases Treatment: A Perspective

We are witnessing an exponential increase in the use of different nanomaterials in a plethora of biomedical fields. We are all aware of how nanoparticles (NPs) have influenced and revolutionized the way we supply drugs or how to use them as therapeutic agents thanks to their tunable physico-chemical properties. However, there is still a niche of applications where NP have not yet been widely explored. This is the field of ocular delivery and NP-based therapy, which characterizes the topic of the current review. In particular, many efforts are being made to develop nanosystems capable of reaching deeper sections of the eye such as the retina. Particular attention will be given here to noble metal (gold and silver), and to polymeric nanoparticles, systems consisting of lipid bilayers such as liposomes or vesicles based on nonionic surfactant. We will report here the most relevant literature on the use of different types of NPs for an efficient delivery of drugs and bio-macromolecules to the eyes or as active therapeutic tools.

Vascular Regeneration for Ischemic Retinopathies: Hope from Cell Therapies

Retinal vascular diseases, such as diabetic retinopathy, retinopathy of prematurity, retinal vein occlusion, ocular ischemic syndrome and ischemic optic neuropathy, are leading causes of vision impairment and blindness. Whilst drug, laser or surgery-based treatments for the late stage complications of many of these diseases are available, interventions that target the early vasodegenerative stages are lacking. Progressive vasculopathy and ensuing ischemia is an underpinning pathology in many of these diseases, leading to hypoperfusion, hypoxia, and ultimately pathological neovascularization and/or edema in the retina and other ocular tissues, such as the optic nerve and iris. Therefore, repairing the retinal vasculature may prevent progression of ischemic retinopathies into late stage vascular complications. Various cell types have been explored for their vascular repair potential. Endothelial progenitor cells, mesenchymal stem cells and induced pluripotent stem cells are studied for their potential to integrate with the damaged retinal vasculature and limit ischemic injury. Clinical trials for some of these cell types have confirmed safety and feasibility in the treatment of ischemic diseases, including some retinopathies. Another promising avenue is mobilization of endogenous endothelial progenitors, whereby reparative cells are moved from their niche to circulating blood to target and home into ischemic tissues. Several aspects and properties of these cell types have yet to be elucidated. Nevertheless, we foresee that cell therapy, whether through delivery of exogenous or enhancement of endogenous reparative cells, will become a valuable and beneficial treatment for ischemic retinopathies.

Inherited Eye Diseases with Retinal Manifestations through the Eyes of Homeobox Genes

Retinal development is under the coordinated control of overlapping networks of signaling pathways and transcription factors. The paper was conceived as a review of the data and ideas that have been formed to date on homeobox genes mutations that lead to the disruption of eye organogenesis and result in inherited eye/retinal diseases. Many of these diseases are part of the same clinical spectrum and have high genetic heterogeneity with already identified associated genes. We summarize the known key regulators of eye development, with a focus on the homeobox genes associated with monogenic eye diseases showing retinal manifestations. Recent advances in the field of genetics and high-throughput next-generation sequencing technologies, including single-cell transcriptome analysis have allowed for deepening of knowledge of the genetic basis of inherited retinal diseases (IRDs), as well as improve their diagnostics. We highlight some promising avenues of research involving molecular-genetic and cell-technology approaches that can be effective for IRDs therapy. The most promising neuroprotective strategies are aimed at mobilizing the endogenous cellular reserve of the retina.

Noncompliance in Prospective Retina Clinical Trials: Analysis of Factors Predicting Loss to Follow-up

PURPOSE

Noncompliance during prospective studies can bias results and limit conclusions. The current study retrospectively investigated the relationship between study subject characteristics and rates of noncompliance in interventional trials involving common causes of blindness.

DESIGN

Retrospective analysis of 10 randomized clinical trials.

METHODS

Subjects were enrolled in investigator-initiated trials studying proliferative diabetic retinopathy, neovascular age-related macular degeneration, diabetic macular edema, and retinal venous occlusive disease. Records were reviewed for hypothesized risk factors of noncompliance and rates of noncompliance, which were defined as at least 1 missed visit or exiting the study early. Demographic information, systemic medical history, and ocular medical history, including visual acuity and central retinal thicknesses, were examined retrospectively using Student t test, Pearson χ² test, and logistic regression.

RESULTS

Of 390 subjects included, 212 (54.4%) were compliant with all scheduled study visits and 178 (45.6%) met criteria for noncompliance, with 53 (13.6%) subjects exiting early. Regression models identified 17 variables that were significant in determining subject noncompliance. Among those, distance, comorbidities, diabetic status, concomitant medications, previous clinic visits, length of study, disease under study, and severe adverse events were highly significant risk factors of noncompliance.

CONCLUSION

The current research identified a substantial proportion of subjects who met the criteria for noncompliance within the trials analyzed. The factors identified in the current work are consistent with published clinical observations and the results of previous clinical trials. These results highlight the importance of considering study design and medical history when designing prospective clinical trials in an attempt to minimize data loss.

[Placoid pigment epitheliopathy and serpiginous choroiditis]

Placoid pigment epitheliopathy and serpiginous choroiditis are among the white dot retinal syndromes and possess similarities that can cause confusion between these two diseases. However, they are very different in terms of their progression and prognosis, which requires a diagnosis of certainty in order to better manage the patients with the diseases and identify potentially serious progressive complications. The clinical presentation, results of testing, differential diagnoses and treatment of these two pathologies are discussed in this article.

RNA editing as a therapeutic approach for retinal gene therapy requiring long coding sequences

RNA editing aims to treat genetic disease through altering gene expression at the transcript level. Pairing site-directed RNA-targeting mechanisms with engineered deaminase enzymes allows for the programmable correction of G>A and T>C mutations in RNA. This offers a promising therapeutic approach for a range of genetic diseases. For inherited retinal degenerations caused by point mutations in large genes not amenable to single-adeno-associated viral (AAV) gene therapy such as USH2A and ABCA4, correcting RNA offers an alternative to gene replacement. Genome editing of RNA rather than DNA may offer an improved safety profile, due to the transient and potentially reversible nature of edits made to RNA. This review considers the current site-directing RNA editing systems, and the potential to translate these to the clinic for the treatment of inherited retinal degeneration.

Treatment for Central-Peripheral Rivalry-Type Diplopia ("Dragged-Fovea Diplopia Syndrome")

PURPOSE

To report the effectiveness of treatments for central-peripheral rivalry (CPR)-type diplopia due to retinal misregistration.

DESIGN

Retrospective, interventional case series.

METHODS

Fifty adults with retinal misregistration and CPR-type diplopia (minimum frequency of "sometimes" at distance and/or for reading) caused by epiretinal membrane (n = 44) or other retinal disorders (n = 6) were enrolled in this study, conducted at adult strabismus clinics, Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, a tertiary medical center. Treatments included Bangerter filter, adhesive tape, Fresnel prism, clear prism (incorporated into glasses or loose prism in the office), iseikonic manipulation (using iseikonic lenses or contact lenses), a MIN lens, or epiretinal membrane (ERM) peeling (alone or in any combination). Not all patients underwent all of these treatments.

RESULTS

Main outcome measurements were diplopia frequency, evaluated using the Diplopia Questionnaire. Success was defined as "never" or "rarely" diplopic for distance and reading, using the Diplopia Questionnaire, at an outcome examination as close as possible to 6 months. Overall, 17 of 50 patients (34%; 95% confidence interval [CI], 21%-49%) were classified as successful. Fresnel prism was successful in 4 of 7 patients (57%; 95% CI, 18%-90%); Bangerter filter in 4 of 28 patients (14%; 95% CI, 4%-33%); ERM peeling in 8 of 18 patients (44%; 95% CI, 22%-69%); and iseikonic manipulation in 1 of 23 patients (using a contact lens; 4%; 95% CI, 0%-22%).

CONCLUSIONS

CPR-type diplopia may be relieved in some patients using nonsurgical treatment options consisting of Fresnel prism or Bangerter filter. ERM peeling was surprisingly successful and should be considered.

Management of Deep Retinal Capillary Ischemia by Electromagnetic Stimulation and Platelet-Rich Plasma: Preliminary Clinical Results

INTRODUCTION

To investigate the efficacy of retinal electromagnetic stimulation and sub-tenon autologous platelet-rich plasma in the treatment of deep retinal capillary ischemia.

METHODS

The study included 28 eyes of 17 patients aged 15-76 years (mean 37.9 years) who had deep retinal capillary ischemia. Patients who had acute-onset paracentral scotoma in the last 1 month were included in the study between January 2018 and January 2019. The diagnosis of deep retinal capillary ischemia was based on clinical history and typical findings of optical coherence tomography angiography. The eyes were divided into three groups: group 1 (n = 7 eyes) received electromagnetic stimulation alone; group 2 (n = 7 eyes) received electromagnetic stimulation and sub-tenon autologous platelet-rich plasma injection; group 3 had no intervention and served as a control group (n = 14 eyes). The patients underwent ten sessions of electromagnetic stimulation in groups 1 and 2. Sub-tenon autologous platelet-rich plasma injection was performed immediately after the first, fifth, and tenth sessions of electromagnetic stimulation in group 2. The deep retinal capillary density and best corrected visual acuity changes were investigated before and after treatment at the first month.

RESULTS

The mean deep retinal capillary density was 52.0% before electromagnetic stimulation and 56.1% after ten sessions of application in group 1; this improvement was statistically significant (p = 0.01). In the combined treatment group (group 2), the mean deep retinal capillary density was 46.9% before the treatment and 56.5% after the treatment; this increase was also statistically significant (p = 0.01). Statistically significant best corrected visual acuity improvement (p = 0.01) could be achieved only in group 2. The combined treatment was significantly superior (p < 0.01) to treatment with only electromagnetic stimulation regarding best corrected visual acuity and deep retinal capillary density. In the control group (group 3), there was no statistically significant change (p = 0.09) in the mean deep retinal capillary density and best corrected visual acuity.

CONCLUSION

Treatment of the underlying cause is a priority in the treatment of deep retinal capillary ischemia. However, in the acute period, local ischemia treatment is necessary to prevent permanent retinal damage and scotomas. In mild cases, only electromagnetic stimulation, which is non-invasive and easy to use, might have a beneficial effect on deep retinal capillary density. In more severe cases, sub-tenon fresh autologous platelet-rich plasma injection together with electromagnetic stimulation may be more effective in the treatment of local ischemia of the retina in order to augment the response.

FUNDING

The Rapid Service Fees were funded by the Ankara University Tecnopolis Institute.

CLINICAL TRIAL REGISTRATION

titck.gov.tr identifier, 2018-136.

[Clinical analysis of juxtapapillary retinal capillary hemangioma]

Objective: To discuss the clinical features and treatment of juxtapapillary retinal capillary hemangioma (JRCH). Methods: Retrospective study of the clinical data of 6 patients (7 eyes) who were diagnosed with JRCH, among which 2 eyes were treated by laser therapy (thermotherapy TTT or photodynamic therapy PDT), 2 eyes were treated by intravitreal anti-VEGF injection, 2 eyes with vitreous hemorrhage were treated with vitrectomy (PPV)+ anti-VEGF, and 1 eye was untreated. Results: In the 6 cases, the gender ratio of male to female is 2∶1 with average age of 46 years. Four eyes were associated with macular edema(57.1%), vitreous hemorrhage(n=2, 28.6%), and epiretinal membrane(n=1, 14.2%) in the initial examination. Three patients were associated with von Hippel-Lindau(VHL). During the follow-up period, the visual acuity of the 2 patients treated by TTT decreased. Among the 2 eyes treated by anti-VEGF, the visual acuity of 1 eye associated with macular edema increased, and the visual acuity of 1 eye with macular epiretinal membrane did not change significantly, the visual acuity of both 2 eyes treated by PPV+anti-VEGF improved, the vision of the 1 eye untreated appeared to be stable. Conclusions: Juxtapapillary retinal capillary hemangioma is the orange or red vascular hamartomas that occur on or adjacent to the optic nerve head. It is often associated with macular edema, vitreous hemorrhage, and local subretinal effusion. Symptomatic treatment of complications can effectively improve the visual acuity of patients, while long-term follow-up observation should be organized for patients without complications, laser treatment appears to be ineffective. (Chin J Ophthalmol, 2019, 55:609-615).

The Foundation Fighting Blindness Plays an Essential and Expansive Role in Driving Genetic Research for Inherited Retinal Diseases

The Foundation Fighting Blindness leads a collaborative effort among patients and families, scientists, and the commercial sector to drive the development of preventions, treatments, and cures for inherited retinal diseases (IRDs). When the nonprofit was established in 1971, it sought the knowledge and insights of leaders in the retinal research field to guide its research funding decisions. While the Foundation’s early investments focused on gaining a better understanding of the genetic causes of IRDs, its portfolio of projects would come to include some of the most innovative approaches to saving and restoring vision, including gene replacement/augmentation therapies, gene editing, RNA modulation, optogenetics, and gene-based neuroprotection. In recent years, the Foundation invested in resources such as its patient registry, natural history studies, and genetic testing program to bolster clinical development and trials for emerging genetic therapies. Though the number of clinical trials for such therapies has surged over the last decade, the Foundation remains steadfast in its commitment to funding the initiatives that hold the most potential for eradicating the entire spectrum of IRDs.

New Ocular Findings in a Case of Chronic Granulomatous Disease in a Child

The authors report a case of a 2-year-old male with chronic granulomatous disease (CGD). On examination, the patient had chorioretinal lesions, peripheral avascular retina, and unilateral glaucoma. CGD is a primary immunodeficiency that leaves the host susceptible to infections and granuloma formation. Chorioretinal lesions are a well-documented finding of CGD. The advent of widefield angiography allowed the authors to detect peripheral retinal nonperfusion in this case. Glaucoma, which by itself has been associated with peripheral avascular retina, has not been previously reported in a case of CGD. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:459-461.].

Adeno-Associated Viral Vectors as a Tool for Large Gene Delivery to the Retina

Gene therapy using adeno-associated viral (AAV) vectors currently represents the most promising approach for the treatment of many inherited retinal diseases (IRDs), given AAV's ability to efficiently deliver therapeutic genes to both photoreceptors and retinal pigment epithelium, and their excellent safety and efficacy profiles in humans. However, one of the main obstacles to widespread AAV application is their limited packaging capacity, which precludes their use from the treatment of IRDs which are caused by mutations in genes whose coding sequence exceeds 5 kb. Therefore, in recent years, considerable effort has been made to identify strategies to increase the transfer capacity of AAV vectors. This review will discuss these new developed strategies, highlighting the advancements as well as the limitations that the field has still to overcome to finally expand the applicability of AAV vectors to IRDs due to mutations in large genes.

Diminished apoptosis in hypoxic porcine retina explant cultures through hypothermia

Simulation of hypoxic processes in vitro can be achieved through cobalt chloride (CoCl2), which induces strong neurodegeneration. Hypoxia plays an important role in the progression of several retinal diseases. Thus, we investigated whether hypoxia can be reduced by hypothermia. Porcine retinal explants were cultivated for four and eight days and hypoxia was mimicked by adding 300 µM CoCl2 from day one to day three. Hypothermia treatment (30 °C) was applied simultaneously. Retinal ganglion, bipolar and amacrine cells, as well as microglia were evaluated via immunohistological and western blot analysis. Furthermore, quantitative real-time PCR was performed to analyze cellular stress and apoptosis. In addition, the expression of specific marker for the previously described cell types were investigated. A reduction of ROS and stress markers HSP70, iNOS, HIF-1α was achieved via hypothermia. In accordance, an inhibition of apoptotic proteins (caspase 3, caspase 8) and the cell cycle arrest gene p21 was found in hypothermia treated retinae. Furthermore, neurons of the inner retina were protected by hypothermia. In this study, we demonstrate that hypothermia lowers hypoxic processes and cellular stress. Additionally, hypothermia inhibits apoptosis and protects neurons. Hence, this seems to be a promising treatment for retinal neurodegeneration.

Cost Utility of Voretigene Neparvovec for Biallelic RPE65-Mediated Inherited Retinal Disease

OBJECTIVE

The gene therapy voretigene neparvovec (VN) is the first Food and Drug Administration-approved treatment for vision loss owing to the ultra-rare RPE65-mediated inherited retinal disorders. We modeled the cost-utility of VN compared with standard of care (SoC).

STUDY DESIGN

A 2-state Markov model, alive and dead, with a lifetime horizon.

METHODS

Visual acuity (VA) and visual field (VF) were tracked to model quality-adjusted life-years (QALYs). VN led to an improvement in VA and VF that we assumed was maintained for 10 years followed by a 10-year waning period. The cost of VN was $850 000, and other direct medical costs for depression and trauma were included for a US healthcare system perspective. A modified societal perspective also included direct nonmedical costs and indirect costs.

RESULTS

VN provided an additional 1.3 QALYs over the remaining lifetime of an individual. The average total lifetime direct medical cost for individuals treated with VN was $1 039 000 compared with $213 400 for SoC, leading to an incremental cost-effectiveness ratio (ICER) of $643 800/QALY from the US healthcare system perspective. Direct nonmedical costs totalled $1 070 900 for VN and $1 203 300 for SoC, and indirect costs totalled $405 400 for VN and $482 900 for SoC, leading to an ICER of $480 100/QALY from the modified societal perspective.

CONCLUSIONS

At the current price, VN was unlikely to reach traditional cost-effectiveness standards compared with SoC. VN has important implications for both development and pricing of future gene therapies; therefore clinical and economic analyses must be carefully considered.

In Vitro Evaluation of AAV Vectors for Retinal Gene Therapy

Gene therapy holds promise for treating previously untreatable retinal disorders. The most promising approaches use gene transfer vectors derived from adeno-associated virus (AAV) to supplement a gene function in the affected cell type. One example is gene therapy for achromatopsia which affects daylight vision. In this case, recombinant AAV (rAAV) vectors are being developed to specifically target cone photoreceptors. Development of rAAV vectors could be facilitated by the use of in vitro models. In this chapter we provide a protocol which utilizes mouse 661W cells, an in vitro model of cone photoreceptors for evaluation of the transduction efficacy of rAAV vectors.