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The suprachoroid is a potential space located between the sclera and choroid of the eye, which provides a novel route for ocular drug or viral vector delivery. Suprachoroidal injection of adeno-associated virus (AAV)8 using transscleral microneedles enables widespread transgene expression in eyes of nonhuman primates, but may cause intraocular inflammation. We characterized the host humoral and cellular immune responses after suprachoroidal delivery of AAV8 expressing green fluorescent protein (GFP) in rhesus macaques, and found that it can induce mild chorioretinitis that resolves after systemic corticosteroid administration, with recovery of photoreceptor morphology, but persistent immune cell infiltration after 3 months, corresponding to a loss of GFP expression from retinal pigment epithelial cells, but persistent expression in scleral fibroblasts. Suprachoroidal AAV8 triggered B cell and T cell responses against GFP, but only mild antibody responses to the viral capsid compared to intravitreal injections of the same vector and dose. Systemic biodistribution studies showed lower AAV8 levels in liver and spleen after suprachoroidal injection compared with intravitreal delivery. Our findings suggest that suprachoroidal AAV8 primarily triggers host immune responses to GFP, likely due to sustained transgene expression in scleral fibroblasts outside the blood-retinal barrier, but elicits less humoral immune reactivity to the viral capsid than intravitreal delivery due to lower egress into systemic circulation. As GFP is not native to primates and not a clinically relevant transgene, suprachoroidal AAV delivery of human transgenes may have significant translational potential for retinal gene therapy.

Purpose: To explore the efficacy of CLS-TA, a proprietary suprachoroidal injectable suspension of triamcinolone acetonide, in noninfectious uveitis (NIU) with macular edema (ME), categorized by anatomic subtype. Methods: Patients diagnosed with ME associated with NIU of any etiology and anatomic subtype were eligible for the phase 3 PEACHTREE trial of CLS-TA. Post-hoc analyses were performed, stratified by discrete anatomic subtype of uveitis (anterior, intermediate, posterior, and panuveitis.) Results: Across all anatomic subtypes at 24 weeks, patients receiving CLS-TA at baseline and week 12 demonstrated mean increases in BCVA ranging from +12.1 to +15.9 letters, mean central subfield thickness (CST) improvement ranging from −120.1 µm to −189.0 µm, and IOP changes ranging from +0.5 to +3.1 mmHg. Overall, reports of adverse events were similar among subtypes. Conclusions: Irrespective of the uveitic anatomic subtype among patients treated for ME associated with NIU, a clinical benefit in participants treated with CLS-TA was demonstrated, with a comparable safety profile. [ABSTRACT FROM AUTHOR]

Gene therapy holds promise as a transformative approach in the treatment landscape of age-related macular degeneration (AMD), diabetic retinopathy (DR), and diabetic macular edema (DME), aiming to address the challenges of frequent intravitreal anti-vascular endothelial growth factor (VEGF) injections. This manuscript reviews ongoing gene therapy clinical trials for these disorders, including ABBV-RGX-314, ixoberogene soroparvovec (ixo-vec), and 4D-150. ABBV-RGX-314 utilizes an adeno-associated virus (AAV) vector to deliver a transgene encoding a ranibizumab-like anti-VEGF antibody fragment, demonstrating promising results in Phase 1/2a and ongoing Phase 2b/3 trials. Ixo-vec employs an AAV2.7m8 capsid for intravitreal delivery of a transgene expressing aflibercept, showing encouraging outcomes in Phase 1 and ongoing Phase 2 trials. 4D-150 utilizes an evolved vector to express both aflibercept and a VEGF-C inhibitory RNAi, exhibiting positive interim results in Phase 1/2 studies. Other therapies reviewed include EXG102-031, FT-003, KH631, OLX10212, JNJ-1887, 4D-175, and OCU410. These therapies offer potential advantages of reduced treatment frequency and enhanced safety profiles, representing a paradigm shift in management towards durable and efficacious cellular-based biofactories. These advancements in gene therapy hold promise for improving outcomes in AMD and addressing the complex challenges of DME and DR, providing new avenues for the treatment of diabetic eye diseases. [ABSTRACT FROM AUTHOR]

Introduction: With the recent FDA approvals of pegcetacoplan (SYFOVRE, Apellis Pharmaceuticals) and avacincaptad pegol (IZERVAY, Astellas Pharmaceuticals), modulation of the complement system has emerged as a promising therapeutic approach for slowing progression of geographic atrophy (GA) in AMD. Areas covered: This article reviews the current understanding of the complement system, its role in AMD, and the various complement-targeting therapies in development for the treatment of GA, including monoclonal antibodies, aptamers, protein analogs, and gene therapies. Approved and investigational agents have largely focused on interfering with the activity of complement components 3 and 5, owing to their central roles in the classical, lectin, and alternative complement pathways. Other investigational therapies have targeted formation of membrane attack complex (a terminal step in the complement cascade which leads to cell lysis), complement factors H and I (which serve regulatory functions in the alternative pathway), complement factors B and D (within the alternative pathway), and complement component 1 (within the classical pathway). Clinical trials investigating these agents are summarized, and the potential benefits and limitations of these therapies are discussed. Expert opinion: Targeting the complement system is a promising therapeutic approach for slowing the progression of GA in AMD, potentially improving visual outcomes. However, increased risk of exudative conversion must be considered, and further research is required to identify clinical criteria and best practices for initiating complement inhibitor therapy for GA. [ABSTRACT FROM AUTHOR]

To study the efficacy and safety of suprachoroidal CLS-TA (proprietary suspension of triamcinolone acetonide) in uveitic macular edema (UME) with and without concurrent systemic corticosteroid or steroid-sparing therapy (ST). Post hoc analysis of the PEACHTREE phase 3 randomized trial. Among UME patients receiving no ST, at week 24, mean BCVA change was +15.6 letters in 68 CLS-TA patients versus +4.9 letters in 49 sham-control patients (p <.001), while mean CST change was −169.8 µm versus −10.3 µm, respectively (p <.001). Among patients receiving ST, at week 24, mean BCVA change was +9.4 letters in 28 CLS-TA patients versus −3.2 letters in 15 sham-control patients (p =.019), while mean CST change was −108.3 µm versus −43.5 µm, respectively (p =.190). No SAEs related to treatment were reported. A clinically meaningful benefit of CLS-TA was noted in UME patients, regardless of concurrent ST usage. Abbreviation and Acronyms CST = central subfield thickness; BCVA = best corrected visual acuity; ME = macular edemaI; IVT = intravitreal; AE = adverse event; FA = fluocinolone acetonide; SD-OCT = spectral-domain optical coherence tomography; NIU = noninfectious uveitis; SAE = serious adverse event; TEAE = treatment emergent adverse event; ITT = intent to treat; CI = confidence interval [ABSTRACT FROM AUTHOR]

Patients with macular edema (ME) associated with uveitis (UME) are at risk for vision loss and decreased quality of life, and they often experience high health care costs and rates of workforce absenteeism. Systemically or locally delivered corticosteroids are the mainstay of treatment for UME. Although traditional corticosteroid treatments may demonstrate high levels of efficacy, systemic delivery carries the risk of potentially serious systemic adverse effects (AEs), and standard local modes of delivery may be associated with low bioavailability in posterior ocular tissues and steroid-associated AEs due to anterior ocular tissue exposure. Drug injection into the suprachoroidal space (SCS) allows for targeted delivery to chorioretinal tissues with high bioavailability in the posterior segment, as well as for inherent drug sequestration away from the anterior segment, which may lower the risk of AEs associated with anterior tissue exposure to steroids. A novel triamcinolone acetonide (TA) injectable suspension formulated for administration to the SCS, SCS-TA (Xipere®; Bausch + Lomb), received FDA approval in 2021 for the treatment of UME. It is administered via the SCS Microinjector® (Clearside Biomedical, Inc), a device specifically designed for SCS delivery of ocular therapeutics. This approval was based on results from the phase 3 PEACHTREE clinical trial (NCT02595398) that demonstrated the clinical efficacy--including significantly increased visual acuity and decreased central subfield thickness--and safety of SCS-TA in patients with UME. Results from this trial, as well as from its long-term observational extension (MAGNOLIA; NCT02952001) and an open-label safety study (AZALEA; NCT03097315), support the possibility that treatment with SCS-TA may address the burden of disease in patients with UME. [ABSTRACT FROM AUTHOR]

Common risk factors for many ocular pathologies involve non-pathologic, age-related damage to the optic nerve. Understanding the mechanisms of age-related changes can facilitate targeted treatments for ocular pathologies that arise at any point in life. In this review, we examine these age-related, neurodegenerative changes in the optic nerve, contextualize these changes from the anatomic to the molecular level, and appreciate their relationship with ocular pathophysiology. From simple structural and mechanical changes at the optic nerve head (ONH), to epigenetic and biochemical alterations of tissue and the environment, multiple age-dependent mechanisms drive extracellular matrix (ECM) remodeling, retinal ganglion cell (RGC) loss, and lowered regenerative ability of respective axons. In conjunction, aging decreases the ability of myelin to preserve maximal conductivity, even with "successfully" regenerated axons. Glial cells, however, regeneratively overcompensate and result in a microenvironment that promotes RGC axonal death. Better elucidating optic nerve neurodegeneration remains of interest, specifically investigating human ECM, RGCs, axons, oligodendrocytes, and astrocytes; clarifying the exact processes of aged ocular connective tissue alterations and their ultrastructural impacts; and developing novel technologies and pharmacotherapies that target known genetic, biochemical, matrisome, and neuroinflammatory markers. Management models should account for age-related changes when addressing glaucoma, diabetic retinopathy, and other blinding diseases. [ABSTRACT FROM AUTHOR]

Glaucoma is a progressive optic neuropathy and a leading cause of irreversible blindness. The disease has conventionally been characterized by an elevated intraocular pressure (IOP); however, recent research has built the consensus that glaucoma is not only dependent on IOP but rather represents a multifactorial optic neuropathy. Although many risk factors have been identified ranging from demographics to co-morbidities to ocular structural predispositions, IOP is currently the only modifiable risk factor, most often treated by topical IOP-lowering medications. However, topical hypotensive regimens are prone to non-adherence and are largely inefficient, leading to disease progression in spite of treatment. As a result, several companies are developing sustained release (SR) drug delivery systems as alternatives to topical delivery to potentially overcome these barriers. Currently, Bimatoprost SR (DurystaTM) from Allergan plc is the only FDA-approved SR therapy for POAG. Other SR therapies under investigation include: bimatoprost ocular ring (Allergan) (ClinicalTrials.gov identifier: NCT01915940), iDose® (Glaukos Corporation) (NCT03519386), ENV515 (Envisia Therapeutics) (NCT02371746), OTX-TP (Ocular Therapeutix) (NCT02914509), OTX-TIC (Ocular Therapeutix) (NCT04060144), and latanoprost free acid SR (PolyActiva) (NCT04060758). Additionally, a wide variety of technologies for SR therapeutics are under investigation including ocular surface drug delivery systems such as contact lenses and nanotechnology. While challenges remain for SR drug delivery technology in POAG management, this technology may shift treatment paradigms and dramatically improve outcomes. [ABSTRACT FROM AUTHOR]

Standard ocular drug delivery methods generally are safe and effective for treating diseases of the eye. However, many routes of administration carry the risk of adverse effects due to drug exposure to anterior ocular tissues. Additionally, these delivery methods may not result in high and consistent levels of a therapeutic agent delivered to target tissues for diseases affecting the posterior segment of the eye. Injection into the suprachoroidal space (SCS) represents an alternative method of ocular drug delivery to the posterior segment. SCS injection facilitates targeted distribution to affected chorioretinal tissues for potential efficacy benefits, compartmentalization away from unaffected anterior segment tissues for potential safety benefits, and a high degree of bioavailability. Furthermore, the SCS may serve as a drug depot for long-acting drug delivery of small-molecule suspensions. Until recently, drug delivery to the SCS could be achieved only in the operating room setting with anesthetic immobilization of the eye and surgical dissection through the sclera. A novel microneedle device, the SCS Microinjector® (Clearside Biomedical, Inc) was developed to permit physicians to administer therapies safely and reliably into the SCS in the office setting. Successful use of SCS injection has been demonstrated with triamcinolone acetonide injectable suspension (Xipere®, Bausch + Lomb), a novel formulation optimized for use with the SCS Microinjector®. FDA approval of this combination drug and device for the treatment of macular edema associated with uveitis (UME) was based on outcomes from the phase 3 PEACHTREE study (NCT02595398); other important studies included its long-term observational extension (MAGNOLIA; NCT02952001) and an open-label safety study (AZALEA; NCT03097315). The SCS Microinjector® together with triamcinolone acetonide injectable suspension for use in the SCS presents an opportunity for safe and effective drug delivery for the treatment of UME and, potentially, for broader use with alternate medications to treat other ocular diseases that impact chorioretinal tissues (eg, age-related macular degeneration, diabetic retinopathy, choroidal melanoma). [ABSTRACT FROM AUTHOR]

Purpose To assess the extended efficacy and safety of suprachoroidal triamcinolone acetonide injectable suspension (CLS-TA) among patients with macular oedema (ME) secondary to non-infectious uveitis (NIU). Methods Patients with uveitic ME were treated with suprachoroidal CLS-TA at baseline and week 12 of the Efficacy and Safety of Suprachoroidal CLS-TA for Macular Edema Secondary to Noninfectious Uveitis: Phase 3 Randomized Trial (PEACHTREE) study. Time to rescue was evaluated over 24 additional weeks for MAGNOLIA. Safety data, visual acuity and retinal central subfield thickness (CST) reduction were also evaluated. Of the 53 eligible patients (46 CLS-TA and 7 control), 33 patients were enrolled (28 CLS-TA and 5 control). Results Over the entire 48-week period for PEACHTREE and MAGNOLIA, the median time to rescue therapy was 257 days versus 55.5 days for the CLS-TA and sham-control arms, respectively. Of 28 CLS-TA treated patients who participated in MAGNOLIA, 14 (50%) did not require rescue therapy through approximately 9 months after the second treatment. Among CLS-TA patients not requiring rescue, there was a mean gain of 12.1 letters and mean CST reduction of 174.5 µm at week 48. No serious adverse events related to study treatment were observed. Conclusion Approximately 50% of patients did not require additional treatment for up to 9 months following the last CLS-TA administration. [ABSTRACT FROM AUTHOR]

Age-related macular degeneration (AMD) is among the leading causes of irreversible blindness worldwide. In addition to environmental risk factors, such as tobacco use and diet, genetic background has long been established as a major risk factor for the development of AMD. However, our ability to predict disease risk and personalize treatment remains limited by our nascent understanding of the molecular mechanisms underlying AMD pathogenesis. Research into the molecular genetics of AMD over the past two decades has uncovered 52 independent gene variants and 34 independent loci that are implicated in the development of AMD, accounting for over half of the genetic risk. This research has helped delineate at least five major pathways that may be disrupted in the pathogenesis of AMD: the complement system, extracellular matrix remodeling, lipid metabolism, angiogenesis, and oxidative stress response. This review surveys our current understanding of each of these disease mechanisms, in turn, along with their associated pathogenic gene variants. Continued research into the molecular genetics of AMD holds great promise for the development of precision-targeted, personalized therapies that bring us closer to a cure for this debilitating disease. [ABSTRACT FROM AUTHOR]

Purpose: To compare ocular pharmacokinetics (PK), systemic absorption, and injectability of triamcinolone acetonide (TA) suprachoroidal (SC) and intravitreal (IVT) suspensions. Methods: New Zealand White (NZW) rabbits received a bilateral injection of 4 mg TA injectable suspension, TRI (TRIESENCE ®; Alcon) through either microneedle-based SC or standard IVT injection. Another group of NZW rabbits received a bilateral SC injection (4 mg) of either TRI or a proprietary TA suspension for SC use, CLS-TA (Clearside Biomedical). Blood and ocular tissues were analyzed for TA over 3 months. Separately, injectability of TRI and CLS-TA through a proprietary SC delivery system (SCS Microinjector®; Clearside Biomedical) was compared using microinjector syringe-plunger glide force measurement. Results: Suprachoroidal delivery of TRI, compared with IVT-TRI, resulted in ∼12-fold higher exposure in the retinal pigment epithelium-choroid-sclera, and comparable exposure in the retina. Conversely, SC-TRI, compared to IVT-TRI, resulted in 460-, 34-, and 22-fold lower exposure in the lens, iris-ciliary body, and vitreous humor, and negligible exposure in the aqueous humor. SC injection of either CLS-TA or TRI resulted in comparable and sustained ocular TA levels. Plasma TA levels were generally undetectable in both studies. A significantly greater and more variable glide force was measured for TRI vs. CLS-TA. Conclusions: Suprachoroidal delivery of TA enabled high and durable TA levels targeted to the chorioretina with limited anterior segment exposure. SC delivery of either CLS-TA or TRI resulted in comparable ocular PK profiles with low systemic exposure; however, CLS-TA required lower and less variable glide force than TRI, potentiating more consistent, controlled administration. [ABSTRACT FROM AUTHOR]

Purpose To evaluate local and systemic safety of suprachoroidal (SC) triamcinolone acetonide injectable suspension (CLS-TA) injections in subjects with non-infectious uveitis (NIU). Design Open-label, prospective multicentre safety study. Participants Thirty-eight subjects with NIU, with and without macular oedema (MO). Methods Treatment consisted of two suprachoroidal injections of CLS-TA 4 mg, 12 weeks apart. Best-corrected visual acuity (BCVA), adverse event (AE) assessment, ophthalmic examinations and optical coherence tomography (OCT) were conducted every 4 weeks for 24 weeks. Blood samples were analysed for plasma triamcinolone acetonide (TA) concentrations. Main outcome measures The main outcome measure was frequency of AEs. Other endpoints included plasma TA concentrations, change in signs of inflammation, BCVA and retinal central subfield thickness (CST). Results Based on a CST of >300 µm, 20 out of 38 subjects had MO at baseline. Mean intraocular pressure (IOP) was 13.3 mm Hg at baseline and 15.2 mm Hg at week 24 in the study eye. A total of six (15.8%) subjects had an IOP rise >10 mm Hg compared with baseline, in the study eye, and two (5.3%) subjects had IOP >30 mm Hg (maximum 34 mm Hg at week 8 and 38 mm Hg at week 20). Cataract formation AEs were reported in four study eyes; one of which was deemed treatment-related. No serious ocular AEs in the study eye occurred in the study. Quantifiable post-injection TA plasma concentration was <1 ng/mL. Efficacy parameters showed improvement over the 24-week study period. Conclusions Suprachoroidally administered CLS-TA was safe and well tolerated over the 24-week, open-label study in NIU subjects with and without MO. [ABSTRACT FROM AUTHOR]

Aim: Choroidal perfusion, affected in age related macular degeneration (AMD), is difficult to objectively assess given the overlying retinal circulation. This study more objectively compared choroidal perfusion parameters in a [...]

Background: This post hoc analysis compared the efficacy and safety of suprachoroidally administered triamcinolone acetonide (CLS-TA) to other commonly available treatments for non-infectious uveitis. Methods: Results from the PEACHTREE study were compared between subjects randomised to CLS-TA not requiring rescue therapy and those subjects randomised to control, who subsequently required rescue therapy. Endpoints included best corrected visual acuity (BCVA), central subfield thickness (CST), treatment emergent adverse events and intraocular pressure (IOP) related safety findings. Results: In this analysis, there were 83 unrescued CLS-TA subjects and 46 rescued control subjects. At Week 24, 51.9% of the unrescued CLS-TA subjects gained =15 letters in BCVA, compared to 37.0% of the rescued control subjects (p = 0.115). Unrescued CLS-TA subjects showed a mean gain of 15.7 versus 10.9 letters in rescued control subjects (p = 0.080). A significantly greater mean reduction in CST was observed for unrescued CLS-TA subjects versus rescued control subjects (174.0 and 148.5 µm; p = 0.040). Of unrescued CLSTA subjects, 4.9% experienced IOP elevations =30 mm Hg at any visit versus 10.9% of rescued control subjects. Further, use of IOP-lowering medications appeared lower in unrescued CLS-TA subjects versus rescued control subjects (7.2% vs. 13.0%). There were no IOP-lowering surgical interventions in either group. Conclusion: CLS-TA subjects experienced significantly greater reduction in CST and tended towards greater improvement in BCVA, compared with rescued control subjects. Suprachoroidally administered CLS-TA showed a lower incidence of IOP-related safety findings. [ABSTRACT FROM AUTHOR]

Background/Aims To assess visual acuity (VA) outcomes and antivascular endothelial growth factor (anti-VEGF) therapy intensity in retinal vein occlusion (RVO)-related macular oedema (ME). Methods A retrospective study was completed in treatment-naïve patients with RVO-related ME from 2013 to 2019, using the Vestrum Health Retina Database. Results Mean baseline age was 72.4 years and 54%were women. In 6 months, in 8876 eyes with branch retinal vein occlusion (BRVO)-related ME, after a mean of 4.5 anti-VEGF injections, VA increased by 9.4 letters (95% confidence interval (CI) for change in VA +8.94 to +9.78, p<0.001) from a baseline of 55.1 letters. In 6737 eyes with central retinal vein occlusion (CRVO)-related ME, after a mean of 4.6 anti-VEGF injections over 6 months, VA improved by 9.2 letters (95% CI +8.50 to +9.87, p<0.001) from a baseline of 37.2 letters. In 1 year, VA gain was similar (BRVO: 7.4 injections, +8.1 letters, 95% CI +7.55 to +8.57, p<0.001; CRVO: 7.6 injections, +7.1 letters, 95% CI +6.31 to +7.95, p<0.001). In 6 months and 1 year, mean letters gain increased with number of anti-VEGF injections. Patient eyes with baseline VA of 20/40 or better tended to lose VA in 1 year. Conclusion Mean change in VA correlates with treatment intensity, but patients with better VA at presentation are susceptible to vision loss, reflecting a ceiling effect. Assessed with the same database, VA gains compare favourably with 1-year VA gains in neovascular age-related macular degeneration and diabetic ME, but exhibit a larger gap when compared with corresponding randomised controlled trials. [ABSTRACT FROM AUTHOR]

Therefore, lentiviral, AAV2/5, and dual AAV vectors have been used in I MYO7A i gene augmentation research, which has demonstrated safe and efficacious rescue of RPE and photoreceptor structure and function in I MYO7A i -knockout mice.[[193], [195]] Preclinical trials of the subretinal lentiviral vector-based gene augmentation therapy SAR421869 (Oxford BioMedica) have also demonstrated safety and efficacy in photoreceptor rescue in I MYO7A i -knockout mice and macaques,[196] though a phase I/II clinical trial investigating the safety of this therapy in human subjects was terminated prematurely due to loss of sponsorship. Avoidance of vitamin A may be recommended due to increased risk of retinal toxicity in the context of ABCA4 deficiency.[83] Limiting exposure to all bright light (light deprivation therapy) reduce the production and accumulation of A2E[84] has also shown some promise for slowing disease progression in a small clinical trial.[85] Similarly, several novel pharmaceutical therapies are currently being developed to decrease A2E formation in the visual cycle.[86] Finally, gene augmentation therapies under investigation are discussed below. All 3 Mendelian patterns of inheritance have been described: autosomal recessive (arRP, 50% to 60%), autosomal dominant (adRP, 30% to 40%) and X-linked (xlRP, 10% to 20%).[23] While 3 genes - I RHO i , I USH2A i , and I RPGR - i account for about 30% of all RP cases,[23] a total of 87 individual disease-causing genes have been identified to date,[29] resulting in a broad phenotypic spectrum and complex genotype-phenotype correlations.[30] Most causative genes are expressed exclusively in photoreceptors and affect only the retina. While many therapies have been suggested to slow the progression of disease or address complications, most IRDs remain incurable, and the mainstay of treatment consists of vision rehabilitation and addressing complications. [Extracted from the article]