Suprachoroidally injected pharmacological agents for the treatment of chorio-retinal diseases: a targeted approach

SUPRACHOROIDAL TRIAMCINOLONE ACETONIDE FOR REFRACTORY POSTOPERATIVE CYSTOID MACULAR EDEMA

PURPOSE

To investigate outcomes of suprachoroidal triamcinolone acetonide (XIPERE, Bausch + Lomb) for the treatment of refractory postoperative cystoid macular edema.

METHODS

Medical records of patients receiving suprachoroidal triamcinolone acetonide for postoperative cystoid macular edema were reviewed. Primary outcomes were visual acuity and central foveal thickness.

RESULTS

A total of 32 eyes from 32 patients with a median (interquartile range) follow-up duration of 6 (2-7) months and 1 (1-2) suprachoroidal triamcinolone acetonide injection were included; 19 (59.4%) had a history of vitrectomy. The median (interquartile range) central foveal thickness decreased from 492 (379-629) µm to 267 (187-388) µm at 1 month (P < 0.001), 362 (218-521) µm at 3 months (P = 0.005), and 339 (206-514) µm at the final visit (P < 0.001). The median logarithm of the minimal angle of resolution visual acuity improved from 0.65 (0.48-0.97, 20/89) at baseline to 0.54 (0.35-0.88, 20/69) (P = 0.058) at 1 month, 0.54 (0.33-0.84, 20/69) at 3 months (P = 0.121), and 0.60 (0.33-0.88, 20/80) at the final visit (P = 0.021). Vitrectomized eyes had similar findings. Six eyes (18.8%) developed elevated intraocular pressure (>24 mmHg) (range: 25-49 mmHg) with a median intraocular pressure elevation of 13.5 mmHg compared with baseline, and all had prior glaucoma or ocular hypertension.

CONCLUSION

Suprachoroidal triamcinolone acetonide reduced macular edema and improved vision in refractory postoperative cystoid macular edema, including vitrectomized eyes. Intraocular pressure should be monitored, especially in those with a history of glaucoma or ocular hypertension.

Long-acting delivery and therapies for neovascular age-related macular degeneration

INTRODUCTION

Neovascular age-related macular degeneration (nAMD) represents a leading cause of severe visual impairment in individuals over 50 years of age in developed nations. Intravitreal anti-vascular endothelial growth factor (VEGF) injections have become the standard of care for treating nAMD; however, monthly or bimonthly dosing represents significant time and cost burden due to the disease's chronic nature and limited medication half-life.

AREAS COVERED

This review summarizes innovative therapeutics and delivery methods for nAMD. Emerging methods for extended drug delivery include high molar concentration anti-VEGF drugs, intravitreal sustained-release polymers and devices, reservoirs for intravitreal delivery, suprachoroidal delivery of small molecular suspensions and gene therapy biofactories. In addition to VEGF-A, therapies targeting inhibition of VEGF-C and D, the angiopoetin-2 (Ang-2)/Tie-2 pathway, tyrosine kinases, and integrins are reviewed.

EXPERT OPINION

The evolving therapeutic landscape of nAMD is rapidly expanding our toolkit for effective and durable treatment. Recent FDA approvals of faricimab (Vabysmo) and high-dose aflibercept (Eylea HD) for nAMD with potential extension of injection intervals up to four months have been promising developments for patients and providers alike. Further research and innovation, including novel delivery techniques and pharmacologic targets, is necessary to validate the efficacy of developing therapeutics and characterize real-world outcomes, demonstrating promise in expanding treatment durability.

Effectiveness of Suprachoroidal Injection of Triamcinolone Acetonide in Diabetic Macular Edema Following Pars Plana Vitrectomy Using a Modified Custom Microneedle

Purpose

The present study evaluated the efficacy of suprachoroidal injection of Triamcinolone Acetonide (SCTA) in diabetic macular edema (DME) following pars plana vitrectomy (PPV) using a modified microneedle.

Patients and methods

A prospective interventional study was conducted on 60 eyes of 60 patients with centrally involved diabetic macular edema following pars plana vitrectomy (PPV). SCTA was performed at the baseline and repeated after 3 months in case of persistent subretinal or intraretinal fluid, central macular thickness (CMT) more than 300 µm or visual loss by more than one line of the Snellen chart.

Results

The present study detected significant reduction of the CMT from 498.3 ± 94.8 µm at the baseline to 212.3 ± 11.9 µm after 12 months of injection with p < 0.001 and a significant improvement of best corrected visual acuity (BCVA) from 1 (0.9-1.2) at the baseline to 0.5 (0.3-0.7) after 12 months of injection with p < 0.001. The intraocular pressure (IOP) increased significantly after 3 months of injection with p < 0.001 and then gradually declined to its normal level after 6 months. Inner segment/outer segment (IS/OS) disruption was the only significant predictor of the final CMT; however, the number of injections, IS/OS disruption, baseline BCVA and the HbA1C level were the significant predictors of the final BCVA after injection.

Conclusion

Suprachoroidal injection of TA using this microneedle resulted in significant anatomical and functional improvement in previously vitrectomized diabetic macular edema patients with no recorded ocular or systemic adverse events.

Advances in ophthalmic therapeutic delivery: A comprehensive overview of present and future directions

Ophthalmic treatment demands precision and consistency in delivering therapeutic agents over extended periods to address many conditions, from common eye disorders to complex diseases. This diversity necessitates a range of delivery strategies, each tailored to specific needs. We delve into various delivery cargos that are pivotal in ophthalmic care. These cargos encompass biodegradable implants that gradually release medication, nonbiodegradable implants for sustained drug delivery, refillable tools allowing flexibility in treatment, hydrogels capable of retaining substances while maintaining ocular comfort, and advanced nanotechnology devices that precisely target eye tissues. Within each cargo category, we explore cutting-edge research-level approaches and FDA-approved methods, providing a thorough overview of the current state of ophthalmic drug delivery. In particular, our focus on nanotechnology reveals the promising potential for gene delivery, cell therapy administration, and the implantation of active devices directly into the retina. These advancements hold the key to more effective, personalized, and minimally- invasive ophthalmic treatments, revolutionizing the field of eye care.

Hollow microneedles for ocular drug delivery

Microneedles (MNs) are micron-sized needles, typically <2 mm in length, arranged either as an array or as single needle. These MNs offer a minimally invasive approach to ocular drug delivery due to their micron size (reducing tissue damage compared to that of hypodermic needles) and overcoming significant barriers in drug administration. While various types of MNs have been extensively researched, significant progress has been made in the use of hollow MNs (HMNs) for ocular drug delivery, specifically through suprachoroidal injections. The suprachoroidal space, situated between the sclera and choroid, has been targeted using optical coherence tomography-guided injections of HMNs for the treatment of uveitis. Unlike other MNs, HMNs can deliver larger volumes of formulations to the eye. This review primarily focuses on the use of HMNs in ocular drug delivery and explores their ocular anatomy and the distribution of formulations following potential HMN administration routes. Additionally, this review focuses on the influence of formulation characteristics (e.g., solution viscosity, particle size), HMN properties (e.g., bore or lumen diameter, MN length), and routes of administration (e.g., periocular transscleral, suprachoroidal, intravitreal) on the ocular distribution of drugs. Overall, this paper highlights the distinctive properties of HMNs, which make them a promising technology for improving drug delivery efficiency, precision, and patient outcomes in the treatment of ocular diseases.

Age-related macular degeneration: suitability of optogenetic therapy for geographic atrophy

Age-related macular degeneration (AMD) is a growing public health concern given the aging population and it is the leading cause of blindness in developed countries, affecting individuals over the age of 55 years. AMD affects the retinal pigment epithelium (RPE) and Bruch's membrane in the macula, leading to secondary photoreceptor degeneration and eventual loss of central vision. Late AMD is divided into two forms: neovascular AMD and geographic atrophy (GA). GA accounts for around 60% of late AMD and has been the most challenging subtype to treat. Recent advances include approval of new intravitreally administered therapeutics, pegcetacoplan (Syfovre) and avacincaptad pegol (Iveric Bio), which target complement factors C3 and C5, respectively, which slow down the rate of enlargement of the area of atrophy. However, there is currently no treatment to reverse the central vision loss associated with GA. Optogenetics may provide a strategy for rescuing visual function in GA by imparting light-sensitivity to the surviving inner retina (i.e., retinal ganglion cells or bipolar cells). It takes advantage of residual inner retinal architecture to transmit visual stimuli along the visual pathway, while a wide range of photosensitive proteins are available for consideration. Herein, we review the anatomical changes in GA, discuss the suitability of optogenetic therapeutic sensors in different target cells in pre-clinical models, and consider the advantages and disadvantages of different routes of administration of therapeutic vectors.

SUPRACHOROIDAL SPACE INJECTION TECHNIQUE: Expert Panel Guidance

PURPOSE

To develop professional guidelines for best practices for suprachoroidal space (SCS) injection, an innovative technique for retinal therapeutic delivery, based on current published evidence and clinical experience.

METHODS

A panel of expert ophthalmologists reviewed current published evidence and clinical experience during a live working group meeting to define points of consensus and key clinical considerations to inform the development of guidelines for in-office SCS injection.

RESULTS

Core consensus guidelines for in-office SCS injection were reached and reported by the expert panel. Current clinical evidence and physician experience supported SCS injection as a safe and effective method for delivering retinal and choroidal therapeutics. The panel established consensus on the rationale for SCS injection, including potential benefits relative to other intraocular delivery methods and current best practices in patient preparation, pre- and peri-injection management, SCS-specific injection techniques, and postinjection management and follow-up.

CONCLUSION

These expert panel guidelines may support and promote standardization of SCS injection technique, with the goal of optimizing patient safety and outcomes. Some aspects of the procedure may reasonably be modified based on the clinical setting and physician judgment, as well as additional study.

Gene therapy for age-related macular degeneration: potential, feasibility, and pitfalls

PURPOSE OF REVIEW

The landscape for age-related macular degeneration (AMD) is rapidly changing with addition of biosimilars and now United States Food and Drug Administration (FDA) approved nonneovascular AMD (nnAMD) treatment options. These developments have inspired a burgeoning pipeline of gene therapy approaches focused on similar antivascular endothelial growth factors (VEGF) and complement related pathways. Historic and more recent setbacks in the gene therapy pipeline, including intraocular inflammatory reactions, have raised important concerns for adverse events related to AMD therapeutics both for gene and nongene approaches. The specific clinical profile of these therapeutics approaching later stage clinical trials are complex and under active investigation; however, these options hold promise to disrupt the current landscape and change management paradigms for one of the leading causes of vision loss worldwide.

RECENT FINDINGS

This review covers current gene therapy approaches for neovascular AMD (nAMD) and nnAMD. Intravitreal, suprachoroidal, and subretinal delivery routes are discussed with attention to technical procedure, capabilities for transgene delivery to target tissue, immunogenicity, and collateral effects. Suprachoroidal delivery is an emerging approach which may bridge some of the practical drawbacks for intravitreal and subretinal methods, though with less elaborated immunologic profile. In parallel to delivery modification, viral vectors have been cultivated to target specific cells, with promising enhancements in adeno-associated viral (AAV) vectors and persistent interest in alternate viral and nonviral delivery vectors. Ongoing questions such as steroid or immunosuppressive regimen and economic considerations from a payer and societal perspective are discussed.

SUMMARY

The present review discusses emerging gene therapy options which could foster new, more durable nAMD and nnAMD therapeutics. These options will need refinement with regards to route, vector, and dosage, and specialists must decipher the specific clinical risk benefit profile for individual patients. Ongoing concerns for immunogenicity or dosage related adverse events could stifle progress, while further vector development and refined delivery techniques have the potential to change the safety and efficacy of currently options in the pipeline.

Light-responsive polymeric nanoparticles for retinal drug delivery: design cues, challenges and future perspectives

A multitude of sight-threatening retinal diseases, affecting hundreds of millions around the globe, lack effective pharmacological treatments due to ocular barriers and common drug delivery limitations. Polymeric nanoparticles (PNPs) are versatile drug carriers with sustained drug release profiles and tunable physicochemical properties which have been explored for ocular drug delivery to both anterior and posterior ocular tissues. PNPs can incorporate a wide range of drugs and overcome the challenges of conventional retinal drug delivery. Moreover, PNPs can be engineered to respond to specific stimuli such as ultraviolet, visible, or near-infrared light, and allow precise spatiotemporal control of the drug release, enabling tailored treatment regimens and reducing the number of required administrations. The objective of this study is to emphasize the therapeutic potential of light-triggered drug-loaded polymeric nanoparticles to treat retinal diseases through an exploration of ocular pathologies, challenges in drug delivery, current production methodologies and recent applications. Despite challenges, light-responsive PNPs hold the promise of substantially enhancing the treatment landscape for ocular diseases, aiming for an improved quality of life for patients.

Recent advances in uveitis therapy: focus on selected phase 2 and 3 clinical trials

INTRODUCTION

Uveitis is a heterogeneous group of ocular conditions characterized by inflammation of the uveal tract. It is a leading cause of blindness in developed countries and exerts significant psychological, social, and economic impact on both patients and the larger society. While there are numerous pharmacotherapy options, posterior segment noninfectious uveitis remains a significant challenge to treat due to its severity, chronicity, and high recurrence rates.

AREAS COVERED

The index review highlights the unmet needs of uveitis pharmacotherapy and its research and the shortcomings of existing ocular and systemic therapeutic options for noninfectious uveitis. The more promising novel ocular drug delivery methods and therapeutic targets/drugs are discussed, and evidence from the clinical trials is evaluated.

EXPERT OPINION

There has been incredible growth in the number of treatment options available to uveitis patients today, especially with the new generation of biologic drugs. Available evidence suggests that these newer options may be superior to conventional immunosuppressive therapies in terms of efficacy and side effect profiles. Further high-quality research and additional clinical trials will be needed to clarify their roles in the stepladder treatment approach of noninfectious uveitis.

A review of emerging tyrosine kinase inhibitors as durable treatment of neovascular age-related macular degeneration

INTRODUCTION

Current treatment for age-related macular degeneration poses a large burden on patients and the inability of patients to adhere to this immense burden can lead to worse visual outcomes. Novel treatments have been proposed to extend treatment intervals and reduce visit burden.

AREAS COVERED

This review article summarizes phase I and phase II clinical trials of tyrosine kinase inhibitors as durable treatment options for patient with neovascular age-related macular degeneration.

EXPERT OPINION

Tyrosine kinase inhibitors have shown substantial promise in reducing treatment burden while maintaining visual acuity and anatomic outcomes with favorable safety profiles. Several platforms have shown positive outcomes in initial trials and are currently moving toward phase III clinical trials.

Suprachoroidal CLS-TA with and without Systemic Corticosteroid and/or Steroid-Sparing Therapy: A Post-Hoc Analysis of the Phase 3 PEACHTREE Clinical Trial

PURPOSE

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).

METHODS

Post hoc analysis of the PEACHTREE phase 3 randomized trial.

RESULTS

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.

CONCLUSIONS

A clinically meaningful benefit of CLS-TA was noted in UME patients, regardless of concurrent ST usage.Abbreviation and AcronymsCST = 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.

Microneedles for advanced ocular drug delivery

In the field of ocular drug delivery, topical delivery remains the most common treatment option for managing anterior segment diseases, whileintraocular injectionsare the current gold standard treatment option for treating posterior segment diseases. Nonetheless, topical eye drops are associated with low bioavailability (<5%), and theintravitreal administration procedure is highly invasive, yielding poor patient acceptability. In both cases, frequent administration is currently required. As a result, there is a clear unmet need for sustained drug delivery to the eye, particularly in a manner that can be localised. Microneedles, which are patches containing an array of micron-scale needles (<1 mm), have the potential to meet this need. These platforms can enable localised drug delivery to the eye while enhancing penetration of drug molecules through key ocular barriers, thereby improving overall therapeutic outcomes. Moreover, the minimally invasive manner in which microneedles are applied could provide significant advantages over traditional intravitreal injections regarding patient acceptability. Considering the benefitsofthis novel ocular delivery system, this review provides an in-depth overviewofthe microneedle systems for ocular drug delivery, including the types of microneedles used and therapeutics delivered. Notably, we outline and discuss the current challenges associated with the clinical translation of these platforms and offer opinions on factors which should be considered to improve such transition from lab to clinic.

Suprachoroidal Injection: A Novel Approach for Targeted Drug Delivery

Treating posterior segment and retinal diseases poses challenges due to the complex structures in the eye that act as robust barriers, limiting medication delivery and bioavailability. This necessitates frequent dosing, typically via eye drops or intravitreal injections, to manage diseases, often leading to side effects with long-term use. Suprachoroidal injection is a novel approach for targeted drug delivery to the posterior segment. The suprachoroidal space is the region between the sclera and the choroid and provides a potential route for minimally invasive medication delivery. Through a more targeted delivery to the posterior segment, this method offers advantages over other routes of administration, such as higher drug concentrations, increased bioavailability, and prolonged duration of action. Additionally, this approach minimizes the risk of corticosteroid-related adverse events such as cataracts and intraocular pressure elevation via compartmentalization. This review focuses on preclinical and clinical studies published between 2019 and 2023, highlighting the potential of suprachoroidal injection in treating a variety of posterior segment diseases. However, to fully harness its potential, more research is needed to address current challenges and limitations, such as the need for technological advancements, refinement of injection techniques, and consideration of cost and accessibility factors. Future studies exploring its use in conjunction with biotech products, gene therapies, and cell-based therapies can lead to personalized treatments that can revolutionize the field of ophthalmology.

Suprachoroidal Triamcinolone Injection in Posterior Scleritis: A Case Report

Suprachoroidal triamcinolone acetonide (SCS-TA) injections were recently approved to treat macular edema secondary to noninfectious uveitis. However, its use in managing posterior scleritis has not been reported. We report the first case of SCS-TA used in the treatment of posterior scleritis. A 67-year-old woman with posterior scleritis complicated by exudative retinal detachment, diagnosed by spectral-domain optical coherence tomography scan (OCT), presented with pain, decreased vision, and redness in the left eye for 8 months. She was previously prescribed topical prednisolone and oral prednisone with minimal improvement. She also had a history of rheumatoid arthritis treated with multiple systemic immunosuppressive agents. After SCS-TA, the patient's pain resolved and visual acuity improved. OCT demonstrated significant reduction in sclerochoroidal thickening. Via its novel delivery method, SCS-TA may be an effective treatment for posterior scleritis. Further studies are needed to establish long-term efficacy and safety of this treatment modality.

Overcoming Treatment Challenges in Posterior Segment Diseases with Biodegradable Nano-Based Drug Delivery Systems

Posterior segment eye diseases present a challenge in treatment due to the complex structures in the eye that serve as robust static and dynamic barriers, limiting the penetration, residence time, and bioavailability of topical and intraocular medications. This hinders effective treatment and requires frequent dosing, such as the regular use of eye drops or visits to the ophthalmologist for intravitreal injections, to manage the disease. Moreover, the drugs must be biodegradable to minimize toxicity and adverse reactions, as well as small enough to not affect the visual axis. The development of biodegradable nano-based drug delivery systems (DDSs) can be the solution to these challenges. First, they can stay in ocular tissues for longer periods of time, reducing the frequency of drug administration. Second, they can pass through ocular barriers, offering higher bioavailability to targeted tissues that are otherwise inaccessible. Third, they can be made up of polymers that are biodegradable and nanosized. Hence, therapeutic innovations in biodegradable nanosized DDS have been widely explored for ophthalmic drug delivery applications. In this review, we will present a concise overview of DDSs utilized in the treatment of ocular diseases. We will then examine the current therapeutic challenges faced in the management of posterior segment diseases and explore how various types of biodegradable nanocarriers can enhance our therapeutic arsenal. A literature review of the pre-clinical and clinical studies published between 2017 and 2023 was conducted. Through the advances in biodegradable materials, combined with a better understanding of ocular pharmacology, the nano-based DDSs have rapidly evolved, showing great promise to overcome challenges currently encountered by clinicians.

Polymer- and lipid-based nanocarriers for ocular drug delivery: Current status and future perspectives

Ocular diseases seriously affect patients' vision and life quality, with a global morbidity of over 43 million blindness. However, efficient drug delivery to treat ocular diseases, particularly intraocular disorders, remains a huge challenge due to multiple ocular barriers that significantly affect the ultimate therapeutic efficacy of drugs. Recent advances in nanocarrier technology offer a promising opportunity to overcome these barriers by providing enhanced penetration, increased retention, improved solubility, reduced toxicity, prolonged release, and targeted delivery of the loaded drug to the eyes. This review primarily provides an overview of the progress and contemporary applications of nanocarriers, mainly polymer- and lipid-based nanocarriers, in treating various eye diseases, highlighting their value in achieving efficient ocular drug delivery. Additionally, the review covers the ocular barriers and administration routes, as well as the prospective future developments and challenges in the field of nanocarriers for treating ocular diseases.

Suprachoroidal triamcinolone acetonide for the treatment of macular edema associated with retinal vein occlusion: a pilot study

BACKGROUND

Suprachoroidal Drug Delivery has emerged in recent years as a novel promising approach, which may help address the clinical unmet needs in the management of Retinal Vein Occlusion (RVO) associated Macular Edema (ME). In this study, we aim to evaluate the feasibility in regard of the potential efficacy and safety of suprachoroidal injection of Triamcinolone Acetonide (TA) using a microinjector as a mono-treatment of ME due to RVO.

METHODS

This trial included 16 eyes of 16 patients with RVO associated ME presenting to the department of ophthalmology, Al Mouwasat university hospital, Syria. 4 mg of preserved TA was injected suprachoroidally 4 mm away from the inferotemporal limbus using a patient-customized microinjector. After injection, patients were followed after 1 week then monthly for 3 months. Primary outcome measures included the percentage of participants with best-corrected visual acuity (BCVA) gain≥15 letters and increased intraocular pressure (IOP) ≥ 20 mmHg in months 1,2, and 3, secondary measures included mean change from baseline BCVA, central subfield thickness (CST), and IOP through each of the follow-up points in addition to other measures.

RESULTS

After injection, BCVA gain≥15 letters occurred in 68.7, 62.5, 50, 50% of patients at week 1 and through months 1,2 and 3 respectively, the mean BCVA improved significantly by 16.4, 16, 14.4, and 11.9 letters (p-value< 0.0005) at week 1 and months 1,2 and 3 respectively. This visual gain was associated with a significant reduction of CST by 290.94 ± 181.76 (week-1) (p-value< 0.0005), 274.31 ± 184.60 (month-1) (p-value< 0.0005), 183.50 ± 165.61 (month-2) (p-value = 0.006) and 137,75 ± 156.25 μm (month-3) (p-value = 0.038). We reported one case of increased IOP ≥ 20 mmHg in the first month that decreased in the second month. The mean change of IOP readings was not statistically significant, with an increase ranging from 0.75 mmHg after the first week (p-value = 0.09) and 0.5 mmHg after 3 months (p-value = 0.72).

CONCLUSION

This study suggests that suprachoroidal TA could be well tolerated and efficacious as a mono-treatment of RVO associated ME. Future clinical trials are required to confirm its longer-term safety and efficacy and to compare this efficacy with the other therapeutic options.

TRIAL REGISTRATION

This study was retrospectively registered at clinicaltrials.gov (ID: NCT05038072) on 08/09/2021. This article was published as a preprint on 22/06/2022. https://doi.org/10.21203/rs.3.rs-1701105/v1 .

Triamcinolone Acetonide Suprachoroidal Injectable Suspension for Uveitic Macular Edema: Integrated Analysis of Two Phase 3 Studies

INTRODUCTION

Macular edema, a common complication of uveitis, may result in vision loss. The aim of this analysis was to report integrated phase 3 trial data for triamcinolone acetonide injectable suspension for suprachoroidal use (SCS-TA) in the treatment of macular edema secondary to noninfectious uveitis using strict inclusion criteria.

METHODS

This analysis included patients with central subfield thickness (CST) ≥ 300 µm and best-corrected visual acuity (BCVA) of ≥ 5 and ≤ 70 Early Treatment Diabetic Retinopathy Study (ETDRS) letters at both screening and baseline who received ≥ 1 study treatment in either PEACHTREE (randomized, double-masked SCS-TA or sham control) or AZALEA (open-label SCS-TA). Patients received SCS-TA 4.0 mg (0.1 ml of 40 mg/ml) or control at baseline and week 12.

RESULTS

In the SCS-TA group (n = 95), 47.4% of patients gained ≥ 15 ETDRS letters from baseline to week 24 versus 16.7% of patients in the control group (n = 60; P < 0.001). Mean change in BCVA in the SCS-TA group was 9.6 letters at week 4 and 13.9 letters at week 24. CST also improved rapidly in the SCS-TA group (mean change: - 158.4 µm at week 4), with sustained reduction throughout the study (mean change: - 163.9 µm at week 24 versus - 19.3 µm in the control group; P < 0.001). No treatment-related serious adverse events (AEs) were reported. Incidence of AEs pertaining to elevated intraocular pressure was 12.6% and 15.0% in the SCS-TA and control groups, respectively; incidence of cataract formation/worsening AEs was 7.4% and 6.7%, respectively.

CONCLUSION

In this integrated analysis utilizing strict inclusion criteria, SCS-TA was found effective in the treatment of patients with macular edema associated with noninfectious uveitis and was generally well tolerated.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02595398, NCT03097315.

Suprachoroidal injection of triamcinolone acetonide plus intravitreal bevacizumab in diabetic macular edema: a randomized pilot trial

BACKGROUND

To investigate the efficacy of injecting suprachoroidal triamcinolone acetonide (SCTA) plus intravitreal bevacizumab (IVB) into patients with center-involving diabetic macular edema (CI-DME).

METHODS

In this phase 2/3 randomized controlled pilot trial, sixty-six eyes with CI-DME and best-corrected visual acuity (BCVA) of at most 20/50 Snellen chart were randomly assigned into two groups. Monotherapy arm received sham injection plus 3 monthly IVB doses and combination arm received a single dose of SCTA and 3 monthly IVB doses. The mean improvements in BCVA and Central subfield thickness (CST), over the three-month was considered the main efficacy outcomes.

RESULTS

The mean BCVA improvements were obtained respectively as - 0.20 ± 0.20 log [minimum angle of resolution (MAR)] (P = 0.004) and 0.37 ± 0.24 log MAR (P < 0.001) in monotherapy and combination arms [between-group analysis (P = 0.014)]. Significant improvements were also observed in CST (P = 0.019) in the combination arm compared to the other. No adverse events (elevated intraocular pressure, cataract) were observed in any of the study arms.

CONCLUSION

Significant improvements in BCVA and retinal anatomical outcomes demonstrated the additive effects of SCTA to those of anti-vascular endothelial growth factors with no short-term side effects and this combination appears to be a promising option in the management of patients with CI-DME.

TRIAL REGISTRATION

The trial was registered in Iranian Registry of Clinical Trials (IRCT20200314046761N1).

Ocular Injection Techniques for Retinitis Pigmentosa: Intravitreal, Subretinal, and Suprachoroidal

Ocular gene therapy represents an emerging and promising therapeutic approach for the treatment of several of the inherited retinal diseases. Currently, the focus has been to investigate monogenic inherited retinal disorders. Genetic and cellular therapies can be delivered to the eye by various injection techniques, including those that are intravitreal, subretinal, and suprachoroidal. Each of these three delivery methods are discussed with regard to their historical background, indications, surgical steps, and follow-up.

Six-month sustained delivery of anti-VEGF from in-situ forming hydrogel in the suprachoroidal space

Patients with wet age-related macular degeneration (AMD) require intravitreal injections of bevacizumab (Bev) or other drugs, often on a monthly basis, which is a burden on the healthcare system. Here, we developed an in-situ forming hydrogel comprised of Bev and hyaluronic acid (HA) crosslinked with poly(ethylene glycol) diacrylate for slow release of Bev after injection into the suprachoroidal space (SCS) of the eye using a microneedle. Liquid Bev formulations were cleared from SCS within 5 days, even when formulated with high viscosity, unless Bev was conjugated to a high molecular-weight HA (2.6 MDa), which delayed clearance until 1 month. To extend release to 6 months, we synthesized in-situ forming Bev-HA hydrogel initially as a low-viscosity mixture suitable for injection and flow in the SCS to cover a large area extending to the posterior pole of the eye where the macula is located in humans. Within 1 h after injection, Bev and HA were crosslinked, which retained Bev for slow release as the hydrogel biodegraded. In vivo studies in the rabbit eye reported Bev release for >6 months, depending on gel formulation and Bev assay. The in-situ forming Bev-HA hydrogel was well tolerated, as assessed by clinical exam, fundus imaging, histological analysis, and intraocular pressure measurement. We conclude that Bev released from an in-situ forming hydrogel may enable long-acting treatments of AMD and other posterior ocular indications.

Suprachoroidal delivery enables targeting, localization and durability of small molecule suspensions

Drug delivery to the suprachoroidal space (SCS®) has become a clinical reality after the 2021 FDA approval of CLS-TA, a triamcinolone acetonide injectable suspension for suprachoroidal use (XIPERE®), administered via a microneedle-based device, the SCS Microinjector®. Suprachoroidal (SC) delivery facilitates targeting, compartmentalization, and durability of small molecule suspensions, thereby potentially addressing some of the efficacy, safety, and treatment burden limitations of current retinal therapies. Herein, the design features of the SCS Microinjector are reviewed, along with the biomechanics of SC drug delivery. Also presented are preclinical evaluations of SC small molecule suspensions from 4 different therapeutic classes (plasma kallikrein inhibitor, receptor tyrosine kinase inhibitor, corticosteroid, complement factor D inhibitor), highlighting their potential for durability, targeted compartmentalization, and acceptable safety profiles following microinjector-based SC delivery. The clinical evaluations of the safety, tolerability and efficacy of SC delivered triamcinolone further supports potential of SC small molecule suspensions as a clinically viable strategy for the treatment of chorioretinal diseases. Also highlighted are current limitations, key pharmacological considerations, and future opportunities to optimize the SC microinjector platform for safe, effective, and potentially long-acting drug delivery for the treatment of chorioretinal disorders.

Suprachoroidal injection of triamcinolone acetonide using a custom-made needle to treat diabetic macular edema post pars plana vitrectomy: a case series

Objective

Diabetic macular edema (DME), the most common cause of diabetes-related visual impairment, may occur following pars plana vitrectomy (PPV) to manage proliferative diabetic retinopathy complications. This retrospective single-centre case series evaluated the efficacy and safety of injecting 4 mg/0.1 ml triamcinolone into the suprachoroidal space using a custom-made needle to treat DME post PPV.

Methods

Data regarding central macular thickness (CMT) using spectral domain-optical coherence tomography and best-corrected visual acuity (by Snellen chart) at baseline (pre-injection), and at 1, 4, and 8 weeks following injection were analysed, along with intraocular pressure (IOP), cataract progression, and ocular safety.

Results

Eleven eyes in 10 patients received 11 suprachoroidal injections. Vision improvement was noted (0.75 log minimum angle of resolution (MAR) at baseline to 0.40 log MAR after treatment). CMT reduced significantly from 456.45 ± 113.42 μm at baseline to 247.63 ± 53.40 μm at 8 weeks following injection. No rise in IOP, or cataract development in the single treated phakic eye, was observed during 8 weeks of follow-up.

Conclusion

Suprachoroidal injection of triamcinolone using a custom-made needle to treat DME post PPV shows promising results with acceptable safety outcomes. Large clinical trials with longer follow-up are needed to evaluate this treatment option for countries with limited health-care resources.

Suprachoroidal triamcinolone acetonide injection: a novel therapy for serous retinal detachment due to Vogt-Koyanagi Harada disease

PURPOSE

To assess the efficacy and safety of Suprachoroidal triamcinolone acetonide injection [SCTA] as an adjunctive therapy in management of Vogt-Koyanagi Harada [VKH] serous retinal detachment.

DESIGN

Prospective parallel group study.

PARTICIPANTS

12 eyes of 6 patients with bilateral multiple serous retinal detachment of VKH in acute phase on systemic steroids.

METHODS

Each patient was received single SCTA injection (SCTA group, n = 6 eyes) and the other non-injected eye (Standard treatment group, n = 6 eyes), patients were followed for 1, 3, and 6 months to assess changes in best corrected visual acuity [BCVA], central foveal thickness [CFT] and intraocular pressure [IOP] between both groups.

MAIN OUTCOME MEASURES

The primary end point was changes in BCVA from baseline till 6^th months follow-up. Secondary end points were changes in CFT and IOP from baseline to 6 months of follow-up.

RESULTS

BCVA at one and three months was significantly better in eyes received SCTA than in non-injected eyes (p-value = 0.026 for each). CFT at one and three months was significantly higher in non-injected eyes than in eyes received SCTA (p-value = 0.028 for each). IOP showed no significant differences between both groups.

CONCLUSIONS

SCTA is an effective adjuvant treatment for VKH serous retinal detachment, without any serious ocular adverse effects or increase in IOP and causing significant reduction in CFT and rapid improvement in BCVA when combined with oral steroids.

Suprachoroidal versus Intravitreal Triamcinolone Acetonide for the Treatment of Diabetic Macular Edema

Purpose

This article aims to compare between intravitreal (IV) and suprachoroidal (SC) triamcinolone acetonide (TA) injection for the treatment of diabetic macular edema (DME) in terms of improvement in both best-corrected visual acuity (BCVA) and central macular thickness (CMT), and development of complications (intraocular pressure (IOP) rise and cataract progression), and to identify the efficient dose of TA using the SC route.

Patients and Methods

This prospective interventional randomized comparative study included 45 eyes of 32 patients, randomly divided into three groups, group I received 4 mg/0.1 mL intravitreal TA (IVTA), group II received 4 mg/0.1 mL suprachoroidal TA (SCTA), and group III received 2mg/0.1 mL SCTA. Patients were followed up for 6 months.

Results

At 1 month, a maximum reduction in CMT (147.33 ± 110.97 µm, 160.80 ± 98.25 µm and 65.64 ± 46.19 µm in groups I, II, and III, respectively) was observed, which was associated with the greatest improvement of BCVA (0.09 ± 0.09, 0.19 ± 0.10 and 0.10 ± 0.09 logMAR lines) in groups I, II, and III, respectively. At 3 months, CMT started to increase, and reduction was not statistically significant compared to baseline, except in group II (4 mg SCTA group) (149.80 ± 106.57 µm with P-value = 0.013). At 6 months, CMT and BCVA returned close to baseline except for group II which had a sustained reduction of 60.16 µm from baseline. Regarding steroid-related complications, IOP elevation of 10 mmHg or more was noted in 1 eye (6.7%), 2 eyes (13.3%), and 1 eye in groups I, II, and III, respectively. Three phakic eyes per group showed cataract progression.

Conclusion

SCTA is a safe and effective route for the treatment of DME, which has comparable effects to IVTA, and may even last longer.

Safety and Efficacy of Suprachoroidal Injection of Triamcinolone in Treating Macular Edema Secondary to Noninfectious Uveitis

Introduction 

One of the leading causes of blindness throughout the world is uveitis, which predominantly results in the feared complication of macular edema. We report the safety and efficacy of suprachoroidal injection of triamcinolone acetonide in the treatment of macular edema secondary to noninfectious uveitis. 

Methodology 

This prospective, nonrandomized interventional study was conducted at Layton Rahmatullah Benevolent Trust (LRBT) Eye Hospital, Lahore, from August 2019 till July 2020. All individuals older than 18 years, nonpregnant females with a central macular thickness of >320 µm were included. Those patients with uncontrolled diabetes, immunodeficiency, or any other disease mandating systemic corticosteroid use were excluded. All patients had a detailed ocular exam one week before the treatment, and 0.1 ml of triamcinolone acetonide 40 mg/ml was injected using a 30-G hollow needle into the suprachoroidal space. After the injection, an eye patch was applied and the patient was observed for three hours. All data were documented in a preformed proforma. 

Results

A total of 30 patients were included in the study with a mean age of 38.1 ± 9.48 years. Statistically significant differences were found between central macular thickness at presentation and at one and three months of the procedure, i.e., 569.60 ± 170.396, 266.77 ± 73.127, and 208.27 ± 37.292 µm, respectively. A similar difference was observed when comparing visual acuity at baseline to visual acuity at one and three months of the procedure (p < 0.001). 

Conclusion 

The current study indicates that a single dose of suprachoroidal injection of triamcinolone acetonide for the treatment of macular edema secondary to uveitis is safe and efficacious. No rise in intraocular pressure (IOP) was observed during the study period. Significant improvements in central macular thickness and visual acuity as well as tolerability and safety of the treatment were seen in our study. Further larger-scale studies are needed to ascertain the long-term benefits of the suprachoroidal triamcinolone acetonide.

Suprachoroidal CLS-TA versus Rescue Therapies for the Treatment of Uveitic Macular Edema: A Post Hoc Analysis of PEACHTREE

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 CLS‐TA 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.

Cultured Human Uveal Melanocytes Express/secrete CXCL1 and CXCL2 Constitutively and Increased by Lipopolysaccharide via Activation of Toll-like Receptor 4

Purpose: Lipopolysaccharide (LPS) can activate Toll-like receptor 4 (TLR4) and increase the expression of CXCL1 and CXCL2, the potent neutrophils chemoattractants, in various cell types. These effects have not been previously reported in the uveal melanocytes. This study was designed to investigate the effects of LPS on the activation of TLR4 and expression of CXCL1/CXCL2 in cultured human uveal melanocytes and the relevant signal pathways.Methods: Effects of LPS on the expression of TLR4 were tested using real-time PCR, flow cytometry and fluorescence immunostaining. Effects of LPS-induced expression/secretion of CXCL1/CXCL2 were studied using real-time PCR in cell lysates and ELISA in conditioned media of cultured uveal melanocytes. Activated NF-κB and phosphorylated MAPK signals were tested in cells with and without LPS treatment using flow cytometry. Effects of various signal inhibitors on p38, ERK1/2, JNK1/2 and NF-κB on the secretion of CXCL1/CXCL2 were tested by ELISA. The effects of neutralized antibodies of CXCL1/CXCL2 on the severity of LPS-induced uveitis were tested in a mouse model.Results: LPS stimulation increased the expression of TLR4 mRNA and protein in culture uveal melanocytes. Constitutive secretion of CXCL1/CXCL2 was detected in uveal melanocytes and was significantly increased dose- and time-dependently by LPS stimulation. LPS mainly increased the activated NF-κB and phosphorylated JNK1/2. LPS-induced expression of CXCL1/CXCL2 was blocked by NF-κB and JNK1/2 inhibitors. The severity of LPS-induced uveitis was significantly inhibited by neutralizing antibody to CXCL1/CXCL2Conclusions: This is the first report on the LPS-induced expression of CXCL1 and CXCL2 by uveal melanocytes via the activation of TLR4. These results suggest that uveal melanocytes may play a role in the immune reaction that eliminates the invading pathogens. Conversely, an excessive LPS-induced inflammatory reaction may also lead to the development of inflammatory ocular disorders, such as non-infectious uveitis.

Potential of miRNA-Based Nanotherapeutics for Uveal Melanoma

Simple Summary

Human uveal melanoma (UM) is the most common primary intraocular tumor with high metastatic risk in adults. Currently, no effective treatment is available for metastatic UM; therefore, new therapeutic approaches are needed to improve overall survival. Given the increased understanding of microRNAs (miRNAs) and their roles in UM tumorigenesis and metastasis, miRNA-based therapy may offer the hope of improving therapeutic outcomes. This review summarizes the actions of select miRNAs examined in preclinical studies using miRNAs as therapeutic targets in UM. The focus of this review is the application of established nanotechnology-assisted delivery systems to overcome the limitations of therapeutic miRNAs. A blend of therapeutic miRNAs and nanodelivery systems may facilitate the translation of miRNA therapies to clinical settings.

Abstract

Uveal melanoma (UM) is the most common adult intraocular cancer, and metastatic UM remains deadly and incurable. UM is a complex disease associated with the deregulation of numerous genes and redundant intracellular signaling pathways. As understanding of epigenetic dysregulation in the oncogenesis of UM has increased, the abnormal expression of microRNAs (miRNAs) has been found to be an epigenetic mechanism underlying UM tumorigenesis. A growing number of miRNAs are being found to be associated with aberrant signaling pathways in UM, and some have been investigated and functionally characterized in preclinical settings. This review summarizes the miRNAs with promising therapeutic potential for UM treatment, paying special attention to the therapeutic miRNAs (miRNA mimics or inhibitors) used to restore dysregulated miRNAs to their normal levels. However, several physical and physiological limitations associated with therapeutic miRNAs have prevented their translation to cancer therapeutics. With the advent of nanotechnology delivery systems, the development of effective targeted therapies for patients with UM has received great attention. Therefore, this review provides an overview of the use of nanotechnology drug delivery systems, particularly nanocarriers that can be loaded with therapeutic miRNAs for effective delivery into target cells. The development of miRNA-based therapeutics with nanotechnology-based delivery systems may overcome the barriers of therapeutic miRNAs, thereby enabling their translation to therapeutics, enabling more effective targeting of UM cells and consequently improving therapeutic outcomes.

Extension study of the safety and efficacy of CLS-TA for treatment of macular oedema associated with non-infectious uveitis (MAGNOLIA)

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.

First Year Results of Suprachoroidal Adipose Tissue Derived Mesenchymal Stem Cell Implantation in Degenerative Macular Diseases

Background and Objectives

This study shows the clinical data of 1-year follow-up of 8 patients with degenerative macular diseases who received suprachoroidal adipose tissue derived mesenchymal stem cell (ADMSC) implantation.

Methods and Results

This prospective, single-center, phase 1/2 study enrolled 8 eyes of 8 patients with degenerative macular diseases of various reasons who underwent suprachoroidal implantation of ADMSCs. All patients had severe visual field defects and severe visual loss. All patients had defective multifocal electroretinography (mf ERG). The worse eye of the patient was selected for the operation. Patients were evaluated on the first day, first month, sixth month and at 1 year postoperatively. Best corrected visual acuity (BCVA), anterior segment and fundus examination, color photography, optical coherence tomography (OCT) and visual field (VF) examination were carried out at each visit. Fundus fluorescein angiography (FFA) and mfERG recordings were performed at the end of the sixth months. All 8 patients completed the 1 year follow-up. None of them had any systemic or ocular complications. Seven of the patients experienced visual acuity improvement, visual field improvement and improvement in the mfERG recordings. We found choroidal thickening in OCT of the four treated eyes.

Conclusions

Even though the sample size is small, stem cell treatment with suprachoroidal implantation of ADMSCs seems to be safe and the improvements were encouraging. To optimize the cell delivery technique and to evaluate the effects of this therapy on visual acuity and the quality of life of these patients, future studies with larger number of cases will be necessary.

Suprachoroidal Delivery of Small Molecules, Nanoparticles, Gene and Cell Therapies for Ocular Diseases

Suprachoroidal drug delivery technology has advanced rapidly and emerged as a promising administration route for a variety of therapeutic candidates, in order to target multiple ocular diseases, ranging from neovascular age-related macular degeneration to choroidal melanoma. This review summarizes the latest preclinical and clinical progress in suprachoroidal delivery of therapeutic agents, including small molecule suspensions, polymeric entrapped small molecules, gene therapy (viral and nonviral nanoparticles), viral nanoparticle conjugates (VNCs), and cell therapy. Formulation customization is critical in achieving favorable pharmacokinetics, and sustained drug release profiles have been repeatedly observed for multiple small molecule suspensions and polymeric formulations. Novel therapeutic agents such as viral and nonviral gene therapy, as well as VNCs, have demonstrated promise in animal studies. Several of these suprachoroidally-administered therapies have been assessed in clinical trials, including small molecule suspensions of triamcinolone acetonide and axitinib, viral vector RGX-314 for gene therapy, and VNC AU-011. With continued drug delivery research and optimization, coupled with customized drug formulations, suprachoroidal drug delivery may address large unmet therapeutic needs in ophthalmology, targeting affected tissues with novel therapies for efficacy benefits, compartmentalizing therapies away from unaffected tissues for safety benefits, and achieving durability to relieve the treatment burden noted with current agents.

Biomechanics of suprachoroidal drug delivery: From benchtop to clinical investigation in ocular therapies

INTRODUCTION

As research in suprachoroidal drug delivery advances, and therapeutic candidates, ranging from small molecule suspensions to gene therapy, progress through clinical trials, an understanding of  suprachoroidal space (SCS) biomechanics assumes increasing importance.Areas covered:Numerous anatomic features play an important role in therapeutic access to the SCS. Methods of access include a catheter, a standard hypodermic needle, and a microinjector with microneedle. Physical and fluidic properties of injectates into the SCS, such as volume, viscosity, particle size, osmotic pressure, and ionic charge of formulation can impact the spread and extent of opening of the SCS. Pharmacokinetic data of several small molecule suspensions yielded favorable ocular distribution and pharmacokinetic profiles. Phase 2 and 3 clinical trials have been completed with a suprachoroidally injected corticosteroid; results and information on procedural details with the microinjector are discussed.

EXPERT OPINION

Suprachoroidal drug delivery has been demonstrated to be a reliable and consistent drug delivery method for targeted treatment of retinal and choroidal disorders to potentially maximize efficacy, while compartmentalizing therapies away from the unaffected tissues to potentially enhance safety. These delivery attributes, along with fluid transport properties and formula customization for pharmacological agents, may allow for more tailored treatment of diseases affecting chorio-retinal tissues.

A Review of Local Therapy for the Management of Cystoid Macular Edema in Uveitis

ABSTRACT

Uveitic macular edema is a significant cause of visual impairment in most uveitis types. Treatment options of uveitis have advanced remarkably in recent years. Up to now, corticosteroids remain the mainstay of treatment. Nonsteroidal immunomodulators, and recently the biologic agents, which can reinforce efficacy and enable discontinuation or reduction of steroids to maintenance doses, are becoming increasingly popular in the management of uveitic macular edema. Several medications can be used in intraocular delivery and more and more sustained releasing implants are being developed. This review will briefly focus on the review of local therapy for the management of cystoid macular edema in uveitis, as many of these novel approaches are currently being evaluated in clinical trials.

Drug-Free, Nonsurgical Reduction of Intraocular Pressure for Four Months after Suprachoroidal Injection of Hyaluronic Acid Hydrogel

Glaucoma is the leading cause of irreversible blindness. Current treatments use drugs or surgery to reduce intraocular pressure (IOP). In this study, a drug-free, nonsurgical method is developed that lowers IOP for 4 months without requiring daily patient adherence. The approach involves expanding the suprachoroidal space (SCS) of the eye with an in situ-forming hydrogel injected using a microneedle. This study tests the hypothesis that SCS expansion increases the drainage of aqueous humor from the eye via the unconventional pathway, which thereby lowers IOP. SCS injection of a commercial hyaluronic acid (HA) hydrogel reduces the IOP of normotensive rabbits for more than 1 month and an optimized HA hydrogel formulation enables IOP reduction for 4 months. Safety assessment by clinical ophthalmic examinations indicate the treatment is well tolerated. Histopathology shows minor hemorrhage and fibrosis at the site of injection. Further analysis by ultrasound biomicroscopy demonstrates a strong correlation of IOP reduction with SCS expansion. Outflow facility measurements show no difference in pressure-dependent outflow by the conventional pathway between treated and untreated eyes, supporting the hypothesis. In conclusion, SCS expansion with an in situ-forming hydrogel can enable extended IOP reduction for treating ocular hypertension and glaucoma without drugs or surgery.

Associations between the Complement System and Choroidal Neovascularization in Wet Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness affecting the elderly in the Western world. The most severe form of AMD, wet AMD (wAMD), is characterized by choroidal neovascularization (CNV) and acute vision loss. The current treatment for these patients comprises monthly intravitreal injections of anti-vascular endothelial growth factor (VEGF) antibodies, but this treatment is expensive, uncomfortable for the patient, and only effective in some individuals. AMD is a complex disease that has strong associations with the complement system. All three initiating complement pathways may be relevant in CNV formation, but most evidence indicates a major role for the alternative pathway (AP) and for the terminal complement complex, as well as certain complement peptides generated upon complement activation. Since the complement system is associated with AMD and CNV, a complement inhibitor may be a therapeutic option for patients with wAMD. The aim of this review is to (i) reflect on the possible complement targets in the context of wAMD pathology, (ii) investigate the results of prior clinical trials with complement inhibitors for wAMD patients, and (iii) outline important considerations when developing a future strategy for the treatment of wAMD.

Suprachoroidally Delivered DNA Nanoparticles Transfect Retina and Retinal Pigment Epithelium/Choroid in Rabbits

Purpose

This study evaluated ocular tolerability and transfectability of nonviral DNA nanoparticles (DNPs) after microneedle-based suprachoroidal (SC) administration, in comparison to subretinal (SR) administration.

Methods

The DNPs consisted of a single copy of plasmid DNA with a polyubiquitin C/luciferase transcriptional cassette compacted with 10 kDa PEG-substituted lysine 30-mer peptides (CK30PEG10k). New Zealand White rabbits (n = 4 per group) received a unilateral SC injection (0.1 mL via a microneedle technique) of ellipsoid-shaped DNPs, rod-shaped DNPs, or saline (negative control). A cohort of rabbits (n = 4) also received a single unilateral SR injection (0.05 mL via a transvitreal approach) of rod-shaped DNPs. At day 7, luciferase activity was measured in the retina and retinal pigment epithelium (RPE)–choroid via bioluminescence assay. A cohort of rabbits received a SC injection of analogous DNPs to assess spread of DNP injectate in the suprachoroidal space (SCS) via optical coherent tomography and histology.

Results

Suprachoroidal injection of DNPs resulted in reversible opening of the SCS circumferentially and posteriorly and was generally well tolerated, with no significant ocular examination score changes, intraocular pressure abnormalities, or changes in electroretinography amplitudes on day 7 compared to the baseline. High luciferase activity was observed in the retina and RPE-choroid of eyes that received SC DNPs (rod and ellipsoid shape) and SR DNPs (rod shape) compared to controls. The mean luciferase activity in RPE-choroid and retina was comparable between SC and SR administrations. Transfection in the RPE-choroid was approximately 10-fold higher than in the retina after either SC or SR administration of DNPs.

Conclusions

Suprachoroidal and SR administration of DNPs resulted in comparable transfection of retina and RPE-choroid.

Translational Relevance

Suprachoroidal delivery of DNPs offers the potential to precisely target chorioretinal tissues while avoiding surgical risks associated with SR injection, and it may offer an office-based nonsurgical gene therapy option for the treatment of retinal diseases.

Dexamethasone delivery to the ocular posterior segment by sustained-release Laponite formulation

This paper presents a novel nanoformulation for sustained-release delivery of dexamethasone (DEX) to the ocular posterior segment using a Laponite (LAP) carrier-DEX/LAP 1:10 w w^-1 formulation; 10 mg ml^-1. In vivo ocular feasibility and pharmacokinetics after intravitreal (IV) and suprachoroidal (SC) administration in rabbit eyes are compared against IV administration of a DEX solution (1 mg ml^-1). Thirty rabbit eyes were injected with the DEX/LAP formulation (15 suprachoroid/15 intravitreous). Ophthalmological signs were monitored at day 1 and at weeks 1-4-12-24 post-administration. Three eyes per sample time point were used to quantify DEX concentration using high-performance liquid chromatography-mass spectrometry. The ocular tissues' pharmacokinetic parameters (lens, vitreous humour, choroid-retina unit and sclera) were studied. DEX/LAP was well tolerated under both administration methods. Peak intraocular DEX levels from the DEX/LAP were detected in the vitreous humour after both deliveries soon after administration. The vitreous area under the curve was significantly greater after both DEX/LAP deliveries (IV: 205 968.47; SC: 11 442.22 ng g^-1 d^-1) than after IV administration of the DEX solution (317.17 ng g^-1 d^-1). Intravitreal DEX/LAP delivery extended higher vitreous DEX levels up to week 24 (466.32 ± 311.15 ng g^-1). With SC delivery, DEX levels were detectable in the choroid-retina unit (12.04 ± 20.85 ng g^-1) and sclera (25.46 ± 44.09 ng g^-1) up to week 24. This study demonstrated the intraocular feasibility of both SC and IV administration of the DEX/LAP formulation. The LAP increased the intraocular retention time of DEX when compared with conventional solutions. DEX/LAP could be considered a biocompatible and useful sustained-release formulation for treating posterior-pole eye diseases.

Clinical Characterization of Suprachoroidal Injection Procedure Utilizing a Microinjector across Three Retinal Disorders

Purpose

This study assessed physician-investigator experience with suprachoroidal (SC) injections, an investigational therapeutic administration technique using a 900 or 1100 µm microneedle to inject drugs into the SC space.

Methods

Datasets from six clinical trials across three diseases (noninfectious uveitis; diabetic macula edema, and retinal vein occlusion) were assessed. In addition to a user survey, retrospective correlations were performed between procedural variables (needle length), and demographics, and ocular characteristics.

Results

In the user survey, 84% (31/37) of physician-investigators did not perceive the SC injections to be meaningfully more challenging than other ocular injections. For the correlation analysis, the 900 µm needle was used for 71% (412/581) of baseline injections, and switching to the longer needle occured in the remaining 29% of baseline injections. No statistical correlations were found between needle lengths and age, race, disorder, refraction, visual acuity, intraocular pressure, retinal central subfield thickness, or lens status. Patient gender and needle length were statistically associated, with 76% (210/275) versus 66% (202/306) of injections administered with 900 µm needles for female and male gender, respectively. Injection quadrant correlated to needle length with 78% (214/275) of superotemporal quadrant injections administered with 900 µm needles, compared with 65% (73/113) of inferotemporal quadrant injections.

Conclusions

Both the user survey and the correlation analysis demonstrated that SC injection is well accepted by physician-investigators, and the two needle lengths accommodate a wide range of anatomic and demographic variables.

Translational Relevance

These results, along with the presented ex-vivo endoscopic imaging, suggest that SC injection could be readily adopted in clinical practice for targeted compartmentalized delivery of ocular therapeutics.

Retinal Tropism and Transduction of Adeno-Associated Virus Varies by Serotype and Route of Delivery (Intravitreal, Subretinal, or Suprachoroidal) in Rats

Viral-mediated gene augmentation offers tremendous promise for the treatment of inherited retinal diseases. The development of effective gene therapy requires an understanding of the vector's tissue-specific behavior, which may vary depending on serotype, route of delivery, or target species. Using an ex vivo organotypic explant system, we previously demonstrated that retinal tropism and transduction of adeno-associated virus type 2 (AAV2) vary significantly depending on serotype in human eyes. However, the ex vivo system has limited ability to assess route of ocular delivery, and relatively little literature exists on tropic differences between serotypes and routes of delivery in vivo. In this study, we demonstrate that retinal tropism and transduction efficiency of five different AAV2 serotypes (AAV2/1, AAV2/2, AAV2/6, AAV2/8, and AAV2/9) expressing enhanced green fluorescent protein driven by a cytomegalovirus promoter vary greatly depending on serotype and route of delivery (intravitreal, subretinal, or suprachoroidal) in rats. With subretinal delivery, all serotypes successfully transduced the retinal pigmented epithelium and outer nuclear layer (ONL), with AAV2/1 displaying the highest transduction efficiency and AAV2/2 and AAV2/6 showing lower ONL transduction. There was minimal transduction of the inner retina through subretinal delivery for any serotype. Tropism by suprachoroidal delivery mirrored that of subretinal delivery for all AAV serotypes but resulted in a wider distribution and greater ONL transduction. With intravitreal delivery, retinal transduction was seen primarily in the inner retina (retinal nerve fiber, ganglion cell, and inner nuclear layers) for AAV2/1 and AAV2/6, with AAV2/6 showing the highest transduction. When compared with data from human explant models, there are substantial differences in tropism and transduction that are important to consider when using rats as preclinical models for the development of ocular gene therapies for humans.

Suprachoroidal CLS-TA plus Intravitreal Aflibercept for Diabetic Macular Edema: A Randomized, Double-Masked, Parallel-Design, Controlled Study

PURPOSE

This study evaluated the potential safety, efficacy, and durability advantages of investigational triamcinolone acetonide suspension (CLS-TA; Clearside Biomedical, Alpharetta, GA) administered suprachoroidally in conjunction with intravitreal aflibercept compared with aflibercept monotherapy for treatment of diabetic macular edema (DME).

DESIGN

TYBEE was a prospective, controlled, double-masked study. Patients were randomized 1:1 to CLS-TA and aflibercept (active) or aflibercept monotherapy (control), and assessed over 24 weeks.

PARTICIPANTS

Treatment-naive DME patients with best-corrected visual acuity (BCVA) of 20 to 70 letters and central subfield retinal thickness (CST) of more than 300 μm.

METHODS

Patients in the active group (n = 36) received CLS-TA and aflibercept at baseline and week 12. Patients in the control group (n = 35) received aflibercept at baseline, week 4, week 8, and week 12. To mask both groups, sham suprachoroidal and intravitreal injections were utilized. All patients were eligible to receive aflibercept as needed at weeks 4, 8, 16, and 20 per prespecified criteria.

MAIN OUTCOME MEASURE

Mean change in BCVA from baseline. Treatment differences were assessed with a 2-sided significance level of 0.10.

RESULTS

Mean BCVA changes from baseline to week 24 were not statistically different in the active and control groups (intention-to-treat [ITT] population: +11.4 letters and +13.8 letters [P = 0.288]; per protocol [PP] population: +12.3 letters and +13.5 letters [P = 0.664]; respectively). Greater improvement in CST was seen in the active versus control group (ITT population: -212.1 μm and -178.6 μm [P = 0.089]; PP population: -226.5 μm and -176.1 μm [P = 0.035]; respectively). Compared with the control group, eyes in the active group received fewer treatments (scheduled plus as-needed treatments averaging 4.6 versus 2.6, respectively). No treatment-related serious adverse events were observed. Ocular adverse events were low for both arms. Cataract events, all assessed as unrelated to treatment, and events of elevated intraocular pressure trended higher in the active group.

CONCLUSIONS

CLS-TA administered suprachoroidally in conjunction with intravitreal aflibercept for treatment of DME provides simliar visual benefit at 24 weeks' follow-up compared with aflibercept monotherapy, is well tolerated and shows modest anatomic benefit with potential to reduce treatment burden.

Intractable Ocular Diseases and Treatment Progress

In recent years, with the aging of the population and the frequent use of electronic devices, many eye diseases have shown a linear upward trend, such as dry eye disease, glaucoma, cataract, age-related macular degeneration, and diabetic retinopathy. These diseases are often chronic and difficult to cure. Based on the structure and barrier of the human eye, this review describes the pathogenesis and treatments of several intractable eye diseases and summarizes the advanced ocular drug delivery systems to provide new treatment ideas for these diseases. Finally, we also look forward to the prospect of RNAi therapy in the treatment of eye diseases.

Gene therapy for neovascular age-related macular degeneration: rationale, clinical trials and future directions

Age-related macular degeneration (AMD) is one of the leading causes of irreversible blindness in the developed world. Antivascular endothelial growth factor therapy has transformed the management and outcome of neovascular AMD (nAMD), although the need for repeated intravitreal injections—even lifelong—and the related complications, high drug costs, frequent clinic visits and repeated imaging have resulted in an enormous burden both to healthcare systems and patients. The application of gene therapy approaches for sustained delivery of a range of antiangiogenic proteins has the promise of helping to address these aforementioned challenges. A number of early phase clinical trials of gene therapy in nAMD have provided encouraging results, with many more ongoing or anticipated. There remain significant areas of controversy, including regarding the optimal treatment targets, routes of administration and potential safety concerns. In this review we aim to provide an update of the current status of gene therapy for nAMD and briefly discuss future prospects.

Efficacy and safety of Suprachoroidal Triamcinolone Acetonide in cases of resistant diabetic Macular Edema

Objective

To evaluate the safety and efficacy of Suprachoroidal Triamcinolone Acetonide (SCTA) injection in patients with treatment resistant Diabetic Macular Edema (DME).

Methods

This was a prospective non randomized interventional study conducted in the vitreoretinal department of Al Ehsan Welfare Eye Hospital, Lahore, Pakistan from March 2018 to September 2018. A total of 24 eyes of 24 patients were included. Baseline Best Corrected Visual Acuity (BCVA), Intra Ocular Pressure (IOP) and Central Subfield Thickness (CST) was recorded. After SCTA, patient was followed up at one and three months and same clinical parameters were recorded again and results analyzed.

Results

Out of 24 patients, 11(45.83%) were males and 13(54.16%) were females. Mean pre injection CST was 636.5 ± 200.11 um. Mean pre injection BCVA was 0.8 ± 0.24 on ETDRS chart. Mean post injection CST at one and three months was 304.54 ± 67.43 and 302.66 ± 66.93 um. Mean post injection BCVA at one and three months was 0.47 ± 0.3 and 0.45 ± 0.27 on ETDRS chart. The results were statistically significant for pre and post injection CST at both one and three months (p-value < 0.00001). Pre and post injection BCVA was also statistically significant (p-value < 0.05).

Conclusion

Preliminary evidence suggests that SCTA is well tolerated and may help in improving functional and structural outcomes of treatment resistant DME.

Efficacy and Safety of Suprachoroidal CLS-TA for Macular Edema Secondary to Noninfectious Uveitis: Phase 3 Randomized Trial

PURPOSE

Injection of pharmacotherapy into the suprachoroidal space, between the sclera and choroid, is an alternative delivery technique developed with the rationale of providing higher drug concentrations to posterior ocular structures compared with other intraocular and periocular injection procedures. This study was conducted to evaluate the safety and efficacy of suprachoroidally injected triamcinolone acetonide formulation (CLS-TA), a suspension of triamcinolone acetonide, in improving vision among patients with noninfectious uveitis complicated by macular edema (ME).

DESIGN

Phase 3 masked, randomized trial.

PARTICIPANTS

One hundred sixty patients with ME secondary to noninfectious uveitis. Patients were required to have a best-corrected visual acuity (BCVA) of 5 or more Early Treatment Diabetic Retinopathy Study (ETDRS) letters (Snellen equivalent, 20/800) and 70 or fewer ETDRS letters read (Snellen equivalent, 20/40) in the study eye.

METHODS

Patients were randomized 3:2 to suprachoroidally injected CLS-TA or sham treatment, with administrations at day 0 and week 12.

MAIN OUTCOME MEASURES

The primary end point was improvement from baseline of 15 or more ETDRS letters in BCVA at week 24. The secondary end point was reduction from baseline in central subfield thickness (CST) at week 24.

RESULTS

In the CLS-TA arm, 47% of patients gained 15 or more ETDRS letters in BCVA versus 16% in the control arm (P < 0.001), meeting the primary end point. Mean reductions in CST from baseline were 153 μm versus 18 μm (P < 0.001). No serious adverse events (AEs) related to treatment were reported. Corticosteroid-associated AEs of elevated intraocular pressure occurred in 11.5% and 15.6% of the CLS-TA and control groups, respectively. Cataract AE rates were comparable (7.3% and 6.3%, respectively).

CONCLUSIONS

Patients in the CLS-TA study arm experienced clinically significant improvement in vision relative to the sham procedure, demonstrating the efficacy of suprachoroidal injection of CLS-TA for the treatment of ME in a vision-threatening disorder.

Collagenase injection into the suprachoroidal space of the eye to expand drug delivery coverage and increase posterior drug targeting

Injection into the suprachoroidal space (SCS) allows drug delivery targeted to sclera, choroid, and retina. Here, we studied SCS injection formulated with collagenase to expand drug delivery coverage and increase posterior drug targeting within SCS by breaking down collagen fibrils that link sclera and choroid in the SCS. When 1 μm latex microparticles were injected with a collagenase formulation using microneedles into the SCS of rabbit eyes ex vivo and incubated at 37 °C for 4 h, microparticle delivery coverage increased from 20% to 45% and enhanced posterior drug targeting. Collagenase concentration was optimized to 0.5 mg/mL to maximize expanded posterior delivery and minimize tissue damage. Effects of collagenase injection within SCS increased and then plateaued 4 h after injection. Simultaneous injection of collagenase and microparticles had a greater effect on expanded delivery in the SCS compared to sequential injection. Collagenase injection into the SCS of rabbit eyes in vivo was also effective to expand delivery and was generally well-tolerated, showing transiently lowered IOP, but no apparent lasting adverse effects on ocular tissues such as sclera, choroid, and retina, as determined by analyzing histology, sclera tensile strength, and fundus imaging. We conclude that addition of collagenase during SCS injection can expand drug delivery coverage and increase posterior drug targeting.

Recent advances in slow and sustained drug release for retina drug delivery

INTRODUCTION

Striking recent advance has occurred in the field of medical retina, greatly because intraocular drugs have been developed, enhancing their clinical efficacy while avoiding systemic side-effects. However, the burden of repeated intraocular administration makes limits the optimal efficacy of treatments, prompting the development of new drugs with prolonged half-life or of sustained drug delivery systems.

AREAS COVERED

In this review, we describe the various drugs and drug delivery systems that have reached the clinical stage and those that are in clinical development and we discuss the limitations to clinical translation.

EXPERT OPINION

Substantial fundamental work is still required to build guidelines on optimal animal models for ocular pharmacokinetics and safety studies depending on the target disease site and the on the type of therapeutic compounds. The effects of a drug administered as a bolus at high concentration in the vitreous might differ from those resulting from the sustained release of a lower concentration, and no delivery platform can be simply adapted to any drug. For the treatment of retinal diseases, development of therapeutic compounds should integrate from its early conception, the combination of an active drug with a specific drug delivery system, administered by a specific route.