Safety of systemic therapy for noninfectious uveitis

Subconjunctival injection of rapamycin-loaded polymeric microparticles for effective suppression of noninfectious uveitis in rats

Noninfective uveitis is a major cause of vision impairment, and corticosteroid medication is a mainstay clinical strategy that causes severe side effects. Rapamycin (RAPA), a potent immunomodulator, is a promising treatment for noninfective uveitis. However, because high and frequent dosages are required, it is a great challenge to implement its clinical translation for noninfective uveitis therapy owing to its serious toxicity. In the present study, we engineered an injectable microparticulate drug delivery system based on biodegradable block polymers (i.e., polycaprolactone-poly (ethylene glycol)-polycaprolactone, PCEC) for efficient ocular delivery of RAPA via a subconjunctival injection route and investigated its therapeutic efficacy in an experimental autoimmune uveitis (EAU) rat model. RAPA-PCEC microparticles were fabricated using the emulsion-evaporation method and thoroughly characterized using scanning electron microscopy, fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. The formed microparticles exhibited slow in vitro degradation over 28 days, and provided both in vitro and in vivo sustained release of RAPA over 4 weeks. Additionally, a single subconjunctival injection of PCEC microparticles resulted in high ocular tolerance. More importantly, subconjunctival injection of RAPA-PCEC microparticles significantly attenuated the clinical signs of EAU in a dose-dependent manner by reducing inflammatory cell infiltration (i.e., CD45+ cells and Th17 cells) and inhibiting microglial activation. Overall, this injectable microparticulate system may be promising vehicle for intraocular delivery of RAPA for the treatment of noninfective uveitis.

AAV-mediated gene therapies for glaucoma and uveitis: are we there yet?

Glaucoma and uveitis are non-vascular ocular diseases which are among the leading causes of blindness and visual loss. These conditions have distinct characteristics and mechanisms but share a multifactorial and complex nature, making their management challenging and burdensome for patients and clinicians. Furthermore, the lack of symptoms in the early stages of glaucoma and the diverse aetiology of uveitis hinder timely and accurate diagnoses, which are a cause of poor visual outcomes under both conditions. Although current treatment is effective in most cases, it is often associated with low patient adherence and adverse events, which directly impact the overall therapeutic success. Therefore, long-lasting alternatives with improved safety and efficacy are needed. Gene therapy, particularly utilising adeno-associated virus (AAV) vectors, has emerged as a promising approach to address unmet needs in these diseases. Engineered capsids with enhanced tropism and lower immunogenicity have been proposed, along with constructs designed for targeted and controlled expression. Additionally, several pathways implicated in the pathogenesis of these conditions have been targeted with single or multigene expression cassettes, gene editing and silencing approaches. This review discusses strategies employed in AAV-based gene therapies for glaucoma and non-infectious uveitis and provides an overview of current progress and future directions.

Pathogenesis and current therapies for non-infectious uveitis

Non-infectious uveitis (NIU) is a disorder with various etiologies and is characterized by eye inflammation, mainly affecting people of working age. An accurate diagnosis of NIU is crucial for appropriate therapy. The aim of therapy is to improve vision, relieve ocular inflammation, prevent relapse, and avoid treatment side effects. At present, corticosteroids are the mainstay of topical or systemic therapy. However, repeated injections are required for the treatment of chronic NIU. Recently, new drug delivery systems that may ensure intraocular delivery of therapeutic drug levels have been highlighted. Furthermore, with the development of immunosuppressants and biologics, specific therapies can be selected based on the needs of each patient. Immunosuppressants used in the treatment of NIU include calcineurin inhibitors and antimetabolites. However, systemic immunosuppressive therapy itself is associated with adverse effects due to the inhibition of immune function. In patients with refractory NIU or those who cannot tolerate corticosteroids and immunosuppressors, biologics have emerged as alternative treatments. Thus, to improve the prognosis of patients with NIU, NIU should be managed with different drugs according to the response to treatment and possible side effects.

Recent advances and future prospects: current status and challenges of the intraocular injection of drugs for vitreoretinal diseases

Effective drug therapy for vitreoretinal disease is a major challenge in the field of ophthalmology; various protective systems, including anatomical and physiological barriers, complicate drug delivery to precise targets. However, as the eye is a closed cavity, it is an ideal target for local administration. Various types of drug delivery systems have been investigated that take advantage of this aspect of the eye, enhancing ocular permeability and optimizing local drug concentrations. Many drugs, mainly anti-VEGF drugs, have been evaluated in clinical trials and have provided clinical benefit to many patients. In the near future, innovative drug delivery systems will be developed to avoid frequent intravitreal administration of drugs and maintain effective drug concentrations for a long period of time. Here, we review the published literature on various drugs and administration routes and current clinical applications. Recent advances in drug delivery systems are discussed along with future prospects.

Single Low-dose Suprachoroidal Triamcinolone Acetonide Injection in Macular Edema Secondary to Noninfectious Posterior Uveitis

PURPOSE

The purpose was to study the anatomical and functional outcome following single low-dose suprachoroidal triamcinolone acetonide (LD-SCTA) (2 mg) injection in noninfectious posterior uveitis.

METHODS

Eleven patients with macular edema (ME) more than 280 μ secondary to noninfectious uveitis were included in the study. A single LD-SCTA (0.5 ml) injection was performed in the study eye with the help of a novel suprachoroidal microneedle (Pricon, Iscon Surgicals, Jodhpur, Rajasthan, India). The study parameters were noted at 4 and 12 weeks post LD-SCTA injection.

RESULTS

Ten of 11 patients had a significant decrease in central macular thickness (CMT). The mean CMT measurement at baseline was 513.6 ± 191.73 μm for the 10 patients who responded to the treatment, which reduced significantly to 265.1 ± 34.72 μm (P < 0.003) and 260.6 ± 34.72 μm (P < 0.002) at 4 and 12 weeks, respectively. The mean best-corrected visual acuity (BCVA) at baseline was 0.84 ± 0.41 logMAR unit which improved to 0.52 ± 0.33 (P < 0.001) and 0.25 ± 0.22 (P < 0.000) at weeks 4 and 12, respectively. The mean intraocular pressure at baseline recorded was 16.36 ± 2.97 mmHg, 19.45 ± 4.80 mmHg (P = 0.06) at 4 weeks, and 17.27 ± 2.53 mmHg (P = 0.35) at 12 weeks. One eye which did not respond to LD-SCTA was a case of recurrent Vogt-Koyanagi-Harada disease.

CONCLUSION

Single LD-SCTA injection is efficacious in reducing CMT in ME, improving BCVA, and controlling the inflammation in noninfectious posterior uveitis. LD-SCTA can be used as a first-line therapy in noninfectious uveitis over other routes of steroid administration with a favorable outcome and safety profile.

Comparative Efficacy and Safety of Advanced Intravitreal Therapeutic Agents for Noninfectious Uveitis: A Systematic Review and Network Meta-Analysis

Background: To compare the efficacy and safety of advanced intravitreal therapeutic regimens, including a dexamethasone implant at 350 and 700 μg; a fluocinolone acetonide (FA) implant, 0.2 µg/day, 0.59 and 2.1 mg; intravitreal bevacizumab, 1.25 mg; intravitreal ranibizumab, 0.5 mg; intravitreal triamcinolone acetonide (IVTA), 2 and 4 mg; and standard of care (SOC, systemic therapy) for noninfectious uveitis.

Methods: We searched the Cochrane Library database, EMBASE, Medline, clinicaltrials.gov until April 2021 with 13 RCTs (1806 participants) identified and conducted a pairwise and Bayesian network meta-analysis with random effects.

Results: No specific regimen showed a statistically significant advantage or disadvantage to another treatment regimen with regard to efficacy. However, the FA implant, 0.59 mg was associated with a higher risk of cataract (RR 4.41, 95% CI 1.51–13.13) and raise in intraocular pressure (IOP) (RR 2.53 95% CI 1.14–6.25) compared with SOC at 24 months. IVTA, 4 mg at 6 months was associated with lower risk of IOP rising compared with FA implant, 0.2 µg/day at 36 months (RR 3.43 95% CI 1.12–11.35).

Conclusion: No intravitreal therapeutic regimens showed a significant advantage or disadvantage with regard to efficacy. However, SOC was associated with lower risk of side effects compared with FA implants. IVTA, 4 mg, might be the best choice with lowest risk of IOP rising.

Systematic Review Registration:clinicaltrials.gov, identifier CRD42020172953

The Efficacy and Safety of Infliximab in Refractory Noninfectious Uveitis: A Meta-Analysis of Observational Studies

Background: Although infliximab has been recommended for the second-line treatment of seronegative spondyloarthropathy- or juvenile idiopathic arthritis-related uveitis, the issue of its systemic efficacy and safety in a broader diversity of refractory noninfectious uveitis is debatable. To assess the short-term and relatively long-term efficacy of infliximab in refractory noninfectious uveitis, we performed a systematic review and meta-analysis of observational studies.

Methods: PubMed, Cochrane Library, EMBASE, and Wanfang Med Online were systematically searched from January 2005 to March 2020. Two investigators independently assessed eligibility. Data were independently collected by two investigators. The pooled proportions were estimated with patients for intraocular inflammation control and improvement of visual acuity. Pooled proportions with 95% credible intervals were computed. Study homogeneity was investigated using I² statistics to quantify the percentage of variation across studies. To pool the results, the Mantel–Haenszel fixed-effects or random-effects models were used.

Results: Of 2316 studies identified, 16 unique studies with 509 unique participants were included in the meta-analysis. The pooled proportions of intraocular inflammation control reached 92% (95% CI: 87%–98%; I²: 1%; p=0.42) and 95% (95% CI: 93%–97%; I²: 0%; p=0.91) in groups of ≤6- and ≥12-month follow-up durations. During the relatively long follow-up period, the pooled proportions of maintaining visual acuity stable or increasing at least one line reached 99% (95% CI: 96%–100%; I²: 0%; p=0.54) in the involved eyes. The corticosteroid-sparing effect of infliximab was also well demonstrated, with the proportion of corticosteroid-sparing success reaching 85.5% (112/131). Besides, about serious adverse events, 2.6% (13/500) of patients experienced hypersensitivity reactions, 2.4% (12/500) of patients experienced serious infections, 1.8% (9/500) of patients experienced autoimmune diseases, and 0.6% (3/500) of patients experienced neoplasia.

Conclusions: This meta-analysis provided evidence that infliximab might be a promising choice in controlling inflammatory activity, gaining visual acuity, and sparing corticosteroid use with relatively few side effects when applied in treating refractory noninfectious uveitis.

Systematic Review Registration: [website], identifier [registration number]

Sirolimus-Loaded Intravitreal Implant for Effective Treatment of Experimental Uveitis

Non-infectious uveitis, an ocular inflammatory condition that affects the iris, ciliary body, choroid, and adjacent tissues (retina, optic nerve, and vitreous), is an important cause of blindness worldwide. Sirolimus (SRL), a potent immunomodulatory drug, has shown promising results in the treatment of inflammatory ocular diseases. Despite this therapeutic potential, its clinical use is a major challenge due to low bioavailability and poor solubility. Poly(lactic-co-glycolic acid) (PLGA) is a biodegradable polymer commonly used for ophthalmic drug delivery due to its suitable characteristics such as biocompatibility, good mechanical properties, and improvement of the pharmacokinetic profile of the drug. In the present study, we investigated the effects of SRL-PLGA implant on experimental autoimmune uveitis in rabbits. Clinical and histopathological examinations were performed, followed by assessment of protein levels and determination of myeloperoxidase (MPO) and N-acetylglucosaminidase (NAG) activity in the aqueous humor/vitreous. As a result, treated eyes had decreased average inflammatory scores, protein significant decreases in treated eyes, assessed after 35 days. Histopathological examination showed less severe intraocular inflammation and decreased tissue damage in treated eyes. According to these results, the SRL-PLGA implant evaluated in this study was apparently safe, reducing inflammation in treated eyes, with an extended effect possibly associated with prolonged release of SRL in the posterior segment of the eye. Therefore, intravitreal SRL-PLGA implant could be a promising alternative for treatment of non-infectious uveitis.