Abstract The treatment of ocular neovascular diseases is being revolutionized by intravitreal therapies targeting vascular endothelial growth factor (VEGF). Two agents are approved for treating ...neovascular age-related macular degeneration and are being evaluated for other retinal conditions: the RNA aptamer pegaptanib and the monoclonal antibody antigen-binding fragment ranibizumab. Bevacizumab, a related antibody, is being used similarly, although its use is off-label. Pegaptanib selectively binds to a VEGF isoform identified as being especially pathogenic in the eye and spares other isoforms, whereas the other two agents nonselectively bind all VEGF isoforms. Because VEGF is involved in a wide variety of physiologic processes, the ocular and systemic safety of anti-VEGF agents is of paramount concern. I provide an overview of safety data for intravitreal anti-VEGF therapies, focusing primarily on randomized, controlled trials. For pegaptanib, an accumulation of data from pivotal trials and a dedicated systemic safety study have revealed no ocular or systemic safety concerns. For ranibizumab, the principal ocular adverse event detected in clinical trials was a low frequency of ocular inflammation, and systemic adverse events included a slightly elevated risk of nonocular hemorrhage and stroke. Safety data from properly designed randomized controlled trials for bevacizumab are not available.
Intravitreal anti-vascular endothelial growth factor (VEGF) injections for exudative age-related macular degeneration (eAMD) are effective and safe but require frequent injections and have ...nonresponding patients. Geographic atrophy/dry AMD (gaAMD) remains an unmet medical need. New therapies are needed to address this leading cause of blindness in the increasing aged population.
This paper reviews the pathogenesis of macular degeneration, current and failed therapeutics, therapies undergoing clinical trials and a rationale for why certain AMD therapies may succeed or fail.
VEGF-inhibitors reduce both vascular leakage and neovascularization. Experimental therapies that only address neovascularization or leakage will unlikely supplant anti-VEGF therapies. The most promising future therapies for eAMD, are those that target, more potently inhibit and have a more sustained effect on the VEGF pathway such as KSI-301, RGX-314, CLS-AX, EYEP-1901, OTX-TKI. GaAMD is a phenotype of phagocytic retinal cell loss. Inhibiting phagocytic activity of retinal microglial/macrophages at the border of geographic atrophy and reducing complement derived activators of microglial/macrophage is the most promising strategy. Complement inhibitors (Pegcetacoplan and Avacincaptad pegol) will likely obtain FDA approval but will serve to pave the way for combined complement and direct phagocytic inhibitors such as AVD-104.
Introduction: The clinical development of anti-VEGF therapies for the treatment of exudative age-related macular degeneration (wet AMD) has revolutionized ophthalmology. Indeed, it has provided ...clinicians and patients with treatments that lessen visual loss from in a disease that once was uniformly blinding. Although blindness is yet to be eradicated from AMD, repeated intraocular anti-VEGF injections are required to preserve a patient's vision. Therefore, further advances in this field are necessary.Areas covered: This review provides an overview of the agents that are in mid-stage phase trials for both exudative (wet AMD) and nonexudative macular degeneration (dry AMD). For wet AMD, new agents intend to enhance efficacy, develop alternative delivery such as eye drops, investigate alternate targets and construct sustained release strategies. For advanced dry AMD, the goal is to develop a strategy to slow or stop progressive loss of retinal tissue seen in geographic atrophy, the hallmark of advanced dry AMD.Expert opinion: It is important to develop better more sensitive biomarkers, validating different approvable clinical trial endpoints and stratifying patients on their genetic polymorphisms. These developments should help to progress the already rapidly developing field of macular degeneration therapy.
Age-related macular degeneration (AMD), a leading cause of visual loss and dysfunction worldwide, is a disease initiated by genetic polymorphisms that impair the negative regulation of complement. ...Proteomic investigation points to altered glycosylation and loss of Siglec-mediated glyco-immune checkpoint parainflammatory and inflammatory homeostasis as the main determinant for the vision impairing complications of macular degeneration. The effect of altered glycosylation on microglial maintained retinal para-inflammatory homeostasis and eventual recruitment and polarization of peripheral blood monocyte-derived macrophages (PBMDMs) into the retina can explain the phenotypic variability seen in this clinically heterogenous disease. Restoring glyco-immune checkpoint control with a sialic acid mimetic agonist targeting microglial/macrophage Siglecs to regain retinal para-inflammatory and inflammatory homeostasis is a promising therapeutic that could halt the progression of and improve visual function in all stages of macular degeneration.
Introduction: Diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) are the two complications of diabetes that cause visual loss and blindness. Laser photo-coagulation in the past ...was used to prevent progression of disease to these advanced stages. Advances in pathophysiologic understanding of DME and PDR have ushered the development of effective targeted therapy that given intravitreally improves vision and prevents blindness. While effective, these therapies require frequent administration and are not universally effective.
Areas covered: This purpose of this paper is to review the current pathophysiologic understanding and treatments for DME and PDR as well as the novel treatments currently being developed. The treatments will be juxtaposed to the factor in the disease cascade being targeted. The potential role of these novel treatment in the clinical armamentarium are postulated.
Expert opinion: Mono-therapy, single category targeting is the current strategy being utilized clinically. However, diabetic retinopathy needs combination therapy. Therapies that will prove successful will address multiple factors involved in the pathogenesis of diabetic retinopathy.
The Ocriplasmin for Treatment for Symptomatic Vitreomacular Adhesion Including Macular Hole (OASIS) trial was designed to evaluate the long-term efficacy and safety profile of ocriplasmin for the ...treatment of symptomatic vitreomacular adhesion (VMA)/vitreomacular traction, including full-thickness macular hole (FTMH).
Phase 3b, randomized, sham-controlled, double-masked, multicenter clinical trial.
Sample size was 220 subjects (146 ocriplasmin, 74 sham) randomized in a 2:1 ratio to receive intravitreal ocriplasmin 0.125 mg or sham injection.
The trial involved 12 visits over 24-months. Inclusion criteria included presence of VMA and best-corrected visual acuity (BCVA) of 20/32 or worse in the study eye. Exclusion criteria included FTMH >400 μm, presence of epiretinal membrane (ERM), and aphakia in the study eye.
The primary efficacy end point was the proportion of subjects with pharmacologic VMA resolution at day 28. Secondary efficacy end points were assessed at month 24 and included proportion of subjects with BCVA gain from baseline, nonsurgical FTMH closure, vitrectomy, and Visual Function Questionnaire 25 (VFQ-25) outcomes.
The OASIS trial met its primary end point with pharmacologic VMA resolution at day 28 being significantly higher in the ocriplasmin group (41.7%) compared with the sham group (6.2%). The treatment effect was maintained until study end. In the ocriplasmin group, pharmacologic VMA resolution at day 28 was higher in subgroups with the following baseline characteristics compared with the complementary subgroups without them: presence of focal VMA, presence of FTMH, absence of ERM, and phakic lens status. In the ocriplasmin group, 50.5% of subjects had a ≥2-line improvement in BCVA from baseline compared with 39.1% of subjects in the sham group. The nonsurgical FTMH closure rate was 30.0% for the ocriplasmin group compared with 15.4% for the sham group. All other secondary end points also favored ocriplasmin over sham. Regarding safety, most adverse events were mild to moderate, had a short onset time, and were transient, with no new safety signals identified.
The OASIS trial demonstrates the long-term efficacy and safety of ocriplasmin, providing improved resolution of symptomatic VMA compared with previous phase 3 trials with no additional safety signals identified.
The leading cause of blindness in the developed world results from several disorders that have pathologic ocular neovascularization as the common pathway leading to vision loss. These disorders ...include exudative age related macular degeneration (AMD), diabetic retinopathy (DR), retinopathy of prematurity (ROP), retinal vein occlusions (RVO) and ocular tumors. Because neovascularization is the common pathway to blindness in these highly prevalent conditions, the recent understanding of the cascade of angiogenesis has led to clinically available molecular therapeutics that have been proven to restore and preserve vision in patients that suffer from these blinding conditions. This article will summarize the emergence of vascular endothelial growth factor (VEGF) as a validated treatment target for and current understanding of the pathophysiology of ocular neovascularization. The article will then cover promising future strategies and therapeutic targets that are aimed at enhancing the efficacy and/or duration of effect of these clinically available anti-VEGF strategies. In particular molecules that target, VEGF, PDGF, Complement, Inflammation and Integrins that are entering or are currently in clinical trials will be reviewed.
An inflammation-resolving polysialic acid-decorated PLGA nanoparticle (PolySia-NP) has been developed to treat geographic atrophy/age-related macular degeneration and other conditions caused by ...macrophage and complement over-activation. While PolySia-NPs have demonstrated pre-clinical efficacy, this study evaluated its systemic and intraocular safety. PolySia-NPs were evaluated in vitro for mutagenic activity using
strains and
, with and without metabolic activation; cytotoxicity was evaluated based on its interference with normal mitosis. PolySia-NPs were administered intravenously in CD-1 mice and Sprague Dawley rats and assessed for survival and toxicity. Intravitreal (IVT) administration in Dutch Belted rabbits and non-human primates was assessed for ocular or systemic toxicity. In vitro results indicate that PolySia-NPs did not induce mutagenicity or cytotoxicity. Intravenous administration did not show clastogenic activity, effects on survival, or toxicity. A single intravitreal (IVT) injection and two elevated repeat IVT doses of PolySia-NPs separated by 7 days in rabbits showed no signs of systemic or ocular toxicity. A single IVT inoculation of PolySia-NPs in non-human primates demonstrated no adverse clinical or ophthalmological effects. The demonstration of systemic and ocular safety of PolySia-NPs supports its advancement into human clinical trials as a promising therapeutic approach for systemic and retinal degenerative diseases caused by chronic immune activation.
To assess the efficacy and safety of intravitreal inserts releasing 0.2 μg/day (low dose) or 0.5 μg/day (high dose) fluocinolone acetonide (FA) in patients with diabetic macular edema (DME).
Two ...parallel, prospective, randomized, sham injection-controlled, double-masked, multicenter clinical trials.
Subjects with persistent DME despite at least 1 macular laser treatment were randomized 1:2:2 to sham injection (n = 185), low-dose insert (n = 375), or high-dose insert (n = 393).
Subjects received study drug or sham injection at baseline and after 6 weeks were eligible for rescue laser. Based on retreatment criteria, additional study drug or sham injections could be given after 1 year.
The primary outcome was the percentage of patients with improvement from baseline best-corrected visual acuity (BCVA) in Early Treatment Diabetic Retinopathy Trial (ETDRS) letter score of 15 or more at month 24. Secondary outcomes included other parameters of visual function and foveal thickness (FTH).
The percentage of patients with improvement from baseline ETDRS letter score of 15 or more at month 24 was 28.7 and 28.6 in the low- and high-dose insert groups, respectively, compared with 16.2 in the sham group (P = 0.002 for each). Benefit occurred for both doses compared with sham at 3 weeks and all subsequent time points. The mean improvement in BCVA letter score between baseline and month 24 was 4.4 and 5.4 in the low- and high-dose groups, respectively, compared with 1.7 in the sham group (P = 0.02 and P = 0.016). At all time points compared with sham, there was significantly more improvement in FTH. Subjects requiring cataract surgery were more frequent in the insert groups, and their visual benefit was similar to that of subjects who were pseudophakic at baseline. Glaucoma requiring incisional surgery occurred in 3.7%, 7.6%, and 0.5% of the low-dose, high-dose, and sham groups, respectively.
Both low- and high-dose FA inserts significantly improved BCVA in patients with DME over 2 years, and the risk-to-benefit ratio was superior for the low-dose insert. This is the first pharmacologic treatment that can be administered by an outpatient injection to provide substantial benefit in patients with DME for at least 2 years.
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