Triple therapy for choroidal neovascularization due to age-related macular degeneration: verteporfin PDT, bevacizumab, and dexamethasone

Contribution of extracellular vesicles for the pathogenesis of retinal diseases: shedding light on blood-retinal barrier dysfunction

Retinal degenerative diseases, including diabetic retinopathy (DR) and age-related macular degeneration (AMD), loom as threats to vision, causing detrimental effects on the structure and function of the retina. Central to understanding these diseases, is the compromised state of the blood-retinal barrier (BRB), an effective barrier that regulates the influx of immune and inflammatory components. Whether BRB breakdown initiates retinal distress, or is a consequence of disease progression, remains enigmatic. Nevertheless, it is an indication of retinal dysfunction and potential vision loss.The intricate intercellular dialogues among retinal cell populations remain unintelligible in the complex retinal milieu, under conditions of inflammation and oxidative stress. The retina, a specialized neural tissue, sustains a ceaseless demand for oxygen and nutrients from two vascular networks. The BRB orchestrates the exchange of molecules and fluids within this specialized region, comprising the inner BRB (iBRB) and the outer BRB (oBRB). Extracellular vesicles (EVs) are small membranous structures, and act as messengers facilitating intercellular communication in this milieu.EVs, both from retinal and peripheral immune cells, increase complexity to BRB dysfunction in DR and AMD. Laden with bioactive cargoes, these EVs can modulate the retinal microenvironment, influencing disease progression. Our review delves into the multifaceted role of EVs in retinal degenerative diseases, elucidating the molecular crosstalk they orchestrate, and their microRNA (miRNA) content. By shedding light on these nanoscale messengers, from their biogenesis, release, to interaction and uptake by target cells, we aim to deepen the comprehension of BRB dysfunction and explore their therapeutic potential, therefore increasing our understanding of DR and AMD pathophysiology.

Analysis of the Molecular Mechanism of Xueshuantong in the Treatment of Wet Age-Related Macular Degeneration (AMD) Using GEO Datasets, Network Pharmacology, and Molecular Docking

At present, the main treatment method for wet AMD is single anti-VEGF therapy, which can require multiple injections, is costly and may have poor efficacy. Studies and clinical experiments have shown that the oral Chinese medicine Xueshuantong combined with anti-VEGF therapy is more effective, and this study aims to explore the molecular mechanism. The TCMSP database was used to identify the main Xueshuantong components. The PubChem database and SWISS Target Prediction data were used to find the SMILES molecular formulas of compounds and corresponding target genes and disease-related genes were searched using the GEO, DisGeNET, and GeneCards databases. Venny was used to identify the intersecting wet AMD-related genes and Xueshuantong targets and Cytoscape software was used to construct direct links between the drug components and disease targets. Then, PPI networks were constructed using the STRING website. R software was used for GO and KEGG enrichment analyses. Cytoscape software was used for topological analyses, and AutoDock Vina v.1.1.2 software was used for molecular docking. 64 compounds corresponding to four drugs were found by the TCMSP database, 1001 total drug targets were found by the PubChem database, 607 wet AMD target genes were found by the GEO, DisGeNET, and GeneCards databases, and 87 Xueshuantong target genes for wet AMD were obtained. Then, by constructing the drug component and disease target network and PPI network, we found that the components closely interacted with VEGF, TNF, caspase 3, CXCL8, and AKT1, which suggested that the therapeutic effects might be related to the inhibition of neovascularization, inflammation, and AKT pathway. Then, GO enrichment analysis showed that the biological processes response to hypoxia, positive regulation of angiogenesis, and inflammatory response were enriched. KEGG enrichment results showed that the HIF-1 and pi3k-akt pathways may mediate the inhibition of wet AMD by Xueshuantong. Topological analysis results identified 10 key proteins, including VEGF, TNF, AKT1, and TLR4. The results of molecular docking also confirmed their strong binding to their respective compounds. In this study, it was confirmed that Xueshuantong could inhibit wet AMD by targeting VEGF, TNF, TLR4, and AKT1, multichannel HIF-1, and the PI3K-AKT pathway, which further proved the therapeutic effects of Xueshuantong combined with single anti-VEGF therapy on wet AMD and provided new insights into the study of novel molecular drug targets for the treatment of wet AMD.

Age-Related Macular Degeneration - Therapies and Their Delivery

Age-related macular degeneration (ARMD) is a degenerative ocular disease that is the most important cause of irreversible vision loss in old-aged people in developed countries. Around fifty percent of vision impairments in developed countries are due to ARMD. It is a multifaceted disease that is associated with both genetic and environmental risk factors. The most important treatments option for ARMD includes laser photocoagulation, photodynamic therapy (PDT), Anti-VEGF Injections, and combination therapies. In this review, we also propose that topical ocular drug delivery with nanocarriers has more attention for the treatment of ARMD. The nanocarriers were specially designed for enhanced corneal residential time, prolonged drug release and action, and minimizing the frequency of administrations. Different types of nanocarriers were developed for the topical ocular delivery system, such as nanomicelles, nanoemulsions, nanosuspensions, liposomes, and polymeric nanoparticles. These topical ocular nanocarriers were administered topically, and they can fix the hydrophobic substances, increase solubility and improve the bioavailability of an administered drug. Hence the topical ocular delivery systems with nanocarriers provide a safe and effective therapeutic strategy and promising tool for the treatment of posterior segment ocular diseases ARMD.

Examining the efficacy of verteporfin photo-dynamic therapy (PDT) at different dose & fluence levels

OBJECTIVES

Photodynamic therapy (PDT) is a vaso-occlusive treatment for a number of chorioretinal vascular pathologies. We aimed to retrospectively analyse efficiency and safety of PDT for different conditions (central serous retinopathy (CSR), age-related macular degeneration (AMD), macular telangiectasia type 2 and choroidal hemangioma) and with different verteporfin parameters.

METHODS

Clinical parameters were ascertained from the medical records of patients undergoing PDT over a 6-year period. This included indications for PDT, dosing regimens of verteporfin PDT (which includes treatment dose of verteporfin and fluence). Response to treatment was measured by best corrected visual acuity (BCVA) and central foveal thickness (CFT) on ocular coherence tomography. Complications and side effects were recorded.

RESULTS

67.4 % (31/46) of PDT treatments performed over the last six years were for CSR. In the CSR cohort, there were significant improvements in BCVA (0.47 ± 0.24 to 0.29 ± 0.27, p < 0.05) and CFT (350.2μm ± 66.9 μm to 286.1μm ± 60.6 μm. In the AMD cohort, there was no change in BCVA (1.08 ± 0.52 to 1.07 ± 0.53, p = 0.96) but significant improvement in CFT (488.2μm ± 164.6 μm to 348.7μm ± 65.7 μm, p < 0.05). There was no significant difference in BCVA or CFT for macular telangiectasia type 2 and choroidal hemangioma.

CONCLUSIONS

PDT continues to have a role in the management of medical retina conditions. Our results show PDT is most effective in improving and stabilizing visual acuity in CSR, with earlier intervention resulting in better outcomes.

Two-year clinical outcomes of triple therapy with photodynamic therapy, anti-vascular endothelial growth factor agent, and triamcinolone acetonide for neovascular age-related macular degeneration

PURPOSE

To analyze the 2-year treatment outcomes of triple therapy with standard-fluence photodynamic therapy (PDT), intravitreal injection of ranibizumab (IVR)/aflibercept (IVA), and sub-tenon injection of triamcinolone acetonide (STTA) for neovascular age-related macular degeneration (nAMD) in Japanese patients.

STUDY DESIGN

A retrospective, clinical case-series study.

METHODS

Forty-four eyes of 44 patients with treatment-naïve nAMD followed for more than 24 months were evaluated. Initial treatment was given with triple therapy and retreatment with IVR/IVA as a pro re nata regimen. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), the number of treatments, and intraocular pressure elevation were analyzed.

RESULTS

The mean age was 73.3 ± 10.0 years. The mean BCVA significantly improved from 0.61 ± 0.30 at baseline to 0.50 ± 0.46 at 24 months (p = 0.034). CRT significantly improved from 373 ± 162 μm at baseline to 200 ± 107 μm at 24 months (p < 0.001). The number of treatments given during the 2-year treatment period was 2.7 ± 1.8. No retreatments were necessary in 18 of 44 eyes (40.9%), with no significant difference between IVR (46.4%) or IVA (31.3%) used during the 2-year follow-up of triple therapy (p = 0.51). Four eyes (9.1%) temporarily required glaucoma eye drop treatments.

CONCLUSION

In nAMD patients, induction treatment with triple therapy resulted in approximately 40% of the patients requiring no retreatment for 2 years. The type of anti-VEGF agents used made no difference in the results.

Exudative versus Nonexudative Age-Related Macular Degeneration: Physiopathology and Treatment Options

Age-related macular degeneration (AMD) is an eye disease typically associated with the aging and can be classified into two types—namely, the exudative and the nonexudative AMD. Currently available treatments for exudative AMD use intravitreal injections, which are associated with high risk of infection that can lead to endophthalmitis, while no successful treatments yet exist for the nonexudative form of AMD. In addition to the pharmacologic therapies administered by intravitreal injection already approved by the Food and Drug Administration (FDA) in exudative AMD, there are some laser treatments approved that can be used in combination with the pharmacological therapies. In this review, we discuss the latest developments of treatment options for AMD. Relevant literature available from 1993 was used, which included original articles and reviews available in PubMed database and also information collected from Clinical Trials Gov website using “age-related macular degeneration” and “antiangiogenic therapies” as keywords. The clinical trials search was limited to ongoing trials from 2015 to date.

Medication Trends for Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is central vision loss with aging, was the fourth main cause of blindness in 2015, and has many risk factors, such as cataract surgery, cigarette smoking, family history, hypertension, obesity, long-term smart device usage, etc. AMD is classified into three categories: normal AMD, early AMD, and late AMD, based on angiogenesis in the retina, and can be determined by bis-retinoid N-retinyl-N-retinylidene ethanolamine (A2E)-epoxides from the reaction of A2E and blue light. During the reaction of A2E and blue light, reactive oxygen species (ROS) are synthesized, which gather inflammatory factors, induce carbonyl stress, and finally stimulate the death of retinal pigment epitheliums (RPEs). There are several medications for AMD, such as device-based therapy, anti-inflammatory drugs, anti-VEGFs, and natural products. For device-based therapy, two methods are used: prophylactic laser therapy (photocoagulation laser therapy) and photodynamic therapy. Anti-inflammatory drugs consist of corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs). Anti-VEGFs are classified antibodies for VEGF, aptamer, soluble receptor, VEGF receptor-1 and -2 antibody, and VEGF receptor tyrosine kinase inhibitor. Finally, additional AMD drug candidates are derived from natural products. For each medication, there are several and severe adverse effects, but natural products have a potency as AMD drugs, as they have been used as culinary materials and/or traditional medicines for a long time. Their major application route is oral administration, and they can be combined with device-based therapy, anti-inflammatory drugs, and anti-VEGFs. In general, AMD drug candidates from natural products are more effective at treating early and intermediate AMD. However, further study is needed to evaluate their efficacy and to investigate their therapeutic mechanisms.

Posterior Segment Ophthalmic Drug Delivery: Role of Muco-Adhesion with a Special Focus on Chitosan

Posterior segment eye diseases (PSEDs) including age macular degeneration (AMD) and diabetic retinopathy (DR) are amongst the major causes of irreversible blindness worldwide. Due to the numerous barriers encountered, highly invasive intravitreal (IVT) injections represent the primary route to deliver drugs to the posterior eye tissues. Thus, the potential of a more patient friendly topical route has been widely investigated. Mucoadhesive formulations can decrease precorneal clearance while prolonging precorneal residence. Thus, they are expected to enhance the chances of adherence to corneal and conjunctival surfaces and as such, enable increased delivery to the posterior eye segment. Among the mucoadhesive polymers available, chitosan is the most widely explored due to its outstanding mucoadhesive characteristics. In this review, the major PSEDs, their treatments, barriers to topical delivery, and routes of topical drug absorption to the posterior eye are presented. To enable the successful design of mucoadhesive ophthalmic drug delivery systems (DDSs), an overview of mucoadhesion, its theory, characterization, and considerations for ocular mucoadhesion is given. Furthermore, chitosan-based DDs that have been explored to promote topical drug delivery to the posterior eye segment are reviewed. Finally, challenges of successful preclinical to clinical translation of these DDSs for posterior eye drug delivery are discussed.

Nanotechnology: revolutionizing the delivery of drugs to treat age-related macular degeneration

Introduction: Age-related macular degeneration (AMD) is a progressive retinal disease that degrades the eye's ability to grasp visual acuity. The antivascular endothelial growth factor (VEGF) therapies have made significant strides in improving the quality of life, and there is a continued opportunity to improve delivery, outcomes, and patient convenience and compliance. The treatments available could gain better clinical outcome from novel therapeutics through nanotechnology application.Areas covered: This review summarizes AMD biology and the pathophysiology of the disease along with the successes and limitations of available therapies. It further discusses the promising nanotechnology modalities that could become the cornerstone of future AMD research for improving delivery and reducing frequency of administration thus, enabling development of novel therapeutics.Expert opinion: The robust translation from preclinical work to clinical outcome for AMD remains an unmet need. Continuing to investigate in deeper understanding of biology and advancing high-quality targets into the clinic in combination with the application of advanced nanotechnology to design patient-centric offerings for both dry and wet AMD is needed. Because of the lack of regulatory precedence, and challenging manufacturing and supply chain need, the future of nano-enabled technologies is challenging but presents exciting treatment options for AMD.

High frequency SD-OCT follow-up leading to up to biweekly intravitreal ranibizumab treatment in neovascular age-related macular degeneration

A remarkable proportion of neovascular age-related macular degeneration (nAMD) patients respond rather poorly to ranibizumab treatment, in spite of the minimum 4-week follow-up and treatment interval. Usually, retreatments are based on nAMD activity as evaluated by Spectral-domain Optical coherence Tomography (SD-OCT), biomicroscopic fundus examination and visual acuity changes. In this prospective pilot study, we aimed to study SD-OCT changes in a high-frequent follow-up manner (weekly (month 0–6), biweekly (month 7–12)) throughout the first year, which consequently led to intravitreal ranibizumab being administered up to biweekly. Best corrected visual acuity (BCVA) was already significantly improved at week 2. Central retinal thickness (CRT), intraretinal and subretinal fluid (SRF) were significantly improved from week 1 onwards. Half of the patients showed nAMD activity at week 2 or 3 and received the first retreatment earlier than 4 weeks after baseline injection. In total, 46% of retreatments were already applied 2 or 3 weeks after the previous treatment. Greater range of CRT and SRF fluctuation during follow-up was associated with lower final BCVA. Lower baseline BCVA and better SRF improvement at week 2 was associated with greater BCVA improvement. In conclusion, high-frequency SD-OCT follow-up provided a good option for adapting treatment in nAMD individually.

Cyclic RGD Peptide Targeting Coated Nano Drug Co-Delivery System for Therapeutic Use in Age-Related Macular Degeneration Disease

Vascular endothelial growth factor (VEGF) expression increased significantly in the pathogenesis of age-related macular degeneration, which induced the formation of pathological blood vessels. Dexamethasone is an exogenous anti-angiogenic drug while bevacizumab is an endogenous anti-angiogenic drug. They both have been widely used in ophthalmology. However, independent administration is not enough to completely block the development of choroidal neovascularization (CNV), and the number of eyes vitreous injections is limited. Reasonable combination of drugs may produce significantly better therapeutic effect than single drug treatment. The cyclic RGD (cRGD) peptide has a particularly high affinity with retinal pigment epithelial cells, where VEGF secretes from. In this study, we prepared nanoparticles of bevacizumab and dexamethasone with cRGD peptide as the target (aBev/cRGD-DPPNs). The particle size of the aBev/cRGD-DPPNs was 213.8 ± 1.5 nm, SEM results showed that the nano-carriers were well dispersed and spherical. The cell uptake study demonstrated the selectivity of the aBev/cRGD-DPPN to ARPE-19 with α_Vβ₃ over expressed. The aBev/cRGD-DPPNs had a better apoptosis induction effect and an obvious inhibitory effect on migration, invasion, and capillary-like structures formation of human umbilical vein epithelial cells. The fluorescein fundus angiography study, immunohistochemistry and histopathological evaluation showed the aBev/cRGD-DPPNs greatly reduced the development of CNV on a rabbit model.

Leveraging Nuclear Receptors as Targets for Pathological Ocular Vascular Diseases

Vasculogenesis and angiogenesis are physiological mechanisms occurring throughout the body. Any disruption to the precise balance of blood vessel growth necessary to support healthy tissue, and the inhibition of abnormal vessel sprouting has the potential to negatively impact stages of development and/or healing. Therefore, the identification of key regulators of these vascular processes is critical to identifying therapeutic means by which to target vascular-associated compromises and complications. Nuclear receptors are a family of transcription factors that have been shown to be involved in modulating different aspects of vascular biology in many tissues systems. Most recently, the role of nuclear receptors in ocular biology and vasculopathies has garnered interest. Herein, we review studies that have used in vitro assays and in vivo models to investigate nuclear receptor-driven pathways in two ocular vascular diseases associated with blindness, wet or exudative age-related macular degeneration, and proliferative diabetic retinopathy. The potential therapeutic targeting of nuclear receptors for ocular diseases is also discussed.

MANAGEMENT OF NEOVASCULAR OCULAR HISTOPLASMOSIS: Past and Present

PURPOSE

To review the wide variety of treatment modalities available for choroidal neovascularization secondary to the presumed ocular histoplasmosis syndrome.

METHODS

A literature search was performed to review the multitude of studies conducted to investigate the efficacy and safety of treatment modalities available for choroidal neovascularization secondary to the presumed ocular histoplasmosis syndrome.

RESULTS

Each treatment modality is reviewed, with the studies summarized and presented to support or refute the method of treatment. Two case reports are presented to demonstrate the treatment regimens.

CONCLUSION

This is a comprehensive review of the treatment modalities available to address choroidal neovascularization secondary to the presumed ocular histoplasmosis syndrome. Investigators will continue to strive toward higher efficacy and safety with future innovations in the field.

Response of Retinal Sensitivity to Intravitreal Anti-angiogenic Bevacizumab and Triamcinolone Acetonide for Patients with Diabetic Macular Edema over One Year

AIM

The aim of this study was to evaluate and compare microperimetry changes in patients with clinically significant diabetic macular edema secondary to diabetes mellitus, following intravitreal injections of bevacizumab or triamcinolone during a follow-up of 1 year after treatment.

MATERIALS AND METHODS

30 patients with clinically significant macular edema were randomized into two groups of 15 patients each. One group initially received three intravitreal injections of 2.5 mg bevacizumab at monthly intervals. The other received a single injection of 8 mg of triamcinolone followed by two sham interventions at monthly intervals. Best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were measured. Macular function was documented by microperimetry at baseline, 3, 6, 9 months and at the last visit of each patient.

RESULTS

In the bevacizumab group, the mean differential light threshold (±standard deviation) under therapy improved significantly from 8.40 (± 3.8) dB to 12.8 (±4.3) dB at the 12-month follow-up visit (p ≤ .05), whereas in the triamcinolone group it increased from 8.0 (± 2.4) dB at baseline to 9.3 (±3.6) dB at the last visit without reaching statistical significance (p > .05). The mean differential light thresholds between the two groups were not statistically significant at baseline or the last visit (p > .05). In the bevacizumab group, the improvement (slope) in mean differential light threshold was significantly superior to the Triamcinolone group (Estimate = 0.588, p ≤ .05).

CONCLUSION

Central macular function as measured by microperimetry in patients with acute DME improved in addition to anatomical restoration after intravitreal bevacizumab and triamcinolone injection. In our clinical study, the measures of the variables in patients receiving bevacizumab were superior to those receiving triamcinolone throughout the one-year observation period.

Adding a Corticosteroid or Switching to Another Anti-VEGF in Insufficiently Responsive Wet Age-Related Macular Degeneration

Purpose

To compare the effect of adding a corticosteroid or switching to another anti-VEGF treatment in patients with exudative age-related macular degeneration (eAMD) with persisting intraretinal fluid on anti-VEGF monotherapy.

Methods

This retrospective, interventional case series involved 43 pseudophakic eyes with eAMD and persistent intraretinal fluid on anti-VEGF treatment that switched treatment to a combination of Ozurdex^® or Triamcinolone and anti-VEGF therapy (group 1) or to another anti-VEGF agent (group 2). The number of injections, time to re-injection, change in central retinal thickness (CRT), and best-corrected visual acuity (BCVA) from 12 months prior to 12 months after switch to third-line therapy were defined as primary outcomes.

Results

Whereas the treatment demand was reduced (from 8.8±2.2 to 4.6±2.9 injections; p=0.001) and the re-injection interval extended in group 1 (from 1.5±0.4 months to 4.4±3.8 months; p=0.001), these parameters did not change in group 2 (7.4±1.6 to 7.3±2.2; p=0.90 and 1.7±0.3 months to 1.9±0.8 months; p=0.75). Mean CRT decreased from 455.7±30.1 and 427.6±36.0µm (groups 1 and 2, respectively) to 359.1±38.2 and 303.1±44.4µm (intergroup p=0.03). The mean baseline BCVA of 62.6±3.8 letters (group 1) and 63.0±1.9 letters (group 2) remained stable under therapy in both groups (intergroup p=0.67).

Conclusion

In eyes with eAMD with persistent intraretinal fluid on anti-VEGF monotherapy despite frequent re-injections, corticosteroids achieved a similar functional and morphological outcome over 12 months as switching to another anti-VEGF therapy, but with a reduced injection burden. In selected cases, corticosteroid treatment may thus be an option for third-line therapy in refractory exudative AMD.

Combination therapy and co-delivery strategies to optimize treatment of posterior segment neurodegenerative diseases

Neurodegenerative diseases affecting the posterior segment of the eye are one of the major causes of irreversible blindness worldwide. The pathogenesis of these retinal pathologies is characterized by a multifactorial etiology, involving the complex interaction of different apoptotic mechanisms, suggesting that effective treatments will require a multimodal approach. Thus, combination therapy based on the potential synergistic activities of drugs with different mechanisms of action is currently receiving considerable attention. Here, we summarize several kinds of strategy for the co-administration of different drugs to the posterior segment of the eye, highlighting those that involve co-delivery from multiloaded drug delivery systems.

Long-acting intraocular Delivery strategies for biological therapy of age-related macular degeneration

As one of the leading causes of central vision loss in elderly population, worldwide cases of age-related macular degeneration (AMD) have seen a dramatic increase over the past several years. Treatment regimens for AMD, especially with biological agents, are complicated due to anatomical and physiological barriers, as well as administration of high doses and frequent regimens. Some clinical examples include monthly intravitreal administration of anti-VEGF antibody ranibizumab (Lucentis®) from Genentech and aflibercept (Eylea®) from Regeneron Pharmaceuticals. Long-acting sustained intraocular drug delivery provides promising solutions, such as Vitrasert® from Bausch & Lomb, an intravitreal biodegradable polymeric implant made from poly(D,L-lactic co glycolic acid) (PLGA), and can be used as a guiding reference to formulate sustained delivery systems. In this review, we discuss the anatomy and physiology of the eye, barriers to delivery, pathology of AMD, opportunities for biological therapeutics, and future prospects of intraocular delivery strategies that are in development for treatment of AMD.

Photodynamic therapy in combination with ranibizumab versus ranibizumab monotherapy for wet age-related macular degeneration: A systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy and safety between photodynamic therapy (PDT) combined with intravitreal ranibizumab (IVR) and ranibizumab monotherapy in treating wet age-related macular degeneration (AMD).

METHODS

A systematic search was performed in the PubMed, Embase, Web of Science and the Cochrane Library databases through December 31, 2017. The methodological quality of the references was evaluated according to the Cochrane quality assessment. RevMan 5.3 software was used to perform the meta-analysis.

RESULTS

Eight RCTs involving 817 participants were included. Wet AMD eyes in the mono-group achieved better best-corrected vision acuity (BCVA) than the combination group in month 12 (WMD = -0.19, 95% CI = -0.32 to -0.06, P = 0.004, I² = 18%). The proportion of patients gaining more than 15 letters from baseline in the mono-group was larger than that in the combination group (RR = 0.70, 95% CI: 0.56 to 0.87, P = 0.001). However, the number of ranibizumab injections with combination therapy was smaller than that with mono-therapy (MD = -1.13, 95% CI: -2.11 to -0.15, P = 0.02, I² = 85%). No significant differences were observed in the proportions of patients losing more than 15 letters, central retinal thickness (CRT), lesion size of choroidal neovascularization (CNV) and adverse events.

CONCLUSIONS

Combination therapy decreased the number of injections of ranibizumab, although its BCVA improvement was inferior to that of monotherapy over 12 months of follow-up. Given the inherent limitations of the included trials, more studies are needed to further validate and update the findings in this area.

Development of Multigenic Lentiviral Vectors for Cell-Specific Expression of Antiangiogenic miRNAs and Protein Factors

Generation of lentivirus (LV)-based vectors holding multiple gene cassettes for coexpression of several therapeutic factors provides potent tools in both gene delivery studies as well as in gene therapy. Here we describe the development of such multigenic LV gene delivery vectors enabling cell-specific coexpression of antiangiogenic microRNA (miRNA) and protein factors and, if preferred, a fluorescent reporter, from RNApol(II)-driven expression cassettes orientated in a back-to-back fashion. This configuration may contribute to the development of new combination therapies for amelioration of diseases involving intraocular neovascularization including exudative age-related macular degeneration (AMD).

Clinical Applications of Dexamethasone for Aged Eyes

The risk of severe eye problems has been found to increase significantly with age, particularly between the fifth and sixth decades of life. Cataracts, dry eye, neovascular age-related macular degeneration, diabetic retinopathy and retinal vein occlusion (RVO) are very common and very different age-related ocular diseases that reduce the patient's quality of life. The rationale for using corticosteroids to treat anterior and posterior ocular segment diseases is driven by inflammation. Dexamethasone, one of the most powerful corticosteroids available, is widely used for topical or intravitreal administration. Topical dexamethasone has proven efficacy for the management of postoperative inflammation in the anterior segment after cataract surgery and symptom relief in dry-eye disease. A new sustained-release 700 µg dexamethasone intravitreal implant (DEX) was recently approved for the treatment of macular edema following RVO, diabetic macular edema, or non-infectious uveitis, and its use is increasing, especially when other therapeutic agents have failed. The most common side effects are increased intraocular pressure and cataract formation. The potency of DEX, alone or in combination with other agents, makes DEX a promising option for treating several retinal diseases.

Simultaneous dexamethasone intravitreal implant and anti-VEGF therapy for neovascular age-related macular degeneration resistant to anti-VEGF monotherapy

PURPOSE

To evaluate the efficacy of a dexamethasone intravitreal implant in combination with intravitreal anti-VEGF agents for treatment resistant neovascular age-related macular degeneration (nvAMD).

METHODS

This study was designed as a single-center, retrospective interventional case series. Consecutive patients with treatment-resistant nvAMD underwent simultaneous combined injection of anti-VEGF agent and dexamethasone intravitreal implant. Eighteen patients with mean age of 81.5 years were included. Patients received average of 26.3 anti-VEGF injections before dual therapy, with mean follow up of 8.2 months after dual therapy.

RESULTS

Dual therapy produced a significant mean decrease in CFT (126.3 μm), compared to a mean increase of 29.9 μm when treated with anti-VEGF monotherapy (p=0.0017). Patients also had mean decrease in MCV of -0.85 mm³ with dual therapy compared with anti-VEGF monotherapy (p=0.0014). There was a moderate correlation between the number of prior anti-VEGF injections and the magnitude of anatomic response, suggesting that shorter disease duration may positively influence response to combined treatment. Although there was a slight trend towards improved mean visual acuity after dual therapy, these differences did not reach statistical significance. Nevertheless, with combination treatment, 33% of patients gained one or more lines of vision. Dual therapy resulted in a significantly lower number of required anti-VEGF injections (4.25 vs 5.33) and an increase of the anti-VEGF injection-free interval to 1.41 months from 1.12 months during the 6 months following dual therapy compared to the same interval before dual therapy. Dual therapy was well tolerated; two eyes developed mild IOP elevation effectively managed with topical therapy and one patient developed worsening cataract.

CONCLUSIONS

Combined treatment of anti-VEGF with the dexamethasone intravitreal implant is a viable alternative for treatment-resistant nvAMD, and may reduce treatment burden. Earlier treatment with dual therapy may be beneficial to maximize anatomic and visual outcomes in these patients.

Combination verteporfin photodynamic therapy ranibizumab-dexamethasone in choroidal neovascularization due to age-related macular degeneration: results of a phase II randomized trial

PURPOSE

To assess whether combination therapy (CT) reduces retreatments when compared to ranibizumab monotherapy (RM), while safely maintaining similar vision outcomes.

METHODS

In this 24-month trial, patients with age-related macular degeneration (AMD) were randomized to 1) quarter-fluence or 2) half-fluence triple therapy (verteporfin photodynamic therapy [vPDT] + ranibizumab + dexamethasone), 3) half-fluence double therapy (vPDT + ranibizumab), or 4) RM. The primary outcomes were number of retreatment visits and change from baseline in visual acuity (VA) at 12 months.

RESULTS

One hundred sixty-two subjects enrolled. There were 4.0 (P=0.02), 3.2 (P<0.001), 4.1 (P=0.03), and 5.7 retreatment visits through month 12, and 5.9 (P=0.03), 4.3 (P<0.001), 5.9 (P=0.02) and 8.7 through month 24, in groups 1, 2, 3, and 4, respectively (P-value comparing with RM). Month 12 VA score change from baseline (95% confidence interval) was +3.6 (-0.9 to +8.1), +6.8 (+2.4 to +11.1), +5.0 (+0.6 to +9.3), and +6.5 (+1.7 to +11.4), respectively.

CONCLUSION

CT resulted in significantly fewer retreatment visits than a RM regimen at months 12 and 24. VA results appeared similar although wide confidence intervals preclude conclusions regarding vision outcomes.

Current advances in the treatment of neovascular age-related macular degeneration

INTRODUCTION

Age-related macular degeneration (AMD) is the most common cause of permanent central visual acuity loss in persons over 65 years of age in industrialized nations. Today, intravitreal vascular endothelial growth factor (VEGF) inhibitors are the mainstay of treatment worldwide. Areas covered: The following review covers the current treatments and challenges of wet AMD management. It also covers emerging therapies including radiation, latest generation anti-VEGF agents, and combination therapies. Expert opinion: Current neovascular AMD therapy is aimed at decreasing the VEGF effect at the choroidal neovascularization (CNV) complex. The most important existing challenges in the treatment of neovascular AMD are improving visual outcomes, decreasing the treatment burden, and minimizing geographic atrophy. Clinicians are using many treatment strategies to minimize intravitreal injections without sacrificing visual outcomes. Combination of anti-VEGF therapy with other previously available treatments that target a different pathophysiological mechanism may be a reasonable clinical strategy to minimize intravitreal injections. Many exciting novel drugs that target newly discovered pathways associated with CNV development and progression hold clinical promise. The results of ongoing randomized clinical trials will answer the important concerns surrounding new drugs and delivery devices: safety and visual outcomes.

Daily Optical Coherence Tomography Examinations after First Antivascular Endothelial Growth Factor Injections: An Interventional Case Series

Purpose. To evaluate daily spectral-domain optical coherence tomography (SD-OCT) changes in naive-treatment patients with diagnosis of exudative age-related macular degeneration (AMD) treated with intravitreous bevacizumab (1.25 mg), during a 30-day follow-up period. Methods. In prospective, interventional study, SD-OCT was performed daily for 30 days after the first intravitreal injection. The baseline, initial-decrease, minimal, and final central retinal thicknesses (CRTs) were assessed. Results. Nine eyes of nine patients with neovascular AMD were enrolled. The mean baseline CRT was 625.3 ± 182.5 μm, and the mean final CRT was 383.4 ± 163.0 μm (mean difference, 206.1 ± 167.6 μm), a difference that reached significance (P = 0.006). After the first injection, the initial decrease in the CRT was seen as an average of one day after injection (mean CRT, 503.6 ± 189.10 μm; P = 0.0431). The speed of the reduction in the CRT tended to decrease by day 17. The mean CRT was 336.5 ± 105.44 μm and the mean minimal CRT on day 30 was 320.75 ± 96.38 μm. Conclusion. The CRT decreased early after the first injection. We observed a tendency for reductions in the speed with which the CRT decreased by day 17 after the first injection, which may affect retreatment regime.

Long-term outcomes of myopic choroidal neovascularisation treated with combined ranibizumab and dexamethasone characterised by multi-modal imaging

AIM

To characterise the long-term outcomes of myopic choroidal neovascularisation (mCNV) treated with combined ranibizumab and dexamethasone, with the use of multi-modal imaging.

METHODS

A retrospective study of 20 eyes with mCNV treated with intra-vitreal ranibizumab and dexamethasone on a treat-as-needed basis were followed up for a mean period of 47 months (range 19-81 months).

RESULTS

The mean age was 55 ± 16 years, with mean refractive error of -9.0 diopters. Subfoveal mCNV was seen in 11 eyes (52 %) and the others were juxtafoveal. At the final visit, 13 patients (65 %) had improvement, while four patients (20 %) had worsening in vision. The average number of ranibizumab and dexamethasone injections required was 3 ± 1.7. There was a significant improvement in the mean visual acuity, reduction of the central retinal thickness, and an enlargement of the area of chorioretinal atrophy. The mean rate of increase in chorioretinal atrophy area was 0.05 ± 0.09 mm²/month. Disruption of the photoreceptor layer, fragmentation of the retinal pigment epithelium, and breaks in the Bruch's membrane with a hyper-reflective lesion causing separation of the outer retinal layers were changes associated with active mCNV seen on optical coherence tomography (OCT).

CONCLUSION

Visual outcomes of mCNV treated with ranibizumab and dexamethasone on a treat-as-needed basis have favourable visual acuity outcomes. Using multi-modal imaging to monitor treatment response, chorioretinal atrophy, which may be related to visual function, should be used as an additional outcome measure to study the effect of combination treatment versus monotherapy.

Triple combination therapy and zeaxanthin for the treatment of neovascular age-related macular degeneration: an interventional comparative study and cost-effectiveness analysis

BACKGROUND

Reports of triple combination therapy for neovascular age-related macular degeneration (AMD) suggest a benefit, as do reports for zeaxanthin. An interventional comparative study was thus undertaken to evaluate the efficacy of triple combination therapy with and without zeaxanthin, as well as the economic viability of the therapies.

METHODS

The cases of 543 consecutive eyes of 424 patients with subfoveal choroidal neovascularization (CNV) secondary to AMD were reviewed. All eyes were treated with triple combination therapy (triple therapy) consisting of: (1) reduced-fluence photodynamic therapy with verteporfin, (2) intravitreal bevacizumab and (3) intravitreal dexamethasone. Therapy was repeated as necessary. One cohort of patients was also given supplementation with 20 mg of oral zeaxanthin (Zx) daily.

RESULTS

The triple therapy group without Zx received a mean of 2.8 treatment cycles and 87 % of patients had stable or improved vision at 24 months. In the triple therapy group with Zx, the mean number of treatment cycles was 2.1, with 83 % of patients having stable or improved vision at 24 months. At 24 months, CNV developed in 12.5 % of fellow eyes treated with triple therapy alone; CNV developed in 6.25 % of eyes treated with triple therapy with Zx (p = 0.03). An average cost-utility analysis revealed that triple therapy was cost-effective with a cost-utility ratio of $26,574/QALY, while triple therapy with Zx was more cost-effective with an average cost-utility ratio of $19,962/QALY. The incremental cost-utility analysis assessing the addition of Zx to triple therapy disclosed Zx supplementation was very cost-effective at $5302/QALY. When it was assumed that triple therapy with Zx reduced fellow eye CNV development by 30.3 %, the incremental cost-utility dropped to (-$6332/QALY), indicating that adding Zx to triple therapy yielded greater patient value, and was also less expensive than using triple therapy alone.

CONCLUSIONS

Triple therapy is comparatively effective and cost-effective. Considerably less treatment is needed than reported in monotherapy studies. The addition of oral Zx appears to further reduce the treatment cycles required, and possibly reduce the risk of CNV development in the fellow eye.

Current choice of treatments for neovascular AMD

Age-related macular degeneration is the leading cause of irreversible blindness in developed countries with the neovascular form accounting for the majority of severe vision loss in the disease. The management of wet age-related macular degeneration has improved drastically in the past decade as anti-VEGF agents took its place at the forefront of treatment. As the choice of therapy is based on a number of factors, this review summarizes the pivotal studies that brought these agents to use and compares the different agents currently available. This review also briefly describes the promising new therapies that are in development.

Individualized Treatment of Neovascular Age-Related Macular Degeneration: What are Patients Gaining? Or Losing?

The widespread use of drugs that bind diffusible vascular endothelial growth factor (VEGF) has revolutionized the treatment of neovascular age-related macular degeneration (AMD). The pivotal ranibizumab and aflibercept registration trials featured monthly intravitreal injections for 12 months, during which visual acuities and macular edema rapidly improved for the first 3 months and modest gains or stabilization continued until the primary endpoint. In many subsequent trials, patients were evaluated monthly and treated as-needed (PRN) according to the results of visual acuity (VA) testing, fundus examinations and optical coherence tomography scans. Compared to monthly-treated control groups, PRN treated patients require fewer injections during the first year but they also experience smaller VA gains (1-3 letters). A small number of prospective trials that directly compared monthly with PRN therapy showed that VA gains with discontinuous therapy lag slightly behind those achieved with monthly injections. Physicians recognize that monthly office visits with frequent intraocular injections challenge patients' compliance, accrue high drug and professional service costs, and clog office schedules with frequently returning patients. To decrease the numbers of both office visits and anti-VEGF injections without sacrificing VA gains, physicians have embraced the treat-and-extend strategy. Treat-and-extend has not been studied as rigorously as PRN but it has become popular among both vitreoretinal specialists and patients. Despite the possible risks associated with discontinuous therapy (decreased VA and increased macular fluid), most physicians individualize treatment (PRN or treat-and-extend) for the majority of their patients. This review chapter explores the many advantages of individualized therapy, while balancing these against suboptimal responses due to the decreased frequency of anti-VEGF injections.

Intravitreal combination of dexamethasone sodium phosphate and bevacizumab in the treatment of exudative AMD

The purpose of this study is to investigate the efficacy and safety of intravitreal dexamethasone sodium phosphate (DSP) combined with bevacizumab for the treatment of neovascular age-related macular degeneration (AMD). In this non comparative case study, 30 eyes of 27 patients with CNV due to AMD received intravitreal DSP (0.2 mg) and bevacizumab (1.25 mg) during a 6-month PRN (pro re nata) dosing regimen. Visual acuity, macular thickness and intraocular pressure (IOP) were monitored and recorded. After 6 months, mean retinal thickness decreased from 423.5 ± 75.3 to 228.2 ± 34.5 and mean visual acuity improved from 0.9 ± 0.39 logMAR to 0.53 ± 0.34 (p = 0.001) logMAR. During the trial period, 81 intravitreal injections were performed in 30 eyes, thus the mean number of injections per eye was 2.7 ± 1.1. 86.7% of the eyes required 3 or less injections while only 13.3% needed 4 or more injections. None of the patients, phakic or pseudophakic, manifested an elevation of IOP during the treatment, ranging between 12 and 22 mmHg. Combined DSP and bevacizumab offers encouraging results in the challenge of AMD treatment, providing immediate response of macular edema, reduced number of intravitreal injections and stabilization or improvement of visual acuity.

Future therapies of wet age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly population, and the prevalence of the disease increases exponentially with every decade after the age of 50 years. While VEGF inhibitors are promising drugs for treating patients with ocular neovascularization, there are limitations to their potential for improving vision in AMD patients. Thus, future therapies are required to have the potential to improve visual outcomes. This paper will summarize the future strategies and therapeutic targets that are aimed at enhancing the efficacy and duration of effect of antiangiogenic strategies.

Multigenic lentiviral vectors for combined and tissue-specific expression of miRNA- and protein-based antiangiogenic factors

Lentivirus-based gene delivery vectors carrying multiple gene cassettes are powerful tools in gene transfer studies and gene therapy, allowing coexpression of multiple therapeutic factors and, if desired, fluorescent reporters. Current strategies to express transgenes and microRNA (miRNA) clusters from a single vector have certain limitations that affect transgene expression levels and/or vector titers. In this study, we describe a novel vector design that facilitates combined expression of therapeutic RNA- and protein-based antiangiogenic factors as well as a fluorescent reporter from back-to-back RNApolII-driven expression cassettes. This configuration allows effective production of intron-embedded miRNAs that are released upon transduction of target cells. Exploiting such multigenic lentiviral vectors, we demonstrate robust miRNA-directed downregulation of vascular endothelial growth factor (VEGF) expression, leading to reduced angiogenesis, and parallel impairment of angiogenic pathways by codelivering the gene encoding pigment epithelium-derived factor (PEDF). Notably, subretinal injections of lentiviral vectors reveal efficient retinal pigment epithelium-specific gene expression driven by the VMD2 promoter, verifying that multigenic lentiviral vectors can be produced with high titers sufficient for in vivo applications. Altogether, our results suggest the potential applicability of combined miRNA- and protein-encoding lentiviral vectors in antiangiogenic gene therapy, including new combination therapies for amelioration of age-related macular degeneration.

Dexamethasone intravitreal implant as adjunct therapy for patients with wet age-related macular degeneration with incomplete response to ranibizumab

PURPOSE

To evaluate the visual and anatomical outcomes of dexamethasone intravitreal implant (DXI; 700 μg, Ozurdex; Allergan, Irvine, California, USA) as adjunctive therapy for patients with refractory wet age-related macular degeneration (AMD).

METHODS

Retrospective review of the medical records of seven patients (seven eyes) who initially responded well to intravitreal ranibizumab but subsequently developed persistent intra/sub-retinal fluid (IRF/SRF) and underwent a single injection of DXI, between May 2012 and May 2013. Two weeks after DXI, the patients continued with their monthly ranibizumab injections. Best corrected visual acuity (BCVA) logarithm of the minimum angle of resolution (logMAR) and central retinal thickness (CRT) were recorded at baseline, 2 weeks, 6 weeks, 3 months and 6 months after DXI injection. Complications were recorded too.

RESULTS

All patients had at least 24 months of ranibizumab treatment. Mean age was 81.5±5.8 years. At baseline, mean BCVA was 0.53±0.13 logMAR (20/70 Snellen) and mean CRT was 273.14±50.94 μm. BCVA did not change significantly after DXI over the follow-up period. However, all eyes had lost fewer than 0.3 logMAR units. Complete resolution of the persistent IRF/SRF was achieved in five eyes (71.4%) at 6 weeks, and remained stable at 3 months. Two weeks after DXI injection, the mean CRT diminished compared with baseline (248.28±31.8 µm; p=0.03) and the greatest reduction was observed at 3 months after DXI injection (241.5±36.6 µm; p=0.04). Progression of lens opacity was detected in one case (50% of phakic eyes). Retreatment with DXI was performed in two eyes.

CONCLUSIONS

DXI appears to be effective in vision stabilisation, decreasing IRF/SRF and improvement of CRT in eyes with refractory wet AMD.

Effects of core vitrectomy in the treatment of age-related macular degeneration

PURPOSE

To investigate the clinical efficacy and safety of an additional core vitrectomy to the standard therapy in patients with exudative age-related macular degeneration (ARMD).

METHODS

In this prospective, controlled, single-centre study, 50 eyes of 50 patients (mean age: 74.1 ± 7.1; median 74 (69/78)) with ARMD were enrolled and randomized 1:1 to group 1 - core vitrectomy additional to three times injections of ranibizumab (3x Rbz) and Group 2 - 3x Rbz (control). 1 16 of 25 eyes in Group 1(64%) and 12 of 25 (48%) in Group 2 had a posterior vitreous detachment (PVD) prior to start of the study. Changes in best-corrected visual acuity (BCVA) using ETDRS charts, central macular thickness and macular volume (OCT) as well as the rate of reinjection with an OCT-based pro renata (PRN) protocol were monitored prospectively over 48 weeks. Forty-seven eyes completed follow-up at week 48.

RESULTS

In Group 1, 4 of 24 lost 1 line of BCVA (16.7%) and 3 of 24 lost 2 lines (12.5%), whereas 17 of 24 gained more than 1 line (70.8%) and improved in average by 9.8 letters. In Group 2, 3 of 23 remained stable and 20 of 23 gained more than or exactly 1 line (78.3%), resulting in 14.3 letters, with no loss of lines. Central macular thickness decreased by 85.58 μm (28.8%) in Group 1 and by 121.43 μm (32.68%) in Group 2 compared with baseline. In Group 1, four patients received three additional and two patients, two additional Rbz injections. In Group 2, three patients received three additional, three patients two and 12 patients one additional Rbz injections. This yielded in an average injection rate of 3.66 in Group 1 and 4.17 in Group 2 over 48 weeks. Posterior vitreous detachment (PVD) was identified in Group 1 in 16 of 24 (66.7%) and in Group 2 in 12 of 23 (52.2%) patients at baseline. At week 48, 6 of 8 (75%) of the patients in Group 1 with initial attached vitreous showed a vitreal detachment, whereas only 1 of 11 (9%) in Group 2 had a new occurred detachment of the vitreous. No systemic or ocular adverse events were noticed.

CONCLUSION

An initial core vitrectomy combined with a conventional ranibizumab injection regimen for exudative AMD patients was safe and lead to similar functional results with less intravitreal ranibizumab injections over 48 weeks.

Proteomics of vitreous humor of patients with exudative age-related macular degeneration

BACKGROUND

There is absence of specific biomarkers and an incomplete understanding of the pathophysiology of exudative age-related macular degeneration (AMD).

METHODS AND FINDINGS

Eighty-eight vitreous samples (73 from patients with treatment naïve AMD and 15 control samples from patients with idiopathic floaters) were analyzed with capillary electrophoresis coupled to mass spectrometry in this retrospective case series to define potential candidate protein markers of AMD. Nineteen proteins were found to be upregulated in vitreous of AMD patients. Most of the proteins were plasma derived and involved in biological (ion) transport, acute phase inflammatory reaction, and blood coagulation. A number of proteins have not been previously associated to AMD including alpha-1-antitrypsin, fibrinogen alpha chain and prostaglandin H2-D isomerase. Alpha-1-antitrypsin was validated in vitreous of an independent set of AMD patients using Western blot analysis. Further systems biology analysis of the data indicated that the observed proteomic changes may reflect upregulation of immune response and complement activity.

CONCLUSIONS

Proteome analysis of vitreous samples from patients with AMD, which underwent an intravitreal combination therapy including a core vitrectomy, steroids and bevacizumab, revealed apparent AMD-specific proteomic changes. The identified AMD-associated proteins provide some insight into the pathophysiological changes associated with AMD.

Present and possible therapies for age-related macular degeneration

Age-related macular degeneration (AMD) is the most common cause of blindness in the elderly population worldwide and is defined as a chronic, progressive disorder characterized by changes occurring within the macula reflective of the ageing process. At present, the prevalence of AMD is currently rising and is estimated to increase by a third by 2020. Although our understanding of the several components underpinning the pathogenesis of this condition has increased significantly, the treatment options for this condition remain substantially limited. In this review, we outline the existing arsenal of therapies available for AMD and discuss the additional role of further novel therapies currently under investigation for this debilitating disease.

Intravitreal steroids for the treatment of retinal diseases

Diabetic macular edema (DME), pseudophakic cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO), and uveitis are ocular conditions related to severe visual impairment worldwide. Corticosteroids have been widely used in the treatment of these retinal diseases, due to their well-known antiangiogenic, antiedematous, and anti-inflammatory properties. Intravitreal steroids have emerged as novel and essential tools in the ophthalmologist's armamentarium, allowing for maximization of drug efficacy and limited risk of systemic side effects. Recent advances in ocular drug delivery methods led to the development of intraocular implants, which help to provide prolonged treatment with controlled drug release. Moreover, they may add some potential advantages over traditional intraocular injections by delivering certain rates of drug directly to the site of action, amplifying the drug's half-life, contributing in the minimization of peak plasma levels of the drug, and avoiding the side effects associated with repeated intravitreal injections. The purpose of this review is to provide an update on the use of intravitreal steroids as a treatment option for a variety of retinal diseases and to review the current literature considering their properties, safety, and adverse events.

Objective area measurement technique for choroidal neovascularization from fluorescein angiography

The purpose of this study was to develop a non-biased method of quantitatively measuring choroidal neovascularization (CNV) areas based on late-phase fluorescein angiography (FA) images. Experimental CNV was induced in Long Evans rats by laser disruption of the Bruch's membrane. FA was performed weekly for 5weeks. Multi-Otsu thresholding (MOT) was used to quantify CNV in late-phase FA images from both experimental rodent CNV and wet age-related macular degeneration (wAMD) patients. Images were automatically thresholded into three levels based on the image histogram, with the highest level containing CNV. To determine the technique's ability to quantify CNV areas, rats were given either triamcinolone acetonide or dexamethasone sodium phosphate to treat CNV and compared to untreated rats. The rat CNV lesion areas measured from 5-week histology sections from each treatment group were compared to areas measured from the corresponding FA images. MOT was able to detect statistical decreases in rodent CNV area in the treatment groups versus control from weeks 3 through 5. The ratio of CNV area measured from histology to area measured from FA images was not statistically different between groups. Finally, to determine the usefulness of MOT on pathological morphologies of CNV, MOT was performed on late-phase FA images from patients with classic and diffuse CNV. The technique was able to segment classical CNV in wAMD patients, but performed poorly with diffuse CNV. MOT provides a robust, objective, and quantifiable area measurement of CNV lesion area in both experimentally-induced and pathological CNV. The results indicate that MOT could be a useful research tool in helping evaluate the effects of therapeutics on CNV growth.

Therapies for neovascular age-related macular degeneration: current approaches and pharmacologic agents in development

As one of the leading causes of blindness, age-related macular degeneration (AMD) has remained at the epicenter of clinical research in ophthalmology. During the past decade, focus of researchers has ranged from understanding the role of vascular endothelial growth factor (VEGF) in the angiogenic cascades to developing new therapies for retinal vascular diseases. Anti-VEGF agents such as ranibizumab and aflibercept are becoming increasingly well-established therapies and have replaced earlier approaches such as laser photocoagulation or photodynamic therapy. Many other new therapeutic agents, which are in the early phase clinical trials, have shown promising results. The purpose of this paper is to briefly review the available treatment modalities for neovascular AMD and then focus on promising new therapies that are currently in various stages of development.

An update on the pharmacotherapy of neovascular age-related macular degeneration

INTRODUCTION

Neovascular age-related macular degeneration (AMD) is currently the most common cause of legal blindness in industrialized countries. The advent of pharmacotherapy with intravitreal VEGF inhibitors has greatly improved outcomes for the treatment of this disease.

AREAS COVERED

The present review is divided into two major sections: the period prior to the use of anti-VEGF agents (triamcinolone acetonide, verteporfin photodynamic therapy) and the period following their introduction (pegaptanib sodium, bevacizumab, ranibizumab, aflibercept). The main pharmacological and clinical characteristics of each therapy are summarized.

EXPERT OPINION

Monotherapy with anti-VEGF agents is currently the 'gold standard' for treating neovascular AMD, but, with several drug choices and various different dosing regimens available, there is still wide variability in how individual clinicians manage their patients. Despite improved visual outcomes, there remains a significant unmet need for better treatments as the frequent office visits and injections associated with anti-VEGF therapy are costly and place a significant burden on patients, their family members and physicians.

Age-related macular degeneration: current treatment and future options

Age-related macular degeneration is the leading cause of visual impairment among older adults in the developed world. Epidemiological studies have revealed a number of genetic, ocular and environmental risk factors for this condition, which can be addressed by disease reduction strategies. We discuss the various treatment options for dry and exudative age-related macular degeneration available and explain how the recommended treatment depends on the exact type, location and extent of the degeneration. Currently, vascular endothelial growth factor (VEGF) inhibition therapy is the best available treatment for exudative age-related macular degeneration but is limited by the need for repeated intravitreal injections. The current treatment regime is being refined through research on optimal treatment frequency and duration and type of anti-VEGF drug. Different modes of drug delivery are being developed and in the future other methods of VEGF inhibition may be used.