Current and emerging therapies for the treatment of age-related macular degeneration

Retinal and Choroidal Neovascularization Antivascular Endothelial Growth Factor Treatments: The Role of Gene Therapy

Neovascularization in ocular vessels causes a major disease burden. The most common causes of choroidal neovascularization (CNV) are age-related macular degeneration and diabetic retinopathy, which are the leading causes of irreversible vision loss in the adult population. Vascular endothelial growth factor (VEGF) is critical for the formation of new vessels and is the main regulator in ocular angiogenesis and vascular permeability through its receptors. Laser therapy and antiangiogenic factors have been used for CNV treatment. Bevacizumab, ranibizumab, and aflibercept are commonly used anti-VEGF agents; however, high costs and the need for frequent intraocular injections are major drawbacks of anti-VEGF drugs. Gene therapy, given the potency of one-time treatment and no need for frequent injections offers the real possibility of such a lasting treatment, with fewer adverse effects and higher patient quality of life. Herein, we reviewed the role of gene therapy in the CNV treatment. In addition, we discuss the advantages and challenges of current treatments compared with gene therapy.

Synthesis and Biological Activities of Naturally Functionalized Polyamines: An Overview

Recently, extensive researches have emphasized the fact that polyamine conjugates are becoming important in all biological and medicinal fields. In this review, we will focus our attention on natural polyamines and highlight recent progress in both fundamental mechanism studies and interests in the development and application for the therapeutic use of polyamine derivatives.

Gene Therapy Intervention in Neovascular Eye Disease: A Recent Update

Aberrant growth of blood vessels (neovascularization) is a key feature of severe eye diseases that can cause legal blindness, including neovascular age-related macular degeneration (nAMD) and diabetic retinopathy (DR). The development of anti-vascular endothelial growth factor (VEGF) agents has revolutionized the treatment of ocular neovascularization. Novel proangiogenic targets, such as angiopoietin and platelet-derived growth factor (PDGF), are under development for patients who respond poorly to anti-VEGF therapy and to reduce adverse effects from long-term VEGF inhibition. A rapidly advancing area is gene therapy, which may provide significant therapeutic benefits. Viral vector-mediated transgene delivery provides the potential for continuous production of antiangiogenic proteins, which would avoid the need for repeated anti-VEGF injections. Gene silencing with RNA interference to target ocular angiogenesis has been investigated in clinical trials. Proof-of-concept gene therapy studies using gene-editing tools such as CRISPR-Cas have already been shown to be effective in suppressing neovascularization in animal models, highlighting the therapeutic potential of the system for treatment of aberrant ocular angiogenesis. This review provides updates on the development of anti-VEGF agents and novel antiangiogenic targets. We also summarize current gene therapy strategies already in clinical trials and those with the latest approaches utilizing CRISPR-Cas gene editing against aberrant ocular neovascularization.

Effect of Repeated Intravitreal Ranibizumab and Aflibercept Injections on the Cornea in Patients with Age-Related Macular Degeneration

Purpose

To assess the effect of repeated intravitreal ranibizumab injections (RI) and aflibercept injections (AI) on the corneal endothelium and central corneal thickness (CCT) in patients with age-related macular degeneration (AMD).

Materials and Methods

In the retrospective study, 110 eyes of 106 patients, aged 52 to 93 years, were analyzed. Fifty eyes were treated only with RI (I group), and 60 eyes were treated only with AI (II group). Every patient received one intravitreal injection of 0.5 mg of ranibizumab once a month or 2 mg of aflibercept for 3 subsequent months. Each patient received only 3 injections during the whole observation period. Corneal analysis was obtained with the specular microscope. Examinations were performed before initial treatment, after each injection, and 6 months after the first injection. Analysis included corneal endothelial cell density (ECD), hexagonal cell percentage (% Hex), coefficient of variation (CoV), and CCT.

Results

There was a statistically significant ECD loss, regardless of the type of the anti-VEGF agent. The mean ECD value in the I group was 2397 ± 459 cells/mm² before RI, 2389 ± 459 cells/mm² after the first RI, 2386 ± 467 cells/mm² after the second RI, 2378 ± 475 cells/mm² after the third RI, and 2357 ± 460 cells/mm² 6 months after the first RI. The mean ECD value in the II group was 2448 ± 493 cells/mm² before treatment, 2456 ± 498 cells/mm² after the first AI, 2426 ± 496 cells/mm² after the second AI, 2402 ± 488 cells/mm² after the third AI, and 2348 ± 473 cells/mm² 6 months after the first AI. In comparison with the group treated with RI, the group treated with AI presented a greater ECD loss at each measuring point. The percentage of hexagonal cells was decreased in both groups. There was a slight increase in polymegathism in both treated groups. Ranibizumab proved to cause a small increase in CCT, while CCT remained unchanged in the aflibercept group.

Conclusions

Repeated intravitreal injections of 0.5 mg of ranibizumab or 2 mg of aflibercept can influence the morphology of the corneal endothelium but not CCT.

Impedimetric Biosensors for Detecting Vascular Endothelial Growth Factor (VEGF) Based on Poly(3,4-ethylene dioxythiophene) (PEDOT)/Gold Nanoparticle (Au NP) Composites

In advanced forms of diabetic retinopathy, retinal vascular occlusive disease and exudative age-related macular degeneration, vision loss is associated with elevated levels or extravasation of vascular endothelial-derived growth factor (VEGF) into the retina, vitreous, and anterior chamber of the eye. We hypothesize that point-of-care biosensors, capable of rapidly and precisely measuring VEGF levels within the eye will assist clinicians in assessing disease severity, and in establishing individualized dosing intervals for intraocular anti-VEGF injection therapy. An impedance biosensor based on a poly(3,4-ethylenedioxythiophene) (PEDOT)/gold nanoparticle (Au NP) composite was developed for detecting VEGF. PEDOT with Au NP was electrochemically deposited on three different medical electrode sensor designs: free-standing pads, screen printed dots, and interdigitated micro-strip electrodes. Anti-VEGF antibody was covalently immobilized on the surface of the polymer films through attachment to citrate-functionalized Au NPs, and the resulting composites were used to detect VEGF-165 by electrochemical impedance spectroscopy (EIS). The PEDOT-Au NP composite materials were characterized using optical microscopy, SEM/EDS, FIB, TEM, and STEM techniques. Among the different micro-electrodes, the interdigitated strip shape showed the best overall film stability and reproducibility. A linear relationship was established between the charge transfer resistance (R_ct) and VEGF concentration. The detection limit of VEGF was found to be 0.5 pg/mL, with a correlation coefficient of 0.99 ± 0.064%. These results indicate that the proposed PEDOT/Au NP composites can be used in designing low-cost and accurate VEGF biosensors for applications such as clinical diagnosis of VEGF-mediated eye disease.

The burden of neovascular age-related macular degeneration: a patient's perspective

Purpose

To quantify the burden and quality of life of patients and their caregivers in a cohort of patients with neovascular age-related macular degeneration (nAMD) in an Australian clinical setting.

Methods

A total of 103 patients undergoing anti-vascular endothelial growth factor (VEGF) therapy for nAMD were asked to complete questionnaires relating to the financial and time burdens of nAMD.

Results

All patients completed the questionnaires. Loss in productivity due to attendance of appointments was 4.4±1.7 hours per month, with additional time lost by caregivers. Financial strain was incurred by direct medical costs associated with intravitreal assessment and injections at an average of AU$199.2±$83.1 per month. Indirect costs incurred averaged $64.8±$79.7 per month. Qualitative indirect costs due to loss of productivity for the patient, unpaid caregivers, and loss of productivity due to premature mortality were also a considerable burden. Overall mean Visual Function Questionnaire and EuroQol 5D-3L scores were correlated with visual acuity and demonstrated patients' subjective decline in quality of vision.

Conclusion

Management of nAMD carries a substantial burden on patients and caregivers. These results provide important information in understanding the effect of anti-VEGF therapy among patients with nAMD. Together with the quality-of-life burden on the patients, the management of nAMD has a significant societal impact.

Switching to aflibercept among patients with treatment-resistant neovascular age-related macular degeneration: a systematic review with meta-analysis

Purpose

To systematically review anatomical and functional outcomes subsequent to switching from bevacizumab/ranibizumab to aflibercept monotherapy in patients with treatment-resistant neovascular age-related macular degeneration (nAMD).

Design

Systematic review and meta-analysis.

Methods

Medline, PubMed, Embase, and Cochrane databases were searched up to July 2016 for available scientific literature which met inclusion criteria. Eligible studies reported visual and anatomical outcomes with at least 6 months of follow-up among patients with nAMD and persistent or resistant exudative fluid despite previous anti-vascular endothelial growth factor (VEGF) therapy (bevacizumab and/or ranibizumab) and were switched to aflibercept monotherapy. Mean changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were pooled using random-effects models with 95% confidence intervals (CIs).

Results

Of 82 papers reviewed, 28 studies met inclusion criteria of this review. Pooled results showed a small mean improvement in BCVA at 6 and 12 months following switching (1.11 letters, 95% CI −0.25 to 2.46, P=0.17 and 0.63 letters, 95% CI −0.26 to 1.52, P=0.17, respectively). There was a significant improvement in mean CRT following switching (−61.90 µm, 95% CI −77.10 to −46.80, P<0.001 and −50.00 µm, 95% CI −63.20 to −36.80, P<0.001 at 6 and 12 months, respectively).

Conclusion

Pooled analysis demonstrated significantly improved anatomical outcomes; however, visual function remained stable, having a comparable effect to other anti-VEGF agents in preservation of vision. These patients had poorly responsive chronic disease with limited potential for visual recovery. Switching to aflibercept with frequent monitoring may be a suitable option for patients who have developed treatment resistance.

Cellular and Molecular Pathology of Age-Related Macular Degeneration: Potential Role for Proteoglycans

Age-related macular degeneration (AMD) is a retinal disease evident after the age of 50 that damages the macula in the centre of retina. It leads to a loss of central vision with retained peripheral vision but eventual blindness occurs in many cases. The initiation site of AMD development is Bruch's membrane (BM) where multiple changes occur including the deposition of plasma derived lipids, accumulation of extracellular debris, changes in cell morphology, and viability and the formation of drusen. AMD manifests as early and late stage; the latter involves cell proliferation and neovascularization in wet AMD. Current therapies target the later hyperproliferative and invasive wet stage whilst none target early developmental stages of AMD. In the lipid deposition disease atherosclerosis modified proteoglycans bind and retain apolipoproteins in the artery wall. Chemically modified trapped lipids are immunogenic and can initiate a chronic inflammatory process manifesting as atherosclerotic plaques and subsequent artery blockages, heart attacks, or strokes. As plasma derived lipoprotein deposits are found in BM in early AMD, it is possible that they arise by a similar process within the macula. In this review we consider aspects of the pathological processes underlying AMD with a focus on the potential role of modifications to secreted proteoglycans being a cause and therefore a target for the treatment of early AMD.

Effects of intravitreal ranibizumab on the untreated eye and systemic gene expression profile in age-related macular degeneration

The purpose of this study was to evaluate the systemic effects of intravitreal ranibizumab (Lucentis) treatment in patients with neovascular age-related macular degeneration (AMD). The impact of intravitreal ranibizumab injections on central retinal thickness (CRT) of treated and contralateral untreated eyes, and differences in gene expression patterns in the peripheral blood mononuclear cells were analyzed. The study included 29 patients aged 50 years old and over with diagnosed neovascular AMD. The treatment was defined as 0.5 mg of ranibizumab injected intravitreally in the form of one injection every month during the period of 3 months. CRT was measured by optical coherence tomography. The gene expression profile was assigned using oligonucleotide microarrays of Affymetrix HG-U133A. Studies have shown that there was a change of CRT between treated and untreated eyes, and there were differences in CRT at baseline and after 1, 2, and 3 months of ranibizumab treatment. Three months after intravitreal injection, mean CRT was reduced in the treated eyes from 331.97±123.62 to 254.31±58.75 μm, while mean CRT in the untreated fellow eyes reduced from 251.07±40.29 to 235.45±36.21 μm at the same time. Furthermore, the research has shown that among all transcripts, 3,097 expresses change after the ranibizumab treatment in relation to controls. Among these transcripts, 1,339 were up-regulated, whereas 1,758 were down-regulated. Our results show the potential systemic effects of anti-VEGF therapy for AMD. Moreover, our study indicated different gene expression in peripheral blood mononuclear cells before and after intravitreal ranibizumab treatment.

Intravitreal anti-VEGF injections for treating wet age-related macular degeneration: a systematic review and meta-analysis

AIMS

Age-related macular degeneration (AMD) is the main cause of blindness. Anti-vascular endothelial growth factor is used to prevent further neovascularization due to wet AMD. The purpose of this systematic review was to investigate the effect and protocol of anti-vascular endothelial growth factor treatment on wet AMD.

METHODS

A comprehensive literature search was performed in PubMed, Embase, the Cochrane Library, CNKI, and reference lists. Meta-analysis was performed using Stata12.0 software, best corrected visual acuity (BCVA), retinal thickness, and lesion size were evaluated.

RESULTS

Twelve randomized controlled trials spanning from 2010 to 2014 and involving 5,225 patients were included. A significant difference was observed between the intravitreal ranibizumab (IVR) group and the intravitreal bevacizumab group (standard mean difference = -0.14, 95% confidence interval [CI] = -0.23 to -0.05). No significant differences were observed in best corrected VA, retinal thickness, or lesion size between IVR and the intravitreal aflibercept group. Compared to monthly injection, IVR as-needed injections (PRN) can raise VA by 1.97 letters (weighted mean difference = 1.97, 95% CI = 0.14-3.794). Combination therapy of IVR and photodynamic therapy can significantly raise VA by 2.74 letters when combined with IVR monotherapy (weighted mean difference = 2.74, 95% CI = 0.26-5.21).

CONCLUSION

The superiority remains unclear between IVR and intravitreal bevacizumab in the treatment of neovascular AMD. Intravitreal aflibercept dosed every 2 months required fewer injection times, but produced similar efficacy as monthly IVR. IVR PRN could significantly increase VA. Combined with photodynamic therapy, IVR therapy could also increase VA effectively.

Small-interfering RNAs (siRNAs) as a promising tool for ocular therapy

RNA interference (RNAi) can be used to inhibit the expression of specific genes in vitro and in vivo, thereby providing an extremely useful tool for investigating gene function. Progress in the understanding of RNAi-based mechanisms has opened up new perspectives in therapeutics for the treatment of several diseases including ocular disorders. The eye is currently considered a good target for RNAi therapy mainly because it is a confined compartment and, therefore, enables local delivery of small-interfering RNAs (siRNAs) by topical instillation or direct injection. However, delivery strategies that protect the siRNAs from degradation and are suitable for long-term treatment would be help to improve the efficacy of RNAi-based therapies for ocular pathologies. siRNAs targeting critical molecules involved in the pathogenesis of glaucoma, retinitis pigmentosa and neovascular eye diseases (age-related macular degeneration, diabetic retinopathy and corneal neovascularization) have been tested in experimental animal models, and clinical trials have been conducted with some of them. This review provides an update on the progress of RNAi in ocular therapeutics, discussing the advantages and drawbacks of RNAi-based therapeutics compared to previous treatments.

The proliferation of malignant melanoma cells could be inhibited by ranibizumab via antagonizing VEGF through VEGFR1

PURPOSE

Angiogenesis is an important mediator in tumor progression. Vascular endothelial growth factor (VEGF) is one of the major cytokines that can influence angiogenesis. However, the potential mechanism of tumor growth inhibition through anti-VEGF agents is still unclear. This study was performed to examine whether ranibizumab could inhibit malignant melanoma growth in vitro and to determine the safety of ranibizumab on human adult retinal pigment epithelium cell line (ARPE-19 cells).

METHODS

Malignant melanoma cells obtained from a clinic were cultured in vitro. VEGF concentrations secreted by malignant melanoma cells and the ARPE-19 cells were examined by enzyme-linked immunosorbent assay (ELISA). The two kinds of cells were both treated with VEGF and its antagonist, ranibizumab. The dynamic changes of the two types of cells were monitored by real-time cell electronic sensing (RT-CES) assay. The effect of ranibizumab on both types of cells was verified by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. The expression of VEGF receptor 1 (VEGFR1) RNA in uveal melanoma was further investigated through the PCR technique.

RESULTS

The levels of VEGF secreted by malignant melanoma cells were much higher than those of ARPE-19 cells, and were markedly decreased in the action of 0.1 mg/ml ranibizumab. However, there was no obvious reduction of VEGF in the presence of ranibizumab for ARPE-19 (p>0.05). Meanwhile, RT-CES showed that the viability of malignant melanoma cells increased greatly in the presence of VEGF. When VEGF was 20 ng/ml, viability of the malignant melanoma cells increased by 40% compared with the negative control. There was no evident effect on proliferation of ARPE-19 (p>0.05). Furthermore, the growth of malignant melanoma cells was obviously inhibited after ranibizumab intervention. When ranibizumab was administered at 0.25 mg/ml, the survival rate of the malignant melanoma cells decreased to 57.5%. Nevertheless, low-dose exposure to ranibizumab had only a slight effect on the growth of ARPE-19, and PCR result demonstrated that VEGFR1 plays a role in this tumor tissue rather than VEGFR2.

CONCLUSIONS

Ranibizumab can selectively inhibit malignant melanoma cell proliferation by decreasing the expression of VEGF; the possible mechanism of the inhibitory effect may involve VEGFR1 antagonism.

Comparison of bevacizumab and ranibizumab in age-related macular degeneration: a systematic review and meta-analysis

AIM

To compare the effectiveness and safety between bevacizumab and ranibizumab in the treatment of age-related macular degeneration (AMD) through a systematic review and meta-analysis.

METHODS

We performed a comprehensive search of randomized controlled trials (RCTs), non-RCTs, case-control and cohort studies that compared bevacizumab and ranibizumab using PubMed and the Cochrane Library. After the related data were extracted by two investigators independently, pooled weighted mean differences (WMDs) and risk ratios (RRs) with 95% confidence intervals (CIs) were estimated using a random-effects or a fixed-effects model.

RESULTS

A total of four RCTs involving 1927 patients and eleven retrospective case series involving 2296 patients were included. For the primary outcomes, no significant differences were found between ranibizumab group and bevacizumab group in visual acuity (WMD: -0.04; 95%CI: -0.08 to 0.00; P=0.06), best corrected visual acuity (WMD: -0.05; 95%CI: -0.10 to 0.00; P=0.05), retina thickness (WMD: -4.69; 95%CI: -13.15 to 3.76; P=0.86) and foveal thickness (WMD: 10.91; 95%CI: -14.73 to 36.56; P=0.40). The pooled analyses in the evaluation of safety showed that compared to bevacizumab, ranibizumab was associated with decreased risks of ocular inflammation (RR: 0.45; 95% CI: 0.23 to 0.89; P=0.02) and venous thrombotic events (RR: 0.27; 95%CI: 0.08 to 0.89; P=0.03). However, there were no significant differences observed in deaths (P=0.69) and arterial thromboembolic events (P=0.71) between the two groups.

CONCLUSION

With equal clinical efficacy, ranibizumab was found to be associated with less adverse events compared to bevacizumab, indicating that ranibizumab might be a safer management.

Visual outcome of intravitreal ranibizumab for exudative age-related macular degeneration: timing and prognosis

Purpose

To describe 1-year clinical results of intravitreal ranibizumab treatment in patients with choroidal neovascularization secondary to exudative age-related macular degeneration (AMD) and to evaluate whether early treatment is a predictive value for prognosis of the disease.

Materials and methods

Clinical records were retrospectively reviewed of 104 eyes that underwent intravitreal ranibizumab therapy for exudative AMD. Patients were divided into two groups according to their symptom duration: group 1, <1 month; and group 2, 1–3 months. After three monthly injections, patients were examined monthly, and subsequent injections were performed as needed.

Results

There were 43 female (48.9%) and 45 males (51.1%). The follow-up time was 13.7±1.9 (12–19) months. The mean logarithm of minimum angle of resolution best-corrected visual acuity (BCVA) improved significantly, from 0.45±0.639 at baseline to 0.08±0.267 at 12 months in group 1, and from 1.06±0.687 at baseline to 0.75±0.563 at 12 months in group 2. The increase in BCVA was statistically significant in group 1 (P=0.009). The mean central retinal thickness (CRT) decreased significantly, from 355.13±119.93 μm at baseline to 250.85±45.48 μm at 12 months in group 1, and from 371.88±91.047 μm at baseline to 268.61±53.51 μm at 12 months in group 2. The decrease in CRT was statistically significant in group 1 (P=0.001).

Conclusion

Intravitreal ranibizumab therapy was effective in significantly increasing mean BVCA and reducing CRT. Shorter duration of AMD, as measured by the subjective duration of visual symptoms, is associated with better visual outcome after treatment.

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.

Recent Patents on Emerging Therapeutics for the Treatment of Glaucoma, Age Related Macular Degeneration and Uveitis

Advancements in the field and rising interest among pharmaceutical researchers have led to the development of new molecules with enhanced therapeutic activity. Design of new drugs which can target a particular pathway and/or explore novel targets is of immense interest to ocular pharmacologists worldwide. Delivery of suitable pharmacologically active agents at proper dose (within the therapeutic window) to the target tissues without any toxicity to the healthy ocular tissues still remain an elusive task. Moreover, the presence of static and dynamic barriers to drug absorption including the corneal epithelium (lipophilic), corneal and scleral stroma (hydrophilic), conjunctival lymphatics, choroidal vasculature and the blood-ocular barriers also pose a significant challenge for achieving therapeutic drug concentrations at the target site. Although many agents are currently available, new compounds are being introduced for treating various ocular diseases. Deeper understanding of the etiology and complex mechanisms associated with the disease condition would aid in the development of potential therapeutic candidates. Novel small molecules as well as complex biotechnology derived macromolecules with superior efficacy, safety and tolerability are being developed. Therefore, this review article provides an overview of existing drugs, treatment options, advances in emerging therapeutics and related recent patents for the treatment of ocular disorders such as glaucoma, age related macular degeneration (AMD) and uveitis.

New Approach of Anti-VEGF Agents for Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of visual loss in older population. Angiogenesis is an important factor associated with the development of CNV due to AMD. Treatment of CNV with intravitreal anti-VEGF monotherapy is currently the standard of care. However, not all patients respond to monotherapy, and modified anti-VEGF treatment regimen and combination therapy may target reducing treatment frequency or improving visual outcome. This paper reviews the many clinical trials that have been performed utilizing several treatment regimens. While many trials have shown that this variable therapy is justifiable, further study is required to determine correct regimens and dosage.

Preclinical aspects of anti-VEGF agents for the treatment of wet AMD: ranibizumab and bevacizumab

Three anti-vascular endothelial growth factor (VEGF) therapies are currently used for the treatment of patients with wet age-related macular degeneration (AMD): pegaptanib, ranibizumab, and bevacizumab. Ranibizumab is an antibody fragment approved for the treatment of wet AMD. Bevacizumab is a full-length antibody registered for use in oncology but unlicensed for wet AMD. However, it is used off-label worldwide not only for wet AMD but also for various other ocular diseases associated with macular edema and abnormal vessel growth. We consider aspects of ranibizumab and bevacizumab in relation to their molecular characteristics, in vitro and in vivo properties, and preclinical safety data. Before 2009, most studies described the short-term toxicity of bevacizumab in multiple cell types of the eye. Since 2009, an increasing number of studies have compared the properties of ranibizumab and bevacizumab and investigated their impact on retinal cell functioning. Compared with bevacizumab, ranibizumab neutralizes VEGF better at low concentrations, maintains efficacy for longer, and has a higher retinal penetration and potency. Studies in animals demonstrate ranibizumab to be better localized to the injected eye, whereas bevacizumab appears to have a greater effect in the fellow eye. In humans, a localized and systemic effect has been reported for both molecules. In conclusion, overlapping yet distinct pharmacological properties of ranibizumab and bevacizumab indicate that safety or efficacy data from one cannot be extrapolated to the other.

Laser treatment in 341 patients with exudative age-related macular degeneration

AIM

To document the prognosis of laser treatment in patients with exudative age-related macular degeneration (AMD).

METHODS

Efficacy of the intervention was evaluated using a before-after method.

RESULTS

A total of 392 eyes of 341 patients with exudative AMD were examined. 77.6% had choroideal neovascularisation (CNV). Before the use of indocyanine green (ICG) angiography, occult CNV was detected in only 1.8% of the eyes, but after the use of ICG angiography, this increased to 19.5% (P<0.001). Of the 349 eyes which were followed up, visual acuity had remained stable in 68.2%. There was a statistically significant relationship between the localization of lesion and visual acuity changes on pre- and post-laser treatment (P<0.001). Also there was a statistically significant relationship between the localization of lesion and recurrence (P<0.05). The recurrence was less in subfoveal lesions than that in juxtafoveal and extrafoveal lesions.

CONCLUSION

ICG angiography is highly important in the treatment of occult CNV.

[siRNA in macular degeneration]

To date aptamers, recombinant antibodies and antibody fragments which interfere specifically in cellular signal transmission by binding transmitters before a signal can be triggered, are the approved therapeutics agents for treatment of ocular angiogenesis. These substances achieve an effective but in most cases temporary inhibition of vascular growth and permeability. Other alternatives to inhibit cellular communication, such as tyrosine kinase inhibition or especially post-transcriptional gene silencing by degradation of messenger RNA (mRNA) induced by small interfering RNA (siRNA) are being evaluated in ongoing studies. In this overview issues related to mechanisms and molecule design, as well as clinical applications and the first clinical experience in ophthalmology reported on siRNA will be discussed.