New trends in intravitreal anti-VEGF therapy for ROP

Retinopathy of Prematurity (ROP) affects premature newborns, and it can cause childhood blindness and visual impairment if untreated. The understanding of the pathogenetic role of Vascular Endothelial Growth Factor (VEGF) has led to development of therapeutic strategies such as intravitreal anti-VEGF drugs. We reported drug efficacy and ROP recurrence rates, extrapolated from the reviewed studies. Association of Pegabtanib and laser photocoagulation confers efficacy in the regression of ROP stage 3 plus in zone I / II in 89.7% of treated eyes, reducing the recurrence rate to 14.6% compared to 50% of laser therapy alone. Irrespective of the dose, Ranibizumab demonstrated average efficacy greater than 75% on regression of active disease with the highest rates of the dose of 0.1 mg (92.5%). The recurrence, on the other hand, is the highest among this new anti-VEGF agents and is around an average of 41.5%, which records the highest values in the case of Aggressive Posterior Rop (APROP). Aflibercept at a dose of 1 mg demonstrated average efficacy of about 81.9% of treated infants, analyzing significantly fewer studies than Ranibizumab. The recurrence rate stands at an average of 28.9%, especially in the later forms of ROP. Using a dose of 0.25 mg of Conbercept, the disease regression rate is currently on average 83%, with an average recurrence rate of 15.24%, the peak of which was observed in cases of ROP in zone I. Further studies are needed to prove safety at long term, because,at the moment, only short-term data are available.

Intravitreal anti-vascular endothelial growth factors, panretinal photocoagulation and combined treatment for proliferative diabetic retinopathy: a systematic review and network meta-analysis

PURPOSE

To conduct a systematic review with network meta-analysis (NMA) of randomized clinical trials (RCTs) comparing panretinal photocoagulation (PRP) versus anti-vascular endothelial growth factor (VEGF) treatment alone or in combination with PRP, for proliferative diabetic retinopathy (PDR).

METHODS

PubMed, Medline and Embase databases were searched for RCTs comparing PRP versus intravitreal anti-VEGF therapy and/or combined PRP and intravitreal anti-VEGF for PDR. The primary outcome measures were the mean best corrected visual acuity (BCVA) change and the regression of neovascularization. Mean change of central macular thickness (CMT), the subgroup analyses of patients without diabetic macular oedema (DME) and the rate of vitreous haemorrhage and vitrectomy were secondary outcomes. Frequentist NMAs were performed.

RESULTS

Twelve RCTs were included. For the 12-month mean BCVA change, NMA showed a better visual outcome in both the anti-VEGF group and combined group compared to PRP [anti-VEGF vs PRP, mean difference (MD) = 3.42; standard error (SE) = 1.5; combined vs PRP, MD = 3.92; SE = 1.65], with no difference between combined group and anti-VEGF (MD = -0.50; SE = 1.87). No difference in neovascularization regression was found between PRP and anti-VEGF alone or in combination with PRP, but there was significant inconsistency (p = 0.016). Subgroup analyses in patients without DME yielded no difference for the 12-month visual outcome between the three interventions, but with significant inconsistency (p = 0.005).

CONCLUSION

This NMA showed limited evidence of comparable efficacy in terms of neovascularization regression between PRP and anti-VEGF therapy alone or in combination with PRP, but better visual outcomes were associated with anti-VEGF use. Intravitreal anti-VEGF therapy could be a valid therapeutic option in association with PRP.

Effect of Topical Instillation of Pegaptanib Sodium Upon Inflammatory Corneal Neovascularization in Rabbits

Purpose: To evaluate the effect of topical instillation of pegaptanib sodium upon inflammatory angiogenesis induced in the rabbit cornea by alkaline cauterization. Methods: Inflammatory angiogenesis was induced by alkaline (sodium hydroxide) cauterization in the corneas of 29 male New Zealand rabbits. The animals were divided into 4 groups: a control group treated with 0.5% carboxymethylcellulose sodium eye drops, a group treated with 1.0% prednisolone acetate eye drops, a group treated with 0.5% pegaptanib sodium diluted in 15 mL 0.5% carboxymethylcellulose sodium, and a group treated with 1.0% pegaptanib sodium diluted in 15 mL 0.5% carboxymethylcellulose sodium. After cauterization, eye drops were administered every 12 hours for 21 days. The animals were evaluated every 3 days after cauterization, and the newly formed vessels were quantified from photographs. The treatment effectiveness was analyzed with 3 parameters of antiangiogenic response: neovascularization area (NA), total vascular length (TVL), and number of blood vessels (BVN). Results: Average NA, TVL, and BVN values were significantly higher in both pegaptanib groups than in the prednisolone group. A nonstatistically significant reduction in parameters on days 18 and 21 was the minimum achieved in both pegaptanib groups. The efficacy of the treatments in relation to the control was significantly greater in the prednisolone group than in the 0.5% pegaptanib group or the 1.0% pegaptanib group (P < 0.001). Conclusion: Topical instillation of 0.5% and 1.0% pegaptanib sodium diluted in 15 mL 0.5% carboxymethylcellulose sodium had no inhibitory effect on corneal neovascularization in this rabbit model.

Anti-VEGF crunch syndrome in proliferative diabetic retinopathy: A review

Anti-vascular endothelial growth factor (anti-VEGF) crunch syndrome describes the progression to tractional retinal detachment following intravitreal anti-VEGF therapy in an eye with proliferative diabetic retinopathy . We reviewed the literature on the anti-VEGF crunch using the PubMed and Cochrane databases. Anti-VEGF crunch typically manifests as sudden vision loss in the affected eye between 1 and 6 weeks following intravitreal anti-VEGF injection, with a mean onset of 13 days. Risk factors for crunch development include the use of a higher anti-VEGF dose and increased severity of diabetic retinopathy with fibrosis. Our review found that intravitreal anti-VEGF, in particular bevacizumab, should be used with caution when treating patients with severe proliferative diabetic retinopathy and pre-existing intraocular fibrosis. In patients where anti-VEGF is used before a planned vitrectomy, we recommend close monitoring for crunch symptoms and proceeding promptly with surgery if there is new or progression of tractional retinal detachment. For eyes with minimal preexisting traction that develop crunch after anti-VEGF treatment, surgeons should proceed to vitrectomy within 7 days. The existing literature on the anti-VEGF crunch is limited by heterogeneity in the way crunch is documented and characterized and the presence of panretinal photocoagulation as a confounding factor. Because of these methodological flaws, the relative frequency of the anti-VEGF crunch cannot be accurately estimated.

VEGF: A KEY PLAYER NOT ONLY IN MACULAR DEGENERATION. A REVIEW

The issue of macular retinal degeneration is one of the key areas of ophthalmology. Recent advances in the targeted delivery of vascular endothelial growth factor (VEGF) suppressants have significantly impacted the patient's prognosis in the form of a significant deceleration in disease progression. Some of the drugs have gradually found their use in other indications (central retinal vein occlusion or diabetic macular edema). The following text gives a brief look at the physiology of VEGF, but not only in the eye, but throughout the human body, particularly in the context of adverse effects resulting from systemic inhibition of its effects.

Agents for the prevention and treatment of age-related macular degeneration and macular edema: a literature and patent review

Introduction: Macular degeneration (MD) and macular edema (ME) are ophthalmologic diseases affecting an increasing number of the aging population. Until recently, there were few therapeutic options for both conditions but the last two decades saw important advances. Areas covered: This review summarizes the agents used for the treatment of age-related MD (AMD), which include verteporfin, for photodynamic therapy, and anti-VEGF agents, the aptamer pegaptanib, the monoclonal antibodies (MAbs) ranibizumab (Lucentis®) and bevacizumab (Avastin®) and the fusion protein aflibercept (Eylea®). All these drugs are effective only for the wet form of AMD, whereas for the dry form there is no treatment available. ME is, on the other hand, treated with nonsteroidal anti-inflammatory drugs and carbonic anhydrase (CA) inhibitors. Recently, MAbs such as ranibizumab and bevacizumab were also shown to be effective for the management of the cystoid and diabetic ME. Expert opinion: There are important advances made in the field in the last years but longer-acting anti-VEGF agents or drugs with less ocular side effects are needed. Many such agents are in clinical development.

Potent anti-angiogenesis and anti-tumour activity of pegaptanib-loaded tetrahedral DNA nanostructure

Objectives

Pegaptanib might be a promising anti‐tumour drug targeting VEGF to inhibit tumour vascular endothelial cell proliferation. However, the poor biostability limited its application. In this study, we took tetrahedron DNA nanostructures (TDNs) as drug nanocarrier for pegaptanib to explore the potent anti‐angiogenesis and anti‐tumour activity of this drug delivery system.

Materials and methods

The successful synthesis of TDNs and pegaptanib‐TDNs was determined by 8% polyacrylamide gel electrophoresis (PAGE), capillary electrophoresis and dynamic light scattering (DLS). The cytotoxicity of pegaptanib alone and pegaptanib‐TDNs on HUVECs and Cal27 was evaluated by the cell count kit‐8 (CCK‐8) assay. The effect of pegaptanib and pegaptanib‐TDNs on proliferation, migration and tube formation of HUVECs induced by VEGF was examined by CCK‐8 assay, wound healing assay and tubule formation experiment. The cell binding capacity and serum stability were detected by flow cytometry and PAGE, respectively.

Results

Pegaptanib‐TDNs had stronger killing ability than pegaptanib alone, and the inhibiting effect was in a concentration‐dependent manner. What's more, pegaptanib‐loaded TDNs could effectively enhance the ability of pegaptanib to inhibit proliferation, migration and tube formation of HUVECs induced by VEGF. These might attribute to the stronger binding affinity to the cell membrane and greater serum stability of pegaptanib‐TDNs.

Conclusions

These results suggested that pegaptanib‐TDNs might be a novel strategy to improve anti‐angiogenesis and anti‐tumour ability of pegaptanib.

Pharmacotherapy of Myopic Choroidal Neovascularization

BACKGROUND

Myopic choroidal neovascularization (CNV) is a common cause of central visual loss in patients with high myopia, and the most common form of CNV in younger individuals. Pharmacologic therapy is the current mainstay of treatment of these patients.

METHODS

Review of pharmacological treatment options for myopic CNV, which primarily involves intravitreal administration of anti-vascular endothelial growth factor (anti-VEGF) agents.

RESULTS

At this time, anti-VEGF therapy agents are the first-line therapy in these patients. Comparative trials have not identified any major differences in treatment outcomes between aflibercept, bevacizumab, and ranibizumab. Only ranibizumab is approved for this indication in the US. Best visual outcomes are associated with younger age, smaller lesion size, and absence of chorioretinal atrophy.

CONCLUSION

Anti-VEGF therapy is generally very effective in the treatment of myopic CNV.

Role of aflibercept for macular edema following branch retinal vein occlusion: comparison of clinical trials

For years, the standard of care for branch-retinal-vein-occlusion-associated macular edema was initial observation followed by grid-pattern laser photocoagulation for persistent edema. Newer pharmacologic options have revolutionized the management of branch-retinal-vein-occlusion-associated macular edema, and the visual outcomes of these eyes are better than ever. However, a variety of available treatment options including intravitreal corticosteroids and intravitreal anti-vascular endothelial growth factor agents have established novel challenges with regard to appropriate drug selection. This review summarizes the available clinical studies with special emphasis on the comparison of intravitreal aflibercept with ranibizumab, bevacizumab, and steroid agents.

Intravitreal pegaptanib for the treatment of ischemic diabetic macular edema

Purpose

Pegaptanib has been shown to be effective in treating diabetic macular edema (DME). In the original Phase II/III trial, however, patients with macular ischemia were excluded. In this study, we treated patients with ischemic DME.

Methods

Macular ischemia was defined as a 30% increase in the area of the foveal avascular zone (FAZ) at 45 seconds on fundus fluorescein angiography. In addition, the participants had diffuse foveal-involving DME with a central subfield thickness (CST) of >300 μm on spectral-domain optical coherence tomography. Five intravitreal pegaptanib injections were given 6 weeks apart. The final study visit was 6 weeks after the fifth injection. The primary outcome was change in the size of FAZ. Secondary outcomes were change in best-corrected visual acuity (BCVA) and the change in CST.

Results

Thirty participants were enrolled. Three were unable to complete the full course of treatment. Their outcomes were carried forward for the first part of this analysis. There was no statistically significant change in the mean size of the FAZ from baseline to the final visit. Subclassifying participants as those with minimal/moderate ischemia (16 participants, FAZ area <1,000 pixels) and those with more severe ischemia (14 participants, FAZ area >1,000 pixels) also showed no statistically significant change in the mean area of the FAZ. On average, BCVA increased and CST decreased from baseline to the final visit, but these changes were not statistically significant. Using per protocol analysis on those participants who completed the full course of treatment, the mean BCVA increased from 49.2 to 53.9 letters (P=0.046).

Conclusion

In this study, intravitreal injection of pegaptanib did not significantly alter the size of the FAZ in participants with varying degrees of ischemic DME. There was, however, a significant improvement in mean BCVA in those who completed the treatment course.

Conbercept (KH-902) for the treatment of neovascular age-related macular degeneration

Age-related macular degeneration (AMD) is a progressive, degenerative disease of the retina that occurs with increasing incidence with age and ranks third among the global causes of visual impairment. VEGF has been implicated in the development and progression of neovascular AMD. Drugs that block VEGF, leading to regression of the abnormal blood vessels, are the mainstay of treatment of neovascular AMD, particularly for subfoveal neovascular lesions. Anti-VEGF agents currently in use in neovascular AMD are pegaptanib (Macugen(®)), ranibizumab (Lucentis(®)), bevacizumab (Avastin(®)) and a soluble VEGF receptor decoy aflibercept (Eylea(®)). Recently, China Food and Drug Administration have approved conbercept for the treatment of neovascular AMD in China. Conbercept appears to offer yet another anti-VEGF drug for use in neovascular AMD. However, there is still a need for large, well-designed, randomized clinical trials to ensure its safety and efficacy.

Population pharmacokinetics of pegaptanib sodium (Macugen(®)) in patients with diabetic macular edema

OBJECTIVE

Population pharmacokinetic modeling of pegaptanib was undertaken to determine influence of renal function on apparent clearance.

METHODS

In a randomized, double-masked multicenter trial, intravitreal pegaptanib (0.3, 1.0, or 3.0 mg/eye) was administered in patients with diabetic macular edema every 6 weeks for 12-30 weeks. A one-compartment model with first-order absorption, distribution volume, and clearance was used to characterize the pegaptanib plasma concentration-time profile.

RESULTS

In 58 patients, increases in area under the concentration-time curve (AUC) to end of the dosing interval (AUC0-tau) and maximum concentration with repeat doses were <6%, indicating minimal plasma accumulation. Sex and race did not have clinically significant effects on pegaptanib exposure. In the final model, the AUC extrapolated to infinite time and maximum concentration increased by ≥50% in older patients (aged >68 years) relative to younger patients due to decreases in creatinine clearance (CRCL), a significant predictor of clearance. Pegaptanib clearance was reduced by 29% when CRCL decreased by 50%. The change in exposure with CRCL (range, 0-190 mL/minute) was < 10-fold with 0.3-3.0 mg doses.

CONCLUSION

While pegaptanib clearance and AUC were significantly influenced by CRCL, the predicted exposure in patients with renal insufficiency or renal failure shows no evidence that a dose adjustment is warranted, given the tenfold margin of safety observed over the dose range of 0.3-3.0 mg.

An open-label, one-year, noncomparative study to evaluate the safety and tolerability of intravitreal pegaptanib sodium in patients with diabetic macular edema

Background

The purpose of this study was to evaluate the safety and tolerability of pegaptanib in patients with diabetic macular edema.

Methods

An open-label, multicenter, noncomparative, one-year study of approximately 500 patients was planned. Recruitment was terminated after enrollment of 46 patients. Enrolled patients were fully informed and reconsented; 12 patients elected to complete the study. Patients received intravitreal injections of pegaptanib 0.3 mg once every 6 weeks or less frequently, as determined by the investigator. Clinical benefit was evaluated after the patient received two or more injections. Ocular and nonocular adverse events were closely monitored throughout the study.

Results

Compared with baseline, mean best-corrected visual acuity increased by week 6. Ten patients reported ocular-related adverse events, none of which were severe, and eight patients reported nonocular adverse events, two of which were severe but unrelated to study treatment. Three serious adverse events, unrelated to study treatment, were reported.

Conclusion

In this limited set of patients with diabetic macular edema, pegaptanib appeared to be well tolerated with evidence of efficacy.

Systemic thromboembolic adverse events in patients treated with intravitreal anti-VEGF drugs for neovascular age-related macular degeneration: an overview

INTRODUCTION

Anti-VEGF therapy improved the quality of life for millions of patients suffering from wet age-related macular degeneration (wet-AMD); unfortunately, this therapy involves multiple injections over many years. The administration of anti-VEGF can overcome the blood-retinal barrier with agents entering the systemic circulation and causing a significant decrease in VEGF serum concentration. Although circulating VEGF protects the integrity and patency of vessels, prolonged anti-VEGF treatment has the potential to increase the risk of thromboembolic events.

AREAS COVERED

In this review, we discuss the safety data from recent trials involving available anti-VEGF drugs.

EXPERT OPINION

During the 2 years of follow-up in the relevant clinical trials, the rates of serious adverse events such as stroke, heart attack and death were similar for patients treated with different anti-VEGF drugs. Moreover the arterial thrombotic risk appears sufficiently low when compared with the natural incidence of arterial thrombotic events in this category of elderly patients and acceptably balanced against the advantage of improved vision. Since the use of these drugs is likely to become increasingly widespread and prolonged, it is desirable that the scientific community improves the pharmacovigilance program on all anti-VEGF drugs, expanding knowledge with studies that compares head to head all four compounds belonging to anti-VEGF armamentarium.

The ABCs of RVO: a review of retinal venous occlusion

Retinal vein occlusions are important causes of loss of vision; indeed, they are the second most common retinal vascular disease, following diabetic retinopathy. For this reason alone, primary eye-care providers must be well versed in diagnosis and management. Risk factors, though not universally agreed upon, include but are not limited to advancing age, systemic hypertension, arteriolarsclerosis, diabetes, hyperlipidaemia, blood hyperviscosity, thrombophilia, ocular hypertension and glaucoma. Typically, visual loss is secondary to macular oedema and/or retinal ischaemia. Treatment modalities have included observation, systemic thrombolysis and haemodilution, radial optic neurotomy, chorioretinal anastomosis, vitrectomy, laser photocoagulation and intravitreal injection of anti-inflammatory and, most recently, anti-vascular endothelial growth factors.

Local and systemic complications after intravitreal administration of anti-vascular endothelial growth factor agents in the treatment of different ocular diseases: a five-year retrospective study

PURPOSE

To observe the frequency of complications in patients undergoing intravitreal anti-VEGF injections for different ocular diseases in a five-year period.

MATERIALS AND METHODS

Charts of patients receiving intravitreal anti-VEGF were retrospectively reviewed. Out of 1173 eyes, 762 were treated with bevacizumab, 382 with ranibizumab, and 29 with pegaptanib. Data recorded included demographic information, clinical findings, total injections received, and info about the onset of adverse effects.

RESULTS

12.86% of the eyes treated with bevacizumab presented side-effects, while ratings in the ranibizumab and pegaptanib groups were 15.97% and 20.69%, respectively. Odds ratios calculated comparing incidences after each anti-VEGF are 0.78 (bevacizumab versus ranibizumab, p = 0.152), 0.57 (bevacizumab versus pegaptanib, p = 0.227), and 0.73 (ranibizumab versus pegaptanib, p = 0.508). A total of 185 complications were detected (62.16% after bevacizumab). Ocular side-effects registered were 40 cases of sustained intraocular pression (IOP) elevation, one infectious uveitis, one retinal detachment, and one sub-retinal hemorrhage. Other cases were related to transient IOP elevation immediately after injection. Systemic complications registered were one case of nausea, one episode of chest pain with acute vision loss, and one case of acute blood hypertension.

CONCLUSIONS

The majority of significant complications occurred in patients receiving multiple bevacizumab administrations. However, results may be affected by the difference in the utilization amount for each drug. AMD patients were the most represented, probably due to greater indication to treatment.

Comparison of subconjunctivally injected bevacizumab, ranibizumab, and pegaptanib for inhibition of corneal neovascularization in a rat model

AIM

To compare the efficacies of subconjunctival bevacizumab, ranibizumab, and pegaptanib sodium injections for the inhibition of corneal neovascularization in an experimental rat model.

METHODS

Sixteen corneas of 16 rats were chemically cauterized and randomized into four groups: bevacizumab group that treated with 0.05mL/1.25mg bevacizumab, ranibizumab group that treated with 0.05mL/0.5mg ranibizumab, pegaptanib group that treated with 0.05mL/0.15mg pegaptanib sodium, and control group that treated with 0.05mL saline solution. Digital photographs of the corneas were taken and analyzed using an image analysis software program. All corneas were excised and examined histologically on the 15(th) day.

RESULTS

Each treatment group had significantly less neovascularized corneal areas and fewer blood vessels than the control group (all P<0.05). In addition, bevacizumab group had significantly less neovascularized corneal areas and fewer blood vessels than ranibizumab and pegaptanib groups (both P<0.05). However, there was no significant difference between the ranibizumab and pegaptanib groups regarding percentage of neovascularized corneal areas and number of blood vessels (both P>0.05).

CONCLUSION

Subconjunctival bevacizumab, ranibizumab, and pegaptanib sodium were effective with no corneal epitheliopathy for inhibiting corneal neovascularization after corneal burn in rats. Bevacizumab was more effective than ranibizumab and pegaptanib sodium.

Emerging roles for antiangiogenesis factors in management of ocular disease

The first antivascular endothelial growth factor (anti-VEGF) was developed as an anticancer drug for colonic carcinomas. Since then, anti-VEGFs have developed in scope and indications. They have revolutionized the treatment of exudative macular degeneration and have had a major impact on treatment of several other conditions. This has resulted in an increased number of patients seeking treatment with new treatment options and has had a considerable financial impact on health care resources. Anti-VEGFs have been used in the treatment of all age groups of the population ranging from infants where it is used for treatment of retinopathy of prematurity to the elderly where it is used in exudative macular eegeneration.

Comparison of the effect between pegaptanib and ranibizumab on exudative age-related macular degeneration with small lesion size

PURPOSE

To compare the effect of pegaptanib versus ranibizumab on exudative age-related macular degeneration (AMD) with small lesion size.

METHODS

This is a retrospective study of 81 eyes from 78 patients with exudative AMD treated and followed up over 12 months. Patients with baseline best corrected visual acuity (BCVA) under 20/400 and with a greatest linear dimension of lesion over 4500 μm were excluded from the study. Twenty-six eyes from 25 patients were treated with three consecutive intravitreal injections of pegaptanib (IVP group) and 55 eyes from 54 patients were treated with three consecutive ranibizumab injections (IVR group). Each therapy was repeated as needed. The alteration in BCVA was evaluated in the IVP and IVR groups.

RESULTS

No differences were detected in baseline parameters between the IVP and IVR groups. The mean BCVA (logMAR) at month 1, 3, 6 and 12 after the initial treatment was improved from baseline in the IVP group (-0.095, -0.17, -0.18 and -0.18, respectively) and in the IVR group (-0.077, -0.15, -0.17 and -0.11, respectively), which was statistically significant. There was no difference in the change in mean BCVA between IVP and IVR groups at the same time periods.

CONCLUSIONS

The visual outcome of IVP was equivalent with IVR in exudative AMD with small lesion size.

The effect of intravitreal anti-VEGF agents on peripheral wound healing in a rabbit model

Purpose

To investigate the effect of intravitreal pegaptanib, bevacizumab, and ranibizumab on blood-vessel formation during cutaneous wound healing in a rabbit model and to compare this effect to placebo controls.

Methods

Forty New Zealand albino rabbits underwent full thickness cutaneous wounds using 6-mm dermatologic punch biopsies. The rabbits were assigned to four groups of ten, each receiving intravitreal injections of pegaptanib, bevacizumab, ranibizumab, or no injection (untreated controls). Five rabbits from each group underwent wound harvesting on day 7 and five from each group on day 14. The skin samples were stained with hematoxylin and eosin (HE), Masson’s trichrome (MT), and CD34 for vascular endothelial cells. Semiquantitative evaluation of HE- and MT-stained slides was performed by one pathologist. Quantitative assessment of mean neovascularization (MNV) scores was obtained from five contiguous biopsy margin 400× fields of CD34-stained sections by four independent observers.

Results

Week 1 MNV scores in CD-34 stained sections were: untreated controls: 11.51 ± 4.36; bevacizumab: 7.41 ± 2.82 (P = 0.013); ranibizumab: 8.71 ± 4.08 (P = 0.071); and pegaptanib: 10.15 ± 5.59 (P = 0.378). Week 2 MNV data were: untreated controls: 6.14 ± 2.25; bevacizumab: 7.25 ± 2.75 (P = 0.471); ranibizumab: 4.53 ± 3.12 (P = 0.297); and, pegaptanib: 6.35 ± 3.09 (P = 0.892). Interobserver variability using intraclass correlation coefficient was 0.961.

Conclusions

At week 1, all three anti-VEGF agents had suppressed MNV scores compared to controls. Although not statistically significant, there was an inhibitory trend, particularly with bevacizumab and ranibizumab. These effects were diminished at 2 weeks, reflecting a transition between the proliferative and remodeling phases of wound healing.

A protocol for the retina surgeon's safe initial intravitreal injections

Purpose

To determine the safety of a surgeon’s initial consecutive intravitreal injections using a specific protocol and to review the complications that may be attributed to the injection procedure.

Design

A retrospective chart review.

Participants

Fifty-nine patients (30 females, 29 males) received intravitreal injections of pegaptanib, bevacizumab, or ranibizumab as part of their treatment for neovascular age-related macular degeneration. The average patient age was 80 years. Twenty-two patients were diagnosed with or suspected of having glaucoma. Each patient received an average of 5.8 injections.

Methods

The charts of 59 patients who received a total of 345 intravitreal injections (104 pegaptanib, 74 bevacizumab, 167 ranibizumab) were reviewed. All injections were performed in an office-based setting. Povidone–iodine, topical antibiotics, and eye speculum were used as part of the pre injection procedure. Vision and intraocular pressure were evaluated immediately following each injection.

Main outcome measures

Incidence of post injection complications, including but not limited to endophthalmitis, retinal detachment, traumatic cataract, and vitreous hemorrhage.

Results

There were no cases of endophthalmitis, toxic reactions, traumatic cataracts, retinal detachment, or vitreous hemorrhage. There was one case each of lid swelling, transient floaters, retinal pigment epithelial tear, corneal edema, and corneal abrasion. There were five cases of transient no light perception following pegaptanib injections.

Conclusion

The incidence of serious complications was very low for the intravitreal injections given. A surgeon’s initial intravitreal injections may be performed with a very high degree of safety using this protocol.

Use of antivascular endothelial growth factor for diabetic macular edema

BACKGROUND

Diabetic macular edema (DME) is one of the manifestations of diabetic retinopathy leading to loss of central vision and visual acuity. It manifests itself with swelling around the central part of the retina, the area responsible for sharp vision. Current treatment includes laser therapy and intravitreal steroids with preventative measures including diabetes control. No one treatment has guaranteed control of diabetic macular edema which leads to deteriorating visual acuity, function and quality of life in patients. Vascular endothelial growth factor (VEGF) has been shown to be a critical stimulus in the pathogenesis of macular edema secondary to diabetes.1 Antiangiogenic therapy encompassed treatment with anti-VEGF which inhibits VEGF-driven neovascularization hence macular edema leading to decreased visual acuity.

OBJECTIVE

For this review, we evaluated the effectiveness of intravitreal anti-VEGF in treating DME.

DATA SOURCES

We identified five trials (n = 525) using electronic databases (Cochrane Central Register of Controlled Trials [Central], Medline((R)), and Excerpta Medica Database [EMBASE((R))]) in October 2008, supplemented by hand searching of reference lists, review articles, and conference abstracts.

METHODS

We included all randomized clinical trials (RCTs) evaluating any form of intravitreal anti-VEGF for treating DME. The main outcome factor was change in best-corrected visual acuity and central macular thickness. One author assessed eligibility, methodological quality, and extracted data. Meta analysis was performed when appropriate.

RESULTS

We included three trials of adequate methodological quality in our meta-analysis. Patients treated with anti-VEGF showed improvement in visual acuity of -0.17 (95% confidence interval [CI]: -0.23, -0.10) and central macular thickness -84.69 (95% CI: -117.09, -52.30). Patients treated with combined anti-VEGF and intravitreal triamcinolone showed improvement of visual acuity of -0.19 (95% CI: -0.27, -0.11) and central macular thickness mean change being -111.20 (95% CI: -148.13, -74.28).

CONCLUSIONS

Anti-VEGF has been associated with an improvement in visual acuity and central macular thickness in the analysis, however trial analysis was of a short duration and further research is needed to determine long-term benefits.

Treatment of retinal pigment epithelial detachment with antiangiogenic therapy

Purpose

Evaluate the efficacy of pegaptanib, a selective anti-vascular endothelial growth factor (VEGF) agent, and bevacizumab, a nonselective anti-VEGF agent, for retinal pigment epithelial detachment (PED) associated with occult choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

Methods

Prospective, comparative, nonrandomized pilot study included patients with PED comprising >50% of total lesion in subfoveal location with visual acuity (VA) 20/40–20/400 and lesions either previously untreated or treated only with photodynamic therapy/verteporfin. Seven patients received pegaptanib 0.3 mg intravitreally (IVT); eight received IVT bevacizumab 1.25 mg. Follow-up occurred every 4–6 weeks for 6 months. Reinjection of initial medication occurred if there was intra- or subretinal fluid observed by optical coherence tomography (OCT) or increased PED. Endpoints were mean changes from baseline to month 6 in VA (ETDRS) and foveal thickness.

Results

At baseline, mean VA was lower, and mean foveal thickness was greater in pegaptanib versus bevacizumab-treated patients (36.1 vs 49.5 letters; 470.4 vs 321.1 μm). Mean improvements to month 6 in VA and foveal thickness were greater for pegaptanib (VA: +9.1 vs +7.2 letters; foveal thickness: −88.2 vs −52.9 μm). On average, pegaptanib-treated patients had slower but more sustained improvement in VA and foveal thickness; bevacizumab-treated patients showed rapid improvement with a slow return towards baseline. Both agents were well tolerated.

Conclusion

Intravitreal injections of pegaptanib or bevacizumab are both efficacious and safe treatments for PED associated with occult CNV secondary to AMD.

Antiangiogenic drugs in the management of ocular diseases: Focus on antivascular endothelial growth factor

Age-related macular degeneration (AMD) complications are the leading cause of severe vision loss among the aging population in the many western countries. The introduction of molecular inhibitors of vascular endothelial growth factor (VEGF), such as pegaptanib, ranibizumab, and bevacizumab, as treatments for wet AMD has provided new hope for affected patients. Now we have these treatment options, which have the possibility to improve or maintain visual acuity for patients suffering from AMD. The treatment needs to be optimized and this is in progress. Based on emerging evidence, adopting a variable VEGF inhibitor-dosing strategy guided by visual acuity assessment and optical coherence tomography are now being tried to reduce the frequency of injections. VEGF inhibitors in combination with photodynamic therapy are another way to optimize treatment. Physicians are waiting for new guidelines for the management of AMD and the results of current and upcoming trials systematically addressing these issues will be expected to provide it.

Development of the anti-VEGF aptamer to a therapeutic agent for clinical ophthalmology

Age-related macular degeneration (AMD) is the main cause of loss of sight in the world and is characterized by neovascularization of the macula. The factors producing choroidal vascularization involve various growth factors, including the vascular endothelial growth factor (VEGF(165)). In this context, the systematic evolution of ligands by exponential enrichment (SELEX) became a tool for developing new therapeutic agents for AMD treatment. The SELEX is a combinatorial oligonucleotide library-based in vitro selection approach in which DNA or RNA molecules (aptamers) are identified by their ability to bind their targets with high affinity and specificity. Recently, the use of the SELEX technique was extended to isolate oligonucleotide ligands for a wide range of proteins of clinical importance. For instance, Pegaptanib sodium, a 28-nucleotide polyethylene glycol RNA aptamer that selectively binds to VEGF(165) and inhibits angiogenesis, was approved by the Food and Drug Administration for the treatment of wet AMD, thereby providing significant benefits to a great number of patients with minimal adverse effects.

Pegaptanib sodium for ocular vascular disease

Pegaptanib sodium (Macugen) is a selective RNA aptamer that inhibits vascular endothelial growth factor (VEGF) 165 , the VEGF isoform primarily responsible for pathologic ocular neovascularization and vascular permeability, while sparing the physiological isoform VEGF 121 . After more than 10 years in development and preclinical study, pegaptanib was shown in clinical trials to be effective in treating choroidal neovascularization associated with age-related macular degeneration. Its excellent ocular and systemic safety profile has also been confirmed in patients receiving up to three years of therapy. Early, well-controlled studies further suggest that pegaptanib may provide therapeutic benefit for patients with diabetic macular edema, proliferative diabetic retinopathy and retinal vein occlusion. Notably, pegaptanib was the first available aptamer approved for therapeutic use in humans and the first VEGF inhibitor available for the treatment of ocular vascular diseases.

Pegaptanib in the treatment of wet, age-related macular degeneration

Age-related macular degeneration (AMD) is a major cause of severe visual loss worldwide. Neovascular (wet) AMD accounts for 90% of the visual loss associated with the disorder and vascular endothelial growth factor (VEGF) has been shown to play a major role in neovascularization and vascular permeability, the major causes of visual loss in AMD, making it an ideal target for therapeutic intervention. To utilize this strategy, pegaptanib, an aptamer that specifically binds to and blocks VEGF165, the VEGF isoform primarily responsible for abnormal vascular growth and permeability in AMD, was developed. Following encouraging preclinical trials, clinical trials showed that pegaptanib stabilized vision and reduced the risk of severe visual loss in the majority of patients with AMD, with some patients showing visual improvement. Pegaptanib has maintained a good safety profile with only occasional adverse effects. Even greater success was achieved when pegaptanib was used in combination with another therapeutic strategy, such as photodynamic therapy or bevacizumab, a pan isoform VEGF inhibitor. Further investigation of pegaptanib for the therapy of wet AMD, particularly in combination with other modes of therapy, should be encouraged.