Ranibizumab combined with verteporfin photodynamic therapy in neovascular age-related macular degeneration: year 1 results of the FOCUS Study

Anti-vascular endothelial growth factor pharmacotherapy for age-related macular degeneration: a report by the American Academy of Ophthalmology

OBJECTIVE

To examine the evidence about the safety and efficacy of anti-vascular endothelial growth factor (VEGF) pharmacotherapies for the treatment of neovascular age-related macular degeneration (AMD).

DESIGN

Literature searches were conducted in May and October 2007 in PubMed with no date restrictions, limited to articles published in English, and in the Cochrane Central Register of Controlled Trials without a language limitation and yielded 310 citations. The first author reviewed the abstracts of these articles and selected 73 articles of possible clinical relevance for review by the panel. The panel deemed 64 of these articles sufficiently clinically relevant to review in full text and assigned ratings of level of evidence to each of the selected articles with the guidance of the panel methodologists.

RESULTS

Eleven studies provided level I evidence for intravitreal pegaptanib and ranibizumab for neovascular AMD; there were no studies rated level I for bevacizumab for neovascular AMD. Five studies were rated as level II, which included studies of ranibizumab and bevacizumab, and the remaining 38 articles retrieved were rated as level III. The studies do not provide information about long-term results or the value (comparative effectiveness) and cost-effectiveness of combined therapies.

CONCLUSIONS

Review of the available literature to date suggests that anti-VEGF pharmacotherapy, delivered by intravitreal injection, is a safe and effective treatment for neovascular AMD for up to 2 years. There is level I evidence to support this conclusion for pegaptanib and ranibizumab, but none for bevacizumab at this time.

Intravenous diclofenac as prophylactic treatment for verteporfin-associated low back pain

PURPOSE

The authors report on the therapeutic effect of intravenous diclofenac on verteporfin associated low back pain (LBP), which is the most frequent adverse effect of photodynamic therapy (PDT) for macular degeneration.

METHODS

The authors studied 818 patients who received PDT with verteporfin for choroidal neovascularization. Systemic blood pressures were recorded in all study participants half an hour before PDT treatment. All patients who experienced LBP during verteporfin infusion were asked to grade their pain as mild (1), moderate (2), severe (3), or unbearable (4).

RESULTS

Thirty-three patients had LBP during their first verteporfin infusion. Of these, 11 subjects (1.34% of all) reported increased pain scores (level 2 to 4) and received intravenous diclofenac ahead of their next PDT. Patients with LBP during verteporfin infusion had significantly higher systolic blood pressures than uncomplicated cases (180 mmHg vs 155 mmHg, p=0.01). Treatment with intravenous diclofenac short before PDT significantly reduced the patients' mean pain score by 1.8 levels (p=0.0001).

CONCLUSIONS

In this study, intravenous application of diclofenac short before verteporfin infusion effectively prevented verteporfin associated LBP in patients with systemic hypertension.

Intravitreous anti-VEGF for diabetic retinopathy: hopes and fears for a new therapeutic strategy

Vascular endothelial growth factor (VEGF) plays a key role in the development of both proliferative diabetic retinopathy (PDR) and diabetic macular oedema (DMO). In recent years, anti-VEGF agents have emerged as new approaches to the treatment of these devastating diabetic complications. Although Phase III studies in the diabetic population are needed, intravitreal anti-VEGF therapy is currently being used in clinical practice. Intravitreal injection is an effective means of delivering anti-VEGF drugs to the retina. However, this is an invasive procedure associated with potentially serious complications, such as endophthalmitis or retinal detachment, which may be significant for patients requiring serial treatment over many years. In addition, although delivered within the vitreous, anti-VEGF drugs could pass into the systemic circulation, which could potentially result in hypertension, proteinuria, increased cardiovascular events and impaired wound healing. Pegaptanib, ranibizumab and bevacizumab are the currently available anti-VEGF agents. Ranibizumab and bevacizumab block all VEGF isoforms, thus impairing both physiological and pathological neovascularisation. Pegaptanib only blocks the VEGF(165) isoform, and would therefore seem the best option for avoiding systemic adverse effects in diabetic patients, although this remains to be demonstrated in clinical trials. In this regard, head-to-head studies designed to evaluate not only the efficacy, but also the systemic adverse effects of these drugs in a high-risk population such as diabetic patients are warranted.

Effect of aspirin therapy on photodynamic therapy with verteporfin for choroidal neovascularization

BACKGROUND

Photodynamic therapy (PDT) with verteporfin is used for treatment of choroidal neovascularization in several conditions. Platelet aggregation is one of the mechanisms by which PDT is thought to work. This study sought to examine the hypothesis that systemic use of aspirin, an inhibitor of platelet aggregation, affects the efficacy of PDT.

METHODS

A retrospective review was conducted of data for patients treated with PDT at one institution between 2001 and 2004. End points included total number of PDT treatments, mean time between PDT treatments, change in visual acuity from baseline to 3 months after last PDT treatment, and concurrent or subsequent treatments other than PDT.

RESULTS

A total of 244 eyes of 222 patients met inclusion criteria, of which 102 eyes from 92 patients were included in the aspirin taking group. Aspirin takers received an average of 3.11 PDT treatments compared with 2.39 PDT treatments for nonaspirin takers (P = 0.001). Decrease in logMAR visual acuity was greater for aspirin takers (P = 0.0003), and a loss of > or =3 lines was seen in 58% of aspirin takers compared with 35% of nonaspirin takers (P = 0.0003). These differences remained statistically significant after controlling for patient age, lesion type, and lesion size.

CONCLUSIONS

Patients taking aspirin required more PDT treatments and had worse visual outcomes than patients not taking aspirin, possibly due to aspirin's ability to inhibit platelet aggregation and thereby diminish the efficacy of PDT.

Potential bias in ophthalmic pharmaceutical clinical trials

To make clinicians aware of potential sources of error in ophthalmic pharmaceutical clinical trials that can lead to erroneous interpretation of results, a critical review of the study design of various pharmaceutical ophthalmic clinical trials was completed. Discrepancies as a result of study shortcomings may explain observed differences between reported ophthalmic trial data and observed clinical results.

High efficiency reconstitution of a human-mouse chimeric Fab of CAb-1 antibody specific to human colon cancer

Monoclonal antibody (mAb) has been widely applied in the treatment of human diseases, especially in malignant tumours. However, most antibodies produced in mouse by hybridoma technology might induce severe human anti-mouse reactions. We had reported a murine mAb CAb-1 of therapeutic interest for its specifically binding to a cell surface glycoprotein of human colon cancer. Here, we attempted to generate a reconstituted human-mouse chimeric Fab (cFab) of CAb-1 in vitro to reduce its antigenicity and increase its capacity of penetration. First, the genes of heavy and light chain variable region (VH, VL) of CAb-1 were cloned. Then, the chimeric light chain (cL) and Fd (cFd) were constructed and expressed in Escherichia coli. Finally, the reconstituted cFab was obtained by gradient dialysis of the mixture of cFd and cL. SDS-PAGE and western blot analysis showed the reconstituted cFab with a recovery rate of 70.2% when the initial total concentration of cL and cFd proteins to be 100 microg/ml. The reconstituted cFab maintained the affinity and specificity to colon cancer cells compared with its parental antibody as determined by immunostaining analysis, FACS and ELISA. Our results established a foundation for further application of the cFab in diagnosis and treatment of colon cancer.

Ranibizumab combined with verteporfin photodynamic therapy in neovascular age-related macular degeneration (FOCUS): year 2 results

PURPOSE

To assess the efficacy and adverse-events profile of combined treatment with ranibizumab and verteporfin photodynamic therapy (PDT) in patients with predominantly classic choroidal neovascularization (CNV) secondary to neovascular age-related macular degeneration.

DESIGN

Two-year, multicenter, randomized, single-masked, controlled study.

METHODS

Patients received monthly intravitreal injections of ranibizumab 0.5 mg (n = 106) or sham injections (n = 56). All patients received PDT on day zero, then quarterly as needed. Efficacy assessment included changes in visual acuity (VA) and lesion characteristics and PDT frequency. Adverse events were summarized by incidence and severity.

RESULTS

At month 24, 88% of ranibizumab + PDT patients had lost <15 letters from baseline VA (vs 75% for PDT alone), 25% had gained >or=15 letters (vs 7% for PDT alone), and the two treatment arms differed by 12.4 letters in mean VA change (P < .05 for all between-group differences). The VA benefit of adding ranibizumab to PDT in year one persisted through year two. On average, ranibizumab + PDT patients exhibited less lesion growth and greater reduction of CNV leakage and subretinal fluid accumulation, and required fewer PDT retreatments, than PDT-alone patients (mean = 0.4 vs 3.0 PDT retreatments). Endophthalmitis and serious intraocular inflammation occurred, respectively, in 2.9% and 12.4% of ranibizumab + PDT patients and 0% of PDT-alone patients. Incidences of serious nonocular adverse events were similar in the two treatment groups.

CONCLUSIONS

Through two years, ranibizumab + PDT was more effective than PDT alone and had a low rate of associated adverse events.

Antiangiogenic therapy with anti-vascular endothelial growth factor modalities for neovascular age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a common cause of severe vision loss in people 55 years and older.

OBJECTIVES

The objective of this review was to investigate the effects of anti-VEGF (vascular endothelial growth factor) modalities for treating neovascular AMD.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE and LILACS. We handsearched ARVO abstracts for 2006, 2007 for ongoing trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. We contacted trial authors for additional data. We summarized outcomes as relative risks (RR), number needed to treat (NNT) and weighted mean differences.

MAIN RESULTS

We included five RCTs of good methodological quality. All five trials were conducted by pharmaceutical companies. An intention-to-treat analysis using the last observation carried forward method was done in most trials. Two trials compared pegaptanib versus sham. One trial compared ranibizumab versus sham, another compared ranibizumab/sham verteporfin PDT versus verteporfin PDT/sham ranibizumab, and the final trial compared ranibizumab plus verteporfin PDT versus verteporfin PDT alone. Fewer patients treated with pegaptanib lost 15 or more letters of visual acuity at one year follow-up compared to sham (pooled relative risk (RR) 0.71; 95% confidence interval (CI) 0.61 to 0.84). The NNT was 6.67 (95% CI 4.35 to 14.28) for 0.3 mg pegaptanib, 6.25 (95% CI 4.17 to 12.5) for 1 mg pegaptanib and 14.28 (95% CI 6.67 to 100) for 3 mg pegaptanib. In a trial of ranibizumab versus sham, RR for loss of 15 or more letters visual acuity at one year was 0.14 (95% CI 0.1 to 0.22) in favour of ranibizumab. The NNT was 3.13 (95% CI 2.56 to 3.84) for 0.3 mg ranibizumab and 3.13 (95% CI 2.56 to 3.84) for 0.5 mg ranibizumab. In a trial of ranibizumab versus verteporfin PDT, RR for loss of 15 or more letters at one year was 0.13 (95% CI 0.07 to 0.23) favouring ranibizumab. The NNT was 3.33 (95% CI 2.56 to 4.76) for 0.3 mg ranibizumab and 3.12 (95% CI 2.43 to 4.17) for 0.5 mg ranibizumab. In another trial of combined ranibizumab plus verteporfin PDT versus verteporfin PDT, RR for loss of 15 or more letters at one year favoured combined therapy (RR 0.3 (95% CI 0.15 to 0.60). The NNT was 4.35 (95% CI 2.78 to 11.11). Pooled RR for gain of 15 or more letters visual acuity at one year was 5.81 (95% CI 3.29 to 10.26) for ranibizumab versus sham, 6.79 (95% CI 3.41 to 13.54) for ranibizumab/sham verteporfin PDT versus verteporfin PDT/sham ranibizumab, and 4.44 (95% CI 1.40 to 14.08) for ranibizumab plus verteporfin PDT versus verteporfin PDT. Frequency of endophthalmitis in included studies was between 0.7% to 4.7% with ranibizumab and 1.3% with pegaptanib. Improvement in vision-specific quality of life was reported for both treatments.

AUTHORS' CONCLUSIONS

Pegaptanib and ranibizumab reduce the risk of visual acuity loss in patients with neovascular AMD. Ranibizumab causes gains in visual acuity in many eyes. Quality of life and cost will be important for treatment decisions. Other agents blocking VEGF are being tested in ongoing trials.

Ranibizumab in neovascular age-related macular degeneration

Neovascular age-related macular degeneration (AMD) is a visually devastating condition resulting from choroidal neovascularization and secondary photoreceptor loss. Ranibizumab and bevacizumab are medications that target vascular endothelial growth factor (VEGF). While other therapies have demonstrated some ability to reduce the risk of losing vision from neovascular AMD, most patients continue to lose some degree of central visual acuity. There is growing evidence that intravitreal administration of ranibizumab and bevacizumab is effective in significantly improving the visual acuity in patients with neovascular age-related macular degeneration.

The future implications and indications of anti-vascular endothelial growth factor therapy in ophthalmic practice

In the last few years anti-vascular endothelial growth factor (VEGF) therapy has changed the paradigm in the treatment of neovascular age-related macular degeneration (ARMD). Besides, its potential use in the treatment of diabetic retinopathy and other possible proliferative vascular disorders has also shown promise. Clinical trial results have shown tremendous beneficial effect of ranibizumab in ARMD. Off-label use of bevacizumab has also shown similar benefit but long-term and clinical trial results do not exist. Some of the potential questions in the use of anti-VEGF are recurring cost, possible long-term effect on physiological function of VEGF and determination of endpoint of treatment. Overall, the use of anti-VEGF therapy in ocular angiogenesis has proven to be beneficial at least now.

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.

Targeting vascular endothelial growth factor: a promising strategy for treating age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in the industrialised world. While treatment options for advanced AMD have been rather limited until recently, the introduction of intravitreal injections of anti-angiogenic agents appears to be a promising and revolutionary mode of treatment for this blinding disease. Vascular endothelial growth factor (VEGF) appears to play a pivotal role in the pathogenesis of choroidal neovascularisation, one of the cornerstones of advanced AMD. Pegaptanib, the first anti-VEGF treatment approved for AMD patients, is a VEGF-neutralising aptamer that specifically inhibits one isoform of VEGF (VEGF-165). Although evidence suggested that pegaptanib was superior to previous treatment options, results with this agent were still unsatisfactory. Ranibizumab is a humanised anti-VEGF monoclonal antibody fragment that inhibits all isotypes of VEGF. This new drug has demonstrated a high efficacy profile in terms of inhibiting disease progression and even improving visual acuity. Bevacizumab is a full-length anti-VEGF antibody that was originally approved for use in metastatic colon cancer and is under investigation as a low-cost off-label alternative for patients with AMD. There is growing evidence that this drug may be an effective and safe alternative to the more expensive ranibizumab, although prospective multicentre trials are required to fully investigate this issue. Undoubtedly, the concept of directly injecting anti-VEGF drugs into the vitreal cavity brings new hope to many AMD patients.

One-year results of photodynamic therapy for small predominantly classic choroidal neovascular membranes secondary to age-related macular degeneration

PURPOSE

To determine the visual and angiographic outcomes of patients with small predominantly classic choroidal neovascular membranes (CNV) undergoing photodynamic therapy (PDT).

METHODS

The subjects were a cohort of patients with age-related predominantly classic CNV with lesion size of greatest linear diameter of 2000 microm or less treated with PDT. Lesion size and visual acuity were recorded at baseline and at 3-month intervals. Visual treatment failure was defined as either loss of at least 15 letters or visual acuity less than 35 letters on a modified Early Treatment Diabetic Retinopathy Study chart. Lesion treatment failure was defined as increase in greatest linear diameter (GLD) of at least 500 microm.

RESULTS

Twenty-five eyes of 25 patients were included. Visual treatment failure occurred in 16 and mean visual acuity dropped from 58 letters to 34 letters (p<0.0001). In 11 of these patients this occurred within the first 3 months. Lesion treatment failure occurred in 18 patients. Mean GLD increased from 1331 to 2935 microm (p<0.0001). Early growth of the lesion was associated with poor visual outcome with growth in GLD in the first 3 months of 310 microm in patients without eventual visual treatment failure and 1131 microm in patients with eventual visual failure (p=0.027).

CONCLUSIONS

Small predominantly classic lesions commonly cause visual deterioration if treated with PDT alone. In the first year over 50% may lose at least 15 letters or drop below 35 letters, with most visual loss occurring in the first 3 months. Visual loss is associated with early lesion growth.

Neue Perspektiven in der Diagnostik

BACKGROUND

Recent advances in optical coherence tomography (OCT) have made it possible to increase resolution and scan velocities so that even greater central areas of the retina can be scanned. The aim of this study is to describe the possibilities offered by this new technology for age-related macular degeneration.

MATERIAL AND METHODS

The study included 20 patients with confirmed active choroidal neovascularization (CNV) as well as pigment epithelial detachment (PED). Three-dimensional imaging was performed with a high-definition raster scanning OCT system (HD-OCT) with an axial resolution of 6 microm and a scan velocity of up to 20,000 A-scans/s. The scanned area measured 6 x 6 mm with a depth of 2 mm. Two-dimensional imaging was carried out with a StratusOCT (Carl Zeiss Meditec).

RESULTS

Comparison of the individual slices showed improved identification of intra- and subretinal structures with the HD-OCT. Demarcation of pathological changes in individual retinal layers is possible with the HD-OCT. Summation images permit accurate localization of a scan. Topographic and volumetric evaluations enable analysis of individual compartments in the entire scanned area and are suitable for monitoring treatment of CNV with anti-VEGF therapy. The raster method decreases the dependence on exploratory methods that have been necessary until now to generate retinal thickness maps.

CONCLUSIONS

This report presents initial experience in using a raster scanning HD-OCT system in patients with neovascular age-related macular degeneration and describes new evaluation functions that aid in obtaining more precise assessment of treatment effect and its impact on the retinal ultrastructure. The results of this study clearly show that development of high-resolution OCT systems in conjunction with development of novel treatment options for exudative diseases offers promising perspectives.

Guidance for the treatment of neovascular age-related macular degeneration

Neovascular age-related macular degeneration is becoming an increasing socio-medical problem as the proportion of the aged population is continuously increasing. However, new insights in the pathogenesis of the disease offer the opportunity to develop targeted therapies that attack the disease process more successfully than ever. This review article will focus on summarizing the actual options in the management of neovascular age-related macular degeneration and provide a short overview about recent therapeutic options in clinical and preclinical evaluation. The recent development of anti-VEGF substances for use in clinical routine has markedly improved the prognosis of patients with neovascular AMD. Intravitreal treatment with substances targeting all isotypes of vascular endothelial growth factor (VEGF), for the first time in the history of AMD treatments, results in a significant increase in visual acuity in patients with neovascular AMD. Overall, antiangiogenic approaches provide vision maintenance in over 90% and substantial improvement in 25-40% of patients. The combination with occlusive therapies like photodynamic therapy (PDT) potentially offers a reduction of re-treatment frequency and long-term maintenance of the treatment benefit. Further developments interacting with various steps in the angiogenic cascade are under clinical or preclinical evaluation and may soon become available. Nevertheless, the growing number of novel therapeutic options will have to provide proof of concept in randomized controlled clinical trials, a major challenge in view of the rapidly evolving field. For those therapies, which are already in clinical use, reasonable diagnostic tools for follow-up need to be developed, as the burden of continuous clinical monitoring of all patients and all indications is significant for patients and doctors. Ultimately, economic issues will be the limiting factor for the clinical availability of different treatment options.

INTRAVITREAL BEVACIZUMAB COMBINED WITH PHOTODYNAMIC THERAPY FOR THE TREATMENT OF OCCULT CHOROIDAL NEOVASCULARIZATION ASSOCIATED WITH SEROUS PIGMENT EPITHELIUM DETACHMENT IN AGE-RELATED MACULAR DEGENERATION

PURPOSE

To evaluate the efficacy of intravitreal injection of bevacizumab combined with photodynamic therapy (PDT) for the treatment of occult choroidal neovascularization (CNV) associated with serous pigment epithelium detachment (s-PED) due to age-related macular degeneration (AMD).

METHODS

In this retrospective study, six patients (six eyes) with subfoveal occult CNV associated with s-PED due to AMD were treated with intravitreal bevacizumab combined with PDT. All patients were treated at baseline with PDT followed by intravitreal bevacizumab 1.25 mg 1 hour later. Afterwards, according to the findings of optical coherence tomography and fluorescein angiography, repeat bevacizumab injections were given, if necessary, monthly for three doses followed by further doses every 3 months. PDT was repeated every 3 months according to the same criteria. Follow-up time was 9 months.

RESULTS

All patients completed their treatment during the first 3 months from baseline. Best-corrected visual acuity (BCVA) improved or remained stable related to the baseline values in all patients at the end of the follow-up time. Mean BCVA improved from 20/67 to 20/42. S-PED and subretinal fluid decreased or disappeared. The mean central 1-mm retinal thickness was reduced from baseline value for the 9-month follow-up period by 128 microm.

CONCLUSION

Intravitreal bevacizumab combined with PDT seems to be a promising treatment with good functional and anatomical results for occult CNV associated with s-PED due to AMD.

Ocular Photodynamic Therapy – Standard Applications and New Indications (Part 2)

Photodynamic therapy (PDT) has become a well-established treatment for vascular forms of age-related macular degeneration (AMD). The implementation of evidence-based medicine principles into the treatment regimen of AMD seems to be immensly important, since AMD continues to be the most frequent cause of blindness among patients older than 65 years in industrialized countries. Numerous randomized prospective studies demonstrated high levels of evidence for the efficacy of various treatment approaches such as laser photocoagulation, PDT, subretinal surgery or novel anti-angiogenic drugs [Arch Ophthalmol 2006;124:597-599]. The high evidence shown by these studies supported the rationale to use PDT also in additional, less frequent, vasoproliferative diseases. Although these 'case series' and 'individual case control studies' have a low level of evidence, they give us important information for treatment decisions in these rare conditions. The goal of this survey is to review the current literature regarding PDT in vasoproliferative and exudative ocular diseases outside AMD. Many studies modified the treatment parameters of PDT to address the specific pathology of the underlying disease. Table 1 summarizes the diseases and treatment parameters that are described in this part 2, the entire table of this review is included in part 1 (www.karger.com/doi/10.1159/ 000101922).

Intravitreales Bevacizumab vs. Verteporfin und intravitreales Triamcinolon Acetonid bei Patienten mit neovaskulärer AMD

AIM

The aim of this study was to compare intravitreal bevacizumab (IVB) and verteporfin therapy in combination with 4 mg intravitreal triamcinolone (PDT-IVTA) in patients with neovascular age-related macular degeneration (AMD).

PATIENTS AND METHODS

A total of 30 eyes of 30 patients with neovascular AMD were included in a prospective, randomized study. Ten eyes received PDT-IVTA with a standard light fluence of 50 J/cm(2) (SPDT-IVTA), ten were treated with PDT-IVTA with a reduced light fluence of 25 J/cm(2) (RPDT-IVTA) and ten received IVB. The main outcome was evaluated using early treatment diabetic retinopathy study (ETDRS) visual acuity, fluorescein angiography and optical coherence tomography (OCT) at baseline as well as at day 1, week 1, 1 month and 3 months after therapy.

RESULTS

At the beginning of therapy, the distribution of the groups was balanced. After 3 months, the SPDT-IVTA group showed a non-significant vision loss of seven letters (p<0.3) while a vision loss of 0.5 letters (p<0.9) was found in the RPDT-IVTA group. At the same time, the IVB group had a vision improvement of 11.8 letters (p<0.001). This vision improvement was statistically significant compared to the results of both PDT-IVTA groups (p<0.005). Central retinal thickness (CRT) decreased up to month 3 in the SPDT-IVTA group by 132 microm, in the RPDT-IVTA group by 78 mum and in the IVB group by 138 microm, (p<0.05 in the three groups). No significant difference in the decrease of CRT was found between the treatment groups after 3 months.

CONCLUSION

IVB shows significantly better results in vision improvement in the short-term compared to the two PDT-IVTA groups. Within 3 months, all groups showed a comparable decrease in CRT. Long-term follow-up is required to evaluate the safety and treatment efficacy of all treatment modalities.

Current Treatment of Age-Related Macular Degeneration

PURPOSE

To review proved and experimental treatments for exudative and nonexudative complications of age-related macular degeneration (AMD), to consider the impact of current therapy on the structure of future clinical trials, and to consider the role of improved diagnostic imaging techniques on the effectiveness of current therapy as well as the structure of future clinical trials in AMD patients.

RESULTS

Defining the cell biology of choroidal new vessel (CNV) formation and geographic atrophy will lead to identification of different biochemical pathways that are the target of AMD treatment. Many treatments and treatment combinations are under study for AMD, but all work through a finite number of pathways. Currently, the most effective proved therapy for AMD-associated CNVs is administered by repeated intravitreal injection of agents that inhibit vascular endothelial growth factor, e.g., ranibizumab. Improved drug delivery will enhance patient satisfaction and possibly will enhance the effectiveness and reduce the risk of current pharmacotherapy for AMD-associated CNVs. Combination therapy (e.g., verteporfin-photodynamic therapy + ranibizumab) appears to reduce the risk and enhance the effectiveness of CNV treatment compared with monotherapy with currently available agents. Improved noninvasive diagnostic imaging may lead to better visual outcomes with existing therapeutic modalities. Improved imaging also may alter favorably the design of future clinical trials for AMD-associated CNVs and thus reduce cost and increase the diversity of sight-saving treatments.

CONCLUSIONS

Delineation of the biochemical basis for CNV formation has led to development of pathway-based pharmacotherapy for AMD patients. Areas of investigation that will advance the field further include combination therapy, improved drug delivery, and improved noninvasive, high-resolution diagnostic imaging. The logistics of future clinical trials will be complicated by the need for an active treatment control group, more stringent definition of successful treatment, and the increased numbers of patients required for combination therapy studies.

Pegaptanib and ranibizumab for neovascular age-related macular degeneration: a systematic review

AIMS

To assess the clinical effectiveness of pegaptanib sodium and ranibizumab for neovascular age-related macular degeneration (AMD).

METHODS

A systematic review of randomised controlled trials (RCTs) identified through searching 12 electronic databases, bibliographies and consultation with experts and manufacturers. RCTs were eligible if they assessed the effects of pegaptanib or ranibizumab with best supportive care, sham injection or photodynamic therapy (PDT) on patients with subfoveal choroidal neovascularisation associated with wet AMD and examined outcomes including visual acuity and adverse events.

RESULTS

Three RCTs of ranibizumab (MARINA, ANCHOR, FOCUS) and two of pegaptanib (VISION study) met the inclusion criteria. The RCTs included patients with different lesion types. The studies showed statistically significant benefit on different measures of visual acuity for patients receiving pegaptanib, ranibizumab or ranibizumab with PDT compared to control (sham injection, PDT or sham injection with PDT) after 12 months. These differences appeared to be clinically significant. Although adverse events were common among those receiving pegaptanib or ranibizumab, they were considered mild to moderate in nature. Meta-analysis of ranibizumab trials and indirect comparison of the two drugs were not possible due to differences in the study populations' lesion types. However, results from the RCTs of ranibizumab tended to show a greater effect on visual acuity than results from the RCT of pegaptanib.

CONCLUSIONS

Pegaptanib and ranibizumab appear to slow or stop the progression of neovascular AMD. Uncertainty remains over the relative benefits of pegaptanib compared with ranibizumab and other unlicensed drugs (eg, Avastin), due to the nature of the evidence. Head-to-head RCTs and economic evaluations comparing these alternatives are needed.

Adult retinal pigment epithelial transplantation in exudative age-related macular degeneration

PURPOSE

To improve visual function by retinal pigment epithelial (RPE) cell transplantation and systemic immunosuppression at the time of surgical removal of subfoveal choroidal neovascularization in exudative age-related macular degeneration (AMD).

DESIGN

An interventional case series of RPE transplantation in exudative AMD.

METHODS

Twelve patients (one eye only) underwent subfoveal membranectomy with transplantation of a sheet of adult human allogeneic RPE cells at a single institution and were followed for one year. Eligibility criteria included age >60, best-corrected acuity < or =20/63 and subfoveal neovascularization < or =9 disk areas on preoperative fluorescein angiography. All patients were started on triple immunosuppression postoperatively. The primary outcome measure was best-corrected vision, with contrast sensitivity and reading speed as secondary outcome measures.

RESULTS

The best-corrected visual acuity (P = .085), contrast sensitivity (P = .204), and the reading speed (P = .077) did not change significantly at one year compared with preoperative values. Transplants showed no signs of rejection in patients who were able to continue the immunosuppressants for six months. Postoperative surgical complications included cataract progression requiring surgery (three of eight phakic eyes), retinal detachment (three eyes), intraoperative retinal breaks (two eyes), and macular pucker (two eyes). None of the patients developed cystoid macular edema on postoperative fluorescein angiography or postoperative inflammation.

CONCLUSIONS

A sheet of adult human allogeneic RPE can be transplanted into the subretinal space in AMD patients at the time of subfoveal membranectomy. Systemic immune suppression appeared to prevent rejection of the transplanted tissue, but did not lead to an improvement in visual function.

Combination therapy for the treatment of ocular neovascularization

The growth of inappropriately regulated, leaky blood vessels is a prominent component of several debilitating eye diseases, such as age-related macular degeneration (AMD), proliferative diabetic retinopathy (PDR), and retinopathy of prematurity (ROP). New pharmacological therapies that target vascular endothelial growth factor-A (VEGF-A) have significantly enhanced the treatment of AMD by limiting the progression of the disease, and in some cases, by improving vision. Although anti-VEGF therapy will undoubtedly prove valuable in the treatment of other neovascular diseases of the eye, improvements with this type of therapy are still required. At present, anti-VEGF therapy requires intravitreal injection and a relatively frequent dosing regimen (4-6 weeks). Furthermore, in experimental models of neovascularization, anti-VEGF treatment becomes less effective at blocking vessel growth and at regressing vessels as the neovascularization develops over time. As such, the use of anti-VEGF therapy in late-stage AMD may be limited. An important strategy for improved treatment of neovascular diseases of the eye could be combination therapy. Combination therapy of anti-VEGF drugs with established treatments, such as photodynamic therapy with verteporfin (PDT-V), or with newly-developed drugs targeting specific kinases, presents opportunities for increased efficacy and improved therapeutic outcome. In this review, we evaluate the opportunities for combination therapy for the treatment of neovascular diseases of the eye.

Ranibizumab for the treatment of neovascular AMD

Age-related macular degeneration (AMD) is the leading cause of adult blindness among individuals aged 50 and older in the Western world, with the neovascular form of AMD responsible for the most severe and rapid visual loss. Although monotherapy with currently available treatments can slow the rate of loss of vision in eyes with neovascular AMD, they do not significantly improve vision. Vascular endothelial growth factor-A (VEGF-A) plays a critical role in the pathogenesis of neovascular AMD, and ranibizumab is a promising new treatment that targets all VEGF-A isoforms and their biologically active degradation products. Clinical trials have reported that ranibizumab treatment resulted in greater proportions of patients achieving a < 15 letter loss of visual acuity and improved vision at 12 and 24 months than control groups. The incidence of serious ocular and systemic adverse events was low in all ranibizumab trials to date. Currently, ranibizumab is the only treatment for neovascular AMD to demonstrate significant improvement in vision for many patients and represents a major advance in treating neovascular AMD.

Emerging Therapies for the Treatment of Neovascular Age-Related Macular Degeneration and Diabetic Macular Edema

Diabetic macular edema (DME) and choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD) are the leading causes of vision loss in the industrialized world. The mainstay of treatment for both conditions has been thermal laser photocoagulation, while there have been recent advances in the treatment of CNV using photodynamic therapy with verteporfin. While both of these treatments have prevented further vision loss in a subset of patients, vision improvement is rare. Anti-vascular endothelial growth factor (VEGF)-A therapy has revolutionized the treatment of both conditions. Pegaptanib, an anti-VEGF aptamer, prevents vision loss in CNV, although the performance is similar to that of photodynamic therapy. Ranibizumab, an antibody fragment, and bevacizumab, a full-length humanized monoclonal antibody against VEGF, have both shown promising results, with improvements in visual acuity in the treatment of both diseases. VEGF trap, a modified soluble VEGF receptor analog, binds VEGF more tightly than all other anti-VEGF therapies, and has also shown promising results in early trials. Other treatment strategies to decrease the effect of VEGF have used small interfering RNA to inhibit VEGF production and VEGF receptor production. Corticosteroids have shown efficacy in controlled trials, including anacortave acetate in the treatment and prevention of CNV, and intravitreal triamcinolone acetonide and the fluocinolone acetonide implant in the treatment of DME. Receptor tyrosine kinase inhibitors, such as vatalanib, inhibit downstream effects of VEGF, and have been effective in the treatment of CNV in early studies. Squalamine lactate inhibits plasma membrane ion channels with downstream effects on VEGF, and has shown promising results with systemic administration. Initial results are also encouraging for other growth factors, including pigment epithelium-derived factor administered via an adenoviral vector. Ruboxistaurin, which decreases protein kinase C activity, has shown positive results in the prevention of diabetic retinopathy progression, and the resolution of DME. Combination therapy has been investigated, and may prove to be quite effective in the management of both DME and AMD-associated CNV, although ongoing and future studies will be crucial to treatment optimization for each condition.

[(Side) effects of VEGF inhibition]

Vascular endothelial growth factor (VEGF) plays a pivotal role for embryo- and organogenesis. By regulating haemodynamics, (lymphoid) vessel architecture, haematopoiesis and immune system, endocrinology and reparative processes in adults, inhibited VEGF can cause multiple adverse events. Although the intravitreal administration of smaller doses can drastically reduce the systemic exposure, possible local side effects on retinal perfusion and survival of neuronal tissue must be taken into consideration. Before experience has been gained with VEGF inhibitors for longer than several years, individual discussion before the use, extensive informed consent and careful follow-up are necessary. From the ethical point of view, the available drugs should not be used without hesitation despite the clear benefit. First experiences with bevacizumab (Avastin), the first available (off-label) drug in Germany, are reported. In future, direct comparison of the different available drugs has to assess possible differences in the risk-benefit profile.

New therapies for neovascular age-related macular degeneration: critical appraisal of the current evidence

During the past 20 years, several multicentre clinical trials have investigated different therapies for neovascular age-related macular degeneration (AMD). These landmark studies have provided the scientific community with powerful data regarding the ability of laser photocoagulation, verteporfin therapy, pegaptanib sodium and submacular surgery to treat particular choroidal neovascular lesion types. Accurate interpretation of data from these trials is essential to enable clinicians to make informed decisions about therapeutic interventions. Furthermore, several new treatment options are likely to become available in the next few years and clinicians will have to decide how effective these therapies may be, and how (or if) they should be used in clinical practice. It is therefore timely to review the strengths and weaknesses of the body of evidence for the currently available therapeutic options for patients with choroidal neovascularization due to AMD. Evaluation of the quality of reporting in past clinical trials will also enable critical review of new studies that will be published in the future. This review summarizes the design, reporting and results of key randomized clinical trials, in addition to evaluating the available evidence for new therapies and identifying the important issues that need to be considered when evaluating their efficacy.

Früher antiexsudativer Effekt – OCT-Monitoring nach intravitrealer Bevacizumab-Applikation

VEGF is more potent than histamine by a factor of 50,000 for inducing increased vessel permeability. Already in the first few minutes, hydraulic conductivity and diffusive permeability are significantly increased, followed by a longer-lasting, marked leakage over 20 h. Specific inhibition of the angiogenic, vasoactive, and permeability-inducing protein VEGF is now possible by new drugs, one of which is the first available (off-label) treatment in Germany for routine clinical use (Avastin). Retinal edema is composed of increased outflow of water and low molecular substances in the interstitial environment and is an important determinate of functional development in different ocular diseases. First experiences with the anti-hyperpermeability effect show early response and high potential in pathologic leakage. Future examinations have to assess when a permanent benefit can be achieved in respect to the other antiproliferative capabilities of the drug.