Loss of reactivity in intravitreal anti-VEGF therapy: tachyphylaxis or tolerance?

Nanoengineering of therapeutics for retinal vascular disease

Retinal vascular diseases, including diabetic retinopathy, neovascular age related macular degeneration, and retinal vein occlusion, are leading causes of blindness in the Western world. These diseases share several common disease mechanisms, including vascular endothelial growth factor (VEGF) signaling, hypoxia, and inflammation, which provide opportunities for common therapeutic strategies. Treatment of these diseases using laser therapy, anti-VEGF injections, and/or steroids has significantly improved clinical outcomes. However, these strategies do not address the underlying root causes of pathology, and may have deleterious side effects. Furthermore, many patients continue to progress toward legal blindness despite receiving regular therapy. Nanomedicine, the engineering of therapeutics at the 1-100 nm scale, is a promising approach for improving clinical management of retinal vascular diseases. Nanomedicine-based technologies have the potential to revolutionize the treatment of ophthalmology, through enabling sustained release of drugs over several months, reducing side effects due to specific targeting of dysfunctional cells, and interfacing with currently "undruggable" targets. We will discuss emerging nanomedicine-based applications for the treatment of complications associated with retinal vascular diseases, including angiogenesis and inflammation.

Aflibercept versus ranibizumab for treating persistent diabetic macular oedema

The purpose of this study was to compare the efficacy of intravitreal aflibercept versus ranibizumab for treating therapy-resistant diabetic macular oedema (DME). A 69-year-old man presented with persistent bilateral DME despite previous ranibizumab treatment. Bilateral study treatment comprised one cycle of three monthly ranibizumab injections (0.5 mg), followed by one cycle of three aflibercept injections (2.0 mg), a second ranibizumab cycle and a second aflibercept cycle. Baseline visual acuity (ETDRS score) was 60 letters for the right eye and 65 letters for the left eye. Baseline central foveal thickness (CFT) was 305 μm for the right eye and 453 μm for the left eye. Substantially improved outcomes were observed during the first aflibercept cycle. CFT was reduced by 150 μm (mean) in both the eyes and decreased below the lowest level achieved during the previous 2.5-year ranibizumab treatment. Visual acuity was improved by 17.5 letters (mean) in both the eyes. Reintroduction of ranibizumab immediately worsened the status of both eyes back to the baseline level. During the final aflibercept cycle, visual acuity and CFT improved to the same levels achieved during the first aflibercept cycle. In this case study, we prospectively switched the treatment three times and observed a dramatic and consistent treatment advantage for aflibercept.

Switch to Aflibercept in the Treatment of Neovascular AMD: One-Year Results in Clinical Practice

PURPOSE

To report the clinical outcomes of intravitreal aflibercept therapy in eyes with refractory and recurrent neovascular age-related macular degeneration (AMD) switched from intravitreal bevacizumab or ranibizumab.

METHODS

This is a retrospective review of eyes with neovascular AMD switched to intravitreal aflibercept with at least 1 year of follow-up after the switch. All patients had had a minimum of 3 injections of bevacizumab or ranibizumab before the switch. Aflibercept was used in patients considered refractory to bevacizumab (group 1) and in recurrent patients on therapy with ranibizumab due to an institutional policy decision (group 2). Changes in best-corrected visual acuity, fluid on optical coherence tomography (OCT), central retinal thickness (CRT) and the frequency of injections were compared.

RESULTS

Eighty-five eyes of 69 patients were analyzed, 39 eyes in group 1 and 46 in group 2. The mean follow-up time was 31.6 months prior to the switch and 14.7 months on treatment with aflibercept. One year after the switch, there was a nonsignificant mean decrease of 2 letters in visual acuity in both groups (group 1: from 58.2 to 55.8 letters, p = 0.086; group 2: from 56.4 to 54.5 letters, p = 0.168), but the mean number of injections per month was significantly lower (from 0.76 to 0.57, p < 0.001). With the switch, 90.6% of the patients showed anatomic improvement with a reduction of fluid on OCT, and both groups presented significant improvement in CRT (group 1: 65.3 µm, p = 0.051; group 2: 91.0 µm, p < 0.001).

CONCLUSION

Aflibercept appears to be a valuable tool for the management of patients with poor responses to other anti-vascular endothelial growth factor drugs. These patients could have anatomic improvement, and the injection intervals could be extended.

Short-term outcomes of switching anti-VEGF agents in eyes with treatment-resistant wet AMD

BACKGROUND

To investigate the short-term outcomes of treatment with intravitreal aflibercept in cases with wet age-related macular degeneration (AMD) resistant to ranibizumab.

METHODS

The study included patients who had been undergoing follow-up for a minimum of three months at the Ankara University Faculty of Medicine Ophthalmology Department's Retina Unit with a diagnosis of wet AMD. All cases had received intravitreal aflibercept injection due to the presence of intraretinal/subretinal fluid and pigment epithelial detachment (PED), as detected by optical coherence tomography (OCT), despite having received intravitreal ranibizumab. Medical records of the cases were investigated retrospectively and the demographic data, treatments administered before aflibercept injection, best-corrected visual acuity (BCVA) before and after aflibercept injection, central macular thickness (CMT), and the presence of intraretinal/subretinal fluid and the height and presence of PED were recorded.

RESULTS

A total of 29 eyes from 11 females and 17 males were included in the study. The mean age was 73.89 ± 7.49 (62-92). The average number of intraocular injections administered before aflibercept injection was 11.75 ± 5.73 (6-25). The mean duration of follow-up following aflibercept injection was 4.55 ± 2.14 (3-11) months, with a mean of 3.44 ± 0.73 (3-5) aflibercept injections during this period. The mean BCVA values before and after aflibercept injection were found to be 0.83 and 0.77 LogMAR, respectively. The mean CMT values before and after aflibercept injection were 471.3 (97-1365) and 345.1 (97-585) microns, respectively (p < 0.001). The PED height before and after aflibercept injection was 350.4 ± 151.7 (129-793) and 255.52 ± 156.8 (0-528) microns, respectively (p < 0.05).

CONCLUSION

Switching to intravitreal aflibercept appears to be an effective treatment modality for patients with AMD who are resistant to ranibizumab. While anatomic success including the effect of reducing the PED height was achieved in the short term following aflibercept injection in all cases, no concomitant increase in visual acuity occurred. This is attributed to the long-term presence of chronic fluid and the development of scar tissue before the treatment.

Evaluation of the Response to Ranibizumab Therapy following Bevacizumab Treatment Failure in Eyes with Diabetic Macular Edema

Background/Aims

Bevacizumab and ranibizumab are routinely used to treat diabetic macular edema (DME). We aim to evaluate the usefulness of switching to ranibizumab therapy following bevacizumab treatment failure in eyes with DME.

Methods

We performed a retrospective analysis of a consecutive group of patients with DME who received ranibizumab injections following the failure of bevacizumab injections. The injections were delivered following a pro re nata protocol every 4–6 weeks. The data collected included demographics, systemic and ophthalmic findings, as well as the central subfield thickness according to spectral-domain OCT.

Results

Eight eyes (5 patients) were included in the study. The median number of bevacizumab injections prior to the switch to ranibizumab was 4, and the median number of ranibizumab injections during the study was 2. The mean follow-up period was 541 ± 258 days. The mean central retinal thickness (CRT) (±SEM) was 539 ± 75 μm before the initiation of bevacizumab treatment, and 524 ± 43 μm after the last bevacizumab injection (p = 0.7). It reduced to 325 ± 26 μm following the ranibizumab injections (p = 0.0063). The best-corrected visual acuity (BCVA) improved in 4 eyes and remained stable in 4 eyes following the ranibizumab injections.

Conclusion

A ranibizumab therapy was effective in reducing the CRT in eyes that failed bevacizumab therapy. A BCVA improvement can also occur in these eyes. Switching between anti-vascular endothelial growth factor compounds may be beneficial in eyes with DME.

Suppression of laser-induced choroidal neovascularization by intravitreal injection of tristetraprolin

AIM

To examine the effect of intravitreal adenoviral vector-mediated tristetraprolin (Ad-TTP) on VEGF mRNA expression in a rat model of laser-induced choroidal neovascularization.

METHODS

Ad-TTP was prepared using a commercial kit. Retinal laser-induced photocoagulation (10 spots per eye) was performed on rats in this experimental choroidal neovascularization (CNV) model. Rats were divided into four groups: control (single intravitreal injection of balanced salt solution, n=10), laser-induced CNV (photocoagulation only, n=20), laser-induced CNV plus Ad-TTP injection (photocoagulation plus a single intravitreal Ad-TTP injection, n=20) and Ad-TTP injection only (n=10). Changes in choroidal morphology were evaluated in ten rats in the laser only and the laser plus Ad-TTP groups. Two weeks after laser injury, the size of CNV was calculated by perfusion with high-molecular-weight fluorescein isothiocyanate (FITC)-dextran. VEGF mRNA expression in retina-choroid tissue from ten rats in each group was measured by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

Two weeks after treatment, the area of laser-induced CNV was reduced by approximately 60% in the rats given the Ad-TTP injection compared with that in the laser-only group. There was a tendency toward decreased VEGF mRNA expression in the Ad-TTP injection groups.

CONCLUSION

A single intravitreal injection of Ad-TTP significantly suppressed CNV size in this experimental laser-induced CNV model. Ad-TTP injection also decreased VEGF mRNA expression compared with that in the laser-induced CNV group. The present study is meaningful as the first study to investigate the effect of tristetraprolin delivered via intravitreal injection.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effect of aflibercept in insufficient responders to prior anti-VEGF therapy in neovascular AMD

PURPOSE

Evaluation of three aflibercept injections at 4-week intervals in patients with neovascular AMD showing an "insufficient anatomic response" to prior anti-VEGF therapy with ranibizumab or bevacizumab.

METHODS

The retrospective analysis included 96 eyes that had received at least three intravitreal 0.5 mg ranibizumab or 1.25 mg bevacizumab injections over a period of no more than 4 months prior to switching to aflibercept. In addition, the selected eyes had to have evidence of persisting or increasing sub- or intraretinal fluid, observed in optical coherence tomography (OCT). All patients received a loading dose of three intravitreal 2 mg aflibercept injections at 4-week intervals. Evaluation included central retinal thickness (CRT) and maximum pigment epithelium (PED) height measured by spectral domain OCT and best-corrected visual acuity (BCVA) prior to the switch of therapy and 4 weeks after the third aflibercept injection.

RESULTS

A significant reduction of mean CRT (-39 μm; p < 0.001) and maximum PED height (-46 μm; p < 0.001) as found 4 weeks after the third aflibercept injection. Eighty-two out of 96 eyes (85 %) had a PED just prior to switching to aflibercept. There was an improvement in BCVA of 1.9 letters 4 weeks after the last aflibercept injection; the vision gain, however, did not reach statistical significance (p = 0.061). The further analysis did not show any correlation of the change in CRT, maximum PED, and BCVA with the number of prior anti-VEGF treatments.

CONCLUSION

Retinal edema and PEDs regressed significantly after switching to aflibercept in patients insufficiently responding to prior therapy with ranibizumab or bevacizumab. No correlation could be found with regard to the number of prior treatments.

A single-arm, investigator-initiated study of the efficacy, safety and tolerability of intravitreal aflibercept injection in subjects with exudative age-related macular degeneration, previously treated with ranibizumab or bevacizumab: 6-month interim analysis

Aim

To evaluate efficacy and safety of intravitreal aflibercept injection (IAI) in subjects who were previously treated with ranibizumab and/or bevacizumab for active exudative age-related macular degeneration (AMD).

Methods

Patients (n=26) were enrolled in a 12-month prospective, interventional, single arm, investigator-initiated study with planned 6-month interim analysis. Patients with active exudative AMD, previously treated with ranibizumab and/or bevacizumab, were treated with 2 mg IAI every month for the first 3 months, followed by a fixed dosing schedule of 2 mg IAI every 2 months. The primary study endpoint was the mean absolute change from baseline central subfield thickness (CST) at month 12 as measured by SDOCT. Secondary outcomes included mean change from baseline best-corrected visual acuity (BCVA) score, percentage of subjects who gained or lost greater than or equal to 15 letters of vision, percentage of subjects who are 20/40 or better, percentage of subjects who are 20/200 or worse, and the incidence of adverse events (AE) and serious AEs.

Results

Planned 6-month interim analysis demonstrated a mean decrease in CST of 38.6 µm (p<0.001) and a mean increase in ETDRS BCVA of +5.9 letters (p<0.001). Fifteen percent of subjects experienced a greater than 15-letter improvement in visual acuity, 84.6% of patients gained visual acuity, and no patient lost 3 lines of vision from baseline. Forty-two percent of subjects were 20/40 or better, and 11.5% of subjects were 20/200 or worse at month 6. No serious ocular or systemic AEs were encountered.

Conclusions

IAI-treated eyes demonstrated improved short-term functional and anatomic endpoints in subjects with active exudative AMD switching from previous anti-VEGF treatment when given in a fixed dosing scheme for 6 months.

Trial registration number

NCT01617148.

Switching intravitreal anti-VEGF treatment in neovascular age-related macular degeneration

PURPOSE

To compare the outcomes after switching between bevacizumab and ranibizumab therapy due to poor treatment effect in neovascular age-related macular degeneration (AMD).

METHODS

This is a retrospective review of patients with neovascular AMD with first treatment using intravitreal bevacizumab (group 1) or ranibizumab (group 2) who switched to the other drug due to poor treatment effect. Primary outcome measures were change in mean best-corrected visual acuity (BCVA) and mean central retinal thickness (CRT) at 1 year and last visit.

RESULTS

Eighty-seven eyes met the inclusion criteria. In group 1 (43 eyes), the mean BCVA decreased from 20/94 to 20/100 at 1 year after being switched (p = 0.573) and to 20/150 (p = 0.015) at final visit (mean 29.2 months, range 12-53). In group 2 (44 eyes), mean BCVA decreased from 20/72 to 20/90 (p = 0.401) and 20/100 (p = 0.081) at 1 year after switch and at final visit (mean 20.1 months, range 10-40), respectively. The mean CRT at switch, 1 year after switch, and at final visit were 344.4 ± 140 µm (mean ± SD), 286.26 ± 155 µm (p = 0.019), and 290.58 ± 196 µm (p = 0.009) in group 1 and 329.36 ± 144 µm, 302.0 ± 179 µm (p = 0.215), and 309.5 ± 220 µm (p = 0.154) in group 2, respectively.

CONCLUSIONS

The mean BCVA decreased over time in both groups; however, nearly 30% of the eyes in each group showed vision improvement after switching. Mean CRT decreased in both groups, which was more pronounced after being switched from bevacizumab to ranibizumab. In neovascular AMD, a switch between ranibizumab and bevacizumab can be considered as a further therapy option if poor treatment effect is seen with the initial therapy.

Twenty-Four-Month Results of Intravitreal Bevacizumab in Macular Edema Secondary to Branch Retinal Vein Occlusion

PURPOSE

The aim of this study is to evaluate the long-term efficacy of intravitreal bevacizumab (IVB) in macular edema (ME) due to branch retinal vein occlusion (BRVO) in a real clinical practice setting at a tertiary referral center.

METHODS

A retrospective analysis of a final total number of 35 eyes of 35 patients with a 24-month follow-up was performed.

RESULTS

At 24 months, mean best-corrected visual acuity improved by 0.09 LogMAR units from baseline (95% CI: -0.03-0.24, p = 0.0674). The mean CFT decreased by 75 microns (95% CI: 27-123, p = 0.0026). The median number of injections was 6 (IQR: 3-9). Macular edema showed complete resolution in 12 eyes (34.3%), responded partially in six eyes (17%), recurred in eight eyes (23%), and remained persistent in nine eyes (25.7%, three eyes at six months, one eye at 12 months, three eyes at 18 months and two eyes at 24 months).

CONCLUSION

Our study shows that treatment with IVB in patients with ME due to BRVO during a period of 24 months provided complete resolution of the ME in more than one-third of patients. In one-third of the cases, ME resolved partially or recurred and in less than one-third of patients ME remained persistent. Visual acuity increased significantly in 23% of patients and remained stable in the majority of patients. However, a median number of six injections was necessary to maintain a lasting beneficial effect. Further long-term prospective studies are required comparing intravitreal bevacizumab with other treatment modalities.

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.

Visual and anatomical outcomes of intravitreal aflibercept for treatment-resistant neovascular age-related macular degeneration

A retrospective chart review of patients with persistent subretinal and/or intraretinal fluid, despite previous treatment with intravitreal ranibizumab (0.5 mg), who were switched to aflibercept injections, was performed. Treatment was three monthly aflibercept (2 mg) injections followed by dosing on pro re nata basis. Main outcome measures included changes in best corrected visual acuity (BCVA), 1 mm central subfield (CSF) retinal thickness, the height of the pigment epithelial detachment (PED), and subfoveal choroidal thickness on optical coherence tomography at 6 months. Thirty-one eyes of 30 patients were analyzed. The mean number of injections before aflibercept conversion was 34.4 ± 11.9. After an average of 4.5 aflibercept injections (range 3 to 6) over 6 months, no significant change in BCVA was observed (P > 0.05). Compared with baseline, there was a significant reduction of the CSF retinal thickness (449 ± 179 versus 269 ± 145 μm, P < 0.001), maximum PED height (262 ± 134 versus 183 ± 100 μm, P < 0.001), and choroidal thickness (192 ± 67 versus 167 ± 51 μm, P < 0.01). Stable visual acuity and anatomical improvement were obtained for up to 6 months after aflibercept conversion. However, choroidal thinning related to treatment was observed.

Switch of anti-VEGF agents is an option for nonresponders in the treatment of AMD

BACKGROUND

Although anti-VEGF therapy of exudative AMD with bevacizumab and ranibizumab proved efficacious in the majority of patients, CNV activity does not respond to continued treatment after repeated injections in a considerable amount of patients. These are referred to as nonresponders. A change of the drug to bevacizumab or ranibizumab could possibly offer an alternative option for the treatment of nonresponding exudative AMD.

METHODS AND MATERIALS

A total of 138 nonresponders who switched therapy from bevacizumab to ranibizumab (n=114) or vice versa (n=24) were included in a retrospective study. Visual acuity (VA) and foveal thickness before and after the switch of therapy were compared. By means of linear regression analysis, we analyzed possible prognostic factors associated with a favorable outcome for visual acuity.

RESULTS

Linear regression analysis revealed a statistically significant benefit for nonresponders when treatment was changed to a different anti-VEGF drug (bevacizumab or ranibizumab). VA at the time of the switch was positively correlated with a beneficial development of VA after changing the drug. There was no significant correlation with age, macular thickness, number of injections before the switch, or the development of VA under treatment before the switch. Both patients switching to Avastin and Lucentis benefitted without statistically significant differences.

CONCLUSIONS

An exchange of bevacizumab with ranibizumab or vice versa should be considered in nonresponders in the treatment of exudative AMD. Further prognostic factors may help to identify patients who might benefit from a switch. These factors should be investigated in further studies.

Retention of good visual acuity in eyes with neovascular age-related macular degeneration and chronic refractory subfoveal subretinal fluid

PURPOSE

To describe the clinical characteristics of a subset of eyes with neovascular age-related macular degeneration (NVAMD) receiving intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy which retain good visual acuity despite chronic, persistent subfoveal subretinal fluid (SRF).

DESIGN

Retrospective, observational case series.

METHODS

Study eyes were identified from a consecutive series of 186 patients treated with anti-VEGF therapy seen for regular follow-up over a 3-month period. The clinical histories of 10 eyes of 9 patients with NVAMD, chronic subfoveal SRF despite continuous anti-VEGF therapy, and good long-term visual acuity of 20/40 or greater were reviewed. Demographic factors, baseline and final visual acuity, neovascular lesion type, duration of persistent fluid, baseline and final subfoveal choroidal thickness, presence of geographic atrophy, and number of anti-VEGF injections were analyzed.

RESULTS

The mean age of patients was 78 years (range 55-91). The mean duration of persistent fluid was 5.2 years (range 1.3-11.0). Long-term visual acuities remained stable at 20/40 or better in all eyes. All eyes had type 1 (sub-retinal pigment epithelial) neovascularization. Average baseline subfoveal choroidal thickness was 285.3 μm and the average follow-up subfoveal choroidal thickness was 239.7 μm. No eyes had the presence of geographic atrophy. The mean number of injections was 36.5 (range 17-66).

CONCLUSION

Some eyes with type 1 neovascularization associated with chronic persistent subfoveal subretinal fluid despite continuous intravitreal anti-VEGF therapy may maintain good long-term visual outcomes. We hypothesize that type 1 neovascularization and greater subfoveal choroidal thickness may exert a protective effect on photoreceptor integrity. Further studies are necessary to assess long-term visual prognosis and predictive factors in patients with type 1 neovascularization leading to persistent subretinal fluid that is recalcitrant to anti-VEGF treatment.

Clinical outcomes after switching treatment from intravitreal ranibizumab to aflibercept in neovascular age-related macular degeneration

PURPOSE

To describe the treatment response to aflibercept in patients with exudative age-related macular degeneration that showed insufficient or diminishing treatment effects under ranibizumab.

METHODS

From December 2012 till June 2013 all patients receiving intravitreal injections of aflibercept after previous treatment with ranibizumab were collected in a database and retrospectively reviewed. Clinical data such as visual acuity or central subfield retinal thickness on optical coherence tomography (OCT) scans were analyzed for the time frame before, during, and shortly after the aflibercept injections. Of particular interest was the comparison of clinical features under ongoing ranibizumab treatment to the time during aflibercept treatment.

RESULTS

Seventy-one eyes of 65 patients were included in the study. All eyes had previous ranibizumab injections in their medical history, the average number of which was nine (range 3-43). For the total group the mean visual acuity (VA) before the first ranibizumab injection was 0.54 logMAR, and after the last ranibizumab injection was 0.57 logMAR. Mean VA changed from 0.47 logMAR before the first aflibercept injection to 0.25 logMAR after the last aflibercept injection. Central subfield retinal thickness (CSRT) on OCT changed from a mean of 417.28 μm to 349.52 μm under ranibizumab treatment and from 338.76 μm to 272.00 μm under aflibercept treatment. Interestingly, 33 % of cases that did not show a functional improvement under ranibizumab therapy gained visual acuity after aflibercept treatment.

CONCLUSION

Aflibercept appears to be an effective choice for patients with neovascular age-related macular degeneration who were resistant to previous therapy of ranibizumab. The longevity of this effect still remains questionable.

Non-responders to treatment with antagonists of vascular endothelial growth factor in age-related macular degeneration

PURPOSE

Most of the publications on modern therapy of neovascular age-related macular degeneration focus on the effect of the treatment. The purpose of this study is to determine the frequency of non-responders to anti-vascular endothelial growth factor (anti-VEGF) treatment and find possible reasons for their failure to respond.

METHODS

The records of patients treated until the end of 2008 the first time with either bevacizumab or ranibizumab were reviewed. Based on the availability of measurable results and according to prior publications showing the effect of the therapy, loss of three lines of distance acuity, increase of retinal thickness or lesion size were identified as indicators of non-responders. Two of these three signs had to be present.

RESULTS

334 eyes of 283 patients were included; 74.55% received bevacizumab and 25.45% received ranibizumab. Overall 14.37% of the eyes were identified as non-responders (14.06% in the bevacizumab group and 15.29% in the ranibizumab group). Baseline distance acuity and vitreo-retinal adhesions were significantly correlated with non-responders. Correlations with age, gender, lesion type, other morphologic features, and the kind of anti-VEGF agent failed to be significant. 10.4% of the non-responders showed a delayed but good response to anti-VEGF treatment.

CONCLUSIONS

About 15% did not sufficiently respond to anti-VEGF treatment. Vitreo-retinal adherences were the only ophthalmologic factor which could be identified to be significantly correlated with insufficient response.

Intravitreal aflibercept for polypoidal choroidal vasculopathy after developing ranibizumab tachyphylaxis

Purpose

To evaluate the effect of aflibercept treatment after developing ranibizumab tachyphylaxis for the treatment of polypoidal choroidal vasculopathy (PCV).

Patients and methods

Ten eyes from ten patients with PCV who developed ranibizumab tachyphylaxis were reviewed. Tachyphylaxis was defined as when repeated intravitreal ranibizumab (IVR) resulted in a complete lack of response after initial treatment response. All treatments were converted to intravitreal aflibercept (IVA) after development of ranibizumab tachyphylaxis. Central retinal thickness (CRT) was compared at baseline, at complete resolution after IVR, at reactivation after IVR, at initial IVA, and at 4 and 12 weeks after initial IVA.

Results

Mean number of IVR treatments before conversion to IVA was 11.3 (range 5–16). All eyes had positive therapeutic responses after conversion to IVA. Mean CRT at 4 and 12 weeks after initial IVA was significantly decreased from baseline initial IVA (P = 0.005).

Conclusion

Switching therapy to aflibercept is effective for patients with PCV who develop tachyphylaxis to ranibizumab.

Aflibercept therapy for exudative age-related macular degeneration resistant to bevacizumab and ranibizumab

PURPOSE

To evaluate the outcome of intravitreal injection of aflibercept in cases with exudative age-related macular degeneration, (AMD) resistant to injections of bevacizumab or ranibizumab.

DESIGN

Retrospective observational case series.

METHODS

A retrospective chart review at a single institution was conducted to identify patients with exudative AMD and choroidal neovascularization (CNV) in 1 or both eyes resistant to treatment with ranibizumab or bevacizumab who were switched to treatment with at least 3 monthly injections of aflibercept. In total, 36 eyes from 31 patients were included. The demographic data, visual acuities, central macular thickness on optical coherence tomography (OCT), complications, and number of injections were reviewed.

RESULTS

The mean patient age was 79 years (range 60-88). There were 13 male and 18 female patients. The number of prior injections with either bevacizumab or ranibizumab ranged from 6-74. After 3 monthly injections of aflibercept, there was a reduction of either subretinal or intraretinal fluid in 18 of 36 (50.0%) of the treated eyes; the amount of fluid remained stable in 15 eyes (41.7%) and worsened in 3 eyes (8.3%). A significant average decrease was observed for the central macular thickness after 3 injections of 65 μm (P = 2.9 × 10(-6)), with no significant change in visual acuity.

CONCLUSIONS

Aflibercept therapy appears to be beneficial in a subset of patients with neovascular age-related macular degeneration who exhibit recurrent or resistant intraretinal or subretinal fluid following multiple injections with either bevacizumab or ranibizumab.

Rapid response of retinal pigment epithelial detachments to intravitreal aflibercept in neovascular age-related macular degeneration refractory to bevacizumab and ranibizumab

PURPOSE

The aim of this study is to report the short-term efficacy of aflibercept in the treatment of neovascular age-related macular degeneration (AMD) with associated retinal pigment epithelial detachment (PED) which is refractory or develops tachyphylaxis to bevacizumab and ranibizumab.

METHODS

The method comprised a retrospective review of the medical records of patients with neovascular AMD and associated PEDs recently treated with aflibercept and previously treated with bevacizumab and ranibizumab.

RESULTS

Three eyes of three female patients of ages 49, 55, and 65 years old with large serous PEDs and subretinal fluid (SRF) associated with occult choroidal neovascularization and neovascular AMD were treated with aflibercept after intravitreal bevacizumab and/or ranibizumab failed to resolve the lesions. All had complete resolution of SRF and complete or near-complete resolution of the PEDs after aflibercept injections over a 3-month period. Visual acuity improved in all three eyes.

CONCLUSION

Intravitreal aflibercept may be an effective treatment option for serous PED in neovascular AMD patients after bevacizumab and ranibizumab have previously failed. Larger studies with longer follow-up are required to determine the role of aflibercept in treatment of PED in neovascular AMD.

Therapeutic potential of intravitreal pharmacotherapy in retinal vein occlusion

Retinal vein occlusion (RVO) is the most common visually disabling disease affecting the retina after diabetic retinopathy. Although the disease entity has long been known, its management is still controversial. Macular edema is the main reason for decreased visual acuity (VA) in this retinal vascular disorder. Recently the vitreous cavity has increasingly been used as a reservoir of drugs for the direct treatment of macular edema through intravitreal injection route. The most widely injected drugs so far have been triamcinolone acetonide (TA) and bevacizumab. The objective of this review is to evaluate the evidence and discuss the rationale behind the recent suggestions that intravitreal pharmacotherapy by corticosteroids and anti-vascular endothelial growth factors may be useful in the treatment of retinal vein occlusion.