Aflibercept administration in neovascular age-related macular degeneration refractory to previous anti-vascular endothelial growth factor drugs: a critical review and new possible approaches to move forward.

PURPOSE: The recent introduction of anti-VEGF drugs has widely changed the prognosis of exudative age-related macular degeneration (AMD), even if a variable percentage of patients showed an insufficient response. Aflibercept is a new anti-VEGF drug approved by FDA for the treatment of exudative AMD with a wider binding capacity than either bevacizumab or ranibizumab. Therefore, the purposes were as follows: (i) to report anatomical and functional outcomes of switching from bevacizumab/ranibizumab to aflibercept previously described in the scientific literature, (ii) to hypothesize the possible pathophysiological mechanisms of the resistance and tachyphylaxis to anti-VEGF drugs, and (iii) to suggest possible clinical actions to increase the chances of success for such difficult cases. METHODS: We reviewed the available scientific literature in Medline, Cochrane database, Current Contents, PubMed, and cross-referencing from identified articles, regarding the treatment of exudative AMD patients refractory to bevacizumab and/or ranibizumab and switched to aflibercept monotherapy. We included in this review all the cases in which the diagnosis of refractory or resistant exudative AMD was properly made, and the results of at least one aflibercept injection were described. FINDINGS: We reported the outcomes of 21 papers for a total of 1066 eyes affected by exudative AMD resistant to previous anti-VEGF drug injections and switched to aflibercept. Enrolled reports were divided into two groups: 5 prospective reports and 16 retrospective reports. All the reported papers conclude their analysis, stating that switching from bevacizumab/ranibizumab to aflibercept injections can improve outcomes successfully in refractory neovascular AMD patients. IMPLICATIONS: Analysis of the papers reported in this review demonstrates that switching from bevacizumab/ranibizumab to aflibercept injections can improve outcomes successfully in refractory neovascular AMD patients. The mechanism for these effects is not yet completely understood.

Intravitreal ranibizumab for predominantly hemorrhagic choroidal neovascularization in age-related macular degeneration.

PURPOSE: To evaluate the effects of intravitreal ranibizumab monotherapy on predominantly hemorrhagic choroidal neovascularization with foveal involvement associated with age-related macular degeneration. MATERIALS AND METHODS: Twenty-two consecutive eyes with hemorrhagic neovascularization were treated with 3 monthly intravitreal ranibizumab injections. Additional injections were administered according to retreatment criteria during 12 months of follow-up. RESULTS: A mean of 6.64 ± 1.36 injections was administered. Overall, the mean visual acuity increased from 10.90 ± 6.02 to 12.81 ± 8.34 ETDRS letters (p > 0.05) at 12 months. The 'early treatment group' gained a mean of 2.83 ± 2.24 ETDRS letters (p < 0.05), while the 'late treatment group' gained a mean of 0.30 ± 1.25 ETDRS letters (p > 0.05) with significant differences between the groups (p < 0.05). A progressive resolution of macular bleeding was registered in 20 patients (mean time: 5.3 ± 1.6 months). CONCLUSIONS: Ranibizumab injections can be considered a beneficial approach for the management of predominantly hemorrhagic choroidal neovascularization with foveal involvement associated with age-related macular degeneration. Furthermore, the time interval between hemorrhage and the first injection seems to be an important predicting factor of final visual acuity.

The rs2071559 AA VEGFR-2 genotype frequency is significantly lower in neovascular age-related macular degeneration patients.

In this prospective, case-control genetic study, 120 consecutive neovascular age-related macular degeneration (AMD) cases and 78 controls were enrolled. Two SNPs (rs2071559 and rs1870377) of VEGF-A receptor-2 (VEGFR-2) gene were analyzed with the technique of Real-Time PCR to investigate a genetic link between AMD and VEGFR-2 gene polymorphisms in Italian patients. The frequency of the VEGFR-2 genotype rs2071559 AA was significantly lower (18.33%) in patients with AMD than in the control subjects (34.62%; P = 0.0095, chi-square test; P(corr) = 0.038; OR = 0.42, 95% CI 0.22 to 0.82). In conclusion, although with the limitations of a small sample size and the few SNPs studied, this study demonstrates a lower frequency of VEGFR-2 rs2071559 AA genotype in an AMD patient population, suggesting future studies on the role VEGFR-2 SNPs.

Choroidal Vascularity Index in Central and Branch Retinal Vein Occlusion.

(1) Background: we aimed to evaluate choroidal vascularity change in eyes with central and branch retinal vein occlusion (RVO). (2) Methods: in this retrospective cross-sectional study, we reviewed the records of 47 patients with recent-onset, naïve, unilateral retinal vein occlusion. Enhanced-depth imaging optical coherence tomography scans were binarized using the ImageJ software; luminal area (LA) and total choroidal area (TCA) were measured. The choroidal vascularity index (CVI) was calculated as the proportion of LA to TCA. Depending on the pattern of macular oedema, eyes were classified as having no macular oedema (nME), cystoid macular oedema (CME), cystoid macular oedema with serous retinal detachment (mixed). (3) Results: CVI, TCA and LA were greater in eyes with RVO than in fellow, unaffected eyes. No difference was found between central and branch RVO except for central macular thickness (CMT). When compared with controls, eyes with CME presented a significant increase in subfoveal choroidal thickness, CMT, TCA, LA and CVI; eyes with mixed macular oedema had greater CMT and CVI than contralateral eyes; no significant differences in any of the considered parameters were observed in eyes with nME. (4) Conclusions: The results suggest that RVO alters the vascularity of the choroid that varies according to the type of macular oedema.

IL-8 and VEGFR-2 polymorphisms modulate long-term functional response to intravitreal ranibizumab in exudative age-related macular degeneration.

AIM: To investigate possible associations between VEGFR-2 and IL-8 gene SNPs and 1-year response to intravitreal ranibizumab for exudative age-related macular degeneration. MATERIALS & METHODS: Sixty-four eyes underwent a loading phase of three monthly intravitreal injections of ranibizumab 0.5 mg/0.05 ml followed by Pro Re Nata retreatment. VEGFR-2 rs2071559 (-604 A/G) and IL-8 rs4073 (-251 A/T) were analyzed. RESULTS: Ranibizumab was significantly more effective as measured by visual acuity in patients harboring the IL-8 rs4073 TT genotype (p = 0.045), whereas patients carrying the VEGFR-2 rs2071559 CC genotype revealed better functional response as measured by mean retinal sensitivity (p = 0.034). CONCLUSION: IL-8 rs4073 and VEGFR-2 rs2071559 genotypes may represent important molecular determinants to modulate final outcomes in neovascular age-related macular degeneration patients.

Long-term safety of orbital radiotherapy for Graves' ophthalmopathy.

We investigated the long-term side-effects of orbital radiotherapy (OR) in 204 patients with Graves' ophthalmopathy (GO), irradiated from 1972-1996 [44 by cobalt unit (CU) and 160 by linear accelerator (LA), mostly combined with glucocorticoids], with a 5- to 25-yr follow-up (median, 11 yr). Cataract was observed in 21 patients (10%) 3-21 yr after OR, with a higher (not significant) prevalence in CU-treated patients (18% vs. 8% in LA-treated patients). The prevalence of cataract was higher, although not significantly, in CU-treated patients aged less than 60 yr, but not in LA-treated patients, compared with the general population. Mild, asymptomatic retinopathy was observed in 1 of 7 patients (14%) with diabetes and hypertension, in 1 of 31 patients (3%) with hypertension alone, and in 0 of 11 patients with diabetes alone. No tumors were observed in 157 patients submitted to computed tomography scan of orbital and adjacent regions. In conclusion, OR is a safe treatment, not associated with an increased frequency of cataract, provided a high voltage apparatus is used. Hypertension, especially if associated with diabetes, may represent a relative contraindication, as it may cause retinopathy. Although no secondary tumors were detected, due to the long latency of radiation-induced tumors, OR should be restricted to patients older than 35 yr.

VEGF-A polymorphisms predict short-term functional response to intravitreal ranibizumab in exudative age-related macular degeneration.

AIM: To investigate the association between VEGF gene SNPs and early response to intravitreal ranibizumab for exudative age-related macular degeneration. MATERIALS & METHODS: Sixty-four patients (64 eyes) were prospectively enrolled and treated for neovascular age-related macular degeneration with ranibizumab monotherapy. Visual acuity was measured using the ETDRS chart. A loading phase of 3 monthly intravitreal injections of ranibizumab 0.5 mg/0.05 ml was performed. The analyzed VEGF-A gene SNPs were rs699947 (-2578A/C) and rs1570360 (-1154G/A); the allelic discrimination was performed in real-time PCR platform. The difference of best corrected visual acuity (ETDRS letters) read before and after treatment was considered as functional outcome. RESULTS: Ranibizumab was significantly more effective as measured by best corrected visual acuity in patients harboring the VEGF-A -2578C allele (from +6.26 to +7.44 ETDRS letters), whereas patients carrying the VEGF-A -2578AA genotype revealed an absence of early functional response to ranibizumab (-1.78 ETDRS letters; p = 0.0192). CONCLUSION: This study suggests that the VEGF-A -2578A/C SNP may represent an important molecular determinant of the early functional outcome of ranibizumab. Original submitted 3 December 2012; Revision submitted 18 February 2013.

Pharmacogenetics of antiangiogenic and antineovascular therapies of age-related macular degeneration.

Age-related macular degeneration (AMD), the most common age-related disease causing irreversible visual loss in industrialized countries, is a complex and multifactorial illness. Researchers have found components of the complement alternative pathway inside drusen and Bruch's membrane of AMD patients, underlying a possible important role of complement factor H in the pathogenesis of AMD. The neovascular (wet) AMD is the most destructive form and it is characterized by invasion of new blood vessels into subretinal spaces with subsequent exudation and bleeding, resulting in scarring of the macular region and loss of the central vision. The hallmark of the neovascular form is the choroidal neovascularization, where VEGF-A has an important role in the pathogenesis of the disease. SNPs of these genes have recently been investigated as potential pharmacogenetic markers of the antiangiogenic and antineovascular therapy of AMD, which includes verteporfin photodynamic therapy and anti-VEGF-A drugs, such as pegaptanib, bevacizumab and ranibizumab. The CFH rs1061170 CT and TT genotypes have been associated with an improvement of visual acuity in bevacizumab or ranibizumab treated patients, whereas patients harboring VEGF-A rs699946 G allele responded better to bevacizumab-based therapy if compared with patients carrying the A allele. In conclusion, the discovery of pharmacogenetic markers for the personalization of the antiangiogenic and/or antineovascular therapy could be, in the future, a key issue in ophthalmology to obtain a personalization of the therapy and to avoid unnecessary costs and adverse drug reactions.