Stewart, Michael

Vascular endothelial growth factor (VEGF) plays a pivotal role in the development of neovascularization and edema from several common chorioretinal vascular conditions. The intravitreally injected drugs (aflibercept, bevacizumab, conbercept, pegaptanib, and ranibizumab) used to treat these conditions improve the visual acuity and macular morphology in most patients. Monthly or bimonthly injections were administered in the phase III pivotal trials but physicians usually individualize therapy with pro re nata (PRN) or treat and extend regimens. Despite these lower frequency treatment regimens, frequent injections and clinic visits are still needed to produce satisfactory outcomes. Newly developed drugs and refillable reservoirs with favorable pharmacokinetic profiles may extend durations of action and require fewer office visits. However, we have learned from previous experiences that the longer durations of action seen in strategically designed phase III trials often do not translate to less frequent injections in real-life clinical practice. Unfortunately, long-acting therapies that produce soluble VEGF receptors (encapsulated cell technology and adenovirus injected DNA) have failed in phase II trials. The development of longer duration therapies remains a difficult and frustrating process, and frequent drug injections are likely to remain the standard-of-care for years to come.

Purpose: To evaluate the safety of single intravitreal 2 mg ziv-aflibercept (0.08 mL) injections for the treatment of choroidal neovascular membranes (CNVM). Methods: Eyes with choroidal neovascular membranes because of several conditions each received single intravitreal injections of 2 mg ziv-aflibercept (0.08 mL). Comprehensive ophthalmic examinations and detailed systemic evaluations were performed at baseline and Days 1, 7, and 30 after injections. Standard electroretinography was performed at baseline and Day 30. Primary outcome measures consisted of safety assessments (signs of clinical toxicity and electroretinographic abnormalities). Secondary outcome measures included changes in best-corrected visual acuity (BCVA) and central subfield thickness (CST) of the macula. Results: Twenty-one eyes of 20 patients (12 males) received injections. Etiologies responsible for the choroidal neovascular membranes included age-related macular degeneration (14), polypoidal choroidal vasculopathy (PCV) (3), myopia (2), and idiopathic juxtafoveal telangiectasia (2). None of the patients complained of worsening vision or pain after the intravitreal injections and no intraocular inflammation was seen. No significant changes in the electroretinographic b/a ratio from baseline to 1 month were measured (scotopic: P = 0.89; photopic: P = 0.13) and mean intraocular pressures were unchanged (14.2 ± 3.6 vs. 13.7 ± 3.0 mmHg; P = 0.62). Mean best-corrected visual acuity did not change significantly from baseline to 1 month (0.66 ± 0.37 logMAR [Snellen equivalent: 20/100] vs. 0.61 ± 0.35 logMAR [Snellen equivalent: 20/80]; P = 0.72) but significant improvements in central subfield thickness were seen (343 ± 177 vs. 210 ± 133 μ m; P = 0.01). Conclusion: Single intravitreal injections of 2 mg ziv-aflibercept (0.08 mL) appear to be safe through 1 month.

Purpose: To report flattening of a treatment-resistant retinal pigment epithelial detachment (PED) due to neovascular age-related macular degeneration after a single intravitreal injection of ziv-aflibercept (Zaltrap). Methods: A 67-year-old woman with a neovascular age-related macular degeneration–related PED was treated with intravitreal injections of bevacizumab and ranibizumab, and in combination with verteporfin photodynamic therapy, before receiving a single intravitreal injection of ziv-aflibercept (1.25 mg/0.05 mL). Results: The patient presented with a visual acuity of 20/30 in the right eye, a PED height of 581 μm, and a central macular thickness of 381 μm. She received eight intravitreal injections of bevacizumab and ranibizumab, one in combination with photodynamic therapy. The height of the PED and the central macular thickness varied over time, but 3 years later, they measured 382 μm and 418 μm, respectively. A single intravitreal injection of ziv-aflibercept resulted in a dramatic reduction in PED height to 140 μm, which was maintained 2 months later. The visual acuity remained stable, and there were no clinical signs of toxicity. Conclusion: Intravitreal ziv-aflibercept safely and effectively improved a treatment-resistant PED. Intravitreal ziv-aflibercept could become a treatment option for neovascular age-related macular degeneration in countries where aflibercept (Eylea) is not available or its cost is prohibitive, but further studies are necessary to establish efficacy and safety.

The widespread use of drugs that bind diffusible vascular endothelial growth factor (VEGF) has revolutionized the treatment of neovascular age-related macular degeneration (AMD). The pivotal ranibizumab and aflibercept registration trials featured monthly intravitreal injections for 12 months, during which visual acuities and macular edema rapidly improved for the first 3 months and modest gains or stabilization continued until the primary endpoint. In many subsequent trials, patients were evaluated monthly and treated as-needed (PRN) according to the results of visual acuity (VA) testing, fundus examinations and optical coherence tomography scans. Compared to monthly-treated control groups, PRN treated patients require fewer injections during the first year but they also experience smaller VA gains (1–3 letters). A small number of prospective trials that directly compared monthly with PRN therapy showed that VA gains with discontinuous therapy lag slightly behind those achieved with monthly injections. Physicians recognize that monthly office visits with frequent intraocular injections challenge patients’ compliance, accrue high drug and professional service costs, and clog office schedules with frequently returning patients. To decrease the numbers of both office visits and anti-VEGF injections without sacrificing VA gains, physicians have embraced the treat-and-extend strategy. Treat-and-extend has not been studied as rigorously as PRN but it has become popular among both vitreoretinal specialists and patients. Despite the possible risks associated with discontinuous therapy (decreased VA and increased macular fluid), most physicians individualize treatment (PRN or treat-and-extend) for the majority of their patients. This review chapter explores the many advantages of individualized therapy, while balancing these against suboptimal responses due to the decreased frequency of anti-VEGF injections.