Eyeworld

EW RETINA 52 January 2015 by Tony Realini, MD, MPH, EyeWorld Contributing Writer Optimal management of macular edema caused by retinal vein occlusion I n the retina world, the past decade can appropriately be called the era of anti-VEGF therapy. Inhibition of vascular endothelial growth factor has transformed the prognosis for many retinal vascular disorders, including neovascular age-related macular degeneration, diabetic macular edema, and macular edema caused by retinal vein occlusive disease. As new therapeutic agents are developed and approved, the treat- ment paradigms for these common conditions continue to evolve. Just a few years ago, the standard therapy for macular edema following branch vein occlusion was grid laser photo- coagulation, and for macular edema following central vein occlusion, there was no good therapy. Now the choices for therapy are plentiful, which can be both a blessing and a curse. Given so many new treatment options, which is best? VEGF inhibition There are three pan-VEGF inhibitors available: bevacizumab (Avastin, Genentech, South San Francisco), Lucentis (ranibizumab, Genentech), and aflibercept (EYLEA, Regeneron Pharmaceuticals, Tarrytown, N.Y.). How do they stack up? Taraprasad Das, MBBS, FRCS, and colleagues in India conducted a prospective, randomized trial com- paring intravitreal injections of bevacizumab and ranibizumab in eyes with macular edema associated with branch vein occlusions, using the change in visual acuity at 6 months as their primary endpoint. After the initial injection, patients were assessed monthly and retreated only if pre-specified criteria were met. "At the end of 6 months, the mean gain in visual acuity was 18 letters in the ranibizumab group and 15 letters in the bevacizumab group," Dr. Das said. Both groups improved significantly compared to baseline (p<0.0001), and bevacizum- ab was statistically non-inferior to ranibizumab, he added. Comparable reductions in OCT-measured central retinal thickness were seen in both groups. The newest anti-VEGF agent, aflibercept, has also been evaluated in eyes with macular edema due to branch vein occlusion. In the VIBRANT study, treatment-naïve patients received either aflibercept 2 mg every 4 weeks or grid laser photocoagulation and were followed for 24 weeks. The primary outcome of this trial was the proportion of patients gaining at least 15 letters (3 lines) of vision. "The proportion of patients who gained at least 15 letters from baseline to week 24 was 53% in the aflibercept group compared to only 27% in the laser group," said David Boyer, MD, Los Angeles. This differ- ence was significant (p<0.001). He added that the mean visual acuity gains in the two groups were 17 and 7 letters, respectively (p<0.0001). Dexamethasone In addition to anti-VEGF agents, corticosteroids can be effective in treating macular edema associated with retinal vein occlusion. Zoya Hameed, MBBS, United Kingdom, conducted a retrospective evaluation of patients with macular edema from either branch or central vein occlusion who were treated with the dexamethasone intravitreal implant or with bevacizumab. "The mean change in best corrected visual acuity over 12 months was –0.04 letters in the dexamethasone group and +9.5 letters in the bevacizumab group," she said. This was significant (p<0.001). Lars-Olaf Hattenbach, MD, Germany, conducted a prospective, randomized trial comparing the dexamethasone implant to ranibi- zumab for macular edema following branch vein occlusion. A single implant was inserted, while ranibi- zumab was given in 3 monthly loading doses followed by PRN retreatment based on pre-specified criteria. "The mean average change in visual acuity over 6 months was +14.2 letters in the ranibizumab group and +9.7 letters in the dexamethasone group," he said. Despite these results, the dexa- methasone implant may have a niche role in managing macular ede- ma following retinal vein occlusion. Amelie Pielen, MD, and coworkers in Germany evaluated the implant's ability to improve visual acuity in eyes with macular edema refractory to anti-VEGF therapy (defined as little or no improvement in visual acuity or central retinal thickness following 3 consecutive anti-VEGF injections). In 30 anti-VEGF non-responder eyes, 1 or 2 dexamethasone implants produced a net gain of 4 letters, Dr. Pielen said. "Intravitreal dexameth- asone also significantly reduced macular edema due to retinal vein occlusion that was refractory to anti-VEGF therapy," she added, describing a 170 µm reduction in central retina thickness on OCT. Optimizing the regimen Seenu M. Hariprasad, MD, University of Chicago, Linda Yau, PhD, and Gary Sternberg, MD, Genentech, conducted the "Effect of Alternate Ranibizumab Dosing Regimens on Visual and Anatomic Outcomes in Patients with Retinal Vein Occlusion—The SHORE Study," a national 15-month, phase 4, ran- domized study. The SHORE Study examined whether as-needed (PRN) treatment with ranibizumab in 202 eligible branch and central retinal vein occlusion patients (RVO), following stability in disease state, offers visual acuity (VA) gains that are comparable to monthly doses over 15 months. Their results were presented in a poster at the 2014 ARVO meeting. All subjects received 7 monthly injections and thereafter contin- ued with monthly injections until achieving stability of visual acuity and OCT-assessed macular thickness. Once stable, patients were random- ized to continue monthly therapy or switched to a PRN regimen. Non-randomized patients continued to receive monthly injections. Primary efficacy analysis com- pared the slope of the BCVA change from baseline curves from month 7 to month 15 between the PRN and monthly arms. According to the study, approxi- mately 80% of patients were ran- domized by month 8. Study authors found no "significant difference in the slopes of the BCVA change from baseline between [month] 7 to Retinal vein occlusion Source: Amar Agarwal, FRCS

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