Can't-Miss Highlights in Retina

Every year, thousands of retina specialists from across the globe gather together for Retina Subspecialty Day at the annual meeting of the American Academy of Ophthalmology. This year, we were treated to a series of excellent clinical trial presentations, interactive point-counterpoint debates, surgical video discussions, and demonstrations of cutting-edge technology and surgical techniques.

Below is a brief summary of some of those presentations.

Hemorrhagic Occlusive Retinal Vasculitis

Dr Dean Eliott provided an excellent overview and update on the rare but terrifying potential complication associated with intracameral vancomycin administration: hemorrhagic occlusive retinal vasculitis (HORV).^[1]

In this condition, patients present with painless, progressive, and severe loss of vision approximately 1 week after intraocular surgery. To date, 36 eyes of 22 patients have been described. All cases are associated with the use of intraocular vancomycin at the time of surgery, mostly commonly given at the end of routine cataract surgery for endophthalmitis prophylaxis. All eyes have had a similar presentation: extensive retinal hemorrhage and vascular occlusion with severe loss of vision. Most patients end up with a visual acuity of 20/100 or worse, many develop neovascular glaucoma, and nearly half of eyes end up with no light perception.

Although the etiology is unknown, it appears that it is an immune or allergic reaction to vancomycin.

Of note, patients who develop HORV in one eye are at risk of developing it in the other eye, even if surgery is performed years later. Therefore, it is important to delay sequential surgery if vancomycin is being used.

It is also important to consider this condition in cases of atypical postsurgical endophthalmitis, where intravitreal vancomycin is a standard treatment. These eyes have a very high risk for disease progression with an outcome of no light perception.

Ang2 and Anti-VEGF Inhibition

Pharmaceutical companies have motivation to develop the next great age-related macular degeneration (AMD) treatment option and are investing heavily in research and development.

One exciting molecule is angiopoietin-2 (Ang2). Inhibition of Ang2 is currently being studied in combination with anti–vascular endothelial growth factor (VEGF) inhibition in phase 2 clinical trials.^[2] Like VEGF, Ang2 is involved in angiogenesis, modulating endothelial cell stabilization. This process is important during human development and also in wound healing but becomes aberrant and destructive in such diseases as AMD. Increased Ang2 levels attract other proangiogenic inflammatory cells and destabilize and sensitize vascular endothelium, making it more able to sprout vascular buds. As such, blocking both VEGF and Ang2 may be more effective than blocking VEGF alone.

Three separate clinical trials are currently evaluating this theory—two for AMD and one for diabetic macular edema. One molecule being developed by Genentech is a monoclonal antibody with bi-specific activity against both VEGF and Ang2. The Fc region of the antibody is disabled, resulting in faster systemic clearance. Regeneron is developing a coformulation of an anti-Ang2 antibody and an anti-VEGF antibody. Both products have done well in phase 1 clinical trials, with visual and anatomic improvements at all dose levels and no evidence of new safety concerns.

Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.

Cite this: Can't-Miss Highlights in Retina - Medscape - Jan 11, 2017.

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