From the American Academy of Ophthalmology Annual Meeting: Anti-VEGF drugs: Not just for retinal pathologies alone

February 28, 2013

Use of anti-vascular endothelial growth factor (VEGF) drugs may be beneficial in patients with neovascular glaucoma and to control complications after filtration surgeries.

 

Use of anti-vascular endothelial growth factor (VEGF) drugs may be beneficial in patients with neovascular glaucoma and to control complications after filtration surgeries.

Many questions remain about their applicability during trabeculectomy, however.

The anti-VEGF drugs, rani­bizumab (Lucentis) and bevacizumab (Avastin), both from Genentech, can be used in patients with neovascular glaucoma to prevent vascularity and to prevent aggressive wound healing and fibrosis after filtering surgeries.

Patients with neovascular glaucoma have an abundance of VEGF in the vitreous and aqueous that stimulates angiogenesis and fibroblast proliferation. Injection of anti-VEGF drugs results in a rapid clinical improvement within days to weeks in iris and angle neovascularization, explained Cynthia G. Mattox, MD, during Glaucoma Subspecialty Day at the recent annual meeting of the American Academy of Ophthalmology, in Chicago.

Important factors to consider, according to Dr Mattox, when using anti-VEGF agents in this patient population is that the drugs have a short half-life, which necessitates additional application of panretinal photocoagulation (PRP) to sustain the treatment effect.

“The 2 primary scenarios in which anti-VEGF [drugs] would be useful are in eyes with mild iris or angle neovascularization and in eyes with severe synechial angle closure resulting from neovascularization,” said Dr Mattox, associate professor of ophthalmology, Tufts University School of Medicine, and director, Glaucoma and Cataract Service, New England Eye Center, Boston.

In the former, anti-VEGF drugs can prevent the development of uncontrolled intraocular pressure and in the latter they can “dramatically reduce” surgical complications, such as bleeding, hyphema, and postoperative inflammation.

In addition, anti-VEGF drugs can markedly improve the pain control in these eyes, Dr Mattox noted. Another area in which anti-VEGF drugs may be useful is postoperative filtration surgery complications.

“The main cause of filtration failure is subconjunctival fibrosis,” she said. “In these eyes, VEGF stimulates angiogenesis and Tenon’s fibroblast proliferation, creates scar formation, and releases more inflammatory cytokines. Anti-VEGF drugs may not cause widespread death of fibroblasts compared with mitomycin C (MMC). The anti-VEGF drugs have a number of theoretical advantages as a tool to modulate postoperative wound healing after filtration surgery.”

Unfortunately, few studies have been conducted on the use of anti-VEGF drugs during glaucoma surgery. While anecdotal evidence points to a beneficial effect of anti-VEGF drugs in trabeculectomy, the early studies have not indicated that ranibizumab or bevacizumab is superior to MMC or 5-fluorouracil during trabeculectomy to control IOP or bleb morphology.

Dr Mattox discussed 1 study of Ahmed valve implantation in pediatric patients (60 eyes). The eyes were divided into 3 treatment groups of 20 eyes each: intraoperative subconjunctival bevacizumab (1.25 mg), intraoperative MMC applied to the sclera beneath the plate, and the Ahmed valve alone.

“Compared with Ahmed valve implantation alone in these eyes, there was a significant improvement in the success rate of the blebs 6 months postoperatively,” Dr Mattox sad. “The bevacizumab group had a 70% complete success rate. The patients in the MMC group had 8 serious complications of scleral or tube erosions. The Ahmed valve alone group had a 60% complete success rate.”

Many questions remain to be answered about the use of anti-VEGF drugs in filtration surgery, such as their superiority over MMC in the long and short term postoperatively. Other problems to be addressed are the study design of such a comparison, the proper delivery method of the anti-VEGF drug being studied, the optimal dose, the time(s) of administration, the frequency and duration of administration, and the potential for combination therapy, Dr Mattox concluded. ■

Ms Charters is a freelance medical writer based in Framingham, Mass.

Disclosure Information: Dr Mattox reports no financial disclosures as related to products discussed in this article.