Friday, November 21, 2008
Farnaz Memarzadeh, MD, describes
anti-VEGF therapy in glaucoma in an interview with Dr. Brian Francis at the 2008 AAO meeting in Atlanta. Dr. Memarzadeh reviews some of the indications where anti-VEGF therapy may be used: neovascular glaucoma (NVG), as an adjunct to
trabeculectomy in place of MMC or 5-FU, or as a rescue therapy in the event of a failed trabeculectomy.
Intravitreal injection of Avastin or Lucentis causes very rapid regression of the neovascularization of the iris and angle, thereby preventing angle closure and further progression. This suggests that if you can get to these patients early enough anti-VEGF treatments may work well.
The first randomized trial of the use of Lucentis in glaucoma is now is underway at Doheny. This phase 1 trial with 30 NVG patients combines Lucentis with standard therapies such as PRP and tube-shunt surgeries. Outcomes measured are intraocular pressures, iris neovascularization, evaluation of the posterior pole, angle neovascularization, and macular edema.
In POAG, Lucentis could be used in “rescuing” failing trabeculectomies (with subconjunctival injections). Using a rabbit model (which is particularly sensitive), Dr. Memarzadeh investigated the use of sub-conjunctival injections of Avastin (vs. 5-FU) in conjunction with trabeculectomy as primary therapy. Using Avastin, she and her colleagues found that bleb survival doubled compared to sham treated (BSS), or 5-FU treated. A poster was presented at AAO on this work that featured data from graded histology slides showing that the Avastin group had the least amount of scar tissue formation. Future comparative work may evaluate intracameral injection vs. subconjunctival vs. intravitreal injections.
Intraoperative use of VEGF inhibitors concurrent with trabeculectomy (in humans) has been done and was recently presented at ARVO.