Comparing pegaptanib and triamcinolone efficacy in the rat choroidal neovascularization model

Objective: To evaluate the prophylactic effect of intravitreal pegaptanib sodium on choroidal neovascularization membrane (CNVM) development and compare its performance with that of triamcinolone acetonide. Methods: In drug-treated and control groups, CNVMs were induced by laser trauma. Immediately after undergoing the laser procedure, animals received intravitreal injections of pegaptanib sodium, 8 or 17 mu g; triamcinolone acetonide, 200 mu g; or a vehicle solution. After 21 days, fluorescein angiography was performed. The CNVM mean diameters and radial thicknesses were measured histologically. Results: Mean CNVM diameters were 10% to 13% smaller in pegaptanib-treated eyes and 43% smaller in triamcinolone-treated eyes compared with laser-only control eyes. Late-stage fluorescein angiography leakage scores, on a scale of 0 to 3, suggested a statistical difference between triamcinolone- (0.6) and pegaptanib(8) mu g-treated (1.5) groups compared with the laser-only control group (2.0). The CNVM mean thicknesses were greater in the pegaptanib(8) (mu g)-(79 mu m) and pegaptanib(17) (mu g)-treated (71 mu m) groups and significantly smaller in the triamcinolone-treated group (26 mu m) compared with the laser-only control group (67 mu m). Conclusion: In this animal model of choroidal neovascularization, intravitreal pegaptanib exhibited marginal or no effect on CNVM development; whereas intravitreal triamcinolone evoked robust inhibition of CNVMs. Clinical Relevance: Pegaptanib treatment may be insufficient to prevent CNVM formation.