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Comparison of Recent AMD Clinical Trials: An Evidence-Based Approach to Treating AMD Patients: Pegaptanib



Pegaptanib sodium is an anti-vascular endothelial growth factor (VEGF) aptamer that was originally known as NX1838.[16,17] Aptamers are chemically synthesized short strands of RNA that adopt highly specific 3-dimensional conformations. Aptamers can bind a target with specificity that equals or exceeds that of a specific antibody. Pegaptanib binds VEGF165, the most abundant form of VEGF, with high specificity and affinity. It recently received approval from the FDA to treat all subfoveal CNV lesions secondary to AMD regardless of lesion size, location, or composition.

The VEGF Inhibition Study in Ocular Neovascularization (VISION)[17] consisted of 2 simultaneous, double-masked, placebo-controlled, multicenter, randomized studies in patients with any lesion composition measuring less than 12 DA in size comparing 3 doses of pegaptanib (0.3, 1, and 3 mg) vs sham injection delivered every 6 weeks for 24 months. Pegaptanib (0.3 mg) effectively prevented less than 3 lines of visual loss in 70% of patients, compared with 55% who received sham injection after 1 year in all CNV lesion subtypes. Pegaptanib maintained vision similarly across all lesion categories. Endophthalmitis was reported in 1.3% of patients; however, the incidence was significantly decreased by instituting standard sterile injection techniques. Pegaptanib also prevented progression to severe vision loss. In the combined analysis, 12% fewer patients treated with pegaptanib than with sham had severe loss in visual acuity of > 30 letters at 54 weeks. After 2 years, the treatment benefit of pegaptanib was 59%, compared with 45% in the sham group.[18] In the combined analysis, pegaptanib was effective in treating all types of CNV lesion compositions; however, the results were not consistent between the 2 individual trials.[19]