Abstract
Purpose: :
To study the effects of pegaptanib sodium intravitreous injection (Macugen®, Eyetech Pharmaceuticals Inc) on the severity of diabetic retinopathy.
Methods: :
Retrospective analysis of a cohort from a multicenter, randomized, controlled trial evaluating pegaptanib for treatment of diabetic macular edema. Subjects received a sham injection or intravitreous pegaptanib (0.3 mg, 1 mg, 3 mg) at study entry, week 6, and week 12, with additional injections and/or focal photocoagulation as needed, during the ensuing 18 weeks, up to a maximum of 6 pegaptanib/sham therapies. Scatter panretinal photocoagulation prior to study enrollment was permitted, but not within 6 months of study entry. Changes in level of diabetic retinopathy were graded on fundus photographs and confirmed on fluorescein angiograms at an independent Reading Center in a masked fashion.
Results: :
Of 172 randomized participants in this Phase 2 DME study, 39 (89%) assigned to 0.3 mg pegaptanib and 30 (73%) assigned to sham injections had fundus photographs graded for ETDRS diabetic retinopathy severity scale at baseline and Week 36 after enrollment. Five (13%) of 39 subjects assigned to pegaptanib compared with 1 (3%) of 30 subjects assigned to sham injection improved by 2 or more levels of retinopathy while 0 (0%) assigned to pegaptanib and 1 (3%) assigned to sham injection worsened by 2 or more levels of retinopathy at Week 36. 33% of the treated subjects improved by 1 step or more, compared with 13% of shams. Examples of improvement were noted among several different features of retinopathy, including severity of venous beading, intraretinal microvascular abnormalities, and retinal neovascularization.
Conclusions: :
This is the first clinical trial to demonstrate the potential of anti–VEGF therapy to improve diabetic retinopathy. Subjects assigned to pegaptanib were more likely to improve in the severity of diabetic retinopathy. These findings suggest a direct beneficial effect of VEGF inhibition on diabetic retinopathy, supported by the finding of decreased macular edema and regression of neovascularization with pegaptanib treatment in this trial.
Keywords: diabetic retinopathy • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • growth factors/growth factor receptors