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2-Year Data from Protocol S

November 13, 2015

Protocol S of the study group is a randomized multi-center clinical trial to evaluate noninferiority of intravitreal ranibizumab vs panretinal photocoagulation (PRP) for the treatment of proliferative diabetic retinopathy, with the primary endpoint as mean visual acuity change letter score over two years. The trial involved 55 clinical sites across the U.S. Two hundred three eyes were randomly assigned to receive PRP treatment, completed in 1 to 3 visits, and 191 eyes received 0.5 mg intravitreous ranibizumab at baseline and as frequently as every 4 weeks based on a structured re-treatment protocol. At 2 years, visual acuity improved by 2.8 letters from baseline in the ranibizumab group compared with an improvement of 0.2 letters from baseline in the PRP group, with a mean difference of 2.2 letters between treatment groups (P < .001). There was less peripheral visual field loss, 213 dB in the ranibizumab group vs. 531 dB in the PRP group, and there were less vitrectomies performed in the ranibizumab group, with 4% of eyes requiring vitrectomy compared with 15% of eyes in the PRP group. When diabetic macular edema was present, ranibizumab was more effective than PRP in preserving central and peripheral visual function, but cost, compliance, nerve function, and patient preference need to be taken into account. In summary, ranibizumab should be considered a viable treatment option in proliferative diabetic retinopathy, particularly in patients requiring anti-VEGF treatment for diabetic macular edema. There were no substantial safety concerns in either group for at least 2 years.


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