Purpose
To assess the effect of intravitreal ranibizumab on diabetic retinopathy (DR) severity.
Methods
Exploratory analysis in participants with diabetic macula edema (DME) meeting eligibility criteria (n=759) including best corrected visual acuity of 20/40 to 20/320 Snellen equivalent and OCT central subfield thickness of ≥275 μm, were randomized 1:1:1 to receive monthly 0.3 mg or 0.5 mg ranibizumab, or sham injections. Sham participants were eligible to receive 0.5 mg ranibizumab during the third year. All participants were eligible for macular laser beginning at Month 3, and panretinal photocoagulation (PRP) was available as needed. Fundus photographs, taken at baseline and pre-specified intervals, were graded by a central reading center; clinical examinations were performed monthly. Analysis outcomes included: ≥2, ≥3-step change on the Early Treatment Diabetic Retinopathy Study (ETDRS) DR Severity Scale in the study eye; and a composite clinical progression outcome including photographic changes plus clinically-important events such as occurrence of vitreous hemorrhage or application of PRP. Time to first DR progression was analyzed by Kaplan-Meier methods to calculate cumulative probabilities by treatment group.
Results
A greater proportion of eyes in the ranibizumab arms had a ≥2- or ≥3-step DR regression (improvement) on the ETDRS severity scale compared to eyes in the sham/0.5 mg crossover group at month 36. A ≥3-step improvement was achieved at 36 months by 3.3%, 15.0% and 13.2% of the sham/0.5 mg crossover, 0.3 mg and 0.5 mg ranibizumab treated eyes, respectively. Through 36 months 33.9% of eyes originally randomized to sham developed proliferative DR (PDR) as measured by the composite outcome, compared to 12.8% and 15.1 % of 0.3 mg and 0.5 mg ranibizumab-treated eyes respectively, although the proportions of participants exhibiting DR progression during the third year were similar in all three arms.
Conclusions
These data, derived from two large randomized, controlled trials of ranibizumab for DME, provide strong evidence that ranibizumab is effective in reducing DR severity and can inhibit clinical progression to PDR evaluated by composite outcomes. However, prolonged delays in initiation of ranibizumab therapy, as in the RIDE/RISE sham group, may limit this therapeutic effect.
Keywords: 499 diabetic retinopathy •
688 retina