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Michael A. Klufas, Allen Chiang, Lauren Hill, Min Tsuboi, Ivaylo Stoilov; Patients ultra-responsive to ranibizumab: rates of ≥4-step improvement in diabetic retinopathy severity in DRCR.net Protocol S. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5358.
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Improvements in diabetic retinopathy (DR) severity are commonly reported as 2-step or 3-step improvements. Here we characterized the proportion of patients with DR who had ≥4-step improvement on the Early Treatment Diabetic Retinopathy Study (ETDRS) DR Severity Scale (DRSS) in response to ranibizumab (RBZ) therapy, and the factors predictive of such improvements from the DRCR.net Protocol S dataset.
Protocol S was a phase 3, randomized, active-controlled clinical trial that compared the efficacy of prompt panretinal photocoagulation to RBZ 0.5 mg for the treatment of proliferative DR. In this post-hoc analysis DR ultra-responders were defined as eyes with improvement by ≥4 steps on the ETDRS-DRSS from baseline (BL). The frequency of ≥4-step DRSS improvement was analyzed retrospectively at years 1 and 2 in RBZ-treated eyes with gradable BL DRSS of ≥47. Outcomes include best-corrected visual acuity (BCVA). Predictors of ≥4-step DR improvement were assessed by univariate and multivariate analyses. The source of the data is the DRCR.net, but the analyses, content, and conclusions presented herein are solely the responsibility of the authors.
The proportion of DR ultra-responders in the RBZ arm at year 1 and 2 was 43/148 (29.1%) and 38/136 (27.9%), respectively. At year 2, BCVA showed better improvements from BL for DR ultra-responders than for those not meeting the ultra-responder criteria (Table). Multivariate analysis further defined eyes with greater or reduced odds of being DR ultra-responders during the 2 year study (Figure). Year 1 DR ultra-responders received a mean (SD) of 7.4 (2.6) RBZ injections in the first year. Year 2 DR ultra-responders received 4.2 (3.4) RBZ injections between year 1 and 2.
In Protocol S, nearly 30% of RBZ-treated eyes were DR ultra-responders at years 1 and 2. While more studies are needed to further confirm predictors of DR ultra-responsiveness to RBZ, these results indicate that RBZ treatment can dramatically improve DR severity in a subset of patients with proliferative DR. Addition of visual outcomes enhances understanding of the impact of treatment on this subset of patients.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
Change from BL in BCVA by ETDRS letters
BL Factors Predictive of ≥4-Step DR Improvement—Multivariate Analysis*
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