Purpose
To analyze the time to first clinically significant improvement in visual acuity and determine predictors of early visual improvement in patients with diabetic macular edema (DME) enrolled in the RIDE and RISE Phase III trials of ranibizumab for DME.
Methods
Patients meeting eligibility criteria (n=759) including best corrected visual acuity (BCVA) of 20/40 to 20/320 Snellen equivalent and central foveal thickness (CFT) of ≥275 μm were randomized 1:1:1 to receive monthly 0.3 mg or 0.5 mg ranibizumab, or sham injections. All patients were eligible for macular laser beginning at month 3. Panretinal photocoagulation was available as needed. In year 3, sham patients were eligible to cross over to 0.5 mg ranibizumab. Using the Kaplan-Meier method, we estimated time to first clinically significant improvement in BCVA defined as a gain of ≥15 letters from baseline on the Early Treatment Diabetic Retinopathy Study chart or Snellen equivalent of 20/40 or better. Baseline characteristics and demographics were explored as predictors of early responders (BCVA gain of ≥15 letters at month 6).
Results
Within the 36-month treatment period a significantly shorter time to first gain of ≥15 letters or improvement in BCVA of 20/40 or better were seen in ranibizumab -treated patients compared to patients originally randomized to sham. Half of the ranibizumab patients who ever gained ≥15 letters did so after ∼11 months of treatment, while 50% of the ranibizumab-treated patients who ever achieved vision of 20/40 or better did so in 71 days (0.3 mg) and 58 days (0.5 mg). Predictors of greater likelihood of gaining ≥15 letters at month 6 were baseline BCVA ≤55 letters and younger age in all arms. In addition, presence of subretinal fluid (SRF) was predictive in the ranibizumab arms only, while lower central foveal thickness (CFT) and no prior therapy for DME were predictive in the sham arm only.
Conclusions
Ranibizumab treatment in DME resulted in a significantly shorter time to first gain of ≥15 letters or improvement in BCVA of 20/40 or better compared to sham. Ranibizumab therapy can help patients with DME to gain ≥15 letters even if there is no rapid VA improvement at the outset of treatment. Predictors for early visual improvements in all arms included lower baseline BCVA and younger age.
Keywords: 499 diabetic retinopathy •
505 edema •
754 visual acuity