Patients who receive intravitreal ranibizumab for treatment of diabetic macular oedema over a 3-year period achieved rapid improvements in vision and oedema.
Findings from 36 months of follow-up in the phase III RISE and RIDE trials also indicated a physiologic benefit of the anti-vascular endothelial growth factor (VEGF) treatment, noted Dr Leonard Feiner, PhD, who is in private practice, Retina Associates of New Jersey, Teaneck, New Jersey, USA.
The trials showed reduction in area of leakage on fluorescein angiography, which continued to increase over time. Earlier treatment initiation may result in better outcomes as well.
"As in age-related macular degeneration (AMD) and retinal vein occlusion (RVO), ranibizumab redefines the standard of care for patients with DME," he said.
About the trials
RISE and RIDE enrolled about 750 patients with best-corrected visual acuity (BCVA) of 20/40 to 20/320 and optical coherence tomography central subfield thickness ≥275 μm.
They were randomly assigned 1:1:1 to monthly intravitreal injection with ranibizumab 0.3 mg, ranibizumab 0.5 mg, or sham. All patients could receive laser photocoagulation beginning at month 3 if their vision or macular oedema was not improving.
The primary endpoint was at 24 months, and thereafter, patients in the sham arm were eligible to be crossed over to ranibizumab.
More than 80% of patients in each treatment arm completed follow-up to 24 months, and retention at 36 months ranged from 73% in the sham arm to about 78.5% in the ranibizumab arms.
Patients originally treated with ranibizumab experienced rapid improvement in BCVA, with notable vision gain seen as early as 7 days, on average.
At 24 months, BCVA had improved by slightly more than 2 lines across all ranibizumab arms and the gains persisted at 36 months.
After crossover to ranibizumab, patients in the sham arm also had an improvement in vision. However, the gain from BCVA at 24 months was only about 2 letters based on an intent-to-treat analysis, with last observation carried forward.
Only about 3 letters in an analysis included only the sham patients who received at least one ranibizumab injection after month 24.
"Findings from subgroup analyses showed that the benefits of ranibizumab treatment for improving vision were consistent," Dr. Feiner said. "However, as expected, patients whose central foveal thickness was 450 μm or greater at baseline had more BCVA improvement than their counterparts with less edema at enrollment."
Analyses of changes in central foveal thickness showing early reductions were maintained with continued ranibizumab treatment.
The crossover to ranibizumab among sham patients resulted in drying of macular edema despite the limited vision benefit.