SEP 16, 2010
This is the first randomized, double-masked study to compare ranibizumab to sham in patients with macular edema secondary to central retinal vein occlusion (CRVO). It was a monitored study conducted at four sites in Norway. Patients were randomized to receive ranibizumab 0.5 mg/0.05 mL or sham each month for the first three months. For the next three months, treatment was given on an as-needed basis.
At six months, mean BCVA improved by 12 letters in the treated group, while the sham group lost a letter. Mean central macular thickness (CMT) decreased by 304 μm in the treated group compared to 151 μm in the control group. Repeated monthly injections were required to maintain efficacy, with 80 percent of patients requiring additional injections. There were no nonresponders in the ranibizumab group. Also, treatment of recurrent macular edema resulted in a new reduction in CMT and improvement in BCVA score.
Lastly, this study provides an insight into the natural course of CRVO over a six-month period. It shows that there is minimal change in mean BCVA scores, even if mean CMT reduces spontaneously. In the sham group, mean CMT at baseline was 587 μm and at month six this decreased to 436 μm. BCVA scores remained stable, decreasing from 41 ETDRS letters to 39 ETDRS letters. If left untreated, severe macular edema may result in functional damage to the neuroretinal tissue over time, resulting in a lasting worsening of BCVA.