Ranibizumab 0.5 mg is safe and effective for patients with macular edema (ME) that is not due to diabetes, retinal vein occlusion (RVO) or neovascular age-related macular degeneration (nAMD), according to findings from the PROMETHEUS randomized trial.

“Although patients with ME resulting from inflammatory conditions or post-uveitis and patients with ME occurring after cataract surgery seem to benefit from ranibizumab treatment, ranibizumab treatment seems to have no benefit in ME resulting from CSC (central serious chorioretinopathy),” the author report. “For idiopathic ME, a more exploratory approach needs to be followed.”

Ranibizumab is clearly safe and effective for patients with ME due to diabetes or RVO, Dr. Staurenghi and his team write. In the 19-country PROMETHEUS study, 178 patients were randomly assigned 2:1 to ranibizumab or sham treatment for two months. Therapy was switched to open-label for 10 additional months, and 156 patients completed the study.

From baseline to month two, best corrected visual acuity (BCVA) improved by 5.7 letters in the intervention group versus 2.9 letters in the control group. At one year, the mean increase in BCVA was 9.6 letters in patients randomized to ranibizumab and 8.7 letters in those originally randomized to the sham treatment.

Treatment effects varied widely among patients with different ME etiologies, from a decrease of 2.0 letters for patients with Coats’ disease to an increase of 25 letters in patients with pattern dystrophies of the retinal pigment epithelium at two months. At 12 months, effects ranged from 5 fewer letters for radiation retinopathy to 28 more letters for pattern dystrophies of the retinal pigment epithelium.

“The higher potential of self-resolution in these ME conditions and the higher potential to gain more with lower baseline BCVA may have contributed to a smaller treatment effect,” Dr. Staurenghi and colleagues write.

“Similarly to the observations in this study, variable treatment effects of anti-VEGF agents in patients with ME resulting from different uncommon causes have been described from previous smaller trials and case reports.”