We have read with interest—particularly as pertaining to our own GALILEO Study —the results of the study reported by Călugăru and Călugăru, which found visual and anatomic improvements in patients with macular edema secondary to central retinal vein occlusion (CRVO) treated with intravitreal bevacizumab injections.
As noted by Călugăru and Călugăru, there are major differences between their study and the GALILEO trial, which evaluated the efficacy and safety of intravitreal aflibercept injections in patients with macular edema secondary to CRVO. Specifically, the patient population in GALILEO was less ischemic and had a longer duration of disease. Given these differences, any comparison between the 2 studies should be interpreted with caution. The nonstandard dose of bevacizumab (2.5 mg) and injection interval (every 6 weeks) used by Călugăru also make comparison with other studies of bevacizumab difficult.
Călugăru and Călugăru note that at week 76 in GALILEO there was a decrease in the visual and anatomic improvements initially observed at week 24, and they hypothesize that this may be attributable to disease progression. We acknowledge that disease progression is a possible explanation of this finding. However, as noted by Heier and associates in their report of the 2-year results of the COPERNICUS study (a sister study to GALILEO), these declines in visual and anatomic improvements in the GALILEO study may be attributable, at least in part, to the pro re nata (PRN) dosing regimen (beginning after week 24) and the every-8-weeks monitoring interval (beginning after week 52).
In both the COPERNICUS and GALILEO studies, patients who were randomized to intravitreal aflibercept showed a continued superiority in visual outcomes over those who were initially randomized to sham, despite the improvements seen in the sham group after switching to PRN dosing with intravitreal aflibercept. As pointed out by Călugăru and Călugăru, these findings suggest that patients with macular edema secondary to CRVO may benefit from early treatment with intravitreal aflibercept.
In conclusion, the GALILEO study demonstrated the efficacy of intravitreal aflibercept in patients with macular edema secondary to CRVO and the importance of prompt treatment for optimal functional gains. Differences in patient populations between the study by Călugăru and Călugăru vs the GALILEO study limit comparisons between these studies, but both support the finding that delaying treatment with anti–vascular endothelial growth factor (VEGF) agents following diagnosis can result in suboptimal visual gains compared with prompt treatment. Levels of ischemia vary vastly in CRVO (note that peripheral nonperfusion can only be evaluated with wide-field angiography, which was not used in either study), as do intraocular VEGF levels; therefore, comparisons are realistic only within identical study populations.