Recurrence of Macular Edema in Branch Retinal Vein Occlusion - a Comparison of Aflibercept and Ranibizumab in a Randomized Trial.

Objective: To prospectively investigate the time to recurrence of macular edema (ME) in patients with branch retinal vein occlusion (BRVO) treated with intravitreal aflibercept or intravitreal ranibizumab injections, and the correlation between subfoveal choroidal thickness (SFCT) at disease onset and the time to edema recurrence.

Design: Randomized, double-masked, controlled clinical trial.

Participants: One hundred and ten patients with treatment-naïve BRVO and ME presenting between 2018-2021 at St. Erik Eye Hospital, Stockholm, Sweden.

Methods: Eligible patients were randomized to receive intravitreal injections with aflibercept 2 mg (Eylea) (n=55) or ranibizumab 0.5 mg (Lucentis) (n=55). ME and SFCT were assessed with optical coherence tomography (OCT). The mean difference in SFCT (diffSFCT) between the study eyes and healthy fellow eyes was calculated. A minimum of three injections were administered monthly until complete resolution of the edema. Thereafter the patients were monitored for edema recurrence. Total follow-up time was 9 months.

Main outcome measures: Time to recurrence of ME after the initial edema resolution, number of injections required for the edema to resolve, and the correlation between SFCT at baseline and time to edema recurrence.

Results: Mean time to recurrence of ME was significantly longer in the aflibercept group, with a mean time of 10.7±2.9 weeks compared to 8.9±1.5 weeks in the ranibizumab group (p<0.001). There was no difference between the groups regarding the number of monthly injections required to obtain edema resolution, with a mean number of 2.1 injections in each group. Overall, a greater SFCT and diffSFCT at baseline was associated with a shorter time to edema recurrence. When analyzing the diffSFCT by quartiles, the mean time to recurrence was 9.2±1.6 weeks in the top quartile (diffSFCT ≥99 μm) compared to 11.2±3.0 weeks in the bottom quartile (diffSFCT ≤10 μm) (p=0.017).

Conclusions: Time to recurrence of ME in BRVO was significantly longer in patients treated with aflibercept compared to those receiving ranibizumab. A greater SFCT and diffSFCT at baseline was associated with a shorter time to edema recurrence, suggesting that these parameters could serve as predictive OCT biomarkers in BRVO.