Abstract
Purpose:
To determine the effect of a switch of anti-vascular endothelial growth factor (anti-VEGF) treatment from PRN Ranibizumab to 8 weekly Aflibercept in patients requiring ongoing nvAMD therapy.
Methods:
A retrospective analysis was performed of 120 eyes switching to 8 weekly Aflicercept injections from Ranibizumab PRN monotherapy between 11/2013 and 11/2014 in a retinal therapy clinic at Moorfields Eye Hospital. All patients had either subretinal (SRF) or intraretinal (IRF) fluid at the time of switch. The central subfield thickness (CST) and change in visual outcome (ETDRS letters) after each injection was assessed to evaluate the efficacy of each injection. Statistical analysis was performed using SPSS v21.
Results:
The median number of Ranibizumab injections given prior to switching to Aflibercept was 8 (IQR 3). The mean change of visual acuity in the whole cohort after three Aflibercept injections was 0.0083±7.62 letters (p=0.990) and the mean reduction in CST was 21.9±55.0µm (p<0.001). The proportion of eyes with CST>300µm decreased from 36/120 (30%) at baseline to 21/120 (17.5%), 18/120 (15%) and 18/120 (15.0%) after the first, second and third doses of Aflibercept. Evaluation of the subset of the 36 eyes with CST>300µm at baseline showed that the CST of 15 eyes (41.6%) decreased to <300µm after one injection but 9 eyes (25%) recurred to >300μm at 8 weekly dosing suggesting a more frequent dosing is required for this group. Four eyes achieved CST<300µm after 2 injections and 2 eyes attained CST<300µm after 3 injections. Evaluation of the 19 eyes that had thickness of >300um at 24 weeks showed that only 2 (1.7%) eyes presented with <300μm before switch to Aflibercept. 10 eyes out of the 36 eyes with CST>300μm at baseline had persistent CST>300μm throughout 24 weeks. Of these, 5/10 (50%) eyes did not receive timely 8 weekly injections. The final visual outcome at 24 weeks was 64.0±16.2 letters in the <300μm group and 61.1±16.6 letters in the >300μm group.
Conclusions:
This review suggests that macular thickness decreases significantly when patients are switched from Ranibizumab to Aflibercept. An 8 weekly Aflibercept dosing regimen is effective when switching patients with CST<300μm but that a 4 weekly loading dose is preferable for patients with CST>300μm.