Predictors of As-Needed Ranibizumab Injection Frequency in Patients With Macular Edema Following Retinal Vein Occlusion

Abstract

To evaluate spectral-domain optical coherence tomography (SD-OCT) biomarkers associated with ranibizumab injection frequency after 7 monthly doses in the prospective, multicenter SHORE study for macular edema due to retinal vein occlusion (RVO). Prospective phase IV clinical trial data. Post hoc analysis of 95 patients who received 7 monthly doses of ranibizumab followed by either pro re nata (PRN) or nonrandomized monthly injections from months 7-15 in eyes with macular edema secondary to RVO. Baseline SD-OCT biomarkers assessed include central subfield thickness (CST), epiretinal membrane presence, intraretinal and subretinal fluid, hyperreflective foci, disorganization of retinal inner layers (DRIL), and disruption of the external limiting membrane, ellipsoid zone, or interdigitation zone. Univariate and multivariable regression analyses evaluated the association between SD-OCT biomarkers and ranibizumab injection frequency. Mean age of patients was 65.3 (SD, 12.7) years. Overall, 57.9% had BRVO/HRVO and 42.1% of eyes had CRVO. Mean BCVA improved (+17.5 [SD, 1.2] Early Treatment of Diabetic Retinopathy Study [ETDRS] letters) during the 7-month fixed dosing period, remaining stable from baseline (+20.1 [SD, 1.5] ETDRS letters) during the PRN phase from months 7-15. The mean number of PRN injections was 4.32 (SD, 2.35). On multivariate regression, greater baseline DRIL (β=0.021, P=.0275) and higher CST at month 3 (β=0.01, P < .001) were associated with a higher total number of PRN injections. Greater baseline DRIL and higher CST at 3 months after starting ranibizumab treatment are associated with more frequent ranibizumab injections in PRN-treated patients with macular edema due to RVO.