Suprachoroidal injection of triamcinolone acetonide plus intravitreal bevacizumab in diabetic macular edema: a randomized pilot trial

Background To investigate the efficacy of injecting suprachoroidal triamcinolone acetonide (SCTA) plus intravitreal bevacizumab (IVB) into patients with center-involving diabetic macular edema (CI-DME). Methods In this phase 2/3 randomized controlled pilot trial, sixty-six eyes with CI-DME and best-corrected visual acuity (BCVA) of at most 20/50 Snellen chart were randomly assigned into two groups. Monotherapy arm received sham injection plus 3 monthly IVB doses and combination arm received a single dose of SCTA and 3 monthly IVB doses. The mean improvements in BCVA and Central subfield thickness (CST), over the three-month was considered the main efficacy outcomes. Results The mean BCVA improvements were obtained respectively as − 0.20 ± 0.20 log [minimum angle of resolution (MAR)] (P = 0.004) and 0.37 ± 0.24 log MAR (P ) in monotherapy and combination arms [between-group analysis (P = 0.014)]. Significant improvements were also observed in CST (P = 0.019) in the combination arm compared to the other. No adverse events (elevated intraocular pressure, cataract) were observed in any of the study arms. Conclusion Significant improvements in BCVA and retinal anatomical outcomes demonstrated the additive effects of SCTA to those of anti-vascular endothelial growth factors with no short-term side effects and this combination appears to be a promising option in the management of patients with CI-DME. Trial registration The trial was registered in Iranian Registry of Clinical Trials (IRCT20200314046761N1).