Combined intravitreal dexamethasone and bevacizumab injection for the treatment of persistent diabetic macular edema (DexaBe study): a phase I clinical study

PURPOSE: The aim of this study is to investigate the safety of combined intravitreal injection of dexamethasone aqueous-solution (IVD) and bevacizumab (IVB) in patients with refractory diabetic macular edema (DME) and its effect on intraocular pressure (IOP), best-corrected visual acuity (BCVA) and central subfield thickness (CSFT). METHODS: This prospective study included 10 patients (10 eyes) with DME refractory to laser photocoagulation and/or anti-vascular endothelial growth factor (anti-VEGF) therapy. A complete ophthalmological examination was performed at baseline, during the first week of treatment, and monthly through week 24. Therapy consisted of monthly injections of combined IVD and IVB “pro re nata” (PRN) if CST > 300 µm. We investigated the impact of the injections on intraocular pressure (IOP), cataract development, Early Treatment Diabetic Retinopathy Study (ETDRS) best corrected visual acuity (BCVA), and central sub-foveal thickness (CSFT) measured by spectral-domain optical coherence tomography (OCT). RESULTS: Eight patients (80%) completed 24 weeks of follow-up. Compared to baseline, mean IOP increased significantly (p < 0.05) and anti-glaucomatous eye drops were necessary for 50% of the patients, CSFT was significantly reduced at all follow-up visits (p < 0.05), although mean BCVA showed no significant improvement. One patient developed dense cataract progression and another showed vitreoretinal traction at week 24. No inflammation or endophthalmitis was observed. CONCLUSION: Treatment of DME refractory to laser and/or anti-VEGF therapy with combined PRN IV dexamethasone aqueous solution and bevacizumab was associated with adverse effects related to the use of corticosteroids. However, there was a significant improvement in CSFT meantime best-correct visual acuity remained stable or improved in 50% of patients.