Combination of intravitreal bevacizumab and erythropoietin versus intravitreal bevacizumab alone for refractory diabetic macular edema: a randomized double-blind clinical trial

Purpose To evaluate the effect of three intravitreal bevacizumab (IVB) injections alone or in combination with intravitreal erythropoietin (EPO) in the treatment of refractory diabetic macular edema (DME). Methods In a randomized double-blind clinical trial, 48 eyes of 34 diabetic patients with refractory DME were enrolled. Eyes were randomly assigned to receive either 3 monthly injections of 0.05 cc (1.25 mg) IVB plus 0.05 cc (1000 unit) EPO or 0.05 cc (1.25 mg) IVB alone. Main outcome was best-corrected visual acuity (BCVA) changes and secondary outcome was central macular thickness (CMT). The patients were followed for 6 months. Results Mean BCVA changes up to 4 and 6 months were insignificant in both groups. It changed from 0.72 +/- 0.56 logMAR at baseline to 0.74 +/- 0.5 (P = 0.85) and 0.71 +/- 0.44 (P = 0.40) in the combination group and from 0.48 +/- 0.39 logMAR to 0.47 +/- 0.35 (P = 0.48) and 0.52 +/- 0.33 (P = 0.69) in the IVB alone group, at 4 and 6 months, respectively. The difference of mean BCVA changes between the groups was insignificant at both 4 and 6 months (P = 0.07 and P = 0.36, respectively). Within the group changes of mean CMT were significant only in the combination group at 4 and 6 months, from 518 +/- 134 mu at baseline to 472 +/- 151 to 475 +/- 167 mu, respectively (P = 0.01 and P = 0.05). Corresponding changes were not significant in the IVB alone group. However, the difference between the groups was not significant at all visits (P = 0.51 and P = 0.71, respectively). Conclusions This clinical trial demonstrated that intravitreal erythropoietin had no additional effect to IVB in the treatment of refractory DME in the short term.