Abstract
Purpose :
Over one-third of patients with diabetic macular edema (DME) have an incomplete response to intravitreal bevacizumab therapy. A clinical trial assessing the efficacy of switching therapy to aflibercept among treatment-resistant patients was performed over 48-weeks.
Methods :
Forty-three patients with persistent DME following at least 4 intravitreal injections of bevacizumab in the prior 6 months were recruited in a single-armed, prospective clinical trial. Five initial loading doses of 2mg of intravitreal aflibercept were administered every 4-weeks until week 20, then the treatment interval was extended to 8-weekly until week 48. Participants underwent a full ophthalmic assessment every 4 weeks including best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) to assess central macular thickness (CMT). Ultra-widefield fluorescein angiography (UWFA) and ultra-widefield imaging were performed at baseline and at 48 weeks. Ischaemic index was calculated based on UWFA images. Diabetic retinopathy (DR) severity was graded using a 9-step ETDRS scale on ultra-widefield images. Paired t-tests were used to assess changes in outcomes.
Results :
At baseline study eyes had received 16.9±11.5 intravitreal anti-VEGF injections over a period of 26.9±23.8 months prior to switch. During the study mean CMT reduced from 417±91µm at baseline to 357±108µm at 48 weeks (60µm reduction, p<0.01). Mean BCVA improved from 67.8±10.3 letters at baseline to 71.8±10.6 letters at 48 weeks (4.0 letter gain, p=0.03). Patients gaining 5 or more letters following the first injection of aflibercept had better BCVA at 48 weeks (5.4±4.9 vs. 1.3±5.6 letters, p=0.03). DR severity remained stable in 79% of participants, improved by 1-step in 18% and worsened by 1-step in 3%. Ischemic index was 0.24±0.30 at baseline and 0.22±0.30 at week 48 (change -0.03, p>0.05). Baseline ischemic index was not associated with change in BCVA or CMT at week 48.
Conclusions :
Switching therapy from bevacizumab to aflibercept resulted in improved visual and anatomical outcomes in this cohort of refractory DME patients. Treatment with aflibercept may have a disease modifying effect of DR in patients with refractory DME and significant prior anti-VEGF treatment.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.