Abstract
Purpose :
<p style="margin: 0px;">To investigate the changes in aqueous vascular endothelial growth factor (VEGF) levels in eyes with diabetic macula edema (DME) treated with intravitreal injection of ranibizumab (IVR) using the pro re nata (PRN) regimen.</p>
Methods :
This prospective study included 14 patients (10 men and 4 women, mean age [±SD], 62 ± 12 years) with eyes that had center-involved DME. Each patient had a central macular thickness (CMT) of >300 μm. Further, at baseline, 0.05 ml of aqueous VEGF was aspirated from each eye for sampling before IVR. At week 4, aqueous VEGF sampling was repeated, after which, a second IVR was administered. From weeks 4 to 48, all eyes were followed-up at intervals of 4 weeks while IVR was administered using the PRN regimen (i.e. the CMT exceeded 300 μm) after aqueous VEGF sampling. Aqueous VEGF levels were measured using the Bio-Plex ProTM (Bio-Rad Laboratories).
Results :
The mean best-corrected visual acuity was significantly ameliorated by 3.6 letters (P = 0.042) and the mean CMT improved significantly by 190.9 µm (P < 0.001). There was a significant decrease (baseline: 322.5±256.9 pg/ml, week 4: 10.7±38.0 pg/ml, P < 0.001) in the aqueous VEGF concentration and it was below the lowest detectable limit in 12 out of 14 eyes at 4 weeks after the first IVR. In the PRN phase, a total of 72 IVRs were performed and the mean aqueous VEGF concentration at that time was 117.8 pg/ml with a range below the lowest detectable limit to 1094.9 pg/ml. In 60% of the eyes (43/72), aqueous VEGF levels were below the lowest detectable limit despite the recurrence of DME.
Conclusions :
The first IVR for DME significantly reduced the aqueous VEGF levels. In the PRN phase, there were many cases in which low levels of aqueous VEGF were observed even in the presence of DME recurrence. In these cases, it was suggested that other factors, in addition to VEGF, could be contributing to the recurrence of DME.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.