Does extending the periods between aflibercept eye injections improve outcomes in patients with diabetic macular edema?

This study looked at the effectiveness of treating diabetic macular edema (DME) with a treat and extend dosing regimen of aflibercept (Eylea). It found that after two years the number of injections was significantly reduced and their effectiveness was maintained.  

DME is a common complication of diabetes resulting in a build-up of fluid in the retina (structure in the back of the eye containing cells sensitive to light). This fluid gathers in the macula, which is the part of the eye responsible for most of our detailed vision. This can cause a serious drop in vision.  

DME is often treated with a course of injections into the eye. Aflibercept is one of the medications used to treat DME. Aflibercept injections are given every four weeks initially, usually for five injections. After this, the treatment can be stopped and then re-started as needed. This is called pro re nata (PRN) dosing. Alternatively, treatment can be continued at longer intervals depending on a patient's response. This is called treat and extend (TE) dosing. Treat and extend dosing can reduce the number of clinic visits needed for monitoring. However, it is not clear if it is as effective as the PRN dosing.

48 patients with DME participated in this study. Patients initially received five aflibercept injections at four-week intervals. After initial treatment, the interval between injections was adjusted based on the central subfield macular thickness (CSMT). CSMT is a measurement of the severity of DME. When the CSMT increased (worsening of DME), the interval between injections was shortened by 4 weeks.  When the CSMT decreased (improvement in DME) the interval between injections was lengthened by 4 weeks to a maximum of 12 weeks.  

After 2 years of treatment, patients had received an average of 12.4 injections. Patients' vision improved by an average of 9.4 letters, which is almost 2 lines of letters on a vision chart. In the second year of treatment patients required an average of 3.9 injections, compared to 8.5 injections in the first year. While fewer injections were done in the second year, vision remained very stable and CSMT decreased from 489 to 298 μm, indicating a significant reduction in DME.  

This study showed that a treat and extend protocol of aflibercept injections for DME results in lasting improvements in vision after two years.

This study involved a relatively small number of patients. More studies are needed to confirm these results. This study was sponsored by Bayer Korea, one of the manufacturers of aflibercept.