Treating Diabetic Retinopathy

June 27, 2011

Until recently, laser photocoagulation – focal laser for diabetic macular edema, and panretinal laser for proliferative disease – has been the mainstay of treatment for diabetic retinopathy.

Recently, a number of clinical trials have provided support for the adjunctive role of anti-VEGF agents and corticosteroids in diabetic macular edema. One of the biological activities of vascular endothelial growth factor (VEGF) is to increase vascular permeability through specific binding to receptors on vascular endothelial cells. In fact, VEGF was originally called vascular permeability factor when it was first discovered.

Retina Institute of Hawaii was an enrolling center in the RISE study of monthly injections of Lucentis for diabetic macular edema (sponsored by Genentech). Genentech recently announced topline results, showing that a significantly higher percentage of patients receiving monthly Lucentis achieved an improvement in vision of at least 15 letters on the eye chart at 24 months, compared with those in a control group, who received a placebo (sham) injection. Genentech awaits the outcome of the RISE study, the second pivotal trial for Lucentis in diabetic macular edema. With positive results in this study, Genentech should be filing for FDA approval sometime in 2011.

Another study, by the Diabetic Retinopathy Clinical Research Network (DRCRnet), a collaborative network dedicated to facilitating multicenter clinical research of diabetic retinopathy (of which RIH is a member), showed that combining Lucentis with focal laser photocoagulation for diabetic macular edema was better than using focal laser alone. The study also showed some benefit of combining corticosteroid therapy with focal laser.

RIH is currently participating in two trials examining high-dose Lucentis in diabetic macular edema – the ongoing READ3 study, and the REEF study, which will be enrolling soon. Given that Lucentis appears to be beneficial for this condition, it seems plausible that higher doses of the drug may result in even better outcomes, and therefore we are excited to be participating in these trials.

RIH is working with Eyetech Pharmaceuticals to conduct an investigator-sponsored study of high-frequency Macugen for diabetic macular edema, called the Guardian study. We are interested to see if higher-frequency anti-VEGF therapy may result in superior outcomes in patients with diabetic macular edema.

Finally, the adjunctive use of anti-VEGF agents also appears to be helpful for our patients undergoing surgery for diabetic retinopathy complications. RIH is examining ways of making proliferative diabetic retinopathy surgery easier.

Given the emerging body of data supporting superior results from combination therapy and regular follow-up in diabetic macular edema, patients should expect to see a shift toward tailored, multi-modality therapy for their diabetic retinopathy. The use of adjunctive pharmacologic treatments should certainly increase as these drugs become FDA approved and reimbursed for in diabetic retinopathy. These additional studies that RIH is participating in will help to further refine how drug therapy will be combined with laser treatment in order to maximize outcomes in our patients.

By: Eugene W.M. Ng, MD, MBA

BACK