Promising early evidence of the superior benefits of drug therapy for diabetic eye disease

A JDRF collaboration between Johns Hopkins researchers and Genentech has shown that a drug for the treatment of diabetic eye disease has performed better in clinical trials than the current standard treatment using laser surgery. These findings, representing the six-month end-point evaluation of the READ-2 clinical trial coordinated by The Johns Hopkins University, were presented Monday at the 2008 Annual Meeting of The Association for Research in Vision and Ophthalmology, in Fort Lauderdale, Florida.

According to Barbara Araneo, Ph.D., director of the complications program at JDRF, “These are very encouraging results, showing that drugs we have been testing in human clinical trials can be effective in slowing or stopping the effects of eye disease brought on by diabetes.”

The multi-center READ-2 Study (Ranibizumab for Edema of the mAcula in Diabetes), which began in December 2006, was designed to test the long-term safety and effectiveness of injections of the drug ranibizumab in patients with diabetic macular edema, a condition characterized by swelling of the central portion of the retina, or macula, at the back of the eye. In addition, the trial sought to determine the comparative efficacy of ranibizumab versus conventional treatment – laser photocoagulation therapy – or both together.

Macular edema, one of the most common causes of blindness, occurs when fluid and protein deposits collect on or under the macula, causing it to thicken and swell.

Participating in the clinical trial were 126 diabetic patients (average age 62) with documented Diabetic Macular Edema prior to enrollment; the majority had 20/80 vision in the eye that was treated. Patients were randomly assigned to receive one of three interventions: ranibizumab, laser photocoagulation, or a combination of the two treatments. At each visit over the course of the six-month treatment period, patients were evaluated for vision, retinal thickening, and general eye health. Although the study ended at six months, patients will be monitored for two years.

Patients treated with ranibizumab experienced significantly greater improvements in visual acuity, or clarity of vision, compared with patients receiving either of the other interventions. On average, the vision of ranibizumab-treated patients improved to 20/63 at month six, compared with essentially unchanged acuity scores of about 20/80 in both the laser and the combination treatment groups.

In addition, patients treated with ranibizumab had a 56 percent reduction in excess retinal thickness, whereas only an 11 percent reduction was seen in those receiving laser treatments.

Source: Juvenile Diabetes Research Foundation International