Ruboxistaurin may prevent visual loss from diabetic retinopathy, study finds

Ruboxistaurin (Arxxant, Eli Lilly) may be a useful new tool to prevent visual loss from diabetic retinopathy based on the results of the DRS2 Study, reported Lloyd Aiello, MD, PhD, during Retina Subspecialty Day. The study showed a reduction in the sustained vision loss compared with placebo.

A total of 685 patients with type 1 or type 2 diabetes participated in this multicenter randomized phase III clinical study that was completed late in 2005, according to Dr. Aiello. He is associate professor of ophthalmology, Harvard Medical School, and investigator and head of eye research, Joslin Diabetes Center, Boston.

The patients received placebo (340 patients) or oral ruboxistaurin (32 mg/day) (345 patients. At least one eye of each patient had a best-corrected visual acuity of 20/125 or better and moderately severe to very severe nonproliferative diabetic retinopathy to be included in the study. The primary end point of the study was sustained moderate vision loss of 15 letters or greater.

"During the course of the study, 9.1% of the patients in the placebo group had a sustained moderate vision loss compared with 5.5% in the group treated with ruboxistaurin," Dr. Aiello said. "This difference was a risk reduction of 40% in the chance of having the same moderate vision loss during the course of the study."

The patients treated with the drug also had a more than doubling of the chance of having a 15-letter or greater gain in vision over the course of the study. In addition, the drug had a good safety profile.

"Treatment with ruboxistaurin reduced the occurrence of a sustained moderate vision loss by 40% in patients with moderately severe to very severe nonproliferative diabetic retinopathy," Dr. Aiello said. "Treatment with ruboxistaurin also reduced the need for treatment with additional focal photocoagulation, reduced visual loss in eyes that required focal photocoagulation, reduced the progression of diabetic macular edema to within 100 microns of the macula, and increased the chance of moderate visual gain."

The FDA reviewed the study data as a new drug application and the drug was deemed approvable. The agency was concerned that there was not two trials with increased specified primary end points of visual loss and additional requirements for another controlled trial and regulatory approval are under discussion.