Eli Lilly & Company's investigational compound, ruboxistaurin (PKC ß Inhibitor) mesylate, may delay the progression of diabetic macular edema in patients with mild to moderate nonproliferative diabetic retinopathy receiving the highest dosage of ruboxistaurin, according to results of a multicenter trial presented during the 18th annual International Diabetes Federation (IDF) meeting.

Diabetic macular edema is an important complication of diabetic retinopathy, a disease of the small blood vessels in the retina of the eye. Diabetic macular edema is characterized by retinal thickening or fluid leakage near the center of the retina, and is a significant cause of vision loss in people with diabetes. Diabetic macular edema occurs in almost 30 per cent of people who have had diabetes for 20 years or more.

"We are very encouraged to see that ruboxistaurin may prevent the development of center-threatening diabetic macular edema, thus delaying the progression of diabetic macular edema in these patients," commented Skip Vignati, M.D., medical director for the ruboxistaurin effort at Lilly. "Based on the trial outcome, additional phase 3 trials will further explore ruboxistaurin's effect on delaying the progression of diabetic macular edema."

The PKC ß Inhibitor Diabetic Macular Edema (PKC-DMES) trial was a multi-center, multi-national, double-masked, placebo-controlled trial, with patients followed for up to 52 months.

The trial included 686 patients with diabetic macular edema and mild to moderate nonproliferative diabetic retinopathy. Ruboxistaurin, when given at 32 mg, displayed a trend (p=0.041) toward a positive effect on the secondary outcome of occurrence of diabetic macular edema involving or imminently threatening the center of the macula. When patients with poor glycemic control at baseline were excluded (defined as a hemoglobin A1C greater than or equal to 10 per cent), ruboxistaurin displayed a borderline positive effect (p=0.019) on the occurrence of diabetic macular edema involving or imminently threatening the center of the macula.

Ruboxistaurin is being studied as a possible treatment for diabetic peripheral neuropathy (damage to the nerves), diabetic retinopathy (including diabetic macular edema) and diabetic nephropathy (damage to the kidneys), the three major diabetic microvascular complications. Because type 2 diabetes is often not diagnosed until years after onset, many patients already have diabetic microvascular complications at diagnosis; three of four patients with diabetes develop at least one complication within 15 years of diagnosis.