LEXINGTON, KY (Dec. 4, 2000) – Research at the University of Kentucky College of Medicine Department of Ophthalmology has contributed to the development of a new sustained-release treatment that may be effective for several sight-threatening retinal disorders.  The new treatment currently is being tested for the chronic deterioration and leakage of retinal blood vessels known as diabetic macular edema (DME).

According to the Centers for Disease Control and Prevention, about 10.3 million people in the United States have been diagnosed with diabetes and another approximately 5.4 million people have undiagnosed diabetes.  In Kentucky, 106,808 adults had diagnosed diabetes in 1994.

Diabetes is the leading cause of blindness in people between the ages of 20 and 74.  About 500,000 people in the United States have DME, and about 75,000 new cases of DME are diagnosed each year.  About 40 percent of individuals with diabetes will develop DME.

The treatment involves a simple surgical procedure to place a tiny implant containing medicine into the back of the eye.  The implant is designed to deliver sustained and consistent therapeutic levels of drugs directly to the diseased area of the eye for up to three years.  This design also is expected to limit the drug’s exposure to the whole body, reduce the dosage needed to be effective, and reduce the need for frequent treatments.

In the initial study for the treatment of DME, the implant delivered fluocinolone acetonide, a powerful anti-inflammatory steroid compound that controls inflammation and inhibits the growth of damaged blood vessels.

“This technology may offer the opportunity to treat DME with a drug instead of an invasive procedure,” said P. Andrew Pearson, M.D., assistant professor, Department of Ophthalmology, UK College of Medicine.  “This may offer an effective method to improve the sight of patients afflicted with this terrible disease.”

Pearson is the principal investigator at the UK College of Medicine for clinical studies conducted with the implant for DME.  The technology for the implant was developed from discoveries by Pearson and others.  Much of the initial work on this technology was conducted at the UK Chandler Medical Center.

Five patients with DME participated in the clinical study recently reported by Pearson, which was designed to determine the safety of the fluocinolone implant.  The patients, who had not responded to prior laser treatment, each underwent the surgical placement of a fluocinolone insert in one eye; the other eye was not treated and was used as the study control.  All patients had resolution of their macular edema in the treated eye, as confirmed by fluorescein angiography (a special dye that allows the blood vessels in the eye to be photographed).  At nine months, the mean visual acuity for the five patients improved from 20/158 to 20/82.  These results compare to the control group whose visual acuity remained essentially unchanged.

The fluocinolone insert was well tolerated by patients.  All patients experienced an increase in intraocular pressure, an expected side effect of this type of drug, which was effectively treated with eye drops.

“The results of this study are encouraging, especially because these patients had failed standard treatment, making their cases very difficult to treat,” Pearson said.

Current treatments for DME are laser photocoagulation, treatment by laser light to reduce leakage into the retina or new blood vessel formation; and for late-stage disease, vitreous surgery.  Such invasive techniques carry inherent risks and have limited success rates with up to 40 percent of patients achieving no benefit.

The technology already is incorporated in Bausch & Lomb’s Vitrasert™ (linear release intravitreal ganciclovir implant), which is FDA-approved to treat cytomegalovirus retinitis, an often-blinding condition associated with late-stage AIDS. 

This technology also is being studied to treat a variety of other sight-threatening intraocular diseases by combining the implant with known therapeutic compounds.  Diseases being targeted include age-related macular degeneration, the deterioration of the central retina, and uveitis, a severe intraocular inflammation.  These diseases, along with DME, affect more than 8 million people worldwide.