During the National Eye Institute clinical trial upon which the paper was based, 30 eyes of 26 persons diagnosed with AIDS and peripheral CMV retinitis were randomly assigned to receive either immediate treatment (within 48 hours of entering the study) or deferred treatment. Patients randomized to the deferred treatment group were monitored every two weeks, and if disease progression was noted by independent observers, patients were offered an implant.
All signs of active infection were eliminated for a median of 226 days in the eyes treated immediately; progression of CMV retinitis developed in the deferred treatment group within 15 days.
"The challenge has been to get the antiviral ganciclovir where it is needed most -- to the back of the eye," said Martin, who is assistant professor of ophthalmology and former chief resident of the Emory Eye Center. "Currently, persons with AIDS experiencing vision loss from CMV retinitis must undergo ganciclovir infusions via chest catheter once or twice a day for the rest of their lives. While systemic administration ensures that the drug will reach other organs affected by CMV, penetration into the eye is low. The possibility of surgically implanting a tiny pellet of ganciclovir into the eye every eight months would be a welcome alternative to these lifetime, daily infusions."
Martin is heading further clinical trials to evaluate the implant when used alone and when used in conjunction with orally administered ganciclovir.
"Other eye patients might also benefit from this drug delivery device, particularly patients with potential vision loss attributed to diabetes, tumors in the eye, age-related macular degeneration and inflammatory conditions such as uveitis, although much research must be conducted on these applications," he said.
-- Lorri Preston