CMV retinitis is an infection in the eye caused by the cytomegalovirus. CMV can also infect other parts of the body. Researchers have been studying a special implant that is put directly into an infected eye. The implant slowly releases ganciclovir, a drug used to treat CMV infection. When the infection is only in the eye, the implants have shown good results. The implant, called Vitrasert, has now been approved for general use by the US Food and Drug Administration (FDA).

Trial results
Between October 1992 and December 1993, study sites in Bethesda, Maryland and Atlanta, Georgia enrolled 26 participants with newly diagnosed CMV retinitis. Participants were divided into two groups. One group was given the implant immediately and the second group was given the implant if the retinitis got worse. Participants in the study had no progression of newly diagnosed CMV retinitis for about eight months using the ganciclovir implant. Among those who received no immediate treatment, the eye infection worsened in about 15 days. Although surgery is required to use the implant, the procedure is performed under local anesthesia, takes less than one hour, and can be done on an outpatient basis.

The implants are designed to release ganciclovir over a period of months. The best time for replacement of the implant is unknown. In the study, the implants released the drug at different rates, making it hard to know when the implant needed to be replaced. The current information is that implants should be replaced after 32 weeks to lessen the likelihood of a relapse. Most participants in the study enjoyed good vision with the implant. By the final followup eye examination, 34 of 39 eyes treated with the implant had nearly perfect vision (20/25). The researchers also reported that nearly all affected eyes had blurred vision immediately after receiving the ganciclovir implant. Normal vision returned on average within 4 weeks.

A second, larger trial studied 148 people with newly diagnosed CMV retinitis. Participants were divided into three groups. One group was treated with standard intravenous ganciclovir. The second group was treated with an implant that released 1 mcg of ganciclovir into the eye every hour. The third group was treated with an implant that released 2 mcg of ganciclovir into the eye every hour.

In this study, both groups receiving the implant had no progression of their CMV for an average of over six months. People receiving standard intravenous ganciclovir experienced progression of their CMV after an average of just over three months.

Side effects
The surgical procedure that places the implant in the eye does have some risks. Of the 148 people in the larger study, four people experienced inner eye inflammation (called endophthalmitis) that led to blindness. There were also 17 cases of retinal detachment. However, as retinal detachment generally occurs in about 18% of people with CMV retinitis, the risk does not seem to be increased by the implant.

Some cautions
Because the implant releases ganciclovir into the eye only, there is concern that those who receive the treatment may develop CMV infections in their unaffected eye and elsewhere in the body. In the first study, the researchers reported a high rate of infection in the second eye. Of the 21 patients who entered the study with only one eye affected, 14 developed CMV retinitis in the other eye. Doctors treated 11 of these patients with ganciclovir implants in their second eye with similar good results. In addition, eight of the 26 study participants developed CMV infections in other organs. These patients were treated with either ganciclovir or foscarnet, the approved treatments for CMV.

There may be ways to reduce the risk of CMV spreading to other parts of the body. A pill form of ganciclovir is now available by prescription. Used in combination with the implant, oral ganciclovir may help protect other parts of the body from CMV. Studies of ganciclovir implants in combination with oral ganciclovir are ongoing. Call The Network for a referral.

If you are having blurred vision or other problems with your eyes, it's important to see an ophthalmologist who is experienced in examining and treating people with HIV. Don't wait. Eye problems can become permanent and even lead to blindness if not treated promptly. An ophthalmologist is a doctor who specializes in eyes.

Chiron Vision, the makers of Vitrasert, have a patient assistance program that can help people having difficulty paying for the treatment. Call (800) 843-1137 for more information.

The Simple Facts Project is a program of The Network. If you need help finding out whether or not a specific drug or therapy is covered by private or public insurance, contact The Network at (800) 734-7104. This information does not intend to promote or endorse any specific treatment for any health related condition.