Vitrasert has been approved for treatment of CMV in subjects with AIDS. The implant releases ganciclovir to the site of disease in the eye in which it is implanted.
The Vitrasert Implant, surgically placed in the posterior segment of the eye, allows diffusion of drug (ganciclovir) locally to the site of infection over an extended period of months. Implantation normally takes less than one hour, requires only local anesthesia, and is conducted in an outpatient, day-surgery setting.
Immediately following insertion of the implant, most subjects experience transient blurred vision in the operated eye, which generally clears within two to four weeks. The implant can be removed when depleted of drug, usually within five to eight months, and a new Vitrasert Implant can be inserted.
Subjects with a Vitrasert implanted unilaterally should be continuously monitored for the development of disease in the other eye or for development of non-ocular CMV manifestations.
Data from Chiron Vision's phase III trial of 188 AIDS subjects with newly diagnosed CMV retinitis have demonstrated that time to disease progression was significantly delayed for subjects who received Vitrasert, compared with those on intravenous (I.V.) ganciclovir. The study showed that eyes in the primary analysis group treated with Vitrasert had a median time to progression of 216 days, versus 104 days for eyes on I.V. treatment.
In addition, results of a clinical study reported by the National Eye Institute (NEI) in the Archives of Ophthalmology showed that the median time to progression of peripheral CMV retinitis in newly diagnosed patients who received the implant was about eight months, or 226 days. Those who received no immediate treatment or those assigned to defer treatment progressed in approximately 15 days.
CMV retinitis affects an estimated 15% to 40% of people with AIDS. CMV retinitis usually begins as a white infiltrate within the retina, and can progress rapidly to cause destruction of retinal tissue. Retinal damage can lead to detachment of the retina, occurring in 15% to 29% of subjects with AIDS-related CMV retinitis, and permanent loss of vision.