Local therapy for cytomegalovirus retinitis
CL Smith
OBJECTIVE: To examine the role of intraocular therapy in the management of cytomegalovirus (CMV) retinitis associated with AIDS. DATA SOURCES: A MEDLINE search was conducted for the years 1980-1997. In addition, relevant articles were cross-referenced to screen for additional information. The AIDS/HIV Treatment Directory was searched for information on ongoing studies. STUDY SELECTION/DATA EXTRACTION: Data regarding the use of local antiviral therapy for CMV retinitis are cited. Emphasis was placed on randomized, controlled trials, but descriptive studies are also included. DATA SYNTHESIS: Intraocular drug administration is an alternative therapy for CMV retinitis that avoids some of the disadvantages associated with systemic treatment. Intravitreal ganciclovir 200-2000 micrograms once weekly has been studied in a number of nonrandomized studies. Although initially effective, intravitreal ganciclovir is associated with a significant relapse rate and development of contralateral CMV retinitis. Intraocular ganciclovir implants offer the advantage of less frequent interventions and constant drug concentrations in the vitreous. Time to progression is significantly longer in patients receiving implants versus intravenous therapy; however, there is a higher incidence of contralateral eye retinitis and extraocular CMV disease with the implants. Currently, the intraocular implant is being studied in combination with oral ganciclovir to decrease the incidence of systemic CMV disease. Foscarnet and cidofovir have also been administered intravitreally for CMV retinitis. Cidofovir may offer the advantage of a long intracellular half-life, which would allow infrequent dosing; however, further study is needed to determine a safe and effective intraocular dosage. CONCLUSIONS: Systemic therapy continues as standard management for CMV retinitis. Local therapy has some advantages and disadvantages, but larger, randomized, controlled trials comparing systemic therapy with local therapy must be completed to define its exact role. Data from an ongoing trial of local plus oral therapy will better define this role.
