Treatment of CMV retinopathy in patients with AIDS

Cytomegalovirus (CMV) retinitis, the most common intraocular infection in patients with AIDS, appears to be increasing in frequency as these patients live longer. Untreated, CMV retinitis progresses throughout the entire retina resulting in blindness. Ganciclovir and foscarnet, as intravenous formulations, are the only two drugs currently approved by the FDA for the treatment of CMV retinitis. In the Foscarnet-Ganciclovir Cytomegalovirus Retinitis Trial (FGCRT), both drugs were shown to be equally effective in controlling the retinitis. As these drugs have different toxic profiles, and different infusion times, the choice of initial therapy will depend on coexisting medical factors, concurrent medications and patient's lifestyle. Additionally, the FGCRT showed that ganciclovir was associated with a 50% greater mortality rate than with foscarnet. More recently, oral ganciclovir was recently approved for maintenance therapy. Local therapy for CMV retinitis has been used as intravitreal injections of either ganciclovir or foscarnet, or investigationally as a sustained release implant of ganciclovir. While it has been shown that local therapy is effective in controlling the retinitis, the contralateral eye and extraocular sites remain unprotected from CMV disease, which invariably is a systemic disease. Finally, clinical trials are underway to determine the effectiveness and toxicities of cidofovir, a nucleotide analogue (given intravenously or intravitreally) and a neutralizing monoclonal anti-CMV antibody used as adjunctive therapy to prolong the time to relapse.