Ganciclovir implants: one year later
Cadman, J.
Gmhc Treatment Issues the Gay Men's Health Crisis Newsletter of Experimental Aids Therapies 11(4-5): 3-6
1997
ISSN/ISBN: 1077-1824 PMID: 11364375 Document Number: 477631
Cytomegalovirus (CMV) is a herpesvirus that can cause opportunistic infections in immunocompromised persons. Lesions of the retina, CMV retinitis, are treated in two phases. Although CMV retinitis is the most common symptom, the virus can cause infections almost anywhere in the body. In general, treatment is done with ganciclovir, foscarnet, or cidofovir as induction and maintenance therapy. Over a year after approval of Chiron Vision's Vitrasert eye implant for treating CMV retinitis, concerns about the safety and efficacy of the implant can be better addressed. The risk of a retinal detachment is still unclear, since patients taking oral ganciclovir seem to have the same risk as those with the implant; it is thought that CMV retinitis itself is the most important risk factor for this disorder. Although the implant is better able to treat CMV retinitis than oral medication, most patients are also taking oral ganciclovir to protect from systemic CMV infection. Bone marrow suppression occurring from systemic therapy can be treated with growth factors such as G-CSF or erythropoietin. Another problematic area is replacement of the implant, and whether this procedure should be done immediately upon depletion of the drug, or upon reactivation of the infection. Use of highly active antiretroviral therapy, resulting in increases in CD4 counts, may decrease the chance of CMV reactivation. Longer-lasting implants are being developed to address the fact that AIDS patients are surviving longer than the eight months covered by the original implant, with the hope that the longer acting implant, and one oral pill per day, would control both CMV retinitis and extraocular disease. The pharmaceutical company, Roche, has put a study of a ganciclovir prodrug, RS 79070, on hold, due to decreased incidences of CMV disease from more effective antiretroviral treatment. RS 79070 would allow a much more feasible dosing schedule than ganciclovir.