Ganciclovir. A pharmacoeconomic review of its use as intravenous or oral maintenance therapy in the management of cytomegalovirus retinitis in patients with AIDS.

Cytomegalovirus retinitis, an opportunistic infection caused by the herpesvirus cytomegalovirus, is a major cause of illness in patients with advanced AIDS. As infected patients require long term drug treatment to delay disease progression and minimise loss of vision, the disease is associated with substantial treatment costs which considerably increase overall expenditure on AIDS-related health care. During the last decade, intravenous ganciclovir has been a mainstay of treatment for patients with cytomegalovirus retinitis. However, notwithstanding its demonstrated efficacy as maintenance therapy for this condition, long term intravenous drug administration is both inconvenient and uncomfortable for many patients. Moreover, neutropenia and catheter-related infections have been reported commonly in patients receiving ganciclovir via the intravenous route. To overcome the limitations of intravenous ganciclovir, an oral formulation of the drug has been developed for use as maintenance therapy. In comparative clinical trials, both intravenous and oral ganciclovir maintenance therapy slowed disease progression and preserved visual acuity in patients with stabilised cytomegalo-virus retinitis, although there was evidence that the intravenous formulation was more effective in terms of delaying recurrence of active disease. This suggests that oral ganciclovir use should be limited to the treatment of patients without evidence of immediately sight-threatening cytomegalovirus retinitis. Three published cost analyses, which were based on efficacy and tolerability data derived from 2 randomised, comparative clinical trials, have shown that oral ganciclovir maintenance therapy offers cost advantages over intravenous maintenance therapy, despite the higher acquisition cost of the oral formulation. The higher overall costs of intravenous maintenance treatment, compared with oral therapy, were attributed to higher drug administration and adverse event treatment costs. In one analysis, estimated lifetime treatment costs of oral maintenance therapy were 25.2% lower than those of intravenous maintenance treatment. As yet, no formal cost-effectiveness evaluations of oral and intravenous ganciclovir have been published. Few published data are available regarding the relative effects of intravenous and oral ganciclovir on quality of life. However, in a health state utility analysis, there was a large overall preference among HIV-infected individuals for oral over intravenous maintenance treatment. In conclusion, oral ganciclovir appears to be a cost-saving and patient-preferred alternative to its intravenous counterpart for the maintenance therapy of AIDS patients with stabilised cytomegalovirus retinitis in whom there is no evidence of sight-threatening disease.