ESTIMATING THE COST-EFFECTIVENESS OF ATOVAQUONE VERSUS INTRAVENOUS PENTAMIDINE IN THE TREATMENT OF MILD-TO-MODERATE PNEUMOCYSTIS-CARINII PNEUMONIA

Pneumocystis carinii pneumonia (PCP) is the most common severe opportu nistic infection, and one of the most costly, among people with AIDS. Over 50% of patients experience toxic effects of the major anti-PCP me dications cotrimoxazole (trimethoprim-sulfamethoxazole) and pentamidin e. Recently, the US Food and Drug Administration approved a new oral d rug therapy, atovaquone, as an alternative to pentamidine for the trea tment of people with mild-to-moderate PCP who are intolerant of cotrim oxazole. We developed a decision tree model to estimate the costs and cost effectiveness of atovaquone therapy compared with intravenous pen tamidine therapy for cotrimoxazole-intolerant patients with mild-to-mo derate PCP. Clinical outcomes were based on data from a phase III tria l comparing the 2 medications. Our economic outcomes were based on tre atment algorithms derived from discharge data, published reports and t he clinical judgement of the co-authors. We estimate the total expecte d cost of treating a patient for an episode of PCP with atovaquone to be $US3990 compared with $US6545 for pentamidine under our baseline sc enario (1995 dollars). Our decision model also provides insight into t he large cost-savings benefits of treating mild-to-moderate PCP on an outpatient basis.