OBJECTIVES: Antiretroviral combinations have been successful in delaying human immunodeficiency virus (HIV) progression; however, drug resistance may occur.  Maraviroc and enfuvirtide are two drugs currently used in treatment-experienced HIV patients.  The objective was to determine the economic impact of maraviroc versus enfuvirtide in HIV patients previously treated with conventional antiretrovirals. METHODS: A Markov model was developed to assess the economic consequences of the targeted therapies.  The type of analysis was cost-minimization based on the premise of clinical equivalence.  The clinical outcome used to support the clinical assumption was the odds ratio of decreasing >=1.0 log10 viral copies/ml over placebo.  Targeted population was composed of adults infected with HIV virus (CCR5 co-receptor tropism), who underwent previous anti-HIV treatments and proved therapeutic failure.  Model input data derived from a previously observed cohort of HIV patients in Brazil.  A lifetime horizon was used.  The economic perspective was that of the Brazilian Ministry of Health (MoH) as a payer and provider of medical services, treatments, and healthcare to its beneficiaries. Costs were expressed in 2010 Brazilian Currency (1BRL=0.59USD).  Univariate and multivariate (Monte Carlo) analyses tested model robustness. RESULTS: An indirect comparison between the interventions showed that the effects of the drugs over placebo was similar from a clinical (odds ratios with approximate values) and statistical (overlapping confidence intervals) standpoints.  Thus, clinical equivalence between the drugs was assumed.  The economic analysis showed that the total cost of anti-HIV treatment per patient with maraviroc was approximately BRL17 thousand lower than enfuvirtide.  Probabilistic sensitivity analysis reported 87% chance of having reduced treatment costs by choosing maraviroc over enfuvirtide. CONCLUSIONS: The use of maraviroc in treatment-experienced HIV patients showed to be beneficial for the Brazilian MoH in reducing the economic burden of the disease.  The estimated annual budget impact ranged between BRL 8.0 to 10.5 million favorable to cost reduction.