Cost-effectiveness analysis of enfuvirtide (ENF) added to an optimized therapy compared with an optimized therapy in patients with HIV/AIDS.

BACKGROUND Fuzeon (enfuvirtide) (ENF) is the first drug among the HIV fusion inhibitors that has shown high efficacy in HIV-1/AIDS patients resistant to conventional antiretroviral agents. PURPOSE To analyze the cost-effectiveness of ENF plus optimized therapy (OT) in HIV patients. METHOD A Markov model was used to calculate the cost-effectiveness of ENF in terms of incremental cost per life-year gained. The model has a 10-year horizon, with monthly cycles, and the perspective is the Spanish National Health System. Efficacy rates and transition probabilities were obtained from clinical and epidemiological trials. Resource use data were retrieved from published literature and a panel of clinicians. Unit costs refer to the year 2003. MAIN OUTCOME MEASURE Incremental cost-effectiveness ratio. RESULTS Adding ENF to OT increased patient life expectancy by 1.6 years (6.2 years with OT compared with 7.8 years with ENF + OT). Total costs were 160,728 euro for OT and 200,859 euro with ENF + OT, mainly due to increasing life expectancy raising resource use and costs. Incremental cost per life-year gained with ENF was 25,082 euro. CONCLUSION ENF plus OT increased life expectancy for HIV-1-treated patients and is an efficient treatment option.