title: Cost-effectiveness of enfuvirtide in treatment-experienced patients with advanced HIV disease.
abstract: OBJECTIVE
  Enfuvirtide (ENF) has been shown to improve short-term virologic responses when given to highly treatment-experienced patients with advanced HIV disease. Because of the high cost of ENF compared with other antiretroviral agents, our objectives were to determine the potential long-term clinical impact and cost-effectiveness of ENF in these patients.
  
  
  METHODS
  We used a computer simulation model of HIV disease to project life expectancy, quality-adjusted life expectancy, cost, and cost-effectiveness of ENF in treatment-experienced patients. Input data were from the T-20 versus Optimized Regimen Only (TORO) 1 and 2 trials, 2 studies comparing ENF plus an optimized background regimen (OBR) with an OBR alone.
  
  
  RESULTS
  ENF plus an OBR increased projected discounted quality-adjusted life expectancy from 45.4 months with an OBR alone to 54.9 months, a difference of 9.5 quality-adjusted life-months. At the current annual ENF cost of US 18,500 dollars per year (in 2001 US dollars), the incremental cost-effectiveness ratio for ENF plus an OBR was US 69,500 dollars per quality-adjusted life-year (QALY) compared with an OBR alone. When 48-week virologic suppression rates for ENF plus an OBR were varied from a 50% reduction to a 250% increase in the suppression rate attributable to ENF, gains in quality-adjusted life expectancy ranged from 4.5 to 25.9 quality-adjusted life-months compared with an OBR alone, with cost-effectiveness ratios ranging from US 97,900 dollars per QALY to US 52,300 dollars per QALY gained. If ENF is continued after the HIV RNA level returns to the pretreatment baseline, the cost-effectiveness ratio increases to US 168,200 dollars per QALY.
  
  
  CONCLUSIONS
  In highly treatment-experienced patients, ENF plus an OBR provides substantial gains in quality-adjusted life expectancy compared with an OBR alone. Although ENF plus an OBR is less cost-effective than other commonly used interventions in HIV disease, its use may be justified, given the poor prognosis of these patients and their otherwise limited options for antiretroviral therapy.
authors.affiliation: Division of Infectious Disease and the Partners AIDS Research Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. psax@partners.org
authors.forename: Paul E
authors.initials: PE
authors.lastname: Sax
authors.forename: Elena
authors.initials: E
authors.lastname: Losina
authors.forename: Milton C
authors.initials: MC
authors.lastname: Weinstein
authors.forename: A David
authors.initials: AD
authors.lastname: Paltiel
authors.forename: Sue J
authors.initials: SJ
authors.lastname: Goldie
authors.forename: Tammy M
authors.initials: TM
authors.lastname: Muccio
authors.forename: April D
authors.initials: AD
authors.lastname: Kimmel
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Freedberg
authors.forename: Rochelle P
authors.initials: RP
authors.lastname: Walensky
mesh_terms: D000328:Adult; D018791:CD4 Lymphocyte Count; D003362:Cost-Benefit Analysis; D004359:Drug Therapy, Combination; D000077560:Enfuvirtide; D005260:Female; D015700:HIV Envelope Protein gp41 / Q000191:economics* / Q000627:therapeutic use*; D023581:HIV Fusion Inhibitors / Q000191:economics / Q000627:therapeutic use*; D015658:HIV Infections / Q000188:drug therapy* / Q000191:economics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000191:economics* / Q000627:therapeutic use*; D011788:Quality of Life; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D014481:United States
chemical_list: D015700:HIV Envelope Protein gp41; D023581:HIV Fusion Inhibitors; D010446:Peptide Fragments; D000077560:Enfuvirtide