title: Cost-effectiveness of tipranavir in treatment-experienced HIV patients in the United States.
abstract: OBJECTIVE
  To compare the estimated long-term outcomes, costs, and cost-effectiveness of tipranavir boosted with ritonavir (TPV/r) versus investigator-selected ritonavir-boosted comparator protease inhibitor (CPI/r) using the observed 48-week data from the RESIST trials in a previously published Markov model.
  
  
  METHODS
  A previously developed 3-stage Markov model was modified to reflect US practice patterns for treatment-experienced HIV patients using 2007 costs and combined phase III tipranavir trial data (RESIST-1 and -2). The 12 model health states were defined by CD4 cell count and viral load that have previously been identified as predictors of HIV/AIDS progression. Resource use and quality of life weights were linked to each health state. Disease progression beyond the 48-week trial period was based on HAART treatment-experienced patients from data collected by the University of South Carolina. Costs were estimated from the payer perspective.
  
  
  RESULTS
  TPV/r patients remained longer in health states defined by higher CD4 cell count and lower viral load compared to CPI/r patients. This reduced the rate of AIDS-defining events by 12.35% over 5 years and resulted in 0.64 quality-adjusted life-years (QALYs) gained (discounted at 3%) over the model time horizon (remaining lifetime). The incremental cost-effectiveness ratio (ICER) of TPV/r versus CPI/r was $56,517/QALY (discounted at 3%). Excluding patients also treated with enfuvirtide reduced the ICER to $46,147/QALY.
  
  
  CONCLUSIONS
  TPVI/r is cost-effective in the United States compared to CPI/r in treatment-experienced HIV-1-infected patients.
authors.affiliation: Medical University of South Carolina, Charleston, South Carolina 29425, USA. simpsonk@musc.edu
authors.forename: Kit N
authors.initials: KN
authors.lastname: Simpson
authors.forename: Graeme
authors.initials: G
authors.lastname: Roberts
authors.forename: Charles B
authors.initials: CB
authors.lastname: Hicks
authors.forename: Henrik W
authors.initials: HW
authors.lastname: Finnern