title: Cost Effectiveness of Protease Inhibitor Monotherapy Versus Standard Triple Therapy in the Long-Term Management of HIV Patients: Analysis Using Evidence from the PIVOT Trial.
abstract: Protease inhibitor (PI) monotherapy can maintain virological suppression in the majority of patients once it has been established on triple therapy and may also have the potential for substantial cost savings arising from the use of fewer drugs. However, the cost effectiveness of PI monotherapy has yet to be demonstrated.
  
  
  
  In this study we examine the cost effectiveness of PI monotherapy with prompt return to combination therapy in the event of viral load rebound compared with ongoing triple therapy (OT) in patients with suppressed viral load on combination antiretroviral therapy (ART) in the UK.
  
  
  
  The analysis used data from the PIVOT trial in which HIV-positive adults with suppressed viral load for ≥24 weeks on combination ART were randomised to maintain OT or to a strategy of PI monotherapy with prompt return to combination therapy if viral load rebounded. A cost-effectiveness analysis including long-term modelling was conducted. Main outcomes included UK National Health Service (NHS) costs and quality-adjusted life-years (QALYs) with comparative results presented as incremental cost-effectiveness ratios.
  
  
  
  PI monotherapy was cost saving as a result of large savings in ART drug costs while being no less effective in terms of QALYs in the within-trial analysis and marginally less effective with lifetime modelling. In the base-case analysis over 3 years, the incremental total cost per patient was -£6424.11 (95 % confidence interval -7418.84 to -5429.38) and incremental QALYs were 0.0051 (95 % CI -0.0479 to 0.0582), resulting in PI monotherapy 'dominating' OT. Multiple scenario analyses found that PI monotherapy was cost saving with no marked differences in QALYs. Modelling of lifetime costs and QALYs showed that PI monotherapy was associated with significant cost savings and was marginally less effective; PI monotherapy was cost effective at accepted cost-effectiveness thresholds in all but one scenario analysis.
  
  
  
  Under most assumptions, PI monotherapy appears to be a cost-effective treatment strategy compared with OT for HIV-infected patients who have achieved sustained virological suppression.
authors.affiliation: The Danish Center for Healthcare Improvements, Faculty of Social Sciences and Faculty of Health Sciences, Aalborg University, Aalborg, Denmark.|HEOR Consult ApS, Copenhagen, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Oddershede
authors.affiliation: Centre for Health Economics, The University of York, York, YO10 5DD, UK. smw501@york.ac.uk.
authors.forename: Simon
authors.initials: S
authors.lastname: Walker
authors.affiliation: MRC Clinical Trials Unit at UCL, Institute of Clinical Trials and Methodology, London, UK.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Stöhr
authors.affiliation: MRC Clinical Trials Unit at UCL, Institute of Clinical Trials and Methodology, London, UK.
authors.forename: David T
authors.initials: DT
authors.lastname: Dunn
authors.affiliation: MRC Clinical Trials Unit at UCL, Institute of Clinical Trials and Methodology, London, UK.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Arenas-Pinto
authors.affiliation: MRC Clinical Trials Unit at UCL, Institute of Clinical Trials and Methodology, London, UK.|Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
authors.forename: Nicholas I
authors.initials: NI
authors.lastname: Paton
authors.affiliation: Centre for Health Economics, The University of York, York, YO10 5DD, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Sculpher
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000191:economics; D017046:Cost Savings; D003362:Cost-Benefit Analysis; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000191:economics; D017320:HIV Protease Inhibitors / Q000008:administration & dosage* / Q000191:economics; D006801:Humans; D008297:Male; D018803:Models, Economic; D019057:Quality-Adjusted Life Years; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome; D006113:United Kingdom; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors