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
BackgroundProtease 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.ObjectivesIn 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.MethodsThe 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.ResultsPI 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 PS6424.11 (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.ConclusionsUnder 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.
PharmacoEconomics