Cost‐efficacy analysis of darunavir/r monotherapy in clinical practice

Purpose of the study To evaluate the economic impact of a swiching strategy to DRV/r mx in clinical practice using Spanish prices. Methods Multicenter retrospective study of four tertiary hospitals in Spain. The analysis includes 147 patients switching to DRV/r mx mainly due to toxicity or simplification from March 2009 to June 2011. The Spanish costs (ex‐factory price+VAT) per patient with HIV RNA<50 copies/ml were calculated, accounting for additional/ switch antiretroviral taken after initial treatment failure and management of adverse events. Cost of adverse events were based on a Spanish publication [1] (updated by the inflation rate until april 2012) The horizon of the analysis was of 48 weeks. Summary of results Baseline characteristics were: women (30.6%), median age (49 yr), IDU (45%), AIDS stage (32%), HCV coinfected (48%, 40% with advanced fibrosis), length of HIV‐RNA<1.7 before DRV/rtv mtx 67.6. Most frequent reasons for switching to DRVr mx were toxicity (62.6%) and simplification (23.8%). If a hospital with 600 patients in ART treatment, switched from 10% to 20% of its patients to DRV/r mx, there is a potential to save up to 448,000€/year. Conclusions Switching to DRV/r mx is a cost‐effective strategy that allows more patients to be treated for a fixed budget. Higher cost saving is expected when toxicity is the reason for switching.Baseline HAART DRV/r Monotherapy DifferenceMean cost per patient (ARV) 8.471€ 5.773€ ‐ 2.698€ Mean cost per patient (AEs) 70€ 5€ ‐ 65€Total Mean cost per patient* 8.541€ 5.778€ ‐ 2.762€Number treated for 1,000,000 117 173 56% HIV RNA<50 copies/ml (OTT) 93,10% 93,10% 0,00%Cost per success 9.174€ 6.207€ ‐ 2.967€Number of success 109 161 52ICER (Incremental Cost Efficacy Ratio)Dominated* Includes ARV and AEs treatment costs.48 Weeks Cost‐Efficacy analysis: Simplification strategy to DRV/r monotherapy% of patients that Switches to DRV/r monotherapy10% 15% 20%Number of patients in ARV treatment 600 600 600Number of patients in DRV/r Monotherapy 60 90 120Before Switch: 1 year cost 512.441€ 768.662€ 1.024.883€After Switch: 1 year cost 346.698€ 520.048€ 693.397€Total Cost Saving 165.743€ 248.614€ 331.486€Hospital Budget Impact Analysis: assuming that 10%–20% of 600 patients in ARV treatment simplifies to DRV/r monotherapy