Predicting direct costs of HIV care during the first year of darunavir-based highly active antiretroviral therapy using CD4 cell counts: evidence from POWER

A review of economic evaluations of darunavir boosted by low-dose ritonavir in treatment-experienced persons living with HIV infection

Darunavir boosted by low-dose ritonavir (DRV/r), at a daily dose of 600/100 mg twice a day (bid), has been shown to be superior to alternative highly active antiretroviral therapy (HAART) regimens for the management of treatment-experienced, HIV-infected adults in the phase IIb POWER trials and the phase III TITAN trial. Economic analyses of different types that have been performed for several countries to investigate the cost effectiveness and budgetary impact of DRV/r 600/100 mg bid for treatment-experienced people living with HIV (PLHIV) based on the clinical data gathered in the POWER and TITAN trials are reviewed for consistency and their value to different decision-makers is assessed. Cost-utility analyses for the USA and several European countries indicate that DRV/r-based HAART is cost effective compared with other standard of care protease inhibitor (PI)-based regimens in PLHIV with evidence of PI resistance. For all of these countries, the estimated cost-utility ratio is well below typical benchmark values and these ratios are robust, as demonstrated by one-way sensitivity and variability analyses and multi-way probabilistic sensitivity analyses. Studies using other metrics including the average 1-year drug cost per patient with a plasma HIV-RNA level less than 50 copies/mL at 48 weeks, the incremental drug cost per additional patient with a plasma HIV-RNA level less than 50 copies/mL at 48 weeks, the total (antiretroviral and non-antiretroviral) costs during the first year of treatment, and the total healthcare budget impact during the first 5 years of treatment provided further evidence of the positive economic outcomes with the use of DRV/r in treatment-experienced PLHIV. Different measures of economic outcomes are useful for different types of decision-makers and different types of decisions. In general, the results of these different types of analyses will be consistent with each other. For darunavir, the economic analyses reviewed in this paper demonstrate that the use of DRV/r 600/100 mg bid in the management of HIV-infected, treatment-experienced adults who have failed at least one of the other currently available PIs is cost effective and may be cost saving.

Modelling the budget impact of darunavir in the treatment of highly treatment-experienced, HIV-infected adults in France

BACKGROUND

A key element for payers in the assessment of the economic profile of a medication is its anticipated impact on the evolution of healthcare budgets.

OBJECTIVES

To forecast the impact of the use of darunavir with low-dose ritonavir 600/100 mg twice a day (bid) in highly treatment-experienced, HIV-infected adults who have failed one or more protease inhibitor (PI)-containing regimen on the budget of the French Sickness Fund (French healthcare system) over a 3-year time horizon.

METHODS

A transition state model based on disease severity was developed that compared the evolution of antiretroviral and non-antiretroviral-related direct costs of care in the target population over 3 years (2007-2009) under two scenarios: (1) darunavir enters the French market in year 1; (2) darunavir is not available to the target population during 2007-2009. Model inputs were derived from a targeted analysis of the French hospital database in HIV, the darunavir POWER 1 and 2 trials and other relevant clinical studies.

RESULTS

In the scenario where darunavir was available from year 1, the proportion of patients in the lower, more costly CD4 cell count strata (≤ 100 cells per mm³) was consistently lower than in the scenario without darunavir in each year of the model (17.0% vs 19.2%, 13.9% vs 18.3% and 10.8% vs 16.8% for years 1, 2 and 3, respectively). As a result, over the entire 3-year period, the net increase of antiretroviral drug costs (+ 5.6 million Euros; €), resulting from the substitution of older, cheaper PIs by darunavir, is expected to be fully compensated by savings in hospitalization costs (€-9.7 million) and expenditures for other HIV-related (non-antiretroviral) medications (€-7.3 million), leading to a net saving of €11.4 million or 2.9% of the total budget in the scenario without darunavir. Various sensitivity analyses confirmed these projected savings.

CONCLUSION

The use of darunavir/ritonavir (DRV/r) 600/100 mg bid, in combination with other antiretroviral agents, in highly pre-treated, HIV-infected adults who have failed one or more PI-containing highly active antiretroviral therapy regimen is not expected to increase the budget of the French healthcare system, in comparison with a scenario without darunavir. Further research is needed to estimate the budget impact of the use of DRV/r in less treatment-experienced, HIV-infected individuals in France.