Moeremans K¹, Annemans L², Smets E³, Wyffels V⁴, Lothgren M⁵, Allegri G⁶

¹IMS HEOR, Brussels, Belgium, ²Ghent University, Ghent, Belgium, ³Johnson & Johnson Pharmaceutical Services, Inc, Beerse, Belgium, ⁴Janssen Cilag NV, Berchem, Belgium, ⁵JANSSEN-CILAG, Sollentuna, Sweden, ⁶TIBOTEC a division of JANSSEN-CILAG SpA Italy, Cologno Monzese, Italy

OBJECTIVES: To determine whether the protease inhibitor (PI) darunavir boosted with low dose ritonavir (DRV/r) is cost-effective, compared to currently available PIs, as part of highly active anti-retroviral therapies (HAART), in highly pre-treated HIV-1-infected adults who failed >1 PI-containing regimen in European healthcare settings. This analysis included Belgium, Italy and Sweden and focused on the payer perspective. METHODS: A Markov model was adapted which contains 6 health states defined by CD4+ T-cell-count range (<50, 51-100, 101-200, 201-350, 351-500 and >500 cells/mm3) and a state “death” (Mauskopf et al, 2006). Clinical trial (POWER1&2) data were used to model the composition of HAART regimens, patient characteristics and transition probabilities during DRV/r or comparator PI(/r) treatment, both combined with optimised background regimen (OBR). After treatment failure, patients were assumed to switch to tipranavir/r-containing regimens ((TPV/r)+OBR). Transition probabilities during TPV/r treatment were obtained from published clinical trials. Utility values and HIV-related mortality were obtained from published literature. Published relative risks of non-HIV mortality in HIV patients were applied to country-specific all-cause mortality statistics. Non-HAART-related costs in each model state were derived from observational studies in each country. Costs and effects were discounted according to local guidelines. The quality-adjusted lifetime incremental cost-effectiveness ratio (ICER) was calculated for the base-case. Univariate and probabilistic sensitivity analyses were applied. RESULTS: For Sweden, Italy and Belgium respectively, quality-adjusted life year (QALY) gains of 1.142, 1.171 and 1.397 were predicted for patients treated with DRV/r in the base-case analysis. The base-case ICER for DRV/r was 6,862€/QALY, 16,668€/QALY and 12,584€/QALY respectively. The DRV/r ICER remained consistently below the often quoted threshold of 30,000€/QALY throughout extensive sensitivity analyses. The probability of an ICER below 30,000€/QALY was above 94% in all countries. CONCLUSIONS: DRV/r is predicted to be cost-effective versus currently available PIs in highly pre-treated HIV-1-infected adults in different European healthcare settings.