LAUSR

AIMS This study evaluated cost-effectiveness of defibrotide versus best supportive care (BSC) for the treatment of hepatic veno-occlusive disease/sinusoidal obstructive syndrome (VOD/SOS) with multiorgan dysfunction (MOD) post-hematopoietic cell transplantation (HCT) in Spain. MATERIALS AND METHODS A two-phase Markov model, comprising a one-year acute phase with daily cycles and a lifetime long-term phase with annual cycles, was adapted to the Spanish setting. The model included a cohort of patients with severe VOD/SOS (defined as VOD/SOS with MOD) post-HCT. For the acute phase, efficacy and VOD/SOS-related length of stay were obtained from a phase 3 defibrotide study (NCT00358501). VOD/SOS-related hospital stays were 7.5 and 23.2 days in defibrotide-treated and BSC patients, respectively. Defibrotide-treated patients spent 30% of their stay in the intensive care unit versus 60% in BSC patients. Assumptions for the long-term phase and utility values were obtained from the literature. Costs were from the Spanish Health System perspective (€2019). Defibrotide cost was based on 25 mg/kg/day over 17.5 days, using local expert opinion. Life-years (LYs), quality-adjusted LYs (QALYs), and costs were estimated over a lifetime horizon, applying a 3% discount rate for costs and outcomes. Sensitivity analyses assessed the robustness of the results. RESULTS Defibrotide produced an additional 1.214 QALYs and 1.348 LYs versus BSC, with a total cost of €33,708 more than BSC alone. However, defibrotide resulted in savings up to €16,644/patient for cost of hospital stay. Difference between costs and effective measures led to ratios of €27,757/QALY and €25,007/LY gained. Additional hospital stays had the greatest influence on base-case results. Probabilistic analysis confirmed the robustness of the deterministic results. LIMITATIONS Limitations include use of historical controls and assumptions extrapolated from the literature. CONCLUSIONS This cost-effectiveness model, adapted to the Spanish setting, showed that defibrotide is a cost-effective alternative to BSC alone in patients with severe VOD/SOS post-HCT.