BACKGROUND: The purpose of this study was to estimate the annual and per-patient budget impact of the treatment of moderate to severe psoriasis in Greece before and after the introduction of ustekinumab.METHODS: A budget impact model was constructed from a national health system perspective to depict the clinical and economic aspects of psoriasis treatment over 5 years. The model included drug acquisition, monitoring, and administration costs for both the induction and maintenance years for patients in a treatment mix with etanercept, adalimumab, infliximab, with or without ustekinumab. It also considered the resource utilization for non-responders. Greek treatment patterns and resource utilization data were derived from 110 interviews with dermatologists conducted in February 2009 and evaluated by an expert panel of 18 key opinion leaders. Officially published sources were used to derive the unit costs. Costs of adverse events and indirect costs were excluded from the analysis. Treatment response was defined as the probability of achieving a PASI 50, PASI 75, or PASI 90 response, based on published clinical trial data.RESULTS: The inclusion of ustekinumab in the biological treatment mix for moderate to severe psoriasis is predicted to lead to total per-patient savings of €443 and €900 in years 1 and 5 of its introduction, respectively. The cost savings were attributed to reduced administration costs, reduced hospitalizations for non-responders, and improved efficacy. These results were mainly driven by the low number of administrations required with ustekinumab over a 5 year treatment period (22 for ustekinumab, compared with 272 for etanercept, 131 for adalimumab, and 36 for infliximab).CONCLUSIONS: The inclusion of ustekinumab in the treatment of moderate to severe psoriasis in Greece is anticipated to have short- and long-term health and economic benefits, both on an annual and per-patient basis.