Background: In the treatment of psoriasis, biologic agents are more expensive than conventional therapy while showing similar or superior efficacy. However, their efficiency in terms of cost/efficacy (cost per responder in clinical trial conditions) is unknown. OBJECTIVE. To estimate the cost/efficacy ratios of adalimumab, etanercept, infliximab, and efalizumab in the management of moderate to severe psoriasis.
Material and methods: A model for the costs analysis was elaborated by building a decision tree for each of the treatments for which scientific evidence was available. The payer perspective (Spanish national health system) was used, only considering drug costs.The efficacy (proportion of patients who respond according to Psoriasis Area Severity Index [PASI] 75 criterion) was assigned according to the results of the clinical trials. When more than 1 trial was available per treatment, a meta-analysis was undertaken. In the case of weight-dependent dosing, the weight of the study participants was adjusted by age and sex to the standard Spanish population with correction for increased weight in individuals with psoriasis. Uncertainty was investigated with a sensitivity analysis.
Results and conclusions: Assigning the efficacy reported in the 15 published clinical trials, the most efficient biologic agent in terms of the cost/efficacy ratio was adalimumab, with one PASI 75 response at a cost of 8,013 Euro. For the remaining biologic agents and with different regimens, the cost per responder ranged from 9,370 Euro to 17,112 Euro. The sensitivity analysis confirmed the robustness of these figures.