Incremental cost-effectiveness ratio analysis of biologic treatments for psoriasis at clinically significant evaluation time points.

The Spanish guidelines for the treatment of psoriasis recommend that drug choice should be guided by the criteria established in the Summary of Product Characteristics (SPC) for each agent and that decisions should be made on a case-by-case basis and take into account economic considerations. Since the introduction of biologic agents, several authors have studied their cost-efficacy. However, none of these studies present an overall view of the results at clinically significant evaluation time points. The equation used for cost-effectiveness analysis, which can support therapeutic decisions, is the incremental cost effectiveness ratio (ICER): ICER = (C1--C2)/(E1--E2), where C1 and E1 are the cost and effect in the treatment group and C2 and E2 are the cost and effect in the control group. The present analysis is intended to provide useful information to guide clinical practice based on the results of a recent meta-analysis, evaluating the most important variables at each time point. The outcomes and time points used were as follows: a 50% reduction in PASI score (PASI 50) at the time point the SPC recommends assessment of response in order to identify primary treatment failure, and PASI 50 and PASI 75 responses at week 24 (the end of the induction phase). The cost of each treatment was calculated on the basis of the pharmaceutical company’s sale price as of January 2014 less the mandatory deduction under Spanish law (Real Decreto 08/2010) plus VAT. In the case of infliximab,