Objectives To carry out a pharmacoeconomic analysis to compare the efficiency of two rheumatoid arthritis treatments in Spain.
Methods The study consisted of a systematic review of efficacy and toxicity as well as a cost-minimization analysis, carried out using a pharmacoeconomic model, comparing the treatment with leflunomide and the combination of infliximab and methotrexate during one year.
Results Clinical trials directly comparing both treatments are not available. The response rate ACR20 combined, after one year, was 53.0% (CI95%: 49.2%-56.4%) with Leflunomide and 42.0% (CI95%: 31.2%-52.5%) with the combination of Infliximab and Methotrexate (P = 0.051). There were no statistically significant differences in the ACR50 response (27.0 vs 21.0, respectively; P = 0.19). There were fewer infections with Leflunomide than with the combination, both respiratory (15.0% and 34.0%, respectively; P = 0.0003) as well as urinary (0.0% and 3.0%, respectively; P = 0.10). In the basic case, the cost per patient of a yearly treatment with Leflunomide or with Infliximab and Methotrexate is estimated to be 315,023 Ptas (Spanish pesetas) (1,893 euros, ?) and 2,596,286 Ptas (15,604 ?), respectively. Therefore, the incremental cost of the combined treatment would be 2,281,263 Ptas (13,711 ?). The sensitivity analysis was carried out using the minimum and maximum costs given by the standard deviations of the unit costs and by modifying other variables, as no significant differences compared to the basic case were found.
Conclusion The cost per patient after one year of treatment is higher with the combination of Infliximab and Methotrexate compared to Leflunomide, this is basically due to the higher acquisition cost of Infliximab.