Cost-utility analysis of relapsing-remitting multiple sclerosis treatment with azathioprine or interferon beta in Spain

Aim. To carry out a cost-utility analysis of the treatment of relapsing-remitting multiple sclerosis (RRMS) with azothioprine (Imurel) or beta interferon (all, Avonex, Rebif and Betaferon). Material and methods. Pharmacoeconomic Markov model comparing treatment options by simulating the life of a hypothetical cohort of women aged 30, from the societal perspective. The transition probabilities, utilities, resource utilisation and costs (direct and indirect) were obtained from Spanish sources and front bibliography. Univariant sensitivity analyses of the base case were performed. Results. In. the base case analysis, the average cost per patient (euros in 2003) of a life treatment, considering a life expectancy of 53 years, would be 620,205, 1,047,836, 1,006,014, 1,161,638 and 968,157 euros with Imurel, all interferons, Avonex, Rebif and Betaferon, respectively Therefore, the saving with Imurel would range between 327,000 and 520,000 euros approximately, The quality adjusted life years (QALY) obtained with Imurel or interferons would be 10.08 and 9.30, respectively, with an average gain of 0.78 QALY per patient treated with Imurel. The sensitivity analyses confirmed the robustness of the base case. The cost of one additional QALY with interferons would range between 413,000 and 1,308,000 euros approximately in the hypothetical worst scenario,for Imurel. Conclusions. For a typical patient with RRMS, treatment with Imurel would be more efficient than interferons and would dominate (would be more efficacious with lower costs) beta interferon.