Cost-effectiveness of injectable disease-modifying therapies for the treatment of relapsing forms of multiple sclerosis in Spain.

OBJECTIVE: To compare the cost-effectiveness of injectable disease-modifying therapies (DMTs) for the first-line treatment of relapsing-remitting multiple sclerosis (RRMS) in Spain. METHODS: A Markov model was developed to estimate the cost-effectiveness of intramuscular interferon beta-1a (IM IFNß-1a), subcutaneous interferon beta-1a (SC IFNß-1a), interferon beta-1b (IFNß-1b) and glatiramer acetate (GA) relative to best supportive care in a hypothetical cohort of 1,000 RRMS patients in Spain. The model was developed from a societal perspective with a time horizon of 30 years. Natural history and clinical trial data were used to model relapse rates and disease progression. Cost and utility data were obtained from a published survey of multiple sclerosis patients in Spain. The primary outcome measure was cost per quality-adjusted life year (QALY) gained. Univariate and probabilistic sensitivity analyses were performed. RESULTS: Compared to best supportive care, the base case cost-effectiveness was 168,629 per QALY gained for IM IFNß-1a, 231,853 per QALY gained for IFNß-1b, 295,638 per QALY gained for SC IFNß-1a, and 318,818 per QALY gained for GA. Results were most sensitive to changes in DMT cost, utility values and treatment effect. CONCLUSIONS: In our cost-effectiveness analysis of first-line injectable DMTs in Spain, we found IM IFNß-1a to be more cost-effective than SC IFNß-1a, IFNß-1b or GA. Sensitivity analyses confirmed the robustness of these results.