Aims: To assess the cost-utility of cladribine tablets versus fingolimod in patients with highly active relapsing-remitting multiple sclerosis (RRMS) in Portugal. Methods: A 1-year cycle cohort-based Markov state transition model was developed to simulate disease progression, measured by Kurtzke Expanded Disability Status Scale (EDSS), relapses, and conversion to secondary-progressive MS (SPMS). Patients were assumed to remain on treatment until progression to EDSS level 7, conversion to SPMS, or complete loss of efficacy due to waning effect. Natural history was based on British Columbia Multiple Sclerosis registry, London Ontario database, UK MS Trust, and cladribine tablets clinical trial (CLARITY). Portuguese all-cause mortality was adjusted for the MS associated increased mortality. Clinical inputs for active treatments (disability progression and relapse rate) were estimated on a network meta-analysis. Utility weights were derived from UK-MS Survey and published literature. Resource consumption by EDSS and due to relapses was based on published literature, National DRG microdata and expert opinion. Unit costs were obtained from official sources. The analysis was conducted from payers' perspective, time horizon of 50 years and discount rate of 5%, for both costs and benefits. Uncertainty was assessed via probabilistic and deterministic sensitivity analyses. Results: Compared to fingolimod, cladribine tablets were associated with a delay in progression, resulting in a gain of 0.85 quality adjusted life years (QALYs) and a cost decrease of 25,935 e. Probabilistic sensitivity analysis resulted in a mean ICER of À31,781 e per QALY and was dominant in 98.7% of the simulations. Cladribine tablets were dominant across the scenario analyses tested. Conclusions: Treatment of highly active RRMS with cladribine tablets was less costly and more effective than treatment with fingolimod. Hence, it is a dominant strategy in the Portuguese setting. No conclusions can be drawn from the present study regarding other treatment options, in particular natalizumab and alemtuzumab.