Cost-effectiveness of oral agents in relapsing-remitting multiple sclerosis compared to interferon-based therapy in Saudi Arabia

BACKGROUND: Promising clinical and humanistic outcomes are associated with the use of new oral agents in the treatment of relapsing-remitting multiple sclerosis (RRMS). This is the first cost-effectiveness study comparing these medications in Saudi Arabia. OBJECTIVES: We aimed to compare the cost-effectiveness of fingolimod, teriflunomide, dimethyl fumarate, and interferon (IFN)-β1a products (Avonex and Rebif) as first-line therapies in the treatment of patients with RRMS from a Saudi payer perspective. DESIGN: Cohort Simulation Model (Markov Model). SETTING: Tertiary care hospital. METHODS: A hypothetical cohort of 1000 RRMS Saudi patients was assumed to enter a Markov model model with a time horizon of 20 years and an annual cycle length. The model was developed based on an expanded disability status scale (EDSS) to evaluate the cost-effectiveness of the five disease-modifying drugs (DMDs) from a healthcare system perspective. Data on EDSS progression and relapse rates were obtained from the literature; cost data were obtained from King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia. Results were expressed as incremental cost-effectiveness ratios (ICERs) and net monetary benefits (NMB) in Saudi Riyals and converted to equivalent $US. The base-case willingness-to-pay (WTP) threshold was assumed to be $100 000 (SAR375 000). One-way sensitivity analysis and probabilistic sensitivity analysis were conducted to test the robustness of the model. MAIN OUTCOME MEASURES: ICERs and NMB. RESULTS: The base-case analysis results showed Rebif as the optimal therapy at a WTP threshold of $100 000. Avonex had the lowest ICER value of $337 282/QALY when compared to Rebif. One-way sensitivity analysis demonstrated that the results were sensitive to utility weights of health state three and four and the cost of Rebif. CONCLUSION: None of the DMDs were found to be cost-effective in the treatment of RRMS at a WTP threshold of $100 000 in this analysis. The DMDs would only be cost-effective at a WTP above $300 000. LIMITATIONS: The current analysis did not reflect the Saudi population preference in valuation of health states and did not consider the societal perspective in terms of cost.