Although interferon beta-1a (IFNß−1a), 1b (IFNß−1b), and fingolimod have been approved as multiple sclerosis (MS) treatments, they have not yet been included on the National List of Essential Medicines (NLEM) formulary in Thailand. This study aimed to evaluate the cost-utility of MS treatments compared with best supportive care (BSC) based on a societal perspective in Thailand.

A Markov model with cost and health outcomes over a lifetime horizon with a 1-month cycle length was conducted for relapsing–remitting MS (RRMS) patients. Cost and outcome data were obtained from published studies, collected from major MS clinics in Thailand and a discount rate of 3 percent was applied. The incremental cost-effectiveness ratio (ICER) was calculated and univariate and probabilistic sensitivity analyses were performed.

When compared with BSC, the ICERs for patients with RRMS aged 35 years receiving fingolimod, IFNβ−1b, and IFNβ−1a were 33,000, 12,000, and 42,000 US dollars (USD) per quality-adjusted life-year (QALY) gained, respectively. At the Thai societal willingness to pay (WTP) threshold of USD 4,500 per QALY gained, BSC had the highest probability of being cost-effective (49 percent), whereas IFNβ−1b and fingolimod treatments showed lower chance being cost-effective at 25 percent and 18 percent, respectively.

Compared with fingolimod and interferon treatments, BSC remains to be the most cost-effective treatment for RRMS in Thailand based on a WTP threshold of USD 4,500 per QALY gained. The results do not support the inclusion of fingolimod or interferon in the NLEM for the treatment of RRMS unless their prices are decreased or special schema arranged.