Drugs for relapsing-remitting multiple sclerosis (RRMS) are costly and not included in the National List of Essential Medicines of Thailand yet. This study aims to conduct an economic evaluation of high-cost drugs for RRMS.

The Markov model was used to estimate lifetime costs and quality-adjusted life years (QALYs) gained. The treatment options include Interferon beta-1a (IFN) and Teriflunomide (TERI) (first-line), Fingolimod (FIN) and Natalizumab (NATA) (second-line), and Alemtuzumab (ALEM) (third-line) compared with usual care. The effectiveness of drugs was retrieved by network meta-analysis. The probability of health state transition was obtained from primary data. Treatment-related costs were derived from the national database. Other costs and utilities were obtained from the study in Thai RRMS patients.

The lowest lifetime costs option was usual care (THB2 million) (USD65,808), while the highest QALY gained option was IFN-NATA-ALEM (8.6 QALY gained). All treatment options were not cost-effective compared with usual care at the threshold of THB160,000 (USD5,300) per QALY gained. However, the option of IFN-NATA-ALEM yielded the lowest incremental cost-effectiveness ratio (ICER), which was THB4.4 million (USD144,778) per QALY gained.

High-cost drugs were not cost-effective; nonetheless, the IFN-NATA-ALEM option could increase QALY gained with the lowest additional budget. The government should negotiate the price of IFN to decrease by eighty percent.