Comparative Cost-Effectiveness of Tofacitinib With Continuing Conventional Synthetic Disease-Modifying Anti-Rheumatic Drugs for Active Rheumatoid Arthritis in South Korea

Introduction The objective of this study was to evaluate the cost-effectiveness of initiating treatment with tofacitinib and subsequently incorporating it into a conventional synthetic disease-modifying anti-rheumatic drug (csDMARD) treatment sequence and to compare the cost-effectiveness of this sequence with that of continuing csDMARDs alone in patients with active rheumatoid arthritis (RA). Methods A cohort-based Markov model was used to evaluate the cost-effectiveness of two tofacitinib treatment sequences compared with that of continuing the csDMARD treatment sequence over a lifetime. Of the two tofacitinib sequences, the first consisted of initial tofacitinib treatment followed by biologic DMARDs (bDMARDs) and the second consisted of csDMARD treatments followed by tofacitinib. A third treatment sequence, continuing the csDMARD treatment sequence before starting bDMARDs, was used as a comparator. Efficacy was assessed using the American College of Rheumatology (ACR) response rates (ACR 20, ACR 50, and ACR 70) after 6 months, which were converted to changes in the health assessment questionnaire-disability index (HAQ-DI) score. Utility was estimated by mapping from the HAQ-DI score, costs were analyzed from a Korean societal perspective, and outcomes were considered in terms of quality-adjusted life-years (QALYs). One-way sensitivity analysis and probabilistic sensitivity analysis were performed to assess the robustness of the model. Results The incremental cost-effectiveness ratios over a lifetime for starting with tofacitinib and incorporating tofacitinib into the csDMARD treatment sequence versus continuing csDMARDs only were US$14,537 per QALY and US$7,086 per QALY, respectively. One-way sensitivity analysis and probabilistic sensitivity analysis confirmed the robustness of these results. Conclusion Starting with tofacitinib and incorporating it into a csDMARDs treatment sequence is cost-effective compared to continuing csDMARDs alone in patients with RA.