Cost-utility analysis of biologic disease-modifying antirheumatic drugs (bDMARD), targeted synthetic DMARD (tsDMARD) and biosimilar DMARD (bsDMARD) combined with methotrexate for Thai rheumatoid arthritis patients with high disease activity

Abstract

BACKGROUND New biologic disease-modifying antirheumatic drugs (bDMARD) as well as their biosimilars (bsDMARD) and targeted synthetic DMARD (tsDMARD) showed greater clinical benefits in the treatment of patients with rheumatoid arthritis (RA) with high disease activity, but imposed higher costs than standard treatment. This study aimed to evaluate the cost-effectiveness of 11 alternative treatment strategies for patients with rheumatoid arthritis with high disease activity with failure of treatment with three conventional DMARD (csDMARD). METHODS A Markov model was constructed using a societal perspective to estimate relevant costs and health outcomes in terms of quality-adjusted life years (QALY) for a lifetime horizon with discounted 3% per year. Alternative treatment strategies including five bDMARD, two targeted tsDMARD, and four bsDMARD in combination with methotrexate (MTX) were compared with standard of care (SoC), i.e., Azathioprine and Cyclosporin. Direct and non-medical care costs were estimated by identifying the resources used and multiplied by the standard costing menu in the year 2022. Utility and transitional probability were collected in three advanced tertiary hospitals. A network meta-analysis was used to estimate the efficacy of each treatment. Lifetime cost, QALYs and incremental cost-effectiveness ratio were calculated compared to the cost-effectiveness threshold of 160,000 THB per QALY gained (4,634 USD). Probabilistic and one-way sensitivity analyses were performed to estimate parameter uncertainties. RESULTS The bDMARD/bsDMARD or tsDMARD combined with MTX provided 0.09 to 0.33 QALY gained with additional costs of 550,986 to 2,096,744 THB compared to SoC. Compared to SoC, the ICER ranged from 2.3 to 8.1 million THB/QALY, and none of these combinations was cost-effective in the Thai context. The results were sensitive to the mortality hazard ratio of patients with high disease activity. CONCLUSIONS The combination of MTX and bDMARD or tsDMARD or bsDMARD was not economically attractive compared to their current practice at the current price. However, they reduced disease activity and improved patient quality of life. The price negotiation process must be conducted to ensure its value for money and financial affordability if included in the pharmaceutical reimbursement list.