Economic Evaluation and Budget Impact of Biosimilar Trastuzumab for HER2-Positive Metastatic Breast Cancer in Thailand: Policy Implications for Access and Affordability

Although biosimilar trastuzumab has improved affordability, it remains not cost-effective at current prices. However, the relatively modest budget impact supports the feasibility of expanding access through targeted price negotiation and policy interventions. Threshold analysis indicated that price reductions to approximately THB 3700 per vial (1-year regimen) and THB 2950 per vial (until-progression regimen) would be required for trastuzumab to achieve cost-effectiveness under the Thai threshold.