Presentation (CTI)

OBJECTIVES: Biosimilars can mitigate rising biologic expenditure through originator price reductions and biosimilar uptake. This study estimated pharmaceutical expenditure savings from biosimilar availability in South Korea and decomposed these savings into effects attributable to originator price reductions and biosimilar uptake.
METHODS: We conducted a budget impact analysis of 12 biologic molecules with biosimilars available in South Korea: adalimumab, aflibercept, bevacizumab, denosumab, eculizumab, etanercept, infliximab, omalizumab, ranibizumab, rituximab, trastuzumab, and ustekinumab. We compared three scenarios: no biosimilar entry; biosimilar listing with originator prices reduced to current levels but no uptake; and the current market with price reductions and observed biosimilar uptake. Health Insurance Review and Assessment Service (HIRA) claims data from March 2021 to March 2025 provided quarterly patient counts and per-patient drug costs. Pre-biosimilar-entry and current HIRA-listed originator prices were used to reconstruct no-biosimilar-entry baseline expenditures. Patient counts for each 2025 quarter were projected using historical trends. Quarterly molecule-specific IQVIA sales volume shares were used to allocate projected use between originators and biosimilars. Savings were decomposed overall and by therapeutic area into price-reduction and uptake-related effects.
RESULTS: Compared with the no-biosimilar scenario, total savings were USD 386.51 million (32% of the hypothetical no-biosimilar market), driven primarily by originator price reductions (USD 336.46 million; 87% of total savings) and, to a lesser extent, observed biosimilar uptake (USD 50.05 million; 13% of total savings). Among major therapeutic areas, savings were largest in oncology (USD 127.99 million), followed by immunology and related diseases (USD 116.32 million) and ophthalmology (USD 62.26 million). Bevacizumab and ranibizumab contributed most to price-reduction and uptake-related savings, respectively (USD 69.69 million and USD 15.27 million).
CONCLUSIONS: Biosimilar availability was estimated to substantially reduce pharmaceutical expenditure, primarily through originator price reductions. Biosimilar uptake provided additional savings, suggesting that policies supporting effective price competition and appropriate biosimilar use may improve the sustainability of biologic spending.