Diverging Impacts of Evergreening and Biosimilars on Trastuzumab Utilization and Costs in South Korea: Implications for Sustainable Access and Market Competition
Author(s)
Minji Kim, BS, Gyeongseon Shin, PharmD, PhD, Seungjin Bae, ScD.
Ewha Womans University, College of Pharmacy, Seoul, Korea, Republic of.
Ewha Womans University, College of Pharmacy, Seoul, Korea, Republic of.
OBJECTIVES: While biosimilars aim to improve affordability, originator companies often employ evergreening strategies, like subcutaneous (SC) formulations, to maintain market share. Using Trastuzumab, South Korea’s first approved anticancer biosimilar, this study examines how these competing strategies shaped utilization trends, market restructuring, and healthcare expenditures.
METHODS: We conducted segmented regression analyses using ARIMA/SARIMA models on two data sources. IQVIA-MIDAS® data (Q1 2013-Q4 2020) included quarterly sales volume (mg per 1,000 mg, converted from standard units) and manufacturer-level sales value (USD, log-transformed) for intravenous (IV) and SC. Additionally, we used the K-CURE national claims database (through Q4 2019), comprising trastuzumab claims, patient counts, and healthcare costs (USD, log-transformed, per patient per year) based on a 10% breast cancer sample linked to staging and mortality. Two intervention points were defined: SC launch (2014Q4) and biosimilar entry (2017Q3). Outcomes included utilization (volume, claims, patients) and expenditures (sales value, total and breast cancer-specific costs).
RESULTS: After SC launch, trends in total trastuzumab sales volume increased by 400,257 mg per quarter, accompanied by rising claims (+28.2/quarter) and patient counts (+8.7/quarter). SC reached 60% market share by Q4 2019, while IV volume (-411.9mg/quarter) and sales value (-9.52%/quarter) showed downward trends. Despite rising utilization, trends in total sales value (-1.09%/quarter,-$186,466/quarter) decreased. After biosimilar entry, trends in total volume (+507,072mg/quarter) and value (+2.12%/quarter, +$362,669/quarter) increased, though patient and claim growth slowed compared to post-SC trends. Meanwhile, IV volume rebounded (+342,156mg/quarter), partly driven by originator IV product use, while SC growth slowed.
CONCLUSIONS: Our findings indicate that SC reformulation created new market segments and increased utilization, whereas biosimilars competed within existing IV markets with limited impact. Without demand-side policies complementing South Korea's price-linking approach, biosimilar cost-saving potential remains constrained by evergreening strategies. Balanced policies supporting both innovation and sustainable competition are essential.
METHODS: We conducted segmented regression analyses using ARIMA/SARIMA models on two data sources. IQVIA-MIDAS® data (Q1 2013-Q4 2020) included quarterly sales volume (mg per 1,000 mg, converted from standard units) and manufacturer-level sales value (USD, log-transformed) for intravenous (IV) and SC. Additionally, we used the K-CURE national claims database (through Q4 2019), comprising trastuzumab claims, patient counts, and healthcare costs (USD, log-transformed, per patient per year) based on a 10% breast cancer sample linked to staging and mortality. Two intervention points were defined: SC launch (2014Q4) and biosimilar entry (2017Q3). Outcomes included utilization (volume, claims, patients) and expenditures (sales value, total and breast cancer-specific costs).
RESULTS: After SC launch, trends in total trastuzumab sales volume increased by 400,257 mg per quarter, accompanied by rising claims (+28.2/quarter) and patient counts (+8.7/quarter). SC reached 60% market share by Q4 2019, while IV volume (-411.9mg/quarter) and sales value (-9.52%/quarter) showed downward trends. Despite rising utilization, trends in total sales value (-1.09%/quarter,-$186,466/quarter) decreased. After biosimilar entry, trends in total volume (+507,072mg/quarter) and value (+2.12%/quarter, +$362,669/quarter) increased, though patient and claim growth slowed compared to post-SC trends. Meanwhile, IV volume rebounded (+342,156mg/quarter), partly driven by originator IV product use, while SC growth slowed.
CONCLUSIONS: Our findings indicate that SC reformulation created new market segments and increased utilization, whereas biosimilars competed within existing IV markets with limited impact. Without demand-side policies complementing South Korea's price-linking approach, biosimilar cost-saving potential remains constrained by evergreening strategies. Balanced policies supporting both innovation and sustainable competition are essential.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
HPR60
Topic
Economic Evaluation, Health Policy & Regulatory, Real World Data & Information Systems
Topic Subcategory
Public Spending & National Health Expenditures, Reimbursement & Access Policy
Disease
Biologics & Biosimilars, Oncology