Monthly Cost of Overall Survival: An Economic Model Comparing Trastuzumab-Deruxtecan (T-DXd) vs Trastuzumab-Emtansine (T-DM1) for Second-Line Treatment of Stage IV HER2+ Breast Cancer in Brazil's Private Healthcare System

Speaker(s)

ABSTRACT WITHDRAWN

OBJECTIVES: When considering optimal treatments for patients, clinicians and payers seek to understand the relative clinical benefits and costs. This study aims to investigate the cost per month of overall survival (OS) for T-DXd vs. T-DM1 in the second line (2L) treatment of stage IV HER2+ breast cancer in Brazil's private healthcare system.

METHODS: A semi-Markov model simulated mean PFS, OS and time to discontinuation (TTD) based on the DESTINY-Breast03 (DB-03) data, with 30 years horizon. TTD measure was used to calculate treatment cost.

Post-2L treatment costs were based on a market research report of 3rd and 4th line treatment patterns post-T-DM1 (n=150) and T-DXd (n=31) discontinuation in Brazil (IQVIA, Patient Diary Survey, 2023). T-DXd post T-DM1 and T-DM1 post T-DXd were both reported as subsequent treatments. Drug prices came from Brazil’s Medicines Market Regulation Chamber.

RESULTS: The semi-Markov model resulted in significant benefits with T-DXd vs. T-DM1, including improved OS (mean 5.32 vs. 4.23 years) and PFS (mean 3.59 vs. 1.32 years). Although initial T-DXd monthly costs were higher (USD 13,939.28 vs. USD 5,033.21), post-discontinuation costs were lower (USD 4,011.60 vs. USD 9,498.39). When considering the complete care cycle, the total costs were USD 460,532.14 vs. USD 393,390.00 respectively. Therefore, less was paid per month of OS (USD 7,210.71 vs. 7,741.07).

CONCLUSIONS: T-DXd shows higher efficacy for 2L HER2+ metastatic breast cancer treatment, with improved OS and PFS. Our findings provide insights about the impact of 2L treatment choice on the complete care cycle cost. This analysis shows a lower cost per month of OS when T-DXd is administered in second line compared with T-DM1 in 2L. Future research should consider quality of life benefits and a complete cost-effectiveness analysis to fully understand the impact of these drugs in this scenario for Brazilian context.

Code

EE539

Topic

Clinical Outcomes, Economic Evaluation

Topic Subcategory

Clinical Outcomes Assessment, Cost-comparison, Effectiveness, Utility, Benefit Analysis

Disease

Drugs, Oncology