Real-World Cardiotoxicity of Biosimilar versus Reference Trastuzumab in Early HER2-Positive Breast Cancer
Main finding · HFResult — go to the resultAdjusted hazard ratio 1.16 95% CI 0.92–1.46Authors' conclusion
As biosimilar trastuzumab use continues to increase, our findings provide reassurance regarding its cardiac safety in the management of early-stage human epidermal growth factor receptor 2 breast cancer.
Study context
- Population
- Adults with early-stage HER2-positive breast cancer treated with trastuzumab and surgery, US claims database, 2018–2024; prior heart failure (HF) excluded43.9% reference trastuzumab
- Participants
- 5,135 adults
- Exposure
- Biosimilar vs reference trastuzumab
- Outcome
- HF risk
Methodological detailsclaims database, multivariable cause-specific Cox regression
- Claims database
- Multivariable cause-specific Cox regression
Main finding
HF
Adjusted hazard ratio
1.16
95% CI 0.92–1.46
By group
Biosimilar trastuzumab vs Reference trastuzumab
aHR 1.16 (95% CI 0.92–1.46)
As reported in the abstract
Observational data: associations, not effects.
Further findings
| Outcome | aHR (95% CI) | |
|---|---|---|
| HF risk by Charlson Comorbidity Index (≥2 vs 0) | 1.52 (1.11–2.08) | |
| HF risk by age (vs 18 to 54 years) — 65 to 74 years vs 18 to 54 years | 1.61 (1.19–2.19) | |
| HF risk by age (vs 18 to 54 years) — ≥75 years vs 18 to 54 years | 1.95 (1.29–2.96) | |
| 0.20.5125Adjusted hazard ratio (log scale) |
Biosimilar trastuzumab adoption · 2018 to 2024
- Biosimilar use increased from 0% in 2018 to 71.3% in 2024
- P < 0.001
Original publication
Real-World Cardiotoxicity of Biosimilar versus Reference Trastuzumab in Early HER2-Positive Breast Cancer. JACC CardioOncol. Published 4 September 2026. doi:10.
Summarised from the published abstract; every number is checked against it