Three-year follow-up from a phase 3 study of SB3 (a trastuzumab biosimilar) versus reference trastuzumab in the neoadjuvant setting for human epidermal growth factor receptor 2–positive breast cancer
Key result
Trastuzumab biosimilar SB3 reduces event-free survival events ~53% versus reference trastuzumab in HER2-positive breast cancer.
- HR 0.47
- 95% CI 0.26-0.87
- n=367
Why the study?
Long-term cardiac safety and efficacy data comparing trastuzumab biosimilar SB3 with reference trastuzumab in HER2-positive early breast cancer were needed.
Does a trastuzumab biosimilar (SB3) have comparable long-term cardiac safety and efficacy to reference trastuzumab in patients with HER2-positive early breast cancer?
Population
367 patients with HER2-positive early breast cancer who completed the phase 3 study
Comparison
Trastuzumab biosimilar SB3 versus reference trastuzumab TRZ
Design
Phase 3 randomized controlled trial extension study
Follow-up
Median 40.8 months for SB3 and 40.5 months for TRZ
Authors
Discussion
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Implication
SB3 was associated with fewer EFS events; leaves open long-term cardiac safety equivalence versus reference trastuzumab in HER2-positive breast cancer.
Study Design
Type
RCT (n=367)
Structured PICO
Does a trastuzumab biosimilar (SB3) have comparable long-term cardiac safety and efficacy to reference trastuzumab in patients with HER2-positive early breast cancer?
P
Population
367 patients with human epidermal growth factor receptor 2-positive early breast cancer who completed a phase 3 study, followed for a median of 40.8 months.
I
Intervention
Trastuzumab biosimilar (SB3)
C
Comparator
Reference trastuzumab (TRZ)
O
Outcome
Incidence of symptomatic congestive heart failure (CHF), asymptomatic significant left ventricular ejection fraction (LVEF) decrease, incidence of other cardiac events, event-free survival (EFS), and overall survivalsafety
Main Result
Hazard Ratio: 0.47 (95% CI 0.26–0.87)
Absolute Event Rate: 9.1% vs 17.1%
Long-term follow-up demonstrates that the trastuzumab biosimilar SB3 has rare cardiotoxicity and higher event-free survival compared to reference trastuzumab in HER2-positive early breast cancer.
Cite This Study
Pivot et al. (2019) conducted an RCT in human epidermal growth factor receptor 2-positive early breast cancer (n=367). SB3 (trastuzumab biosimilar) vs. reference trastuzumab (TRZ) was evaluated on Event-free survival (EFS) events (HR 0.47, 95% CI 0.26-0.87). The trastuzumab biosimilar SB3 reduced event-free survival events compared to reference trastuzumab (9.1% vs 17.1%; HR 0.47, 95% CI 0.26-0.87) in patients with HER2-positive early breast cancer.