- Adjuvant therapy with trastuzumab emtansine (T-DM1) rather than trastuzumab alone decreased invasive recurrence of human epidermal growth factor receptor 2-positive (HER2+) early-stage breast cancer by 50% (HR, 0.5; P<.0001 in patients with residual invasive disease after undergoing neoadjuvant chemotherapy and her2-targeted therapy taxane before surgery.>
Why this matters
- Residual invasive disease in the breast or axillary nodes is linked to a higher risk for recurrence and death.
- Phase 3 trial of 1486 patients with HER2+ early breast cancer and residual invasive disease, randomly assigned 12 weeks after surgery to receive 14 cycles of trastuzumab or T-DM1 adjuvant therapy.
- The research was funded by Roche and Genentech. Dr. Geyer has received travel support from Roche and AstraZeneca, medical writing support from AbbVie and Roche, and honoraria from Celgene.
- 3-year invasive disease-free survival (IDFS) was 88.3% with T-DM1 vs 77% with trastuzumab.
- Benefits seen across all included subgroups and demographics.
- Adverse effects were mostly grade 1 or 2, including platelet count drop, liver enzyme elevations, and sensory neuropathy.
- Confirmation of positive HER2+ relied on pretreatment core biopsy of primary tumor, not residual tumor.
- Open-label design.