SAN ANTONIO – Swapping trastuzumab out for the drug-antibody conjugate trastuzumab emtansine (T-DM1; Kadcyla) as adjuvant therapy resulted in a halving in the risk of invasive disease or death in patients with HER2-positive early breast cancer with residual invasive disease after neoadjuvant chemotherapy and HER2-targeted therapy, including trastuzumab.
For the primary endpoint in the KATHERINE trial of invasive disease-free survival – defined as freedom from ipsilateral invasive breast tumor recurrence, ipsilateral locoregional invasive breast cancer recurrence, contralateral invasive breast cancer, distant recurrence, or death from any cause – T-DM1 was associated with a hazard ratio of 0.50 (P less than .001).
The 3-year invasive disease-free survival rate for 743 patients treated with T-DMI 1 was 88.3%, compared with 77% for 743 patients treated with trastuzumab, reported Charles E. Geyer Jr., MD, from Virginia Commonwealth University, Richmond, at the San Antonio Breast Cancer Symposium.
In a video interview, Dr. Geyer discussed results of KATHERINE, which suggest that T-DM1 should be considered as a new standard of care in this patient population.
Dr. Geyer reported travel support from Roche and AstraZeneca, medical writing support from AbbVie and Roche, and honoraria from Celgene.