Neoadjuvant Ado-trastuzumab Emtansine vs. Trastuzumab in Early Breast Cancer
As neoadjuvant therapy for patients with HER2-positive/hormone receptor–positive breast cancer, ado-trastuzumab emtansine (formerly known as T-DM1) resulted in a “clinically meaningful” pathologic complete response with no need for chemotherapy in some cases, according to research published by Nadia Harbeck, MD, of the University of Munich, and colleagues, in the Journal of Clinical Oncology.
In this prospective phase II trial, 375 patients with early breast cancer and HER2-positive/ hormone receptor–positive status were randomly assigned to receive the antibody-drug conjugate of trastuzumab with or without endocrine therapy or trastuzumab with endocrine therapy. After 12 weeks of therapy, pathologic complete response was observed in 41% of patients treated with ado-trastuzumab emtansine, 41.5% of patients treated with ado-trastuzumab emtansine and endocrine therapy, and 15.1% of patients treated with trastuzumab and endocrine therapy.
Additionally, 40% of patients treated with ado-trastuzumab emtansine and 47% treated with ado-trastuzumab emtansine and endocrine therapy required no additional chemotherapy after surgery, compared with 22% of those treated with trastuzumab and endocrine therapy.
Dr. Harbeck and colleagues concluded that based on these results, “a substantial number of patients” may be spared the adverse effects of systemic chemotherapy.