ERBB2-Positive Breast Cancer: How Does T-DM1 Measure Up Against Standard Neoadjuvant Treatment?
Posted: Wednesday, October 6, 2021
The randomized phase II PREDIX HER2 trial compared standard neoadjuvant therapy of docetaxel, trastuzumab, and pertuzumab (DTP) with ado-trastuzumab emtansine (T-DM1) for patients with ERBB2-positive breast cancer, with no significant difference in the pathologic complete response rate between the two treatments. In addition, T-DM1 was found to have a more favorable toxicity profile. The study, prompted by the toxicity of the standard combination therapy, was conducted by Thomas Hatschek, MD, PhD, of the Karolinska University Hospital, Stockholm, and colleagues in JAMA Oncology.
“With appropriate patient selection and dynamic therapy adaptation based on early response assessment, T-DM1 may have the potential to become a successful strategy for treatment de-escalation,” stated the investigators.
The Swedish study included 197 women with tumors greater than 20 mm or lymph node metastases, who were randomly assigned to two treatment groups: six cycles of DTP (standard therapy) or T-DM1 (investigational therapy). A pathologic complete response, defined as ypT0 or Tis ypN0 and measured using fluorine-18–labeled fluorodeoxyglucose positron-emission tomography/computed tomography at baseline and after two and six cycles was achieved in 45 patients (45.5%) in the standard-treatment group (n = 99) and 43 patients (43.9%) in the investigational-therapy group (n = 98). The different results were not statistically significant (P = .82).
A further analysis of the 72 patients with hormone receptor–negative tumors showed a higher pathologic complete response rate (62.5%) versus that in the 125 with hormone receptor–positive tumors (36.0%). This difference in response occurred in both the standard-treatment and investigational-therapy groups.
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.
