Hatschek T, Foukakis T, Bjöhle J, et al. - Findings indicate that neoadjuvant treatment can be de-escalated with trastuzumab emtansine (T-DM1) monotherapy in selected patients with ERBB2 (formerly HER2)-positive breast cancer, because treatment with standard neoadjuvant combination docetaxel, trastuzumab, and pertuzumab (DTP) was found to be equal to T-DM1.

• This randomized phase 2 trial involved 202 patients with ERBB2-positive tumors larger than 20 mm and/or verified lymph node metastases.

• Patients were randomized to receive 6 cycles of DTP (standard group, n=99) or T-DM1 (investigational group n=98); overall 197 were evaluable for the primary endpoint (pathologic complete response).

• Similar pathologic complete response (pCR) was evident in standard group (45.5%) vs investigational group (43.9%).

• Higher pCR rate in hormone receptor–negative tumors vs in hormone receptor–positive tumors was evident in both treatment groups, in a subgroup analysis.