The only evaluation in this setting that's presently going on, labeled:
"A Multicenter, Multinational Phase II Study to Assess the Clinical Safety and Feasibility of T-DM1 Sequentially With Anthracycline-Based Chemotherapy, As Adjuvant or Neoadjuvant Therapy for Patients With Early Stage HER2-Positive Breast Cancer"
is indeed a single-arm open-label study. It's to assess the safety, feasibility and efficacy of trastuzumab emtansine (T-DM1) AFTER COMPLETION of anthracycline-based adjuvant/neoadjuvant chemotherapy in patients with early HER2-positive breast cancer. Patients will receive T-DM1 3.6 mg/kg intravenously on Day 1 of each 3-week cycle, for up to 17 cycles.
Link points to trial specifics including participating centers, some of which already have completed their assigned task.
http://clinicaltrials.gov/archive/NC..._08_15/changes