for people ages 18 years and up (full criteria)
study started
estimated completion



This is a Phase III, two-arm, randomized, double-blind placebo-controlled study in participants with HER2-positive primary breast cancer who have received preoperative chemotherapy and HER2-directed therapy, including trastuzumab followed by surgery, with a finding of residual invasive disease in the breast and/or axillary lymph nodes.

Official Title

A Phase III, Randomized, Double-Blind, Placebo-Controlled Clinical Trial to Evaluate the Efficacy and Safety of Adjuvant Atezolizumab or Placebo and Trastuzumab Emtansine for HER2-Positive Breast Cancer at High Risk of Recurrence Following Preoperative Therapy


Breast Cancer Breast Neoplasms Recurrence Trastuzumab Ado-Trastuzumab Emtansine Atezolizumab Maytansine Trastuzumab Emtansine


You can join if…

Open to people ages 18 years and up

  • Histologically confirmed invasive breast carcinoma
  • Centrally-confirmed human epidermal growth factor receptor 2 (HER2)-positive invasive breast cancer
  • Centrally confirmed PD-L1 and hormone receptor status
  • Clinical stage at disease presentation: cT4/anyN/M0, any cT/N2-3/M0, or cT1-3/N0-1/M0 (participants with cT1mi/T1a/T1b/N0 are not eligible)
  • Completion of pre-operative systemic chemotherapy including at least 9 weeks of taxane and 9 weeks of trastuzumab (anthracycline and/or additional HER2-targeted agents are permitted)
  • <=12 weeks between primary surgery and randomization
  • Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1
  • Screening left ventricular ejection fraction (LVEF) >= 50% and no decrease in LVEF by >15% from the pre-chemotherapy LVEF. If no pre-chemotherapy LVEF, screening LVEF >= 55%
  • Life expectancy >= 6 months
  • Adequate hematologic and end organ function

You CAN'T join if...

  • Stage IV breast cancer
  • An overall response of disease progression according to the investigator at the conclusion of preoperative systemic therapy
  • Prior treatment with T-DM1, or atezolizumab, or other immune checkpoint inhibitors
  • History of exposure to various cumulative doses of anthracyclines
  • History of other malignancy within 5 years prior to screening, except for appropriately treated carcinoma in situ of the cervix, non-melanoma skin carcinoma, Stage I uterine cancer, or ductal carcinoma in situ (DCIS)
  • Current grade >=2 peripheral neuropathy
  • History of idiopathic pulmonary fibrosis, organizing pneumonia, or pneumonitis
  • History of or active autoimmune disease or immune deficiency
  • Treatment with immunostimulatory or immunosuppressive agents
  • Cardiopulmonary dysfunction
  • Any known active liver disease


  • UCLA Medical Center accepting new patients
    Santa Monica California 90404 United States
  • California Cancer Associate for Research & Excellence accepting new patients
    Fresno California 93720 United States
  • Roy and Patricia Disney Family Cancer Center- Providence Saint Joseph Medical Center accepting new patients
    Burbank California 91505 United States
  • Glendale Adventist Medical Ctr accepting new patients
    Glendale California 91206 United States
  • Innovation Clinical Research Institute accepting new patients
    Whittier California 90603 United States


accepting new patients
Start Date
Completion Date
Hoffmann-La Roche
Phase 3 research study
Study Type
Last Updated