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Study of Combination Chemotherapy Plus Trastuzumab

3,260 women with HER2-low, early-stage breast cancer needed

Trial Starts: January 2011 Trial Ends: January 2017

Written By Nicole Katze, MA, Editor and Manager, Content Development
Reviewed By Claudine Isaacs, MD, FRCPC

Researchers from the National Surgical Breast and Bowel Project seek women with early-stage, HER2-low breast cancer for a phase III study. The trial team is exploring whether adding trastuzumab (Herceptin) to combination chemotherapy improves invasive disease-free survival.

HER2-low breast cancer is not considered “true” HER2-positive disease by doctors, but does have more HER2 receptors on cells than is normal. Doctors can test whether a cancer is HER2-low using both IHC, immunohistochemistry, or ISH, in situ hybridization, tests.

Invasive disease-free survival, IDFS, is the time from the start of trial treatment to breast cancer coming back in the same breast, nearby lymph nodes, or distant organs.

Background and Goals 

Past research shows treating breast cancer with more than one chemotherapy medicine at a time —combination chemotherapy — helps kill more cancer cells. Giving chemotherapy after surgery is also known to help destroy remaining cancer cells.

In HER2-positive breast cancer, too many HER2 receptors — or proteins on the surface of breast cells — signal the cells to grow out of control. This process fuels the growth of the cancer. Doctors know that medicines like trastuzumab work by attaching to the receptors to stop them from telling the cells to grow. Trastuzumab is standard of care for people with HER2-positive breast cancer.

HER2-low breast cancer does not have enough HER2 proteins to be called HER2-positive, but has enough that it might respond to anti-HER2 therapies like trastuzumab.

At present, trasutuzmab isn’t given to people who are do not have “true” HER2-positive results. However, some doctors believe giving trastuzumab when cancer is HER2-low may be more effective than treating with chemotherapy alone. This study will assess whether using trastuzumab with combination chemotherapy is better than using combination chemotherapy alone to treat women with HER2-low breast cancer. They will do this by seeing which treatments result in the longest IDFS.

The trial team will also collect data on disease-free, breast cancer-free, recurrence-free, and overall survival, as well as any serious treatment side effects.


Participants will be assigned to one of two treatment groups:

  • Combination chemotherapy alone, or
  • Combination chemotherapy plus trastuzumab

In both groups, participants’ doctors will decide whether they have treatment with a combination of docetaxel (Taxotere) and cyclophosphamide (Cytoxan), known as CT, or with a combination of doxorubicin hydrochloride (Adriamycin) and cyclophosphamide combination chemotherapy, then paclitaxel (Taxol), known as AC-T.

After completing all treatment cycles, participants will be followed-up every 6 months for 5 years, and then once a year for another 5 years.


You may be eligible to take part in this study if you

  • are a woman over age 18
  • have early-stage, lymph-node positive breast cancer defined as HER2-low on IHC and ISH testing as follows
    • IHC test result of 1+, or
    • IHC test result of 2+ AND ISH test result of +1, +2, or a HER2 gene copy number of less than 4 per nucleus
    • have negative lymph nodes but are at high risk of recurrence because the tumors were large, high grade, tested over 25 on theOncoType DX test or the cancer is estrogen- and progesterone-receptor negative
    • have already had either lumpectomy or mastectomy
    • are in generally good health

You may not be eligible if you

  • are already participating in the NSABP’s trial B-39
  • have been treated with anthracycline- or taxane-based chemotherapy in the past
  • have been treated with trastuzumab in the past
  • have already started post-surgery chemotherapy
  • have had or started radiation therapy

For more information or to find out if you are eligible, talk with your doctor about trial NCT01275677 on

Study Locations

This study is being held in over 1,000 locations throughout the United States, Canada, Ireland and Puerto Rico. For full location details and contact information, visit