Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Poster display session

3356 - Lower response to T-DM1 in metastatic breast cancer patients with HER2 IHC score of 2 and FISH positive compared with IHC score of 3


11 Sep 2017


Poster display session


Cytotoxic Therapy;  Breast Cancer


Shu Yazaki


Annals of Oncology (2017) 28 (suppl_5): v74-v108. 10.1093/annonc/mdx365


S. Yazaki, J. Hashimoto, S. Ogita, E. Nakano, T. Yamauchi

Author affiliations

  • Division Of Medical Oncology, St. Luke's International Hospital, 104-8560 - Tokyo/JP


Abstract 3356


Ado-trastuzumab emtansine (T-DM1) is the standard second line chemotherapy for HER2 overexpressed metastatic breast cancer (MBC). Tumor HER2 status is measured by either immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH). A previous study showed no difference in objective response rate (ORR) with trastuzumab monotherapy between IHC 3+ and IHC 2+/FISH positive groups. It is not known whether response to T-DM-1 differs between IHC 3+ and IHC 2+/FISH positive patients. The aim of this study is to compare the efficacy of T-DM1 in IHC 3+ group to that of IHC 2+/FISH positive group.


We retrospectively identified and reviewed the medical records of all patients with HER2 positive MBC who received T-DM1 in our hospital from October 2013 to December 2016. In the efficacy analysis, we excluded five patients who had HER2 negative tumors at metastatic sites.


A total of 44 patients were identified and 36 patients were available for efficacy analysis of ORR. Median age was 58 years old (range 28-80). 95.5% received prior trastuzumab. 45.5% received at least one chemotherapy for MBC, 29.5% received more than four lines of chemotherapy. 79.5% had IHC 3+ and 20.5% had IHC 2+/FISH positive. ORR was 16/30 (53.3%) in IHC 3+ group and was 0/6 (0%) in IHC 2+/FISH positive group (P = 0.024). Median progression free survival (PFS) was 7.0 months (95% CI, 5.58 to 8.42) in IHC 3+ group and was 2.0 months (95% CI, 0.00-4.57) in IHC 2+/FISH positive group.


ORR and PFS were significantly worse in HER2 IHC 2+/FISH positive patients compared with IHC 3+ patients. This is the first report to demonstrate the difference of T-DM1 efficacy by HER2 test results.

Clinical trial identification

Legal entity responsible for the study

St. Luke's International Hospital




All authors have declared no conflicts of interest.

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings
  • Necessary cookies enable core functionality. The website cannot function properly without these cookies, and you can only disable them by changing your browser preferences.