HER2+ Breast Cancer

Breast cancer patients with PI3KCA mutations are less likely to achieve a pathological complete response from dual HER2 blockade in the neoadjuvant setting.

Exploratory analysis of biomarkers in the BOLERO-3 trial suggests that the addition of everolimus to trastuzumab plus vinorelbine for HER2-positive advanced breast cancer may be most beneficial in patients with low PTEN or high pS6 levels.

The FDA's Oncologic Drugs Advisory Committee voted 13-0 with one abstention in support of pertuzumab in combination with trastuzumab and docetaxel for patients with HER2-positive breast cancer in the neoadjuvant setting.

Trastuzumab is the clear standard of care for firstline therapy for nearly all HER2-positive breast cancers, and the oncology community has come a long way toward understanding how best to use the drug.

Exploratory analyses by intrinsic subtype showed that HER2-positive breast cancer is molecularly heterogeneous with varying degrees of sensitivity to HER2-targeted therapy.

Debu Tripathy, MD, co-leader, Women's Cancer Program, University of Southern California Norris Comprehensive Cancer Center, discusses targeting HER2 in breast cancer.

Women with the highest expression of HER2 had the most benefit from T-DM1, while the presence of PIK3CA mutations had no effect on response to T-DM1 but did interfere with response to capecitabine/lapatinib.

Rebecca L. Aft, MD, PhD, discusses the identification of patients with breast cancer at high risk of recurrent disease development by detection of HER2-positive disseminated tumor cells in bone marrow of patients with HER2-negative tumors.

Although recent findings suggest some patients with HER2-negative breast cancer would benefit from therapies directed against overexpression of the protein, two leading oncologists do not see an immediate impact on clinical practice as further validation is needed.