HER2+ Breast Cancer

New treatments for HER2-positive (HER2+) tumors have dominated media coverage of breast cancer breakthroughs over the past year, but William Gradishar sees promise on many fronts.

The combination of everolimus, trastuzumab, and vinorelbine, as given in the BOLERO-3 trial in patients with pretreated HER2-positive advanced breast cancer, is adequately tolerated, and adverse events are manageable.

Pathologic complete response to neoadjuvant chemotherapy had a significant correlation with survival in early HER2-positive breast cancer after 4 years of follow-up.

Bevacizumab did not improve invasive disease-free survival or overall survival when added to adjuvant therapy for HER2-positive breast cancer in the large randomized BETH trial.

New evidence suggests that HER2-positive breast cancer may not only be immunogenic, but also that trastuzumab may relieve suppression of antitumor immunity.

Sherene Loi, MD, PhD, on the association between immune cells and a pathologic complete response in patients with breast cancer after being given chemotherapy and trastuzumab.

The American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) have released updated recommendations for HER2 testing in 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.