Investigational drugs in early stage clinical trials for the treatment of HER2+ breast cancer.

INTRODUCTION: Despite improvements in the management of HER2+ breast cancer, metastatic disease is still fatal. Usually, these patients receive several lines of chemotherapy associated with HER2 targeted treatments. Most of the trials using innovative approaches are positioning themselves in disease that is resistant to pertuzumab and trastuzumab emtansine (TDM1). AREAS COVERED: We describe the recent advances in clinical development of anti-HER2 treatments. To this aim, we used literature search via Pubmed and made an inventory of abstracts published during the last two years in major oncology conferences. EXPERT OPINION: Further changes will probably occur during the next decade in the management of metastatic HER2-positive breast cancer. This is mainly driven by the fact that the two mainstay drugs (pertuzumab and TDM-1) that confer prolonged survival (56 months) to these patients are currently being used in the treatment of early-stage disease in a subset of patients. Thus, there is an urgent need to develop new, innovative approaches in those patients whose disease has become resistant to these highly potent drugs. Several new antibody-drug conjugates, bispecific antibodies or new generation tyrosine kinase inhibitor (TKIs) hold promise and should be assessed and compared with drugs currently used.