HER2 is a protein which, when abnormal (mutated), can fuel cancer growth. Many breast cancers overproduce this protein. They may be treated with drugs that target HER2, like trastuzumab or lapatinib.
Some women with breast cancer test negative for HER2 overexpression but have mutations in the HER2 gene. Doctors want to know if they might also benefit from therapies that target HER2.
In this study, researchers want to evaluate the safety and effectiveness of neratinib in women with metastatic breast cancer that does not overexpress the HER2 protein but contains a mutation in the HER2 gene. Neratinib is an investigational drug that blocks some of the functions of the HER2 protein. It is taken orally (by mouth).