The study is designed as a prospective, single-arm, nonrandomized, open-label, phase I/II trial of radiation therapy (RT) followed by intrathecal (IT) trastuzumab/pertuzumab in the management of HER2+ breast leptomeningeal disease (LMD). Treatment will be initiated with RT, whole brain RT (WBRT) and/or focal brain/spine RT followed by IT trastuzumab/pertuzumab.
The purpose of this study is to find out if radiation therapy followed by intrathecal trastuzumab and pertuzumab is safe and will result in improved survival in HER2 positive breast cancer which has metastasized to the leptomeninges.