Radiation Therapy Followed by Intrathecal Trastuzumab/Pertuzumab in HER2+ Breast Leptomeningeal Disease

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.