Intrathecal trastuzumab in the management of HER2+ breast leptomeningeal disease: a single institution experience

Purpose Leptomeningeal disease is a rare and devastating presentation of advanced stage metastatic breast cancer with historically poor overall survival. We assessed the safety and feasibility of intrathecal (IT) trastuzumab in HER2+ leptomeningeal disease. Methods A total of 13 patients were treated at our institution with IT trastuzumab beginning November 2012 and followed until November 2017. Outcomes including craniospinal progression as well as overall survival (OS) following initiation of IT trastuzumab were assessed from review of the clinical chart and radiologic examinations. Results The median age of patients was 48 (range 29–75). Median time from breast cancer diagnosis to development of brain metastases was 87.7 months with a median of 4.6 months from brain metastases diagnosis to the development of leptomeningeal disease. Previous whole brain radiotherapy was received by the majority of patients (92%) and prior surgery for brain metastases was performed in 23%. Median duration of IT trastuzumab treatment was 6.4 months. Median time from IT trastuzumab start to craniospinal progression was 5.7 months with 6- and 12-month Kaplan–Meier rates of 41 and 21%, respectively. Sustained responses > 6 months were achieved in 4 patients. Median survival from the start of IT trastuzumab was 10.6 months with 6- and 12-month OS rates of 68 and 47%, respectively. IT trastuzumab was well tolerated with one patient developing ventriculitis, which resolved with IV antibiotics. Conclusions IT trastuzumab was well tolerated with prolongation of OS over historical controls. IT trastuzumab should be considered for management of HER2+ leptomeningeal disease patients.