EAPH-14. MOLECULAR BIOLOGY AND PHASE I STUDY OF GM-CSF AND INTRATHECAL TRASTUZUMAB IN CHILDREN WITH RECURRENT POSTERIOR FOSSA EPENDYMOMA

Posterior fossa ependymoma (PF EPN) is a pediatric central nervous system malignancy that has poor outcome to standard therapeutic approaches. The majority of PF EPN tumors have increased HER2 expression. Trastuzumab is a monoclonal antibody that targets HER2, and sargramostim (GM-CSF) stimulates hematopoietic progenitor cell proliferation. The combination of trastuzumab and GM-CSF has been shown to trigger antibody-dependent cell cytotoxicity in vitro in PF EPN cell lines. Due to reduced blood-brain barrier penetration of trastuzumab, intrathecal (IT) administration is an attractive method for delivery for treatment of recurrent PF-EPN