TRLS-15. TARGETED THERAPY IN PEDIATRIC CNS TUMORS - A SINGLE INSTITUTION EXPERIENCE

Primary central nervous system malignancy treatment remains a difficult problem despite advancement in techniques. Personalized medicine is evolving in making treatment decisions and particular molecular characteristics allow new targeted therapies to be specific and effective. We retrospectively present patients with primary CNS tumors receiving targeted therapy from 2016 to the present date. Outcomes included length of therapy, time until progression of disease, and overall response. Our study includes 32 patients with malignancies such as Astrocytoma, Ganglioglioma, Glioblastoma, and Diffuse Intrinsic Pontine Glioma (DIPG), among others. Analysis was based on patients’ underlying malignancy and included variables such as identified mutations, targeted therapy, progression vs resolution of disease, and time to progression of disease after initiation of targeted therapy. Overall results show 23 patients with at least 1-year-survival. The most common targeted therapy was Trametinib, treating tumors of glial origin. 14 patients showed no progression after starting targeted therapy, the majority low grade Gliomas and Medulloblastomas. Multiple mutations were found with the most frequent being BRAF. Of our 11 patients with BRAF mutations, 8 had no progression of disease after starting Trametinib or Dabrafenib. Patients with Atypical Teratoid Rhabdoid Tumors (ATRT) were treated with either Alisertib or Alisertib/Tazemetostat and 2 out of 4, both treated with Alisertib maintenance therapy, had no disease progression after targeted therapy. Best outcomes with no disease progression were primarily Gliomas, treated with Trametinib, and Medulloblastomas, treated with Vismodegib. Of our patients with DIPG, treated with Ribociclib, average time to disease progression on targeted therapy was 4.7 months and survival rate was 33%. We have shown excellent use of targeted therapy and our analysis highlights the need for continued exploration of targeted therapy among patients with CNS tumors.