LGG-56. TREATMENT WITH VEMURAFENIB IN PEDIATRIC PATIENTS WITH LOW-GRADE GLIOMAS WITH BRAF V600E MUTATION. REPORT OF 4 CASES

Abstract BACKGROUND BRAF mutations, resulting in aberrant activation of the MAPK pathways are critical in low grade gliomas (LGG) pathogenesis. BRAF V600E mutation (BRAF V600E +) is present in 10 - 20% of this tumors, mostly in Pleomorphic Xanthotrocytoma (PXA) and gangliogliomas. Vemurafenib has shown efficacy on patients with LGG by inhibition of BRAF serine-threonine kinase. OBJECTIVE To report the experience at two institutions, in the use of Vemurafenib for pediatric patients with LGG BRAF V600E+, relapsed or refractory to standard treatments with chemo/radiotherapy. MATERIALS AND METHODS Pediatric patients with BRAF V600E + LGG treated with vemurafenib between January 2015 and december 2017 at Hospital de Niños Ricardo Gutierrez and FLENI were included. RESULTS 4 patients were included. 3 male/1 female. Ages: 1, 2, 4 and 12 years. DIAGNOSIS 2 Pilomyxoid Astrocytomas, 2 gagliogliomas. 3/4 localized disease (1 metastatic patient, ganglioglioma). PREVIOUS TREATMENTS 2 patients: 3 lines of chemotherapy (vinblastine/ Vincristine- Carboplatin, Temozolomide), 2 patients radiotherapy. Vemurafenib dosis: 240-480 mg twice daily. Median time of treatment: 17 months (r: 18-48). Response (clinical and by MRI): very good in 3 patients and stable disease 1 patient. Toxicity: 4 patients skin (rash/nevus/ photosesitization), 1 patient neurologic (disestesia). Suspend treatment for toxicity: 1 patient (transient suspension). CONCLUSION in our experience all patients had response, 3 of them a very good one. Dermatologic toxicity was the most common but is well tolerated.