Clinical response to dabrafenib plus trametinib in a pediatric ganglioglioma with BRAF p.T599dup mutation.

In this follow-up report, we present updated information regarding a previously reported pediatric patient with a World Health Organization grade I ganglioglioma harboring a BRAF p.T599dup mutation (Miller et al. 2018). This patient, based on our initial finding, is receiving combination targeted therapy with a selective BRAF inhibitor (dabrafenib) plus MEK inhibitor (trametinib). The combination therapy was started after the patient experienced progressive tumor growth and worsening neurological symptoms, including visual changes, headaches, and peripheral neuropathy, despite 10 months of treatment with adjuvant chemotherapy (vinblastine). The patient has been receiving dabrafenib plus trametinib for 15 months and continues to have stable disease as well as improved neurological symptoms. Although combinatorial therapy targeting BRAF and MEK using dabrafenib and trametinib, respectively, is indicated for tumors harboring a BRAF p.V600E/K mutation, our report demonstrates efficacy of this combination in a non-V600E BRAF-mutated tumor. The identification of BRAF alterations may assist clinicians in determining alternative targeted treatment strategies, especially considering the paucity of effective treatments for primary brain tumors and the poor prognosis associated with many central nervous system (CNS) diagnoses. Additional case studies or larger cohort reports will continue to clarify the efficacy of BRAF and/or MEK inhibitors in patients whose tumors harbor a BRAF alteration.