H3 K27M MUTANT GLIOMAS ARE SELECTIVELY KILLED BY ONC201, A SMALL MOLECULE INHIBITOR OF DOPAMINE RECEPTOR D2

INTRODUCTION Histone H3 K27M mutations distinguish a subgroup of midline gliomas in children and young adults with devastating prognosis for which there are no effective medical therapies. In a recent phase 2 trial in adult recurrent glioblastoma with ONC201, a small molecule selective antagonist of the dopamine receptor D2 (DRD2) and D3 (DRD3), a 22 year old female with recurrent H3 K27M mutant glioblastoma had tumor regression of 92% that has persisted >15 months. Furthermore, antiseizure medication was discontinued and no ONC201 side effects were observed. Based on this exceptional response, we tested whether H3 K27M mutant gliomas were selectively sensitive to ONC201-induced apoptosis.