CLRM-02 SINGLE CENTER EXPERIENCE OF DOPAMINE ANTAGONIST ONC-201 FOR RECURRENT H3K27M-MUTANT GLIOBLASTOMA IN ADULTS

OBJECTIVE: To report the single center experience of three adult subjects receiving ONC-201 as part of the ONC018 expanded access clinical trial [NCT03134131]. BACKGROUND: ONC-201 is an oral investigational antagonist against the D2 dopamine receptor that has shown encouraging results for malignant gliomas harboring the H3K27M mutation in the H3 histone complex. Responses have been reported in pediatric subjects with such tumors. H3K27M tumors are generally located in the midline of the central nervous system which co-localize, for unknown reasons, with key dopaminergic pathways. An expanded access clinical trial (ONC018) was available to eligible patients allowing them access to this agent pending FDA review. DESIGN/METHODS: Our site enrolled three subjects on the ONC018 trial. We present the demographic, clinical, and molecular characteristics for our enrolled subjects. We report the tolerability, adverse events, and outcome measures including survival, time-to-progression, response, Karnofsky Performance Status [KPS] and quality-of-life measured by the MD Anderson symptom inventory instrument [MDASI]. RESULTS: Three subjects were registered at our site onto ONC018 with age range 18-44yrs, 2/3 female, residing in Norway, India and United states. Tumor locations: brainstem, corpus callosum and thalamus. Pathology: glioblastoma(3/3), MGMT methylated (2/3), IDH1 mutant (0/3), EGFR amplification (0/3) and ATRX (3/3). Median change from baseline KPS: ≤20% decrease; MDASI:2/3 experienced decrease from baseline [median 6%],consistent with improved quality of life. No clinically significant laboratory abnormalities. No serious adverse events observed in any cases. All adverse events grade I-II. CONCLUSIONS: In three subjects with H3K27M-mutant malignant glioma that received ONC201 as part of this expanded access clinical trial, we found that study drug was quite tolerable. No serious adverse events nor radiographic responses were seen. Analyses of larger study cohort and additional randomized controlled trials are necessary to provide insight into the safety and efficacy of this agent for this patient population.