ONC201 is an oral selective antagonist of the dopamine D2 receptor and direct activator of caseinolytic protease P. In a phase II study, ONC021 was shown to be well tolerated with notable efficacy in patients with the rare neuroendocrine neoplasms pheochromocytomas-paragangliomas, although biomarkers for activity remain to be elucidated.

See related article by Anderson et al., p. 1773