On November 19, 2019 Oncoceutics, Inc. reported a publication in the journal Nature Communications demonstrating selective antagonism of the G-protein coupled receptor (GPCR) dopamine receptor D2 (DRD2) by Oncoceutics’ lead candidate imipridone, ONC201 (Press release, Oncoceutics, NOV 19, 2019, View Source [SID1234558321]).

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ONC201 was found to specifically bind and antagonize DRD2, and its functionally redundant family member DRD3, without affecting other dopamine receptors, other GPCRs, nuclear hormone receptors, kinases, or other drug targets of FDA-approved cancer therapies. Additionally, a biologically inactive isomer of ONC201 did not antagonize DRD2, indicating that antagonism of this receptor may be linked to anti-cancer efficacy as shown in other publications (Clinical Cancer Research and Neoplasia).

The publication also describes the novel approach taken by Oncoceutics collaborators in the laboratory of Olivier Elemento, PhD, Director of the Englander Institute for Precision Medicine at Weill Cornell Medicine. The researchers used a novel machine-learning platform, called BANDIT, created in the Elemento Lab that suggested DRD2 as a target of ONC201. This method used the molecular structure of ONC201, its in vitro efficacy profile, and its publicly available bioactivity assay results as inputs to compare ONC201 against all small molecules with known targets.

"This publication represents years of collaborative work that uncovered DRD2 as the first known binding target of ONC201," said Joshua Allen, PhD and Senior Vice President of R&D of Oncoceutics. "Along with downstream biomarkers, the dopamine pathway has guided tumor type selection and interpretation of activity of ONC201 in clinical trials. So far, we have observed the most robust single agent efficacy in malignancies that exhibit dysregulation of the dopamine pathway and grow in a dopamine-rich microenvironment, such as midline gliomas."

"Our findings have helped uncover imipridone small molecules as a unique chemical scaffold for targeting GPCRs," said Dr. Elemento. "We are pleased to see the clinical translation of our precision medicine efforts in ONC201 clinical trials and hope this information can be used to identify additional indications for this new therapy."

"The unique mechanism of action of ONC201 is now well defined," said Martin Stogniew, PhD and Chief Development Officer of Oncoceutics. "The most conserved downstream effect of ONC201 in tumor cells is activation of the integrated stress response. Several additional downstream effects, such as dual inactivation of Akt/ERK, induction of TRAIL and DR5, and degradation of Myc also occur in many tumor models, along with immunostimulatory effects involving NK cells and cancer stem cell depletion. These effects aggregately explain the broad antitumor activity observed in multiple models and are likely trigged by the interaction ONC201 with DRD2 and/or ClpP, a recently uncovered additional binding target of the molecule."

For further reference, please refer to additional publications on ONC201 and imipridone small molecules.