dordaviprone (ONC201)

Based on a clinical staged small molecular hClpP activator ONC201, a class of novel hClpP agonists with a [1,8]naphthyridinone scaffold were designed, synthesized and evaluated in a series of biochemical and biological assays. Mechanism studies for the representative compound F20 indicated that it can potently bind to and activate hClpP, efficiently promote the degradation of hClpP substrates, robustly induce ATF4/CHOP regulated integrated stress responses, strongly inhibit cell growth and effectively induce apoptosis in a subset of cancer cell lines. F20 showed good PK profiles when dosed by intravenous injection and exhibited moderate oral bioavailability in mice.

Imipridones are a promising strategy for further testing and development in mUM.

P1, N=20, Active, not recruiting, University of Nebraska | Trial primary completion date: Aug 2024 --> Oct 2026

P1/2, N=120, Recruiting, M.D. Anderson Cancer Center | Trial completion date: Nov 2024 --> Nov 2026 | Trial primary completion date: Nov 2024 --> Nov 2026

The results support the idea that treatment of castrate-resistant prostate cancer by imipridones may not be significantly impacted by neuroendocrine differentiation as a therapy-resistance mechanism. The results support further testing of imipridones across subtypes of androgen-sensitive and castrate-resistant prostate cancer.

Our results have relevance to activity of ONC201 in PCa where most castrate-resistant androgen-independent cancers are not therapy resistant due to NET differentiation. Importantly, NET differentiation does not promote resistance to ONC201 supporting further clinical investigations across the spectrum of PCa.

Based on the founding member of imipridones, ONC201, a class of dehydrogenated imipridone derivatives was designed, synthesized, and evaluated in a series of biochemical and biological assays as human caseinolytic protease P (hClpP) activators...More importantly, XT6 exhibited a promising pharmacokinetic profile in rats and could penetrate the blood brain barrier. It showed highly potent in vivo antitumor activity in a MIAPACA2 cell line derived pancreatic cancer model in BALB/c nude mice.

P2, N=27, Not yet recruiting, University of Nebraska | Phase classification: P1 --> P2

P1, N=58, Recruiting, UNC Lineberger Comprehensive Cancer Center | Trial completion date: Jan 2025 --> Jul 2025

P1, N=27, Not yet recruiting, University of Nebraska | Initiation date: Apr 2024 --> Jul 2024

P1/2, N=17, Terminated, Chimerix | Active, not recruiting --> Terminated; This study was terminated due to a change in corporate priorities. The decision to terminate the study was not based on any safety concerns.

DNMG with H3K27M mutations share many similarities with their midline counterpart, suggesting that they correspond to a rare anatomical presentation of these tumors. This is of paramount importance, as they may benefit from new therapeutic approaches such as ONC201.

The imipridones ONC201 and ONC206 induce mitochondrial dysfunction and have emerged as promising therapies for DMG patients. Clinical translation of our studies has the potential to enable precision metabolic therapy and imaging for DMG patients. Imipridones induce GABA accumulation in diffuse midline gliomas, an effect that can be leveraged for therapy and non-invasive imaging.

Here, we applied the principles of computer-aided drug discovery to identify a novel low-molecular-weight compound, TLR inhibitory compound 10 (TIC10), and its potent derivative (TIC10g), which demonstrated dual inhibition of TLR7 and TLR9 signaling pathways...Western blot analysis revealed that TIC10g downregulated the phosphorylation of the p65 subunit of nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinases (MAPKs), including extracellular-signal-regulated kinase, p38-MAPK, and c-Jun N-terminal kinase. These findings indicate that the novel ligand, TIC10g, is a specific dual inhibitor of endosomal TLRs (TLR7 and TLR9), disrupting MAPK- and NF-κB-mediated proinflammatory gene expression.

P2, N=360, Recruiting, University of California, San Francisco | Phase classification: P1/2 --> P2

The mechanism of impairment of ONC201/206/212 effect caused by dopamine pre-treatment appears to involve upregulation of anti-apoptotic p-Bad, XIAP, FLIP and pAkt. Our results shed light on mechanisms of cancer cell protection by dopamine after imipridone treatment, heterogeneity among different tumor cell types, and suggest that effects of dopamine adaptation on tumor cells may impact on cell survival pathways in ways that may or may not depend on expression of dopamine receptors.

P1/2, N=360, Recruiting, University of California, San Francisco | Phase classification: P2 --> P1/2 | Trial completion date: Jun 2027 --> Jun 2029

The pharmacological activation of ClpP using TIC10, currently in phase III clinical trials for cancer, successfully replicates this phenotype both in vitro and in vivo and markedly reduces aneurysm development in a mouse model of elastase-induced aortic aneurysms. Our mechanistic exploration indicates that ClpP activation regulates the VSMC phenotype by modifying the cellular NAD+/NADH ratio and activating Sirtuin 1. Our findings reveal the crucial role of mitochondrial proteostasis in the regulation of the VSMC phenotype and propose the ClpP protease as a novel, actionable target for manipulating the VSMC phenotype.

The IHC of the excised tumor grafts further confirmed the higher apoptosis and lower metastasis and cell proliferation. Thus, our MUC1 targeting binary drug-releasing liposomal formulation showed higher drug payload, enhanced plasma stability, and accumulation of drugs in the pancreatic orthotopic tumor and thus is a promising therapeutic alternative for the treatment of PDAC.

P2, N=324, Recruiting, University of California, San Francisco | Active, not recruiting --> Recruiting | N=143 --> 324

Simultaneous inhibition of the PI3K/AKT and MEK pathways with ONC201 is an attractive approach to potentiate the effect of GEM. Our findings provide insight into rational-directed precision chemo and immunotherapy therapy in PDAC.

P1, N=27, Not yet recruiting, University of Nebraska | Trial completion date: Jan 2027 --> Apr 2027 | Initiation date: Jan 2024 --> Apr 2024 | Trial primary completion date: Jan 2026 --> Apr 2026

H3K27M-mutant diffuse gliomas occasionally occur in nonmidline cerebrum. ONC201 exhibits activity in H3K27M-mutant gliomas irrespective of CNS location.

In this study, for the first time, piezoelectrically catalyzed Mg -doped hydroxyapatite (Mg-HAP) nanoparticles, which are coated with a mesoporous silica layer and loaded with ONC201 as an agonist to specifically target the death receptor DR5 on tumor cells, ultimately developing an Mg-HAP@MS/ONC201 nanoparticle (MHMO NP) system, are engineered...In summary, a dual-targeting therapy system that targets both tumor cells and the tumor microenvironment under piezoelectric catalysis is designed. This system holds substantial potential for advancements in tumor immunotherapy.

Despite advances in treatment, a significant proportion of patients with chronic lymphocytic leukemia (CLL) will relapse with drug-resistant disease.The imipridones, ONC-201 and ONC-212, are effective against a range of different cancers, including acute myeloid leukemia (AML) and tumors of the brain, breast, and prostate. These drugs induce cell death through activation of the mitochondrial protease, caseinolytic protease (CIpP), and the unfolded protein response (UPR).Here we demonstrate that the novel imipridone analog, TR-57, has efficacy as a single agent and synergises with venetoclax against CLL cells under in vitro conditions that mimic the tumor microenvironment. Changes in protein expression suggest TR-57 activates the UPR, inhibits the AKT and ERK1/2 pathways and induces pro-apoptotic changes in the expression of proteins of the BCL-2 family.The study suggests that TR-57, as a single agent and in combination with venetoclax, may represent an effective treatment option for CLL.

P2, N=19, Terminated, Fox Chase Cancer Center | N=36 --> 19 | Suspended --> Terminated; Slow accrual

Our results suggest that ONC201 in combination with TRAIL may be an effective and non-toxic option for the treatment of gastric adenocarcinoma by inducing apoptosis via activation of the ISR, increased cell surface expression of DR5 and down-regulation of inhibitors of apoptosis. Our results demonstrate in vivo anti-tumor effects of ONC201 plus TLY012 against gastric cancer that could be further investigated in clinical trials.

ONC201, ONC206, and ONC212 are imipridones showing pro-apoptotic anti-cancer response...Additionally, pediatric solid tumor cells were treated with single-agent therapy with histone deacetylase inhibitors (HDACi) vorinostat, entinostat, and panobinostat, showing cell killing with all 3 HDACi drugs, with panobinostat showing the greatest potency...Our results introduce a novel class of small molecules to treat pediatric solid tumors in a precision medicine framework. Use of impridones in pediatric oncology is novel and shows promising pre-clinical efficacy in pediatric solid tumors, including in combination with HDAC inhibitors.

P1, N=20, Active, not recruiting, University of Nebraska

We provide specific detail of recent efforts to monitor CSF and plasma H3K27M cell-free DNA in patients undergoing therapy with the imipridone ONC201. Lastly, we discuss the future of therapeutic monitoring of H3K27M-DMG, including biomarkers such as mitochondrial DNA, mutant and modified histones, and novel sequencing-based approaches for improved detection methods.

Our studies reveal a therapeutic vulnerability of DIPG cells through targeting the SUV39H1-H3K9me3 pathway and compensatory signaling loops for treating this devastating disease. Combining SUV39H1-targeting chaetocin with other agents such as ONC201 may offer a new strategy for effective DIPG treatment.

P3, N=450, Recruiting, Chimerix

P2, N=0, Withdrawn, Masonic Cancer Center, University of Minnesota | N=36 --> 0 | Not yet recruiting --> Withdrawn

P2, N=143, Active, not recruiting, University of California, San Francisco | Recruiting --> Active, not recruiting | N=324 --> 143

P1, N=20, Active, not recruiting, University of Nebraska | Recruiting --> Active, not recruiting

Herein, we report on the combination study arm with ONC201, an orally available DRD2 and ClpP agonist, and paxalisib, a dual PI3K-mTOR inhibitor for patients who completed standard-of-care radiation (Cohort 2). The current median OS is encouraging compared to historical controls. At the meeting, we will present updated molecular characterization and early biological correlates in association with clinical outcomes including toxicity, OS, PK, and central imaging confirmed progression-free survival.

The patient continuing to receive the combination at progression and following reirradiation also experienced a marked decrease in tumor size (MR axial diagnosis scan = 1248 mm2, current tumour area = 315 mm2, ~75% reduction), 10 months following radiological detection of progression. These data inform the phase II clinical trial (NCT05009992).

Overall, our data demonstrates the efficacy of ONC201 in H3K27M-mutant DMG and supports ONC201 as the first monotherapy to improve outcomes in patients with H3K27M-mutant DMG for whom few therapeutic options currently exist. Mechanistically, ONC201 disrupts integrated metabolic and epigenetic pathways and reverses pathognomonic H3K27me3 reduction.

P1, N=24, Not yet recruiting, National Cancer Institute (NCI) | Trial completion date: Feb 2025 --> Jan 2028 | Initiation date: May 2023 --> Mar 2024 | Trial primary completion date: Feb 2025 --> Jan 2026

P1, N=27, Suspended, University of Nebraska | Not yet recruiting --> Suspended

TIC10 can effectively inhibite the proliferation of leukemia cells and induce apoptosis, and have a certain intervention effect on AML induced by MLL-AF9, indicating that TIC10 as a potential candidate drug for the treatment of leukemia.

Transcriptomic analysis in everolimus resistant breast patient tumors and mitochondrial functional assays in resistant cell lines demonstrated increased mitochondrial respiration dependency, contributing to ONC201/TIC10 sensitivity. We propose that ONC201/TIC10 and modulation of mitochondrial function may provide an effective add-on therapy strategy for patients with metastatic ER+ BCs resistant to mTOR inhibitors.