Clinical Efficacy of ONC201 in H3K27M-Mutant Diffuse Midline Gliomas Is Driven by Disruption of Integrated Metabolic and Epigenetic Pathways

A Phase 1 Randomized Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of Single Escalating Oral Doses of Dordaviprone and the Effects of Food on the Bioavailability of Dordaviprone in Healthy Adult Subjects

Dordaviprone (ONC201) is a novel, small molecule imipridone with antitumor effects in glioma patients. This study evaluated the pharmacokinetics and safety of dordaviprone following single escalating doses (Part A), as a capsule content mixed with applesauce or Gatorade (sports drink) [Part B1]), and with or without food [Part B2]. The most common treatment-emergent adverse events pooled across study parts (Parts A, B1, and B2) were headache, dizziness, and headache, respectively; all were mild. Systemic dordaviprone exposure increased dose proportionally following administration of 125-625 mg of dordaviprone. Following dordaviprone capsule contents sprinkled on applesauce or dissolved in sports drink, the geometric mean ratios, and 90% confidence intervals (CIs) of the dordaviprone area under the concentration versus time curve (AUC) fell within the bioequivalence (BE) limits of 80.00%-125.00%; however, for Cmax the 90% CI lower limit (0.70) fell below BE limits when sprinkled on applesauce. The geometric mean ratios and 90% CIs of dordaviprone administered under fed versus fasted conditions fell within BE limits of 80.00%-125.00% for the AUC, indicating no food effect on total exposure; however, maximum concentration (Cmax) (90% CI 0.55, 0.67) fell below BE limits.

Personalized combination therapy for diffuse midline glioma: A case report

The present study aimed to analyze the efficacy of personalized combination therapy for patients with H3K27M mutant diffuse midline glioma (DMG) so as to explore new treatment options for further clinical research. The clinical data and prognosis of a patient with H3K27M mutant DMG are summarized and discussed in the context of the relevant literature. The patient was a 20-year-old female diagnosed with DMG treated with a combination of surgery, radiotherapy, chemotherapy, electric field therapy, immunotherapy and targeted therapy. An overall survival time of 28 months was achieved. In summary, personalized treatment strategies are expected to provide longer-lasting survival benefits for patients with DMG.

Therapeutic approaches for targeting the pediatric brain tumor microenvironment

Central nervous system (CNS) tumors are the most frequent solid malignant tumors in pediatric patients and are the leading cause of tumor-related death in children. Treatment for this heterogeneous group of tumors consists of various combinations of safe maximal surgical resection, chemotherapy, and radiation therapy which offer a cure for some children but often cause debilitating adverse late effects in others. While therapies targeting the tumor microenvironment (TME) like immune checkpoint inhibition (ICI) have been successful in treating some cancers, these therapies failed to exhibit treatment efficacy in the majority of pediatric brain tumors in the clinic. Importantly, the pediatric TME is unique and distinct from adult brain tumors and designing therapies to effectively target these tumors requires understanding the unique biology of pediatric brain tumors and the use of translational models that recapitulate the TME. Here we describe the TME of medulloblastoma (MB) and diffuse midline glioma (DMG), specifically diffuse intrinsic pontine glioma (DIPG), and further present the current drug delivery approaches and clinical administration routes targeting the TME in these tumors, including preclinical and clinical studies.

A Phase 1 Study to Evaluate the Absorption, Metabolism, and Disposition of Dordaviprone in Healthy Adult Participants

Dordaviprone (ONC201) is a novel, small-molecule imipridone with antitumor activity in patients with a glioma. Six healthy male participants received a single 625-mg (100-µCi) oral dose of [14C]-dordaviprone. Blood, plasma, urine, and feces were collected up to 288 hours after dosing and analyzed by liquid scintillation counting. Metabolite profiles were evaluated using liquid chromatography-radiometric detection, and metabolite identification was accomplished by liquid chromatography with tandem mass spectrometry. Concentrations of drug-derived radioactivity in blood and plasma peaked at 1 hour after dosing and were below the limit of quantitation by 72 hours (whole blood) to 96 hours (plasma) after dosing. Seventy-one percent of the administered radioactivity was recovered in urine and 20% in feces. In plasma, the major circulating compounds were dordaviprone and the inactive metabolite ONC207, each contributing approximately one third of the total radioactivity area under the curve. Of the 19 metabolites identified in plasma, no other single metabolite contributed more than 10% to the total radioactivity area under the curve. Unchanged dordaviprone was a minor component in excreta (less than 0.3%), with multiple metabolites identified in urine and feces. Given the lack of dordaviprone in excreta and the metabolites formed, the primary route for dordaviprone elimination was through urinary excretion of oxidative metabolites.

Multi-omics landscape of alternative splicing in diffuse midline glioma reveals immune- and neural-driven subtypes with implications for spliceosome-targeted therapy

Introduction

H3K27-altered diffuse midline glioma (DMG) is a highly aggressive glioma subtype, accounting for approximately 60% of pediatric high-grade gliomas, with a median survival of less than 12 months. Due to its predominant localization in the brainstem, conventional surgical resection is often unfeasible, underscoring the urgent need for alternative therapeutic strategies. While previous studies on DMG have primarily focused on regulatory mechanisms at the protein level, the role of alternative splicing in DMG remains largely unexplored. Given its potential impact on gene regulation and tumor progression, a comprehensive analysis of alternative splicing could provide novel insights into targeted or immune therapeutic strategies, complementing existing transcriptomic studies of DMG.

Methods

To investigate the alternative splicing landscape of DMG, we performed transcriptome sequencing (RNA-seq) on patient-derived H3WT and H3K27-altered DMG cell lines, integrating these data with RNA-seq and single-cell transcriptomic (scRNA-seq) datasets from published sources. This comprehensive approach enabled us to delineate the alternative splicing landscape of H3K27-altered DMG and validate its distinct features at the cellular level.

Results

Our multi-omics analysis revealed significant transcriptional alterations in H3K27-altered DMG compared to H3WT DMG, particularly in pathways related to neuro-regulation, metabolism, and immunity. Further in-depth analysis identified extensive alternative splicing changes in H3K27-altered DMG, predominantly associated with RNA modifications and key alterations in extracellular matrix and nucleotide metabolism. Integrating these findings, we characterized five RNA-associated proteins that enabled a binary classification of DMG into neural and immune subtypes, with each subtype exhibiting distinct prognostic and transcriptomic features. Notably, we identified RALYL as a potential key regulator in DMG progression.

Discussion

Our findings indicate that H3K27-altered DMG exhibits significant alternative splicing alterations, which play crucial roles in tumorigenesis and progression. Additionally, our study identified an RNA-binding protein-based classification of DMG and characterized RALYL as a potential regulatory factor, highlighting its potential as a novel therapeutic target.

Effective targeting of PDGFRA-altered high-grade glioma with avapritinib

PDGFRA is crucial to tumorigenesis and frequently genomically altered in high-grade glioma (HGG). In a comprehensive dataset of pediatric HGG (n = 261), we detect PDGFRA mutations and/or amplifications in 15% of cases, suggesting PDGFRA as a therapeutic target. We reveal that the PDGFRA/KIT inhibitor avapritinib shows (1) selectivity for PDGFRA inhibition, (2) distinct patterns of subcellular effects, (3) in vitro and in vivo activity in patient-derived HGG models, and (4) effective blood-brain barrier penetration in mice and humans. Furthermore, we report preliminary clinical real-world experience using avapritinib in pediatric and young adult patients with predominantly recurrent/refractory PDGFRA-altered HGG (n = 8). Our early data demonstrate that avapritinib is well tolerated and results in radiographic response in 3/7 cases, suggesting a potential role for avapritinib in the treatment of HGG with specific PDGFRA alterations. Overall, these translational results underscore the therapeutic potential of PDGFRA inhibition with avapritinib in HGG.

Targeted therapy for pediatric glioma: RAF(t)ing in the molecular era

BACKGROUND

Pediatric gliomas are the most frequently occurring central nervous system tumors in children. While targeted therapies have been widely applied in the treatment of many adult cancers, their use in pediatric gliomas has lagged behind. However, recent advances in multiomics profiling of pediatric gliomas, coupled with the approval of inhibitors against Raf serine/threonine kinase (RAF), isocitrate dehydrogenase 1/2 (IDH1/2) and neurotrophic receptor tyrosine kinase (NTRK), have spurred significant progress in this field. In light of these developments, this review aims to provide a comprehensive overview of current advancements and the evolving landscape of targeted therapeutic strategies and approaches for pediatric gliomas.

DATA SOURCES

Data analyzed in this study were obtained from the literature from PubMed, as well as other online databases and websites, including ClinicalTrials.gov and the Pediatric Neuro-Oncology Consortium.

RESULTS

Based on findings from multiomics profiling, significant insights have been gained into the genetic and molecular landscape of pediatric gliomas, enabling the identification of key mutations and potentially targetable lesions. These advancements provide rationales for the development of more precise treatment strategies and targeted therapies. Recent approvals of targeted therapies and ongoing clinical trials in pediatric gliomas are converging on the targeting of key signaling molecules and metabolic pathways.

CONCLUSIONS

In the molecular era, targeted therapies offer new hope for more effective and personalized treatment options for pediatric glioma patients. By developing and tailoring treatments to target specific molecular and metabolic vulnerabilities, targeted therapies have the potential to improve the clinical management of pediatric gliomas, ultimately enhancing both the treatment experience and overall prognosis of these patients.

Diversity of metabolic features and relevance to clinical subtypes of gliomas

Gliomas carry a dismal prognosis and have proven difficult to treat. Current treatments and efforts to target individual signaling pathways have failed. This is thought to be due to genetic and epigenetic heterogeneity and resistance. Therefore, interest has grown in developing a deeper understanding of the metabolic alterations that represent drivers and dependencies in gliomas. Therapies that target glioma-specific metabolic dependencies overcome the challenges of disease heterogeneity. Here, we present the diverse metabolic features of each current clinical subtype of glioma. We believe that this approach will enable the development of novel strategies to specifically target the various clinical and molecular subtypes of glioma using these metabolic features.

Relative Bioavailability of Dordaviprone (ONC201) is Not Affected by Co-Administration of the Proton-Pump Inhibitor Rabeprazole

Dordaviprone (ONC201) is a novel, orally administered, anti-cancer, small molecule imipridone with demonstrated antitumor effects in patients with glioma. Dordaviprone in vitro solubility is significantly reduced at pH >4.5. Concomitant use of acid reducing agents (ARAs) may therefore impact dordaviprone solubility and bioavailability. This open-label, single-sequence, three-period crossover study evaluated the effect of proton-pump inhibitor rabeprazole on dordaviprone pharmacokinetics (PK). Periods were consecutive and comprised of period 1 (days 1-3), period 2 (days 4-9), and period 3 (days 10-13). In period 1, participants received a single oral 625 mg dose of dordaviprone on day 1. In period 2, participants received six consecutive days of QD 20 mg rabeprazole alone. In period 3, patients received one oral dose of 20 mg rabeprazole (the seventh consecutive daily dose), followed 2 h later by a single 625 mg dordaviprone oral dose. PK blood samples were collected and analyzed from pre-dose 72 h following dordaviprone administration in periods 1 and 3. Dordaviprone exposure PK parameters were similar following administration of dordaviprone alone or with rabeprazole. Geometric mean ratios and 90% CIs for dordaviprone exposure parameters with and without rabeprazole following dordaviprone administration fell within bioequivalence limits of 80.00%-125.00% for Cmax (97.19% [86.43-109.28]), AUClast (102.21% [95.19-109.75]), and AUCinf (102.27% [95.21-109.86]), indicating no effect of multiple oral doses of rabeprazole on dordaviprone relative bioavailability. Six of the 16 participants reported treatment-emergent adverse events (TEAEs); dordaviprone-related TEAEs were reported by three participants and were limited to mild nausea and dizziness. No dordaviprone dose adjustment or ARA treatment modification is warranted.

Leptomeningeal dissemination in H3 K27M- mutant diffuse midline gliomas: clinical characteristics, risk factors, and prognostic insights

PURPOSE

This study aimed to describe the incidence, clinical and pathological features, and outcomes of H3 K27M- mutant Diffuse Midline Glioma (DMG) patients with leptomeningeal dissemination (LMD) and systematically investigate the predictive and prognostic factors to clarify the response to treatment after the onset of LMD.

METHODS

A total of 304 patients diagnosed with DMG from October 17, 2017, to October 17, 2023, were enrolled in this study, of which 32 patients were diagnosed with LMD. Logistic regression analyses were conducted to identify the predictors of LMD, including clinical, molecular, and imaging data. Univariable and multivariable cox regression analyses were used for overall survival (OS) and post-LMD survival (PLS) analysis.

RESULTS

The median OS and PLS were 12.5 and 8.0 months respectively. Tumor with contrast-enhanced lesions reaching ependyma (Ventricular contact type I) was the only independent risk factor for LMD. Male sex and ventricular contact type I were independent risk factors for primary LMD. In all LMD patients, Karnofsky Performance Status (KPS) of ≥ 90 and radiotherapy were statistically significantly associated with longer OS, and primary LMD was significantly associated with shorter OS. Supratentorial location and chemotherapy after LMD diagnosis were independent favorable prognostic factors on PLS. In primary LMD subgroup analysis, radiotherapy was the only independent favorable prognostic factor on OS.

CONCLUSIONS

The association between contrast-enhanced lesions and ventricular involvement is an independent predictive factor for LMD in DMG patients. Radiotherapy and preoperative KPS may contribute to improved overall survival in these patients. Chemotherapy is a potential treatment option following an LMD diagnosis.

Updates in Diagnostic Techniques and Experimental Therapies for Diffuse Intrinsic Pontine Glioma

Diffuse intrinsic pontine glioma (DIPG) is a rare but extremely malignant central nervous system tumor primarily affecting children that is almost universally fatal with a devastating prognosis of 8-to-12-month median survival time following diagnosis. Traditionally, DIPG has been diagnosed via MR imaging alone and treated with palliative radiation therapy. While performing surgical biopsies for these patients has been controversial, in recent years, advancements have been made in the safety and efficacy of surgical biopsy techniques, utilizing stereotactic, robotics, and intraoperative cranial nerve monitoring as well as the development of liquid biopsies that identify tumor markers in either cerebrospinal fluid or serum. With more molecular data being collected from these tumors due to more frequent biopsies being performed, multiple treatment modalities including chemotherapy, radiation therapy, immunotherapy, and epigenetic modifying agents continue to be developed. Numerous recent clinical trials have been completed or are currently ongoing that have shown promise in extending survival for patients with DIPG. Focused ultrasound (FUS) has also emerged as an additional promising adjunct invention used to increase the effectiveness of therapeutic agents. In this review, we discuss the current evidence to date for these advancements in the diagnosis and treatment of DIPG.

The Complexity of Malignant Glioma Treatment

Malignant glioma is a highly aggressive, therapeutically non-responsive, and deadly disease with a unique tumor microenvironment (TME). Of the 14 currently recognized and described cancer hallmarks, five are especially implicated in malignant glioma and targetable with repurposed drugs: cancer stem-like cells, in general, and glioma stem-like cells in particular (GSCs), vascularization and hypoxia, metabolic reprogramming, tumor-promoting inflammation and sustained proliferative signaling. Each hallmark drives malignant glioma development, both individually and through interactions with other hallmarks, in which the TME plays a critical role. To combat the aggressive malignant glioma spatio-temporal heterogeneity driven by TME interactions, and to overcome its therapeutic challenges, a combined treatment strategy including anticancer therapies, repurposed drugs and multimodal immunotherapy should be the aim for future treatment approaches.

On the use of external controls in clinical trials

Externally controlled trials have commonly been used when conducting a randomized controlled trial (RCT) is not feasible or ethical. By allowing the study of new treatments, use of external controls can lead to accelerated advances in the management of rare diseases. The use of external controls, however, introduces new challenges due to potential differences between the population the external controls are enrolled from and the population the patients on the new trial are enrolled from. Some differences include, but are not limited to, differences in how patients are diagnosed and treated, differences in the case mix of the underlying populations, differences in the ability to measure outcomes, and differences in data collection. We discuss the potential benefits and challenges of externally controlled trials, as well as strategies to mitigate bias, including the estimand and target-trial emulation framework. We also provide a brief overview of statistical methodology commonly used in these settings. We note that although the strategies presented may help mitigate some of these challenges, they cannot replace an RCT framework, and investigators should be aware of the potential limitations of externally controlled trials.

Precision radiotherapy with molecular-profiling of CNS tumours

Diagnoses of CNS malignancies in the primary and metastatic setting have significantly advanced in the last decade with the advent of molecular pathology. Using a combination of immunohistochemistry, next-generation sequencing, and methylation profiling integrated with traditional histopathology, patient prognosis and disease characteristics can be understood to a much greater extent. This has recently manifested in predicting response to targeted drug therapies that are redefining management practices of CNS tumours. Radiotherapy, along with surgery, still remains an integral part of treating the majority of CNS tumours. However, the rapid advances in CNS molecular diagnostics have not yet been effectively translated into improving CNS radiotherapy. We explore several promising strategies under development to integrate molecular oncology into radiotherapy, and explore future directions that can serve to use molecular diagnostics to personalize radiotherapy. Evolving the management of CNS tumours with molecular profiling will be integral to supporting the future of precision radiotherapy.

Targeted therapy in pediatric central nervous system tumors: a review from the National Pediatric Cancer Foundation

Central nervous system tumors represent the leading cause of cancer-related mortality in children. Conventional therapies of surgery, radiation, and cytotoxic chemotherapy have insufficient efficacy for some pediatric CNS tumors and are associated with significant morbidity, prompting an ongoing need for novel treatment approaches. Identification of molecular alterations driving tumorigenesis has led to a rising interest in developing targeted therapies for these tumors. The present narrative review focuses on recent progress in targeted therapies for pediatric CNS tumors. We outline the key implicated cellular pathways, discuss candidate molecular therapies for targeting each pathway, and present an overview of the clinical trial landscape for targeted therapies in pediatric CNS tumors. We then discuss challenges and future directions for targeted therapy, including combinatorial approaches and real-time drug screening for personalized treatment planning.

Paediatric strategy forum for medicinal product development in diffuse midline gliomas in children and adolescents ACCELERATE in collaboration with the European Medicines Agency with participation of the Food and Drug Administration

Fewer than 10 % of children with diffuse midline glioma (DMG) survive 2 years from diagnosis. Radiation therapy remains the cornerstone of treatment and there are no medicinal products with regulatory approval. Although the biology of DMG is better characterized, this has not yet translated into effective treatments. H3K27-alterations initiate the disease but additional drivers are required for malignant growth. Hence, there is an urgent unmet need to develop new multi-modality therapeutic strategies, including alternative methods of drug delivery. ONC201 (DRD2 antagonist and mitochondrial ClpP agonist) is the most widely evaluated investigational drug. Encouraging early data is emerging for CAR T-cells and oncolytic viruses. GD2, B7-H3 and PI3K signalling are ubiquitous targets across all subtypes and therapeutics directed to these targets would potentially benefit the largest number of children. PI3K, ACVR1, MAPK and PDGFRA pathways should be targeted in rational biological combinations. Drug discovery is a very high priority. New specific and potent epigenetic modifiers (PROTACS e.g. SMARCA4 degraders), with blood-brain penetrance are needed. Cancer neuroscience therapeutics are in early development. Overall survival is the preferred regulatory endpoint. However, the evaluation of this can be influenced by the use of re-irradiation at the time of progression. An efficient clinical trial design fit for regulatory purposes for the evaluation of new therapeutics would aid industry and facilitate more efficient therapy development. Challenges in conducting clinical trials such as the need for comparator data and defining endpoints, could be addressed through an international, first-in-child, randomised, complex innovative design trial. To achieve progress: i) drug discovery; ii) new multi-modality, efficient, collaborative, pre-clinical approaches, possibly including artificial intelligence and, iii) efficient clinical trial designs fit for regulatory purposes are required.

Development of Small Molecular Hyper-activators of Human Caseinolytic Peptidase P (hClpP) with a [1,8]-naphthyridinone Scaffold as Novel Anti-cancer Agents

Based on a clinical staged small molecular hClpP activator ONC201, a class of novel hClpP agonists with a [1,8]naphthyridinone scaffold was 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.

An integrated perspective on single-cell and spatial transcriptomic signatures in high-grade gliomas

High-grade gliomas (HGG) are incurable brain malignancies in children and adults. Breakthrough advances in transcriptomic technologies unveiled the intricate diversity of cellular states and their spatial organization within HGGs. We qualitatively integrated 55 neoplastic transcriptomic signatures described in 17 single-cell and spatial RNA sequencing-based studies. Our review delineates a spectrum of cellular states, represented by the expression of specific genes, which can be conceptualized along a "reactive-developmental programs" axis. Additionally, we discussed the potential cues influencing these cellular states, including how spatial organization may impact transcriptomic dynamics. Leveraging these insightful discoveries, we discussed a novel, evolutive way to integrate the different transcriptomic signatures in two or three dimensions, incorporating developmental states, their proliferative capacity, and their possible transition towards reactive states. This integrated analysis illuminates the diverse cellular landscape of HGGs and provides a valuable resource for further elucidation of malignant mechanisms, and for the design of therapeutic endeavors.

Mapping the developmental trajectory of human astrocytes reveals divergence in glioblastoma

Glioblastoma (GBM) is defined by heterogeneous and resilient cell populations that closely reflect neurodevelopmental cell types. Although it is clear that GBM echoes early and immature cell states, identifying the specific developmental programmes disrupted in these tumours has been hindered by a lack of high-resolution trajectories of glial and neuronal lineages. Here we delineate the course of human astrocyte maturation to uncover discrete developmental stages and attributes mirrored by GBM. We generated a transcriptomic and epigenomic map of human astrocyte maturation using cortical organoids maintained in culture for nearly 2 years. Through this approach, we chronicled a multiphase developmental process. Our time course of human astrocyte maturation includes a molecularly distinct intermediate period that serves as a lineage commitment checkpoint upstream of mature quiescence. This intermediate stage acts as a site of developmental deviation separating IDH-wild-type neoplastic astrocyte-lineage cells from quiescent astrocyte populations. Interestingly, IDH1-mutant tumour astrocyte-lineage cells are the exception to this developmental perturbation, where immature properties are suppressed as a result of D-2-hydroxyglutarate oncometabolite exposure. We propose that this defiance is a consequence of IDH1-mutant-associated epigenetic dysregulation, and we identified biased DNA hydroxymethylation (5hmC) in maturation genes as a possible mechanism. Together, this study illustrates a distinct cellular state aberration in GBM astrocyte-lineage cells and presents developmental targets for experimental and therapeutic exploration.

ONC206, an imipridone derivative, demonstrates anti-colorectal cancer activity against stem/progenitor cells in 3D cell cultures and in patient-derived organoids

BACKGROUND

Colorectal cancer (CRC) remains one of the most frequently diagnosed and life-threatening malignancies worldwide. CRC's high recurrence rates and drug resistance have been correlated with a subpopulation of dormant slowly dividing cells termed CRC stem cells (CCSCs). Consequently, there is a pressing need to identify novel therapeutics that can effectively and specifically target CCSCs. Imipridones are promising structurally related anticancer molecules that showed efficacy in several solid and hematological preclinical models and phase I/II/III clinical trials. This study mainly aimed to assess the potential anticancer effects of ONC206, an imipridone derivative, on CRC three-dimensional in vitro culture systems using HCT116 and HT29 cells. Importantly, the study aimed at using CRC patient-derived organoids (PDOs) to test the potential therapeutic effect of ONC206.

METHODS

Two-dimensional cell proliferation, viability, migration, and invasion assays were used to assess the effects of ONC206 on two colorectal cancer cell lines, HCT116 and HT29, in vitro. Immunofluorescence imaging, flow cytometry, and western blot analysis were also performed to investigate the mechanism of action of this drug. Sphere formation assay and CRC PDOs were employed to evaluate the effect of ONC206 on CRC cells in a 3D setting and specifically its potency in targeting the CRC stem/progenitor subpopulation of cells.

RESULTS

Our results showed that ONC206 was more potent than its parental molecule ONC201 in inhibiting the proliferation and viability of HCT116 and HT29 cells. Moreover, ONC206 significantly reduced the migration and invasion indices of CRC cells. These effects were accompanied by an increase in reactive oxygen species (ROS) production, sub-G1 phase accumulation, and apoptosis in HCT116 and HT29 cells. Furthermore, ONC206 significantly inhibited the 3D colonospheres growth and self-renewal ability of CCSCs more potently than ONC201, which was associated with a decrease in the expression of CSC-related markers. Lastly, ONC206 significantly reduced the growth of organoids derived from CRC patients.

CONCLUSION

Collectively, our findings demonstrate that ONC206 is an effective anticancer molecule capable of targeting CCSCs, which may represent a novel therapeutic strategy that can overcome CRC resistance and recurrence.

Single-molecule systems for the detection and monitoring of plasma-circulating nucleosomes and oncoproteins in diffuse midline glioma

The analysis of cell-free tumor DNA (ctDNA) and proteins in the blood of patients with cancer potentiates a new generation of non-invasive diagnostic approaches. However, confident detection of tumor-originating markers is challenging, especially in the context of brain tumors, where these analytes in plasma are extremely scarce. Here, we apply a sensitive single-molecule technology to profile multiple histone modifications on individual nucleosomes from the plasma of patients with diffuse midline glioma (DMG). The system reveals epigenetic patterns unique to DMG, significantly differentiating this group of patients from healthy subjects or individuals diagnosed with other cancer types. We further develop a method to directly quantify the tumor-originating oncoproteins, lysine 27 to methionine substitution in histone H3 (H3-K27M) and mutant p53, from <1 mL of plasma, allowing for the accurate molecular classification of patients with DMG. We show that our strategy correlates with MRI and droplet-digital PCR (ddPCR) measurements of ctDNA, highlighting the clinical potential of single-molecule-based, multi-parametric assays for DMG diagnosis and treatment monitoring.

Central nervous system tumors in adolescents and young adults: A Society for Neuro-Oncology Consensus Review on diagnosis, management, and future directions

Adolescents and young adults (AYAs; ages 15-39 years) are a vulnerable population facing challenges in oncological care, including access to specialized care, transition of care, unique tumor biology, and poor representation in clinical trials. Brain tumors are the second most common tumor type in AYA, with malignant brain tumors being the most common cause of cancer-related death. The 2021 WHO Classification for central nervous system (CNS) Tumors highlights the importance of integrated molecular characterization with histologic diagnosis in several tumors relevant to the AYA population. In this position paper from the Society for Neuro-Oncology (SNO), the diagnosis and management of CNS tumors in AYA is reviewed, focusing on the most common tumor types in this population, namely glioma, medulloblastoma, ependymoma, and CNS germ cell tumor. Current challenges and future directions specific to AYA are also highlighted. Finally, possible solutions to address barriers in the care of AYA patients are discussed, emphasizing the need for multidisciplinary and collaborative approaches that span the pediatric and adult paradigms of care, and incorporating advanced molecular testing, targeted therapy, and AYA-centered care.

Targeted detection of sequence variants in cell-free DNA from cerebrospinal fluid in pediatric central nervous system tumors

The emergence of liquid biopsy technologies holds great promise in the cancer setting, including in pediatric central nervous system (CNS) tumors. In contrast to broad lower-depth sequencing, commonly referred to as low pass whole genome sequencing (WGS), targeted platforms with a higher depth of coverage have also been established. Here, we review targeted liquid biopsy techniques with applicability to pediatric CNS tumors. These include polymerase chain reaction (PCR), both droplet digital PCR and reverse transcription-based PCR, Sanger sequencing, and next-generation sequencing approaches that incorporate amplicon- and hybrid capture-based methods. The goal of this paper is to facilitate an understanding of these targeted techniques and provide a context for clinical relevance within disease categories, as well as a discussion on optimizing real-world implementation for pediatric CNS tumors.

Detection of H3F3A K27M or BRAF V600E in liquid biopsies of brain tumor patients as diagnostic and monitoring biomarker: impact of tumor localization and sampling method

Gliomas are the most common brain tumor type in children and adolescents. To date, diagnosis and therapy monitoring for these tumors rely on magnetic resonance imaging (MRI) and histopathological as well as molecular analyses of tumor tissue. Recently, liquid biopsies (LB) have emerged as promising tool for diagnosis and longitudinal tumor assessment potentially allowing for a more precise therapeutic management. However, the optimal strategy for monitoring gliomas by LB remains to be determined. In this study, we analyzed circulating tumor DNA (ctDNA) from 78 liquid biopsies (plasma n = 44, cerebrospinal fluid n = 34 (CSF)) of 35 glioma patients, determining H3F3A K28M (K27M) and BRAF V600E mutation allele frequency using droplet digital PCR (ddPCR). All results were correlated to clinically relevant parameters including diagnostic imaging and CSF aspiration site (ventricular vs lumbar) with respect to tumor localization. Regarding diagnostic accuracy, the calculated sensitivity score in the H3F3A K27M cohort was 84.61% for CSF and 73.68% for plasma. In the BRAF V600E cohort, we determined a sensitivity of 83.3% in plasma and 80% in CSF. The overall specificity was 100%. With respect to the CSF aspiration, the intra-operatively obtained CSF demonstrated 100% detection rate, followed by ventricular CSF obtained via Ommaya Reservoir/shunt puncture (93%) and CSF obtained via lumbar puncture (66%). Notably, this further correlated with the proximity of the CSF site to tumor localization. Longitudinal CSF monitoring demonstrated a good correlation to clinical and radiological disease evolution. Importantly, we show for the first time that monitoring BRAF V600E by ddPCR could serve as treatment response assessment in gliomas. In summary, our observation may inform recommendations with regard to location of CSF aspiration when incorporating LB into future treatment protocols.

Mitochondrial metabolism: A moving target in hepatocellular carcinoma therapy

Mitochondria are pivotal contributors to cancer mechanisms due to their homeostatic and pathological roles in cellular bioenergetics, biosynthesis, metabolism, signaling, and survival. During transformation and tumor initiation, mitochondrial function is often disrupted by oncogenic mutations, leading to a metabolic profile distinct from precursor cells. In this review, we focus on hepatocellular carcinoma, a cancer arising from metabolically robust and nutrient rich hepatocytes, and discuss the mechanistic impact of altered metabolism in this setting. We provide distinctions between normal mitochondrial activity versus disease-related function which yielded therapeutic opportunities, along with highlighting recent preclinical and clinical efforts focused on targeting mitochondrial metabolism. Finally, several novel strategies for exploiting mitochondrial programs to eliminate hepatocellular carcinoma cells in metabolism-specific contexts are presented to integrate these concepts and gain foresight into the future of mitochondria-focused therapeutics.

Synergistic combination therapy with ONC201 or ONC206, and enzalutamide or darolutamide in preclinical studies of castration-resistant prostate cancer

Androgen receptor (AR) signaling is a target in prostate cancer therapy and can be treated with non-steroidal anti-androgens (NSAA) including enzalutamide, and apalutamide for patients with advanced disease. Metastatic castration-resistant prostate cancer (mCPRC) develop resistance becomes refractory to therapy limiting patient overall survival. Darolutamide is a novel next-generation androgen receptor-signaling inhibitor that is FDA approved for non-metastatic castration resistant prostate cancer (nmCRPC). Imipridone ONC201/TIC10 is first-in-class small molecule imipridone that activates the integrated stress response (ISR), upregulates TNF-related apoptosis-inducing ligand (TRAIL) and has activity against CRPC alone or in combination with enzalutamide in preclinical models. We hypothesized that combination of imipridones with androgen receptor signaling blockers such as darolutamide may synergize in anti-tumor efficacy against mCRPC cells. mCRPC cell lines 22RV1, LNCaP, DU145 and PC3 were treated with imipridones ONC201, ONC206, apalutamide, darolutamide, or enzalutamide as single agents or in combinations. Combinations of ONC201 or ONC206 and androgen receptor signaling blockers demonstrated synergistic effects in mCRPC cells. Combinations of ONC201 and darolutamide or enzalutamide reduced PSA levels in LNCaP cells and induced of ATF4 in both LNCaP and 22RV1 cell lines. Darolutamide synergized with ONC201 regardless of AR status or castration sensitivity in vitro. Flow cytometric analysis showed increased intra-tumoral NK cells in mice treated with ONC201 and combination of ONC201 and darolutamide. Trends of increased TRAIL activation within NK cells were also observed in treatment groups. ONC201 and darolutamide demonstrated anti-tumor effects in vivo in the 22RV1 CRPC model. Our results prompt further translational and clinical studies with imipridones ONC201 or ONC206 in combination with enzalutamide or darolutamide for treatment of castrate resistant advanced or metastatic prostate cancer.

Discovery of CLPP-1071 as an Exceptionally Potent and Orally Efficacious Human ClpP Activator with Strong In Vivo Antitumor Activity

Human sapiens caseinolytic protease P (ClpP) is essential for maintaining mitochondrial proteome homeostasis, and its activation is increasingly recognized as a promising cancer therapy strategy. Herein, based on structure-guided drug design, we discovered a series of potent ClpP activators by introducing a methyl group to the imipridone scaffold of the ClpP activator ONC201 in Phase III clinical trials. Through structural optimization of the lead compound, the most optimal compound, CLPP-1071, exhibited exceptionally potent ClpP agonistic activity (EC50 = 23.5 nM, 107.1-fold stronger than ONC201) and inhibited the proliferation of HL60 cells (IC50 = 4.6 nM, 169.2-fold stronger than ONC201). CLPP-1071 possesses good pharmacokinetic properties and effectively prolongs the lifespan in the MOLM13 and HL60 xenograft models in mice through oral administration. CLPP-1071 is the most potent and orally efficacious ClpP activator reported to date.

Comments and Controversies in Oncology: The Tribulations of Trials Developing ONC201

Our international team highlights issues with efficacy reports in several studies on DMG with the new drug ONC201.

TR-107, an Agonist of Caseinolytic Peptidase Proteolytic Subunit, Disrupts Mitochondrial Metabolism and Inhibits the Growth of Human Colorectal Cancer Cells

Oxidative phosphorylation is an essential metabolic process for cancer proliferation and therapy resistance. The ClpXP complex maintains mitochondrial proteostasis by degrading misfolded proteins. Madera Therapeutics has developed a class of highly potent and selective small-molecule activators (TR compounds) of the ClpXP component caseinolytic peptidase proteolytic subunit (ClpP). This approach to cancer therapy eliminates substrate recognition and activates nonspecific protease function within mitochondria, which has shown encouraging preclinical efficacy in multiple malignancies. The class-leading compound TR-107 has demonstrated significantly improved potency in ClpP affinity and activation and enhanced pharmacokinetic properties over the multitargeting clinical agent ONC201. In this study, we investigate the in vitro efficacy of TR-107 against human colorectal cancer cells. TR-107 inhibited colorectal cancer cell proliferation in a dose- and time-dependent manner and induced cell cycle arrest at low nanomolar concentrations. Mechanistically, TR-107 downregulated the expression of proteins involved in the mitochondrial unfolded protein response and mitochondrial DNA transcription and translation. TR-107 attenuated oxygen consumption rate and glycolytic compensation, confirming inactivation of oxidative phosphorylation and a reduction in total cellular respiration. Multiomics analysis of treated cells indicated a downregulation of respiratory chain complex subunits and an upregulation of mitophagy and ferroptosis pathways. Further evaluation of ferroptosis revealed a depletion of antioxidant and iron toxicity defenses that could potentiate sensitivity to combinatory chemotherapeutics. Together, this study provides evidence and insight into the subcellular mechanisms employed by colorectal cancer cells in response to potent ClpP agonism. Our findings demonstrate a productive approach to disrupting mitochondrial metabolism, supporting the translational potential of TR-107.

EZHIP's role in diffuse midline glioma: echoes of oncohistones?

The enhancer of zeste inhibitory protein (EZHIP) is typically expressed during germ cell development and has been classified as a cancer-testis antigen (CTA) in various cancers. In 2020, 4% of diffuse midline gliomas (DMGs) were shown to aberrantly express EZHIP, mirroring the DMG hallmark histone H3 K27M (H3K27M) oncohistone mutation. Similar to H3K27M, EZHIP is a negative regulator of polycomb repressive complex 2 (PRC2), leading to global epigenomic remodeling. In this opinion, we explore the similarities and disparities between H3K27M- and EZHIP-DMGs with a focus on their shared functional hallmark of PRC2 inhibition, their genetic and epigenomic landscapes, plausible differences in the cell of origin, and therapeutic avenues. Upcoming research on EZHIP will help better understand its role in gliomagenesis and DMG therapy.

Pediatric diffuse intrinsic pontine glioma radiotherapy response prediction: MRI morphology and T2 intensity-based quantitative analyses

OBJECTIVES

An easy-to-implement MRI model for predicting partial response (PR) postradiotherapy for diffuse intrinsic pontine glioma (DIPG) is lacking. Utilizing quantitative T2 signal intensity and introducing a visual evaluation method based on T2 signal intensity heterogeneity, and compared MRI radiomic models for predicting radiotherapy response in pediatric patients with DIPG.

METHODS

We retrospectively included patients with brainstem gliomas aged ≤ 18 years admitted between July 2011 and March 2023. Applying Response Assessment in Pediatric Neuro-Oncology criteria, we categorized patients into PR and non-PR groups. For qualitative analysis, tumor heterogeneity vision was classified into four grades based on T2-weighted images. Quantitative analysis included the relative T2 signal intensity ratio (rT2SR), extra pons volume ratio, and tumor ring-enhancement volume. Radiomic features were extracted from T2-weighted and T1-enhanced images of volumes of interest. Univariate analysis was used to identify independent variables related to PR. Multivariate logistic regression was performed using significant variables (p < 0.05) from univariate analysis.

RESULTS

Of 140 patients (training n = 109, and test n = 31), 64 (45.7%) achieved PR. The AUC of the predictive model with extrapontine volume ratio, rT2SRmax-min (rT2SRdif), and grade was 0.89. The AUCs of the T2-weighted and T1WI-enhanced models with radiomic signatures were 0.84 and 0.81, respectively. For the 31 DIPG test sets, the AUCs were 0.91, 0.83, and 0.81, for the models incorporating the quantitative features, radiomic model (T2-weighted images, and T1W1-enhanced images), respectively.

CONCLUSION

Combining T2-weighted quantification with qualitative and extrapontine volume ratios reliably predicted pediatric DIPG radiotherapy response.

CLINICAL RELEVANCE STATEMENT

Combining T2-weighted quantification with qualitative and extrapontine volume ratios can accurately predict diffuse intrinsic pontine glioma (DIPG) radiotherapy response, which may facilitate personalized treatment and prognostic assessment for patients with DIPG.

KEY POINTS

Early identification is crucial for radiotherapy response and risk stratification in diffuse intrinsic pontine glioma. The model using tumor heterogeneity and quantitative T2 signal metrics achieved an AUC of 0.91. Using a combination of parameters can effectively predict radiotherapy response in this population.

Development of novel imipridone derivatives with potent anti-cancer activities as human caseinolytic peptidase P (hClpP) activators

Based on a clinically staged small molecular hClpP activator ONC201, a class of imipridone derivatives was designed and synthesized. These compounds were evaluated in a protease hydrolytic assay, as well as cell growth inhibition assays in three cancer cell lines, MIA PACA-2, HCT116, and MV4-11. A number of compounds that can more potently activate hClpP and more effectively inhibit cell growth in the three cancer cell lines than ONC201 were identified. The most potent compound, ZYZ-17, activated hClpP with an EC50 value of 0.24 µM and inhibited the growth of the three cancer cell lines with IC50 values of less than 10 nM. Mechanism studies for ZYZ-17 revealed that it potently activates cellular hClpP, efficiently induces the degradation of hClpP substrates, and robustly induces apoptosis in the three cancer cell lines. Furthermore, ZYZ-17 demonstrated a promising pharmacokinetic (PK) profile and exhibited highly potent in vivo antitumor activity in a pancreatic cancer MIA PACA-2 xenograft model in BALB/c nude mice.

Imipridones inhibit tumor growth and improve survival in an orthotopic liver metastasis mouse model of human uveal melanoma

BACKGROUND

Uveal melanoma (UM) is a highly aggressive disease with very few treatment options. We previously demonstrated that mUM is characterized by high oxidative phosphorylation (OXPHOS). Here we tested the anti-tumor, signaling and metabolic effects of imipridones, which are CLPP activators, which inhibit OXPHOS indirectly and have demonstrated safety in patients.

METHODS

We assessed CLPP expression in UM patient samples. We tested the effects of imipridones (ONC201 and ONC212) on the growth, survival, signaling and metabolism of UM cell lines in vitro, and for therapeutic efficacy in vivo in UM liver metastasis models.

RESULTS

CLPP expression was detected in primary and mUM patient samples. ONC201 and 212 decreased OXPHOS effectors, inhibited cell growth and migration, and induced apoptosis in human UM cell lines in vitro. ONC212 inhibited OXPHOS, increased metabolic stress and apoptotic pathways, inhibited amino acid metabolism, and induced cell death-related lipids. ONC212 also decreased tumor burden and increased survival in vivo in two UM liver metastasis models.

CONCLUSIONS

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

Targeting Mitochondria in Glioma: New Hopes for a Cure

Drugs targeting mitochondrial energy metabolism are emerging as promising antitumor therapeutics. Glioma treatment is extremely challenging due to the high complexity of the tumor and the high cellular heterogeneity. From a metabolic perspective, glioma cancer cells can be classified into the oxidative metabolic phenotype (mainly depending on mitochondrial respiration for energy production) and glycolytic phenotype or "Warburg effect" (mainly depending on glycolysis). Herein, we reviewed the function of novel bio-active molecules targeting oxidative phosphorylation (OXPHOS), mitochondrial membrane potential and mitochondrial dynamics. These molecules exhibit intriguing preclinical and clinical results and have been proven to be promising candidates to be further developed for glioma therapy. However, despite these initial encouraging results, it is imperative to rigorously assess the side effects of these metabolic drugs, which have a non-negligible toxicity profile.

Deep mutual learning on hybrid amino acid PET predicts H3K27M mutations in midline gliomas

Predicting H3K27M mutation status in midline gliomas non-invasively is of considerable interest, particularly using deep learning with 11C-methionine (MET) and 18F-fluoroethyltyrosine (FET) positron emission tomography (PET). To optimise prediction efficiency, we derived an assistance training (AT) scheme to allow mutual benefits between MET and FET learning to boost the predictability but still only require either PET as inputs for predictions. Our method significantly surpassed conventional convolutional neural network (CNN), radiomics-based, and MR-based methods, achieved an area under the curve (AUC) of 0.9343 for MET, and an AUC of 0.8619 for FET during internal cross-validation (n = 90). The performance remained high in hold-out testing (n = 19) and consecutive testing cohorts (n = 21), with AUCs of 0.9205 and 0.7404. The clinical feasibility of the proposed method was confirmed by the agreements to multi-departmental decisions and outcomes in pathology-uncertain cases. The findings positions our method as a promising tool for aiding treatment decisions in midline glioma.

Patenting perspective of modulators of ClpP endopeptidase: 2019-present

INTRODUCTION

ClpP is a highly conserved serine protease that plays a crucial role in maintaining protein homeostasis in both bacterial cells and human mitochondria. Several studies have demonstrated the potential of ClpP as a drug target, with ClpP modulators, including both inhibitors and activators, showing promise in treating a range of conditions such as drug-resistant bacteria, malignant cancers, and fatty liver disease.

AREA COVERED

This review provides an overview of patents related to ClpP modulators filed over the last five years, detailing their claims and therapeutic applications. The sources of patent information included databases of the European Patent Office, the China Patent Office and the U.S.A. patent Office, while relevant research articles were accessed through PubMed.

EXPERT OPINION

The number of patents concerning ClpP modulators is on the rise, reflecting advancements in related research. By summarizing and outlining relevant patents, we aim to stimulate further interest among researchers, ultimately leading to the development of effective drugs based on ClpP modulators. The broad spectrum of diseases associated with ClpP dysfunction underscores the potential for ClpP modulators to address a wide range of therapeutic needs.

Spatial transcriptomics analysis identifies therapeutic targets in diffuse high-grade gliomas

Introduction

Diffuse high-grade gliomas are the most common malignant adult neuroepithelial tumors in humans and a leading cause of cancer-related death worldwide. The advancement of high throughput transcriptome sequencing technology enables rapid and comprehensive acquisition of transcriptome data from target cells or tissues. This technology aids researchers in understanding and identifying critical therapeutic targets for the prognosis and treatment of diffuse high-grade glioma.

Methods

Spatial transcriptomics was conducted on two cases of isocitrate dehydrogenase (IDH) wild-type diffuse high-grade glioma (Glio-IDH-wt) and two cases of IDH-mutant diffuse high-grade glioma (Glio-IDH-mut). Gene set enrichment analysis and clustering analysis were employed to pinpoint differentially expressed genes (DEGs) involved in the progression of diffuse high-grade gliomas. The spatial distribution of DEGs in the spatially defined regions of human glioma tissues was overlaid in the t-distributed stochastic neighbor embedding (t-SNE) plots.

Results

We identified a total of 10,693 DEGs, with 5,677 upregulated and 5,016 downregulated, in spatially defined regions of diffuse high-grade gliomas. Specifically, SPP1, IGFBP2, CALD1, and TMSB4X exhibited high expression in carcinoma regions of both Glio-IDH-wt and Glio-IDH-mut, and 3 upregulated DEGs (SMOC1, APOE, and HIPK2) and 4 upregulated DEGs (PPP1CB, UBA52, S100A6, and CTSB) were only identified in tumor regions of Glio-IDH-wt and Glio-IDH-mut, respectively. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) enrichment analyses revealed that upregulated DEGs were closely related to PI3K/Akt signaling pathway, virus infection, and cytokine-cytokine receptor interaction. Importantly, the expression of these DEGs was validated using GEPIA databases. Furthermore, the study identified spatial expression patterns of key regulatory genes, including those involved in protein post-translational modification and RNA binding protein-encoding genes, with spatially defined regions of diffuse high-grade glioma.

Discussion

Spatial transcriptome analysis is one of the breakthroughs in the field of medical biotechnology as this can map the analytes such as RNA information in their physical location in tissue sections. Our findings illuminate previously unexplored spatial expression profiles of key biomarkers in diffuse high-grade glioma, offering novel insight for the development of therapeutic strategies in glioma.

Therapeutic targeting of differentiation-state dependent metabolic vulnerabilities in diffuse midline glioma

H3K27M diffuse midline gliomas (DMG), including diffuse intrinsic pontine gliomas (DIPG), exhibit cellular heterogeneity comprising less-differentiated oligodendrocyte precursors (OPC)-like stem cells and more differentiated astrocyte (AC)-like cells. Here, we establish in vitro models that recapitulate DMG-OPC-like and AC-like phenotypes and perform transcriptomics, metabolomics, and bioenergetic profiling to identify metabolic programs in the different cellular states. We then define strategies to target metabolic vulnerabilities within specific tumor populations. We show that AC-like cells exhibit a mesenchymal phenotype and are sensitized to ferroptotic cell death. In contrast, OPC-like cells upregulate cholesterol biosynthesis, have diminished mitochondrial oxidative phosphorylation (OXPHOS), and are accordingly more sensitive to statins and OXPHOS inhibitors. Additionally, statins and OXPHOS inhibitors show efficacy and extend survival in preclinical orthotopic models established with stem-like H3K27M DMG cells. Together, this study demonstrates that cellular subtypes within DMGs harbor distinct metabolic vulnerabilities that can be uniquely and selectively targeted for therapeutic gain.

Discovery of Dehydrogenated Imipridone Derivatives as Activators of Human Caseinolytic Protease P

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. Mechanism studies for one of the most potent compounds, XT6, indicated that it can potently bind to both recombinant and cellular hClpP, effectively promote the formation of hClpP tetradecamer, efficiently induce the degradation of hClpP substrates, robustly upregulate the expression of ATF4, and strongly inhibit the phosphorylations of AKT and ERK. 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.

ONC206 targeting ClpP induces mitochondrial dysfunction and protective autophagy in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the most common form of liver cancer, accounting for approximately 90 % of all cases. ONC201, a member of the imipridone drug family, has shown promising therapeutic potential and a good safety profile in both malignant pediatric central nervous system tumors (diffuse midline glioma [DMG]) and hematologic malignancies. ONC206 is a more potent analog of ONC201. However, the ONC206 potential and mechanism of action in HCC remain to be elucidated. We found that ONC206 hindered HCC growth by suppressing cell proliferation and inducing apoptosis. Moreover, ONC206 induced cytoprotective autophagy, and blocking autophagy enhanced the proapoptotic effect of ONC206. Additionally, ONC206 induced mitochondrial swelling, reduced the mitochondrial membrane potential (MMP), and led to the accumulation of mitochondrial ROS in HCC cells, ultimately resulting in mitochondrial dysfunction. The HCC patient samples exhibited notably elevated levels of caseinolytic protease proteolytic subunit (ClpP), which serves as a mediator of ONC206-induced mitochondrial dysfunction and the activation of protective autophagy. knockdown of ClpP reversed the cytotoxic effects of ONC206 on HCC cells. In summary, our results provide the first insight into the mechanism by which ONC206 exerts its anti-HCC effects and induces protective autophagy in HCC cells through ClpP.

An Update on H3K27M-altered Diffuse Midline Glioma: Diagnostic and Therapeutic Challenges in Clinical Practice

H3K27-altered diffuse midline glioma (DMG H3K27-altered) is a relatively newly-designated WHO entity which primarily affects the midline structures of the central nervous system (CNS), including the brainstem (predominantly pontine region), thalamus, midbrain, or spinal cord, and primarily affects children and young adults. Despite the proximity of these tumors to eloquent areas in the CNS, novel stereotactic approaches have facilitated the ability to obtain tissue diagnoses without significant morbidity, providing molecular diagnostic information in more than half of patients. Conventionally fractionated radiation therapy to a total dose of 54-60 Gy in 27-30 fractions and 24 Gy in 12 fractions play a crucial role in the definitive treatment of these tumors in the primary and salvage settings, respectively. Hypofractionated regimens may allow for accelerated treatment courses in selected patients without jeopardizing disease control or survival. The decision to add concurrent or adjuvant systemic therapy mainly relies on the physicians' experience without solid evidence in the literature in favor of any particular regimen. Recently, novel agents, such as ONC201 have demonstrated promising oncologic outcomes in progressive/recurrent tumors and are currently under investigation in ongoing randomized trials. Given the scarcity of data and well-established guidelines due to the rare nature of the disease, we provide a contemporary overview on the molecular underpinnings of this disease entity, describe the role of radiotherapy and systemic therapy, and present practice management principles based on the published literature.

The oncolytic adenovirus Delta-24-RGD in combination with ONC201 induces a potent antitumor response in pediatric high-grade and diffuse midline glioma models

BACKGROUND

Pediatric high-grade gliomas (pHGGs), including diffuse midline gliomas (DMGs), are aggressive pediatric tumors with one of the poorest prognoses. Delta-24-RGD and ONC201 have shown promising efficacy as single agents for these tumors. However, the combination of both agents has not been evaluated.

METHODS

The production of functional viruses was assessed by immunoblotting and replication assays. The antitumor effect was evaluated in a panel of human and murine pHGG and DMG cell lines. RNAseq, the seahorse stress test, mitochondrial DNA content, and γH2A.X immunofluorescence were used to perform mechanistic studies. Mouse models of both diseases were used to assess the efficacy of the combination in vivo. The tumor immune microenvironment was evaluated using flow cytometry, RNAseq, and multiplexed immunofluorescence staining.

RESULTS

The Delta-24-RGD/ONC201 combination did not affect the virus replication capability in human pHGG and DMG models in vitro. Cytotoxicity analysis showed that the combination treatment was either synergistic or additive. Mechanistically, the combination treatment increased nuclear DNA damage and maintained the metabolic perturbation and mitochondrial damage caused by each agent alone. Delta-24-RGD/ONC201 cotreatment extended the overall survival of mice implanted with human and murine pHGG and DMG cells, independent of H3 mutation status and location. Finally, combination treatment in murine DMG models revealed a reshaping of the tumor microenvironment to a proinflammatory phenotype.

CONCLUSIONS

The Delta-24-RGD/ONC201 combination improved the efficacy compared to each agent alone in in vitro and in vivo models by potentiating nuclear DNA damage and in turn improving the antitumor (immune) response to each agent alone.

Insights from a multicenter study on adult H3 K27M-mutated glioma: Surgical resection's limited influence on overall survival, ATRX as molecular prognosticator

BACKGROUND

H3 K27M-mutated gliomas were first described as a new grade 4 entity in the 2016 World Health Organization classification. Current studies have focused on its typical appearance in children and young adults, increasing the need to better understand the prognostic factors and impact of surgery on adults. Here, we report a multicentric study of this entity in adults.

METHODS

We included molecularly confirmed H3 K27M-mutated glioma cases in patients ≥ 18 years diagnosed between 2016 and 2022. Clinical, radiological, and surgical features were analyzed. Univariate and multivariate analyses were performed to identify prognostic factors.

RESULTS

Among 70 patients with a mean age of 36.1 years, the median overall survival (OS) was 13.6 ± 14 months. Gross-total resection was achieved in 14.3% of patients, whereas 30% had a subtotal resection and 54.3% a biopsy. Tumors located in telencephalon/diencephalon/myelencephalon were associated with a poorer OS, while a location in the mesencephalon/metencephalon showed a significantly longer OS (8.7 vs. 25.0 months, P = .007). Preoperative Karnofsky-Performance Score (KPS) ≤ 80 showed a reduced OS (4.2 vs. 18 months, P = .02). Furthermore, ATRX loss, found in 25.7%, was independently associated with an increased OS (31 vs. 8.3 months, P = .0029). Notably, patients undergoing resection showed no survival benefit over biopsy (12 vs. 11 months, P = .4006).

CONCLUSIONS

The present study describes surgical features of H3 K27M-mutated glioma in adulthood in a large multicentric study. Our data reveal that ATRX status, location and KPS significantly impact OS in H3 K27M-mutated glioma. Importantly, our dataset indicates that resection does not offer a survival advantage over biopsy.

Discovery of 5-(Piperidin-4-yl)-1,2,4-oxadiazole Derivatives as a New Class of Human Caseinolytic Protease P Agonists for the Treatment of Hepatocellular Carcinoma

Chemical agonism of human caseinolytic protease P (HsClpP) is increasingly being recognized as a potential anticancer strategy due to its critical role in maintaining mitochondrial homeostasis. We unveil the discovery of 5-(piperidin-4-yl)-1,2,4-oxadiazole derivatives as a novel class of HsClpP agonists and demonstrate for the first time the application of HsClpP agonists in the treatment of hepatocellular carcinoma (HCC) (Pace, A.; Pierro, P. The new era of 1,2,4-oxadiazoles. Org. Biomol. Chem. 2009, 7 (21), 4337-4348). Compound SL44 exhibited potent HsClpP agonistic activity in the α-casein hydrolysis assay (EC50 = 1.30 μM) and inhibited the proliferation of HCCLM3 cells (IC50 = 3.1 μM, 21.4-fold higher than hit ADX-47273). Mechanistically, SL44 induces degradation of respiratory chain complex subunits and leads to apoptosis in HCC cells. In vivo results demonstrated that SL44 has potent tumor growth inhibitory activity and has a superior safety profile compared to the kinase inhibitor sorafenib. Overall, we developed a novel class of HsClpP agonists that can potentially be used for the treatment of HCC.

Sequential intravenous and intracerebroventricular GD2-CAR T-cell therapy for H3K27M-mutated diffuse midline gliomas

H3K27M-mutant diffuse midline gliomas (DMGs) express high levels of the GD2 disialoganglioside and chimeric antigen receptor modified T-cells targeting GD2 (GD2-CART) eradicate DMGs in preclinical models. Arm A of the Phase I trial NCT04196413 administered one IV dose of autologous GD2-CART to patients with H3K27M-mutant pontine (DIPG) or spinal (sDMG) diffuse midline glioma at two dose levels (DL1=1e6/kg; DL2=3e6/kg) following lymphodepleting (LD) chemotherapy. Patients with clinical or imaging benefit were eligible for subsequent intracerebroventricular (ICV) GD2-CART infusions (10-30e6 GD2-CART). Primary objectives were manufacturing feasibility, tolerability, and identification of a maximally tolerated dose of IV GD2-CART. Secondary objectives included preliminary assessments of benefit. Thirteen patients enrolled and 11 received IV GD2-CART on study [n=3 DL1(3 DIPG); n=8 DL2(6 DIPG/2 sDMG). GD2-CART manufacturing was successful for all patients. No dose-limiting toxicities (DLTs) occurred on DL1, but three patients experienced DLT on DL2 due to grade 4 cytokine release syndrome (CRS). Nine patients received ICV infusions, which were not associated with DLTs. All patients exhibited tumor inflammation-associated neurotoxicity (TIAN). Four patients demonstrated major volumetric tumor reductions (52%, 54%, 91% and 100%). One patient exhibited a complete response ongoing for >30 months since enrollment. Eight patients demonstrated neurological benefit based upon a protocol-directed Clinical Improvement Score. Sequential IV followed by ICV GD2-CART induced tumor regressions and neurological improvements in patients with DIPG and sDMG. DL1 was established as the maximally tolerated IV GD2-CART dose. Neurotoxicity was safely managed with intensive monitoring and close adherence to a management algorithm.

Apatinib combined with temozolomide in diffuse midline glioma: a novel and effective therapy

PURPOSE

Diffuse midline glioma (DMG), H3 K27M-mutant is a type of diffuse high-grade glioma that occurs in the brain midline carrying an extremely poor prognosis under the best efforts of surgery, radiation, and other therapies. For better therapy, we explored the efficacy and toxicity of a novel therapy that combines apatinib and temozolomide in DMG.

METHODS

A retrospective analysis of 32 patients with DMG who underwent apatinib plus temozolomide treatment was performed. Apatinib was given 500 mg in adults, 250 mg in pediatric patients once daily. Temozolomide was administered at 200 mg/m2/d according to the standard 5/28 days regimen. The main clinical data included basic information of patients, radiological and pathological characteristics of tumors, treatment, adverse reactions, prognosis.

RESULTS

The objective response rate was 24.1%, and the disease control rate was 79.3%. The median PFS of all patients was 5.8 months, and median OS was 10.3 months. A total of 236 cycles of treatment were available for safety assessment and the toxicity of the combination therapy was relatively well tolerated. The most common grade 3 toxicities were myelosuppression including leukopenia (5.08%), neutropenia (4.24%), lymphopenia (2.12%), thrombocytopenia (1.69%) and anemia (1.27%). Grade 4 toxicities included neutropenia (2.12%), thrombocytopenia (2.12%) and proteinuria (1.69%). All the adverse events were relieved after symptomatic treatment or dose reduction.

CONCLUSIONS

Apatinib plus temozolomide could be an effective regimen with manageable toxicities and favorable efficacy and may outperform temozolomide monotherapy, particularly in newly diagnosed adults with tumors located outside the pons. The novel therapy deserves further investigation in adult DMG patients.