bluuebunny/crossref_metadata_2025 huggingface dataset:
CTNI-57. REAL-WORLD EVIDENCE OF THE FREQUENCY OF POST-SURGICAL INITIAL OBSERVATION IN PATIENTS WITH IDH-MUTANT GLIOMA
Authors: Nisnboym Ziv Michal , Bhagnani Tarun , Binder Gary , Chacar Christelle , Potluri Ravi , Werwath Timothy , Dewey Jonathan , Peters Katherine
Published: November 2024

BACKGROUND

After initial resection of IDH-mutant gliomas, initial observation is an option for low-risk patients, to postpone potential therapy-related toxicities without impacting survival. Since NCCN guidelines for risk stratification are considered controversial, we aimed to assess the frequency of initial observation in IDH-mutant gliomas using real-world evidence in the US.

METHODS

We evaluated Optum claims from 2016-2021 of patients age ≥12 with ICD-10 codes for incident glioma. Since ICD-10 does not distinguish IDH-mutant from IDH-wild type (GBM) gliomas, we excluded patients with factors indicative of GBM (age>60/ hypofractionated RT/ carmustine wafer/ tumor-treating fields) to create a baseline cohort. We then evaluated the subgroup age <40 (<40 cohort), who have higher IDH-mutant incidence. To distinguish initial observation from surgical recovery, we assessed time from index surgery to first intervention. When 90% of first interventions had occurred those still without intervention were considered to undergo initial observation.

RESULTS

The baseline and <40 cohorts comprised 5404 and 646 patients, respectively. In the baseline cohort, 56% had intervention by day 90 (most commonly concurrent chemoradiation); peak intervention rate was 60%. Initial observation rate was 44%. In the <40 cohort, 47% had an intervention by day 90; peak intervention rate was 52%. Initial observation rate was 53%.

CONCLUSIONS

In both cohorts ≥90% of patients with likely IDH-mutant gliomas not initiating treatment within 3 months post-surgery continued in active observation. Initial observation rates were 44-53%, well above the levels we had expected based on NCCN guidelines. The cohorts likely include some GBM patients, for whom observation is unaccepted, and therefore these rates may understate actual initial observation rates for IDH-mutant glioma patients. These findings suggest that clinicians and patients have chosen initial observation over existing treatments, evincing a need for additional treatment options for this younger group of patients with considerably long life expectancy.
CTNI-59. TUMOUR VOLUMES PREDICT PROGNOSIS AND RESPONSE TO TREATMENT WITH DEPATUXIZUMAB MAFADOTIN
Authors: Gan Hui , Lau Eddie , Lee Sze Ting , Pillai Sruti , Gorlia Thierry , van den Bent Martin , Scott Andrew
Published: November 2024

BACKGROUND

Preclinical data demonstrates that tumor volumes predicted response to the anti-EGFR ADC Depatuxizumab mafadotin (Depatux-M) because of reduced drug delivery in large tumors. We investigated the impact of tumor volumes on outcomes with Depatux-M in the EORTC randomized phase 2 Intellance 2 study on recurrent glioblastoma (NeuroOncol 22(5):684).

METHODS

260 patients were randomized to Depatux-M, Depatux-M with temozolomide, or control treatment (lomustine/temozolomide). Manual segmentation of enhancing tumor on baseline MRI scans was performed and compared with OS and PFS using SPSS Version 29.0: Kaplan-Meier survival analysis including log rank test and Cox regression analyses; categorical data were compared with Fishers’ exact test; correlation between 2D and 3D measurements with Pearson’s correlation.

RESULTS

MRI scans and data from 240/260 (92%) patients were available. Firstly, we confirmed that tumor volumes were a significant prognostic variable. Significant differences were seen in OS between the 0-20 vs 20-40 ml groups (321 vs 216 days, p<0.001) and between the 20-40ml vs 40+ groups (216 vs 150 days, p<0.001) with corresponding differences in PFS. Tumor volumes were also predictive of benefit from Depatux-M, with only patients with smaller tumors benefiting from Depatux-M. Patients in the 0-20 ml and 20-40 ml group group had superior OS when treated with Depatux-M compared to controls (356 vs 309 days, p=0.011 and 229 vs 178 days, p=0.028 respectively). Conversely, the 40 ml + group had no benefit (146 vs 152 days, p=0.875) as predicted. The benefit was maximal in the combination arm, with OS improvement in the 0-20 ml group (437 vs 309 days, p=0.007) and 20-40ml groups (225 vs 178 days, p=0.009). The impact of tumor volumes was confirmed in multi-variate analysis and superior to similar analysis with 2D RANO measurements.

CONCLUSIONS

Tumor volumes are an important prognostic variable in recurrent glioblastoma and modulate survival to large molecules like Depatux-M.
CTNI-61. PRELIMINARY RESULTS OF A PHASE I/II TRIAL OF SELINEXOR AND TEMOZOLOMIDE IN RECURRENT GLIOBLASTOMA
Authors: Chow Frances , Berens Michael , Palmer Joycelynne , Villalona-Calero Miguel , Ney Douglas , De La Fuente Macarena , Jaeckle Kurt , Kizilbash Sani H , Nasany Ruham Alshiekh , Hrachova Maya , Porter Alyx B , Piccioni David , Hoang Kimberly , Lipinski Lindsay , Strowd Roy , Giglio Pierre , Mantica Megan , Schiff David , Gore Steven , Portnow Jana
Published: November 2024

BACKGROUND

Selinexor (SEL) is a first-in-class XPO1 inhibitor with potent antitumor activity through the nuclear retention and reactivation of tumor suppressor proteins, reduced translation of oncogenes, and decreased expression of anti-apoptotic proteins. As a single agent, SEL has demonstrated brain penetration and clinically relevant responses in glioblastoma. We seek to enhance the effect and benefit of SEL by priming with temozolomide (TMZ).

METHODS

Through an NCI Project Team, we developed a multi-institutional phase I/II clinical trial which opened across the NCI Experimental Therapeutics Clinical Trial Network. Eligibility included histologically confirmed 1st recurrent MGMT promoter methylated glioblastoma. We evaluated safety, tolerability, and dose finding with an IQ 3 + 3 design of TMZ 150mg/m2 on days 1-5 of a 28-day cycle plus SEL on days 8 and 15.

RESULTS

From October 2022 to March 2024, we enrolled 12 patients (n=11 evaluable) into phase I of the study. Patient characteristics included 82% male, median age 62 (range 50-77), 64% white. The median number of cycles administered was 6 (range 1-12). Two dose levels (SEL 60mg and SEL 80mg) were evaluated. No dose-limiting toxicities (DLTs) were observed. The most common treatment related adverse events were nausea (58%), decreased platelet count (50%), fatigue (50%), constipation (42%), vomiting (25%), decreased lymphocyte count (25%), and decreased neutrophil count (25%). Grade 3+ treatment related adverse events included nausea, grade 3 (n=1); decreased lymphocyte count, grades 3-4 (n=2); and anorexia, grade 3 (n=1). Phase I has completed enrollment and the recommended phase II dose will be SEL 80mg. Additional results will be presented.

CONCLUSION

Results suggest that a sequential dosing regimen of SEL+TMZ is feasible, well-tolerated, and may minimize the cumulative toxicity of SEL. The phase II randomized portion of this trial is enrolling nationwide and will investigate efficacy and candidate molecular signatures of vulnerability (NCI #10505, NCT05432804).
CTNI-65. DETERMINANTS OF LONG-TERM SURVIVAL IN PATIENTS WITH IDH-MUTANT GLIOMAS
Authors: Katzendobler Sophie , Weller Jonathan , Niedermeyer Sebastian , Blobner Jens , Trumm Christoph , Egensperger Rupert , Harter Patrick , von Baumgarten Louisa , Stoecklein Veit , Tonn Joerg-Christian , Weller Michael , Thon Niklas
Published: November 2024

BACKGROUND

Survival times of patients with IDH-mutant gliomas is variable and can extend to decades. Many studies only provide progression-free rather than overall survival times and prognostic factors remain ill-defined. Here we explored clinical disease characteristics of long-term survivors within a large cohort of patients with extended follow-up.

METHODS

This single-center, retrospective analysis included 114 patients with IDH-mutant glioma that either died due to tumor-related causes or survived at least 15 years after first diagnosis. Patient characteristics, outcomes, and prognostic factors were stratified by short- (< 15 years) versus long-term (≥ 15 years) survival. Initial diagnosis was (re-)classified according to the WHO 2016 classification. Uni- and multivariate analyses were performed.

RESULTS

Overall, 66 patients (58%) were diagnosed with astrocytoma and 48 patients (42%) with oligodendroglioma. Median follow-up of the survivors was 16.6 years (range 15-28.9). 62 tumor-related deaths (54%) had been reported at database closure. Patients that died before reaching 15 years survival time had been diagnosed with astrocytoma in 41 (72%) and oligodendroglioma in 16 cases (28%). The long-term survivor cohort comprised 25 patients (44%) with astrocytoma and 32 patients (56%) with oligodendroglioma. Long-term survival was associated with grade 2 histology (p < 0.01), smaller tumor volumes (p < 0.01), and lack of contrast enhancement (p = 0.02). 41 long-term survivors (72%) were initially monitored by a wait-and-scan strategy as opposed to 16 patients (28%) in the cohort of short-term survival (p<0.01). In patients with oligodendroglioma, a higher KPS was associated with longer survival (HR 0.25; 95% CI 0.02-0.67; p = 0.05). Tumor resection (HR 0.43; 95% CI 0.22-0.86; p = 0.02) and wait-and-scan strategies (HR 0.34; 95% CI 0.14-0.79; p = 0.01) were associated with longer survival in patients with astrocytoma.

CONCLUSION

Tumor resection followed by a wait-and-scan strategy may yield excellent survival times, especially in patients with IDH-mutant grade 2 astrocytoma. Age appears not be an important predictor for survival in patients with IDH-mutant gliomas.
CTNI-78. PNOC008: A PILOT TRIAL TESTING THE CLINICAL BENEFIT OF USING MOLECULAR PROFILING TO DETERMINE AN INDIVIDUALIZED TREATMENT PLAN IN CHILDREN AND YOUNG ADULTS WITH NEWLY DIAGNOSED HIGH-GRADE GLIOMA (EXCLUDING DIFFUSE INTRINSIC PONTINE GLIOMA)
Authors: Kilburn Lindsay , Franson Andrea , Cooney Tab , Kline Cassie , Stoller Schuyler , Reddy Alyssa , Banerjee Anu , Packer Roger , Bendel Anne , Skrypek Maggie , Minturn Jane , Abdelbaki Mohamed , Whipple Nicholas , Chan Priya , Crawford John , Crotty Erin , Waanders Angela , Elster Jennifer , Raabe Eric , George Elizabeth , Pinto Soniya , Supakul Nucharin , Kraya Adam , Prados Michael , Nazarian Javad , Solomon David , Long-Boyle Janel , Molinaro Annette , Waszak Sebastian , Mueller Sabine
Published: November 2024

BACKGROUND

Despite multiple clinical trials in young patients with newly diagnosed high grade gliomas (HGG), survival remains poor. PNOC008 is a single-arm, multi-center pilot trial, investigating the feasibility, toxicity, and efficacy of a molecularly guided individualized treatment approach following radiotherapy.

METHODS

Patients aged ≤21 years with newly diagnosed, localized, hemispheric HGG (Stratum A) or non DIPG, diffuse midline glioma (DMG) (Stratum B) were eligible. Comprehensive molecular profiling (targeted gene panel, whole exome, and whole transcriptome sequencing) was performed on primary tumor tissue. The molecular data was reviewed by a dedicated tumor board that recommended an individualized treatment plan combining up to four FDA approved drugs. Patients were followed for toxicity and efficacy. Circulating tumor DNA (ctDNA), imaging, and quality of life (QOL) measures were collected at multiple timepoints.

RESULTS

Fifty-five HGG patients enrolled between 2018 and 2023 (median age 11 years [range 2-20], n=31 female, n=29 Stratum A), including H3K27-altered (n=17), H3/IDH-wildtype diffuse pediatric-type (n=16), and H3G34-mutant diffuse hemispheric glioma (n=12). In 44 patients that followed the recommended treatment, median overall survival (OS) from time of study enrollment was 26.5 months in Stratum A (lower 95% CI: 18.5) and 23.6 months in Stratum B (lower 95% CI: 16.8), and 30 months in H3G34-mutant patients (n=10, lower 95% CI:24.6) with median follow-up of 34.5 months for all patients (lower 95% CI: 32.2). The treatment recommendations most commonly included alkylator with targeted therapy combinations. The often novel drug combinations were generally well tolerated with grade 3 or 4 treatment-related adverse events being mostly hematologic. Central imaging, ctDNA, and QOL analyses are underway.

CONCLUSIONS

A personalized treatment approach using comprehensive transcriptomic and genomic analysis is feasible and well tolerated with encouraging survival data in children and young adults with HGG. Further analyses of molecular subgroups and correlatives are ongoing.
CTNI-80. 177LU-DOTATATE IN PATIENTS WITH RECURRENT MENINGIOMA
Authors: Nasrollahi Elham , Drappatz Jan
Published: November 2024

BACKGROUND

There are no effective medical therapies for patients with meningioma who progress after surgical and radiotherapeutic interventions. Somatostatin receptor type 2 (SSTR2) represents a promising treatment target in meningiomas. Here, we describe our experience with use of 177Lu-DOTATE in recurrent meningioma

PATIENTS AND METHODS

This is a retrospective study. All patients had progressive intracranial meningiomas and were heavily pre-treated. Patients underwent 68Ga-DOTATATE PET-MRI at baseline and received 177Lu-DOTATATE every eight weeks for up to four doses. We collected patient demographics, tumor grade, treatment history prior to starting 177Lu-DOTATATE, duration of treatment, toxicities, overall survival (OS) and progression-free survival (PFS). Descriptive statistics were used to summarize patient’s characteristics.

RESULTS

Seven patients (female = 2, male = 5) with progressive meningiomas (WHO 1 = 1, 2 = 1, 3 = 5) were enrolled. Median age was 56 (range 41-72) years. All patients previously underwent tumor resection and at least one course of radiation. Treatment with 177Lu-DOTATATE was well tolerated. Three patients achieved PFS-6. One patient with malignant meningioma remains progression free at 13 months. Three patients remain on active treatment. Best radiographic response was stable disease (SD) in six patients.

CONCLUSIONS

Treatment with 177Lu-DOTATATE was well tolerated and demonstrated encouraging efficacy. Updated survival data will be presented.
CTNI-85. FINAL RESULTS FROM N2M2/NOA-20
Authors: Wick Wolfgang , Lanz Lisa-Marie , Wick Antje , Harting Inga , Dettmer Susan , Suwala Abigail , Ketter Ralf , Tabatabai Ghazaleh , Seliger Corinna , Glas Martin , Burger Michael , Timmer Marco , Ringel Florian , Mildenberger Iris , Schulz-Schaefer Walter , Renovanz Mirjam , Bendszus Martin , Sahm Felix , Platten Michael , Kessler Tobias
Published: November 2024

BACKGROUND

MGMT promoter methylation determines benefit from temozolomide (TMZ). Trials aiming at replacing TMZ with targeted agents in not molecularly selected patient populations have failed. Solid evaluation of the MGMT promotor methylation status is critical.

METHODS

The phase I/IIa umbrella trial NCT Neuro Master Match (N2M2) in patients with newly diagnosed glioblastoma aimed at showing safety, feasibility, and preliminary efficacy of targeted compounds in addition to radiotherapy. In five subtrials (alectinib, idasanutlin, palbociclib, vismogedib and temsirolimus) patients were included according to the best matching molecular alteration. Patients without matching alterations were randomized between atezolizumab, asunercept or TMZ as standard of care. Primary objective of the phase I parts of the trial was dose finding or dose validation. In the phase IIa trials, centrally determined progression-free survival at six months (PFS-6) is used as endpoint for efficacy with interim analyses for futility (H0: p=0.231).

RESULTS

From May 2018 through July 2022, 301 patients were enrolled and 228 treated in 13 German NOA sites. MGMT was determined locally and confirmed centrally by pyrosequencing as well as methylation arrays. The TMZ subtrial showed a PFS-6 of 18.52% (10/54 patients) (p=0.8311) and a median overall survival (mOS) of 12.1 months. Asunercept: PFS-6 of 15.4% (4/26) (p=0.8825) and mOS of 13.0 months. Atezolizumab: PFS-6 of 21.4% (9/42) (p=0.660) and mOS of 11.7 months. Palbociclib with patients demonstrating CDK4 amplification or CDKN2A/B codeletion: PFS-6 of 24.4% (10/41) (p=0.4823) and mOS of 12.6 months. Temsirolimus with patients demonstrating mTOR activation: PFS-6 of 39.1% (18/46) (p=0.0109) and mOS of 15.4 months. For the other arms, phase IIa has not been reached.

CONCLUSIONS

There is clinical activity of temsirolimus in patients with tumors harboring an activated mTOR pathway although this is not positively prognostic without mTOR inhibition; there is no clinical activity for asunercept and atezolizumab in not molecularly selected patients nor palbociclib in molecularly selected patients. Potential biomarkers will be discussed.
DNAR-02. M33 CONDENSES CHROMATIN THROUGH NUCLEAR BODY FORMATION AND METHYLATION OF BOTH HISTONE H3 LYSINE 9 AND LYSINE 27
Authors: Shen Chiung-Chyi , Yang Wen-Ming , Yang Yi-Chin
Published: November 2024

Heterochromatin, a type of condensed DNA in eukaryotic cells, has two main categories: Constitutive heterochromatin, which contains H3K9 methylation, and facultative heterochromatin, which contains H3K27 methylation. Methylated H3K9 and H3K27 serve as docking sites for chromodomain-containing proteins that compact chromatin. M33 (also known as CBX2) is a chromodomain-containing protein that binds H3K27me3 and compacts chromatin in vitro. However, whether M33 mediates chromatin compaction in cellulo remains unknown. Here we show that M33 compacts chromatin into DAPI-intense heterochromatin domains in cells. The formation of these heterochromatin domains requires H3K27me3, which recruits M33 to form nuclear bodies. G9a and SUV39H1 are sequentially recruited into M33 nuclear bodies to create H3K9 methylated chromatin in a process that is independent of HP1α. Finally, M33 decreases progerin-induced nuclear envelope disruption caused by loss of heterochromatin. Our findings demonstrate that M33 mediates the formation of condensed chromatin by forming nuclear bodies containing both H3K27me3 and H3K9me3. Our model of M33-dependent chromatin condensation suggests H3K27 methylation corroborates with H3K9 methylation during the formation of facultative heterochromatin and provides the theoretical basis for developing novel therapies to treat heterochromatin-related diseases. Keywords: H3K27 methylation; H3K9 methylation; Heterochromatin; M33 (CBX2); Nuclear body (NB); Progerin.
DNAR-03. ONCOMAGNETIC TREATMENT KILLS GLIOMA CELLS BY INHIBITING MITOCHONDRIAL ELECTRON TRANSPORT AND BY INDUCING OXIDATIVE STRESS AND DNA DAMAGE
Authors: Hambarde Shashank , Pandey Arvind , Baskin David , Helekar Santosh
Published: November 2024

A new noninvasive cancer therapeutic device developed in our laboratory called the Oncomagnetic device involves repeated stimulation with oscillating magnetic fields (sOMF) produced by spinning permanent magnets. It is technologically and mechanistically distinct from the Optune® device approved by the FDA and provides a novel approach for CNS tumor treatment. In 7 end-stage GBM patients, this device reversed the progression of recurrent tumors causing >30% reduction in their contrast-enhanced volumes within 4 – 8 weeks of treatment. Immune-competent mice with implanted mouse glioma cells in their brains also showed marked reduction in tumor size, increased survival (p< 0.05, n = 9) and greater DNA damage (γ-H2AX foci) in implanted tumor after sOMF treatment. Normal mice exposed to sOMF for 4 months had no adverse effects on the brain and other organs. In-vitro, sOMF inhibited mitochondrial ETC complex-I and markedly increased reactive oxygen species (ROS) levels in GBM cells. Detection of γ-H2AX and 53BP1 foci showed that sOMF caused significant DNA damage in GBM cells and diffuse intrinsic pontine glioma (DIPG) cells but not in normal astroglial SVGp12 cells. GBM cells exposed to sOMF for 4 h caused cell cycle arrest in the G1 phase and 30% - 40% loss of surviving colonies detected by clonogenic cell survival assay, while normal SVGp12 cells were not affected. This loss of survival in GBM cells was rescued by the antioxidant Trolox. These results indicate that sOMF stimulation has high anticancer potency comparable to low dose radiation therapy at the cellular level with an underlying mechanism of action that is substantially different from that proposed for Optune® TTF.
DNAR-04. TUMOUR TREATING FIELDS (TTFIELDS) AND DNA DAMAGE RESPONSE (DDR) INHIBITORS ENHANCE GLIOMA CELL DEATH THROUGH CHEMO-/RADIOSENSITISATION
Authors: Jones Callum , Collis Spencer , Rominiyi Ola , Myers Katie , Vanderlinden Aurelie , McGarrity-Cottrell Connor
Published: November 2024

High grade gliomas are the most common primary brain cancer malignancies with ~300,000 global diagnoses each year with glioblastomas (WHO grade IV) conferring the worst prognoses. This arises from their treatment resistance, rationalised by the presence of glioma stem cell-like (GSC) tumour sub-regions and high intratumoural spatio-heterogeneity. TTFields are clinically approved alternating electric fields of intermediate frequency that exert anti-mitotic effects and invoke downregulation of the DDR. Therefore, TTFields alongside clinically developed, and blood brain barrier (BBB) penetrating DDR inhibitors (DDRi) could boost cell death and overcome treatment resistance through chemo-/radiosensitisation. Primary GSC cell lines were derived from surgically resected and clinically defined tumour core and invasive edge regions and grown in more biologically relevant 3D-printed AlvetexTM scaffolds, offering highly clinically relevant models. Cells were then pre-treated with DDRi, subjected to chemo-/radiotherapy and then incubated under TTFields (200 kHz, 72 hrs) with their survival measured by clonogenic assays after 3 weeks. Immunofluorescence and western blot analysis were used to analyse the combination treatment effects on the DDR. In multiple 3D-grown core/edge GSC models, western blot analyses revealed that the DDR was altered by TTFields and clonogenic survival assays revealed that TTFields alongside DDRi led to significant chemo-/radiosensitisation. TTFields alongside DDRi effectively enhances cell death by significant treatment sensitisation effects in clinically relevant 3D GSCs which exhibit extensive intra and intertumoral spatio-heterogeneity. Given that all the DDRi used are BBB penetrable and are either clinically approved or in clinical trials, TTFields could additionally compliment these treatment regimens in gliomas to boost their efficacy.
DNAR-05. VALIDATING THE ERK5 PROTAC OS11 AS A POTENTIAL NOVEL THERAPEUTIC INEX VIVO GLIOMA STEM CELL MODELS OF INTRATUMOURAL HETEROGENEITY AND RESIDUAL DISEASE
Authors: Lad Nikita , Jones Callum G , Myers Katie N , McGarrity-Cottrell Connor L , Finegan Katherine G , Rominiyi Ola , Collis Spencer J
Published: November 2024

Glioblastoma is a grade IV brain tumour with poor survival rates of 15 months post-diagnosis, and 5-year survival rates of 10%. Limited progress over the past 40 years to improve the current treatment regimen of surgery and chemo-/radio-therapy are mainly due to tumour heterogeneity that drive resistance mechanisms. The persistence of glioma stem-like cells (GSCs) sub-populations, particularly within post-surgical residual tumour tissue. ERK5 is an emerging oncology drug target that we previously highlighted as a potential target for combined therapy with temozolomide (TMZ) in glioblastoma due to heightened ERK5 expression, which is associated with poor survival. This current project aims to expand on our previous findings by establishing whether targeting ERK5 can sensitise glioblastoma cells to TMZ using primary derived ex vivo GSC models of intratumor heterogeneity and residual disease. Primary GSC models were derived from patients at the Royal Hallamshire Hospital. The PROTAC OS11 (CRUK & University of Manchester) was used to degrade ERK5. DNA damage and cell survival were evaluated following treatment of TMZ alone and in combination with OS11. Consistent with our findings in established glioma cell lines, OS11 was able to robustly degrade ERK5 in a 3D GSC model for at least 72hrs. Combining OS11 and TMZ in GSCs led to a significant increase in DNA damage, with MGMT negative cells exhibiting a greater increase in DNA damage compared to MGMT positive cells. However, unlike our previous findings in established cell lines, this did not lead to reduced cell survival in combination with TMZ. These findings further support the preclinical use of ex vivo models that better represent intratumoural heterogeneity and post-surgical GCS niches. Overall, these data highlight the value of preclinical validation in more clinically relevant models to identify the best possible novel therapeutic approaches to pursue further towards clinical delivery.
DNAR-06. EPITRANSCRIPTOMIC TRNA MODIFICATIONS TARGETING ADENOSINE (A) AT POSITION 37 IN GBM
Authors: Yamamoto Takahiro , Matsuura Jin , Fujimura Atsushi , Chujo Takeshi , Wei Fan-Yan , Shinojima Naoki , Kuroda Jun-ichiro , Mukasa Akitake , Tomizawa Kazuhito
Published: November 2024

GBM stands as the most aggressive brain tumor in adults. The median overall survival is less than 2 years despite conventional treatments. Recent advancements in DNA analysis have delineated the molecular characteristics of gliomas, leading to revisions in the WHO classification based on DNA profiles. However, the role of RNA modifications, epitranscriptomics, remains poorly understood in glioma. In this study, we underscore the significance of tRNA modifications targeting adenosine at position 37 in GBM. Transfer RNA isopentenyl transferase 1 (TRIT1) is identified as an isopentenyl transferase catalyzing the conversion of A into i6A at position 37 of tRNA, a nucleotide adjacent to the anticodon region. Additionally, i6A is further modified to 2-methylthio i6A (ms2i6A) by cyclin-dependent kinase 5 regulatory subunit associated-protein 1 (CDK5RAP1) within mitochondrial tRNA. Analysis of TCGA data reveals elevated TRIT1 mRNA expression levels in GBM compared to non-tumor samples. Furthermore, a low expression group of TRIT1 in gliomas demonstrates improved survival outcomes according to data from the CGGA, implicating TRIT1 in glioma progression. Functional assays involving TRIT1 knockdown in human GBM cell lines result in decreased cell viability, indicating its functional significance. Moreover, our data suggest that this phenotype may be mediated through translational control of selenoprotein W (SEPW1) via tRNA^(Ser)Sec modification. GO analysis of TRIT1 and SEPW1 in TCGA data further supports this proposed mechanism. At position 37 of tRNA, we also found that CDK5RAP1 in mitochondrial tRNAs is indispensable for sustaining glioblastoma initiating cell (GIC)-related traits. CDK5RAP1 maintains the self-renewal capacity, undifferentiated state, and tumorigenic potential of GICs, independent of translational control of mitochondrial proteins. Notably, CDK5RAP1 abrogates the antitumor effect of i6A by converting i6A to ms2i6A and shields GICs from excessive autophagy triggered by i6A. This work underscores the critical role of tRNA modifications in glioma pathogenesis. We will report these findings alongside RNA modification profile data and clinical data from glioma patients.
DNAR-09. GB13 IS A POTENT NEOADJUVANT TREATMENT OPTION FOR IL13RA2-EXPRESSING GBM AND IMPROVES STANDARD-OF-CARE THERAPY
Authors: Laukhuff Harrison , Woodruff Maija , Schrecengost Randy
Published: November 2024

Glioblastoma (GBM) is the most common primary adult brain cancer and is uniformly fatal. Despite maximum safe surgical resection followed by radiation and temozolomide chemotherapy, current median survival is 14-18 months. GB13 is a novel therapy for treatment of GBM and received Orphan Drug Designation by the Food and Drug Administration (FDA) for treatment of malignant gliomas. GB13 specifically targets the tumor-restricted IL13Ra2 receptor that is highly expressed in GBM, among other cancers, but not on non-cancerous cells. IL13Ra2 represents a clinically viable target for directed therapies and is being explored by numerous approaches. Previous data demonstrate that GB13 potently kills GBM and diffuse midline glioma (DMG) cells and tumors, IL13Ra2 correlates to GB13 sensitivity and, GB13 can significantly improve the cytotoxic effects of ionizing radiation (IR) when tested in models of pediatric diffuse midline glioma. In the current studies, the ability of GB13 to enhance the effects of IR were explored using IL13Ra2-positive and negative GBM models. Major findings demonstrate that neoadjuvant GB13 treatment increases cytotoxic effects of IR, enhances cell apoptosis and decreases cell viability. These results were not observed in IL13Ra2-negative settings, demonstrating the necessity for this clinical target. Mechanistically, increased cell death was caused by sustained apoptotic signaling through caspase-mediated pathways. Preclinical models support the use of GB13 prior to radiation for decreased tumor proliferation. Using multiple models, our results identify a temporal benefit for treating GBM tumors prior to IR and this should be tested in future clinical studies.
DNAR-12. STEAROYL-COA DESATURASE REGULATES DNA DAMAGE REPAIR IN GBM BY MODULATING PARP1 ACTIVITY
Authors: Mnatsakanyan Hayk , Roumieh Elie , Pechdimaljian Caline , Hokayem Joelle El , Sammarco Alessandro , Badr Christian
Published: November 2024

Glioblastoma (GBM) is the most prevalent malignant brain cancer in adults, notorious for its aggressiveness and resistance to therapy. GBM patients commonly receive radiation therapy combined with temozolomide (TMZ), which engages tumor cells to promote lethal DNA damage and subsequent cytotoxicity. Active DNA repair mechanisms, particularly in a subset population of GBM stem-like cells (GSCs), drive therapeutic resistance, thus largely contributing to the bleak prognosis of GBM. Poly (ADP-ribose) polymerases (PARPs) are essential in various cellular processes, including DNA repair. We have previously reported that fatty acid desaturation mediated by Stearoyl-CoA desaturase 1 (SCD1) plays a cytoprotective role in GSCs. Inhibiting SCD prevents tumor initiation and inhibits DNA damage repair, hence sensitizing to radiation and TMZ. Yet, the mechanistic role of SCD in DNA damage regulation remained unknown. Here, we found that the expression of both human isoforms of SCD, SCD1, and SCD5, directly correlates with PARP protein levels and subcellular localization. Downregulating SCD1/5 in GSCs resulted in significantly lower levels of PARP1, coupled with increased DNA damage, as well as reduced DNA damage repair and chromosome assembly. Conversely, cells overexpressing SCD1/5 exhibited higher PARP1 expression and lower levels of basal DNA damage compared to control GSCs. Notably, SCD1/5 overexpression also led to increased resistance to TMZ. We show that SCD1/5 regulates PARP activity by controlling PARP1 subcellular localization. In addition to decreased total levels of PARP following SCD1/5 downregulation, we also found increased PARP1 self-PARylation. Using confocal microscopy, we show that when SCD1/5 is repressed, PARylated PARP translocates from the nucleus to the cytosol, rendering it unable to bind DNA and recruit DNA-repairing machinery. In conclusion, our study provides a direct link between fatty acid metabolism and PARP1-mediated DNA damage repair.
DDEL-02. PRECLINICAL EFFICACY OF IL13RΑ2-TARGETING POLYPEPTIDE-DRUG CONJUGATE (SELF-DEPOTTM ONCOPDC) IN GLIOBLASTOMA AND DIFFUSE INTRINSIC PONTINE GLIOMA
Authors: Bae Jeon Won , Gwon Yunjeong , Kim Jung Eun , Jung Wooram , Kim Soobin , Shin Kyuri
Published: November 2024

Glioblastoma (GBM) and diffuse intrinsic pontine glioma (DIPG) are currently incurable cancers. Systemic chemotherapy shows limited efficacy because of the intact blood-brain barrier. Convection-enhanced delivery (CED) offers promise by concentrating high doses of chemotherapeutics directly within these tumors. However, drugs administered via CED often face challenges in confirming precise target delivery and are quickly cleared by increased interstitial fluid flow and drug efflux transporters. This highlights the urgent need for innovative drugs that demonstrate target specificity and prolonged retention capabilities. Intrinsically disordered polypeptides (IDPs), derived from tropoelastin, self-assemble into water-insoluble structures with extended retention properties triggered by body temperature. IL13Rα2, differentially amplified in U87MG GBM and SF8628 DIPG cells, serves as a target for therapeutic intervention. An IL13Rα2-targeting IDP (XM161) was developed by incorporating IL13Rα2 binding sequences into the IDP domains. XM161 demonstrated high selectivity in binding to IL13Rα2, with Kd values of 1,786 nM for IL13Rα1 and 12.8 nM for IL13Rα2. Conjugation of XM161 with SN38, a potent topoisomerase I inhibitor, resulted in XM161-SN38, which remained in a dissolved state up to 50°C but formed insoluble aggregates above 27°C in the presence of cerebrospinal fluid. XM161-SN38 exhibited strong cytotoxicity against U87MG and SF8628 cells, with IC50 values of 14.2 nM and 0.48 nM, respectively. Importantly, XM161-SN38 demonstrated efficacy in overcoming Temozolomide resistance in T98G GBM cells, with IC50 values of 3.35 nM compared to 10.87 nM for unconjugated SN38. In orthotopic xenograft models established in BALB/cSlc-nu/nu male mice using U87MG-Luc2 cells, three doses (3 x 0.95 μg SN38 equivalents) of XM161-SN38 delivered via CED were well tolerated and significantly extended median survival to over 65 days, providing a notable survival benefit compared to untreated controls (42 days) and Topotecan-treated group (42.5 days). These findings validate the feasibility and therapeutic potential of XM161-SN38 for GBM treatment. Ongoing studies are underway to investigate the safety and pharmacokinetics of XM161-SN38 in tumor-naive mouse brains.
DDEL-14. NOVEL BLOOD BRAIN BARRIER PENETRATING BI-SPECIFIC ANTIBODY THERAPY FOR BREAST CANCER BRAIN METASTASIS
Authors: Sharma Shilpa , Ebrahimpour Afshin , Ge Xin , Kaur Balveen
Published: November 2024

Breast cancer is the second leading cause for brain metastasis after lung cancer. While Her2 +ve tumors respond to her2 targeted antibody therapy, these antibodies are unable to cross the blood brain tumor barrier to effectively target metastases hidden in the ‘CNS sanctuary’. To overcome this hurdle, we have modified Her2 targeting Herceptin to create a CNS penetrating antibody that is transported in a unidirectional fashion into brain tumors. The modified BBB penetrating Herceptin is processed by the tumor specific microenvironment after crossing the BBB, such that the modified antibody is then trapped in the tumor ECM. This has the potential to increase tumor retention and reduce systemic toxicity. The BBB penetrant anti Her2 antibody (Herceptin) binds to Her2 on breast cancer cells and suppresses activation of Her2 signaling in vitro. Western blot analysis shows reduction of Her2 phosphorylation and down stream signaling with both unmodified and BBB modified Herceptin. This permits recruitment and retention of the antibody into the CNS tumors. Using fluorescence imaging and IHC of intracranial tumors we have validated that the BBB modified Herceptin is localized into intracranial tumors. We are currently evaluating the safety and therapeutic benefit of this approach in mice bearing intracranial tumors.
DDDR-04. PRECLINICAL INVESTIGATION OF A NOVEL BRAIN PENETRANT COMBINATION THERAPY TARGETING RAF AND MEK FOR MELANOMA BRAIN METASTASIS
Authors: Yamazawa Erika , Nayyar Naema , Ijad Nazanin , Torrini Consuelo , Migliarese Christian , Summers Elizabeth , Marion Braxton , Williams Richard , Suriben Rowena , Perez Michelle , Grandinetti Brooke , Wakimoto Hiroaki , Brastianos Priscilla
Published: November 2024

INTRODUCTION

Up to 75% of patients with advanced melanoma develop brain metastases. BRAF mutations are found in 50-55% of melanoma brain metastases. Current BRAF/MEK inhibitors, such as dabrafenib and vemurafenib, have shown responses on the order of 50-60% in patients with BRAF-mutant melanoma; however, responses are not durable. Better therapies are needed with improved penetration of the blood brain barrier. This study aims to evaluate the efficacy of two novel brain-penetrant inhibitors, KIN-7136 (MEK inhibitor) and KIN-8391 (RAF inhibitor), in preclinical mouse models of melanoma brain metastases driven by aberrant BRAF-MEK signaling.

METHODS

CellTiter-Glo® 2.0 Cell Viability Assay (Promega) was used for in vitro cell viability assays. Intracranial A375 melanoma models were generated in athymic nude mice to assess the pharmacodynamics, safety, and efficacy of combination therapy of KIN-7136 and KIN-8391.

RESULTS

In mice, the brain-to-plasma unbound partition coefficients (Kpuu) of KIN-7136 and KIN-8391 were 0.67 and 0.7 respectively, higher than the comparators binimetinib and belvarafenib, demonstrating improved brain exposure. The IC50s of KIN-7136/ KIN-8391 in melanoma cell lines were 27.0/36.5 nM in A375 (BRAF V600E), 78.6/35.4 nM in HMV2 (BRAF G469V), 183.0/699.0 nM in SK-MEL-2 (NRAS Q61R), and 53.9/110.0 nM in SK-MEL30 (BRAF D287H and E275K), respectively. KIN-7136 and KIN-8391 synergistically inhibited HMV2, SK-MEL-2, and SK-MEL-30 cells. Pharmacodynamic studies showed that both KIN-7136 and KIN-8391 suppressed phospho-ERK, a downstream component of BRAF-MEK signaling, in A375 xenografts in mice. Daily oral treatment with a combination of KIN-7136 and KIN-8391 was well-tolerated and extended overall survival to 64 days (median survival), compared to the vehicle control and monotherapies with KIN-7136 or KIN-8391 (28, 58, and 46.5, respectively) in the A375 intracranial tumor model.

CONCLUSION

These preclinical data confirm the synergistic effect of KIN-7136 and KIN-8391 in BRAF-mutant melanoma brain metastases models, supporting further research to advance its clinical translation.
DDDR-05. SPATIALLY RESOLVED DRUG SENSITIVITY PROFILING IN GLIOBLASTOMA
Authors: Buck Alicia , Lee Sohyon , Wegmann Rebekka , Mena Julien , Vasella Flavio , Friesen Julia , Regli Luca , Le Rhun Emilie , Zeitlberger Anna Maria , Neidert Marian Christoph , Tatari Nazanin , Hutter Gregor , Weller Michael , Snijder Berend , Weiss Tobias
Published: November 2024

BACKGROUND

Glioblastoma is the most common malignant primary brain tumor in adults, characterized by poor overall survival and an urgent need for more effective treatment strategies. Macroscopic heterogeneity, as observed through MR imaging, divides the tumor into distinct regions: a tumor-cell dense contrast-enhancing tumor core and a non-contrast-enhancing infiltration zone that appears hyperintense on T2/FLAIR imaging. The infiltration zone contains both infiltrating tumor cells and non-malignant cells from the local brain microenvironment. Although genomic and transcriptomic differences between the tumor core and the infiltration zone have been reported, functional differences, such as differential drug sensitivities, remain largely unknown.

METHODS

To investigate this, we collected region-specific glioblastoma patient tissue samples from both the contrast-enhancing tumor core and the non-contrast-enhancing but 5-aminolevulinic acid (5-ALA) fluorescent infiltration zone during surgery. Using pharmacoscopy, a microscopy-based single-cell drug screening platform, we assessed drug responses across regions and patients.

RESULTS

To determine whether drug responses within a single tumor region were more similar compared to responses across different regions we collected multiple tissue samples from each tumor region in seven patients. We identified region-specific drug responses for temozolomide and lomustine, among other drugs, in some of the patients. However, drug sensitivities were not consistent within the same region across different patients. Thus, across patients, the region-specific drug responses were obscured by patient heterogeneity. To address intra- and inter-tumor drug response heterogeneity, we developed a complementarity score based on region-specific drug response data of 60 drugs across 23 paired samples. The complementarity score identified promising drug combinations that demonstrated strong anti-tumor activity across tumor regions and patients.

CONCLUSIONS

Monotherapy approaches have largely failed in glioblastoma, despite extensive molecular profiling efforts aimed at identifying tumor-specific vulnerabilities. Identifying drug combinations that synergistically target the locoregional heterogeneity of glioblastoma may open up new avenues of personalized therapy.
DDDR-12. INHIBITION OF NOTCH PATHWAY VIA A NOVEL MONOCLONAL ANTIBODY PROLONGS SURVIVAL IN HIGH GRADE GLIOMA MODELS
Authors: Tosi Umberto , Ghita Greta , Saha Nayanendu , Mrad Zaki Abou , Giantini-Larsen Alexandra , Nikolov Dimitar , Yang Yanhong , Tabar Viviane
Published: November 2024

High grade gliomas (HGGs) have poor prognosis partially owing to a glioma-stem cell (GSC) population that escapes most therapeutic modalities. Inhibition of NOTCH signaling, necessary for GSC maintenance, has shown promise, however clinically limited by systemic (on-target, off-tumor) side effects. Thus, we develop a novel monoclonal antibody, 1H5, inhibitory against a disintegrin and metalloproteinase 10 (ADAM10), a protein responsible for NOTCH signaling initiation in tumor tissue, to treat HGGs. Patient-derived, glioma cell lines were treated with 1H5 to determine therapeutic IC50 and characterize downstream, NOTCH-related effectors. A patient-derived explant system, which best replicates the tumor microenvironment in vitro, was generated and treated. An orthotopic xenograft model (PDX) of HGG was created and treated with convection enhanced delivery (CED) of 1H5 to assess tumor volume and survival. We determined that ADAM10 is found in a majority of IDH-wildtype HGGs, but not on IDH-mutant HGGs or low-grade gliomas. 1H5 has nanomolar IC50 against a large library of HGG patient-derived cell lines, achieving cell death via NOTCH-signaling inhibition. In explants, treatment with 1H5 significant delays explant progression (p = 0.01), expansion (4.1-fold decrease, p = 0.007), and reduces the fraction of ADAM10+ cells (from 63.3% to 2.6%, p = 0.004), of replicating cells (from 10.0% to 0.9%, p = 0.006), and of GSCs (SOX2+ cells; from 65.8% to 12.8%, p = 0.06). In vivo, CED of 1H5 both slows down tumor growth compared to vehicle-treated controls (2.2-fold decrease in tumor volume, p = 0.03), and significantly prolongs survival (p = 0.01), without the development of significant side effects, through a reduction of replicating cells (p = 0.01) and SOX2+ GSCs (p < 0.0001), in a dose-dependent fashion. In conclusion, 1H5 is efficacious against HGG preclinical models both in vitro and in vivo by targeting NOTCH signaling. This posits 1H5 as a new promising therapeutic worthy of expeditious clinical translation.
DDDR-14. IMPROVED ANTI-GLIOBLASTOMA EFFICACY BY BRG399, A NOVEL ORAL MICROTUBULE BINDING AGENT
Authors: Kendirli Mustafa Tansel , Nastke Maria-Dorothea , Aristizabal-Henao Juan , Khojasteh Abbas , Kiebish Michael , Chimmanamada Dinesh , Vishnudas Vivek , Recht Lawrence , Gesta Stephane
Published: November 2024

Glioblastoma (GBM) is a highly malignant form of brain tumor with a poor prognosis despite advances in treatments. Therapeutic resistance/relapse remains a significant challenge necessitating the development of novel approaches. BRG399 is a brain permeant, non P-gp substrate, microtubule-targeting agent that displays anti-cancer activity in vitro and in vivo. BRG399 was well tolerated in rat and dog toxicology studies. Anti-cancer activity (IC50) of BRG399 in in vitro models of GBM was assessed to have potency ranging from 42nm to 89nM in the 3 cell lines tested. Here, in vivo tumor activity of BRG399 was assessed in Sprague Dawley rats implanted with 3x105 C6 rat glioma cells into the right entorhinal cortex/subiculum region. 14 days post successful implantation tumors were assessed by MRI, rats were randomized to receive vehicle (2% Labrasol) or BRG399 (5, 10, 20 mg/kg groups) twice daily by oral gavage for 16 days, and MRIs were performed on survivors on days 31 and 45 post implantation. BRG399 administration resulted in a marked improvement in survival (from 7.7 ± 2.6 days to 25.5 ± 15.6 days, log-rank test, p:0.007) compared to controls. Six animals receiving BRG399 remained alive beyond day 60 of post-treatment initiation. To assess biodistribution of BRG399 in the brain, rats were implanted with C6 cells and tumor establishment assessed 12 days later by MRI. Animals were treated with vehicle or BRG399 (10, 20, 25 mg/kg) and plasma and brains were collected for bioanalytical assessment. Tissue single cell biodistribution was performed using TIMSTOF FLEX spatial OMICS. These results demonstrate a therapeutic effect of BRG399 on intracranial glioma-bearing rats with survival of the BRG399 treatment groups of strong statistical significance over the control group. Analysis of drug levels in plasma and brain will serve as guidance for dose and scheduling decisions for further therapeutic development.
DDDR-15. UTILIZING DEEP DOCKING AND ARTIFICIAL INTELLIGENCE FOR THE DISCOVERY OF NOVEL PARP1-SELECTIVE INHIBITORS FOR USE AGAINST BRAIN TUMORS
Authors: Truong Sarah , Ban Fuqiang , Smith Jason , Zhai Beibei , Ramos Louise , Marzban Mona , Ghaidi Fariba , Adomat Hans , Chen Xiaoqi , Langlands John , Brown Dennis , Bacha Jeffrey , Collins Colin , Cherkasov Artem , Daugaard Mads
Published: November 2024

Brain tumors, including primary brain tumors and central nervous system (CNS) metastases, remain among the most challenging malignancies to treat, with therapeutic options often limited by the inability of drugs to penetrate the blood-brain barrier. Poly(ADP-ribose) polymerase (PARP) is a key enzyme in DNA repair, and inhibition of PARP1 specifically drives synthetic lethality in BRCA-mutated disease. While they’ve achieved commercial success, first generation PARP inhibitors are limited in their utility as they cannot readily pass through the blood-brain barrier and have adverse side effects, likely driven by the collateral inhibition of PARP2. Development of a PARP1-selective, CNS penetrant inhibitor could reduce toxicity, while providing a new therapeutic option for brain tumors. Traditional drug discovery methods are time-consuming and costly, necessitating innovative approaches. Here, we describe the application of Deep Docking, an advanced artificial intelligence (AI) approach, to discover a novel, PARP1-selective inhibitor for use against brain tumors. Deep Docking utilizes deep learning to accelerate the prediction of the binding affinity of a large number of compounds to target proteins, streamlining the virtual screening process and allowing for rapid docking of billions of compounds against the PARP1 protein. Additionally, state-of-the-art generative algorithms and deep learning techniques for predicting drug-like properties such as metabolism, permeability, and safety profiles, can be combined to rapidly perform hit-to-lead optimization. We will present preliminary Deep Docking screening results from billions of compounds, identifying several with predicted high binding affinities for PARP-1. Validating in vitro and in vivo data, including PARP1 selectivity, metabolic stability, pharmacokinetic profile, CNS penetration and safety profile, will be described. Application of the Deep Docking AI platform is being used to significantly accelerate the discovery of a selective PARP-1 inhibitor for brain tumors. This approach will not only improve the efficiency of drug discovery but also enhance the specificity and efficacy of potential therapeutics.