bluuebunny/crossref_metadata_2025 huggingface dataset:
NCOG-36. IMPACT OF COLLAGEN TILE BRACHYTHERAPY AS TREATMENT FOR RECURRENT GLIOBLASTOMAS ON FUNCTIONAL STATUS AND QUALITY OF LIFE
Authors: Garcia Michael , Brachman David , Lee Stuart , Peach Matthew Sean , Wanebo John , Smith Kris , Chen Clark , Kotecha Rupesh , Ahluwalia Manmeet , Hanft Simon , Nowlan Adam , McCracken David , Floyd John , Shah Mitesh , Richardson Angela , Patel Toral , Pham Huong , Ryan Robert , Wasilewski Andrea , Shen Colette , Robin Adam , Ranjan Tulika , Bojanowski-Hoang Kimberly , DiNapoli Vincent , Chamoun Roukoz , Choutka Ondrej , Mercado Catherine , Haydon Devon , Leng Lewis , Rodriguez Analiz , Deb Nimisha , Patel Akash , Piccioni David , Campbell Lisa , Patel Sita , Hall Angela
Published: November 2023

BACKGROUND

Recurrent glioblastoma is an aggressive disease with dismal prognosis despite advances in standard therapy, making the maintenance of functional status and quality of life (QOL) in patients an important endpoint during treatment. Here, we report functional status (KPS) and QOL metrics (LASA and FACT-Br) at 6-months post-treatment for recurrent glioblastoma patients treated with maximal safe resection followed by intraoperative placement of collagen tile brachytherapy with Cesium-131 (Surgically Targeted Radiation Therapy or STaRT), a novel brachytherapy carrier.

OBJECTIVE

To assess the impact of STaRT on KPS and QOL among patients with recurrent glioblastoma (rGBM) at 6-months post-treatment.

METHODS

Patients were treated between 10/2020 and 05/2023 as part of a multi-institutional registry study (NCT#04427384). KPS was used to measure functional status. Linear Analog Self-Assessment (LASA) and Functional Assessment of Cancer Therapy – Brain (FACT-Br) were used to measure QOL. All assessments were collected at pre-surgery, and 1,3, and 6-months post-treatment.

RESULTS

57 rGBM patients were treated on the Registry between 10/2020 and 05/2023. Of the 57 participants, 47 participants remain in the study, with 21 participants reaching the 6-month time point (5 exits, 5 deaths). Median age was 60 years (range 28-81). Methylguanine methyltransferase (MGMT) promoter was methylated in 17.5%, unmethylated in 38.5%, and unknown in 44%. Gross total resection was achieved in 72% of participants. Median KPS was 80% (range 40%-100%) at screening versus 70% (range 40%-90%) at 6 months post-treatment. Median LASA was 37 (range 8-50) at pre-surgery versus 34 (range 5-48) at 6-months post-treatment. Minimally important differences (MID) were noted between pre-surgery (136.9 ± 29.5) and 6-months post-treatment (112.5 ± 35.7) for the FACT-Br Total Score.

CONCLUSION

This interim data analysis supports further investigation of STaRT as a treatment for recurrent glioblastomas as a means of providing stable functional status and quality of life.
NCOG-40. PATTERNS OF PROGRESSION IN PATIENTS WITH NEWLY DIAGNOSED PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA FOLLOWING TREATMENT WITH HIGH-DOSE METHOTREXATE
Authors: Cappelli Louis , Newman Jennifer , Sharif Muhammad , Kayne Allison , Epperla Narendranath , Elguindy Ahmed , Palmer Joshua , Alnahhas Iyad , Shi Wenyin
Published: November 2023

INTRODUCTION

Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin's lymphoma that primarily affects the brain. Recurrence of PCNSL within the central nervous system is common, but patterns of intracranial recurrence following induction chemotherapy have not been extensively studied. This study aims to elucidate the patterns of recurrence and progression in PCNSL.

METHODS

Adult patients from two institutions with newly diagnosed PCNSL that received HD-MTX based chemotherapy from 2011-2023 were included. Patient charts and diagnostic imaging were retrospectively reviewed. The pattern of recurrence/progression was reviewed by comparing the initial diagnostic MRI to the first recurrence MRI (T1 post-contrast and FLAIR sequence). Distant recurrences were defined as separate lesions from the previous primary enhancing lesion, located outside the initial FLAIR abnormality observed on imaging. Local recurrences were characterized as new lesions overlapping with the primary enhancing lesion/FLAIR abnormality.

RESULTS

25 patients were identified to have been diagnosed with PCNSL and progressed through initial definitive treatment with HD-MTX based chemotherapy. 2/25 received initial management with radiation therapy. Median age at diagnosis was 66 years. The median time to progression was 18.1 months (Range; 0.9-70). Twelve of the 25 patients had a complete response to initial systemic therapy, 6 had a partial response, and 7 patients had disease progression through chemotherapy. Eleven of the 25 patients were found to have multifocal disease at diagnosis. 13/25 (52%) patients had distant recurrence only, 5/25(20%) had only local recurrence, and 7/25 (28%) displayed both local and distant recurrence pattern.

CONCLUSION

In this retrospective review, for patients diagnosed with PCNSL who are able to undergo HD-MTX we identified that the majority of disease recurrence is outside or distant to the primary disease site vs locally (80% vs 20%). Such findings should be verified with a larger cohort and can help direct further consolidation strategies.
NCOG-41. REAL WORLD EXPERIENCE WITH TTFIELDS WITH EMPHASIS ON THERAPY COMPLIANCE
Authors: Jelgersma Claudius , Akkas Gülsüm , Alsolivany Joan , Wasilewski David , Gastl Bastian , Vajkoczy Peter , Misch Martin , Kaul David , Bullinger Lars , Onken Julia
Published: November 2023

Tumor Treating Fields (TTF) therapy has emerged as a significant adjunctive component in the treatment of high-grade tumors following its validation in the EF-14 trial in 2017. The incorporation of TTF therapy, alongside cyclic temozolomide (TMZ) therapy, has demonstrated enhanced outcomes in terms of PFS and OS when the useage exceeds 18 hours per day (75% compliance rate). Post-hoc analysis of the EF-14 trial has demonstrated that compliance rates exceeding 90% are associated with an additional benefit. Given the cost-intensive nature and significant constraints associated with the therapy, our objective is to generate real-world data on compliance through a retrospective analysis at a high-throughput academic center. Between June 2015 and February 2022, a total of 115 patients were prescribed TTFields as pa rt of their treatment for high-grade glioma. Mean age was 50y and mean preoperative Karnofsky Index 80-90. The average duration of therapy was 8 months. The majority of patients (74%) initiated therapy concurrently with 1st-line treatment, while only 25% managed to start concomitant to the first cycle of temozolomide. 16.7% started TTFields in the 2nd-line and 9.3% in the 3rd-line setting. Thirteen patients discontinued TTFields treatment within the first 3 months and were consequently excluded from further compliance analysis. Across the study cohort, the median compliance rate was 72% (SD 22%), with an average of 41 days of breaks observed. Compliance was highest during the first 3 cycles, with rates of 79%, 73%, and 72%, respectively. Linear regression analysis did not identify any predictors of compliance, including age at surgery, timing of therapy, duration of therapy, gender, and preoperative Karnofsky Index. These findings highlight the importance of monitoring and promoting adherence to TTFields therapy to maximize its potential benefits in the management of high-grade gliomas. Further strategies are warranted to expedite the start of therapy and improve long-term compliance.
EXTH-09. GM-CSF AND IL-7 FUSION CYTOKINE ENGINEERED TUMOR VACCINE GENERATES LONG-TERMTH-17 MEMORY CELLS AND INCREASES OVERALL SURVIVAL IN AGED SYNGENEIC MOUSE MODELS OF GLIOBLASTOMA
Authors: Shireman Jack , Gonugunta Nikita , Pattnaik Akshita , Zhao Lei , Wang Xiaohu , Galipeau Jacques , Dey Mahua
Published: November 2023

Age-related immune dysfunctions, such as decreased T-cell output, are closely related to pathologies like cancers and lack of vaccine efficacy among the elderly. Engineered fusokine, GIFT-7, a fusion of IL-7 and GM-CSF, can reverse aging-related lymphoid organ atrophy. We generated a GIFT-7 fusokine tumor vaccine and employed it in aged syngeneic mouse models of glioblastoma, and found that peripheral vaccination with GIFT-7TVax resulted in thymic regeneration and generated durable long-term anti-tumor immunity specifically in aged mice. Global cytokine analysis showed increased pro-inflammatory cytokines including IL-1b in the vaccinated group that resulted in hyperactivation of dendritic cells. In addition, GIFT-7 vaccination resulted in increased T-cell trafficking to the brain and robust Th-17 long-term effector memory T-cell formation. TCR-seq analysis showed increased productive frequency among detected rearrangements within the vaccinated group. Overall, our data demonstrate that aging immune system can be therapeutically augmented to generate lasting anti-tumor immunity.
EXTH-10. QUAD-DM1: A HIGHLY POTENT DRUG CONJUGATE FOR BREAST CANCER AND BREAST CANCER BRAIN METASTASIS TREATMENT
Authors: Debinski Waldemar , Fink Kaitlin N , Rossmeisl John , Mott Ryan T , Herpai Denise
Published: November 2023

Triple-negative breast cancer (TNBC) remains an unmet need in medicine. Previously, we and others found that interleukin 13 receptor alpha 2 (IL-13RA2), EphA2, EphA3 and EphB2 receptors are over-expressed in almost all patients with glioblastoma (GBM). We performed a first-of-a-kind Phase I clinical trial in dogs with spontaneous gliomas using a cocktail of cytotoxins targeting IL-13RA2 and EphA2 receptor. The majority of dogs experienced >50% of tumor regression; four dogs exhibited >92% tumor shrinkage and several dogs became long-term survivors. Next, we pursued the novel idea of targeting four tumor-associated receptors, instead of two, with one pharmaceutical compound. To this end, we produced a multivalent ligand, termed QUAD. More recently, we found that a conjugate of QUAD with emtansine (DM1), a microtubule-disrupting agent, demonstrated a specific killing potency on GBM cells, in low picomolar range. Unexpectedly, we observed that human breast cancer cells are also highly responsive to this drug candidate. We thus examined the presence of the four receptors in breast cancer cells and tissue micro-arrays, including involved lymph nodes, and in paired primary tumor - brain metastases, spanning two molecular subtypes of breast cancer: TNBC and HER2+. We found that the four targeted receptors are expressed in almost all breast cancer and related metastases to brain specimens, based on the expression levels for the genes and the gene products. Furthermore, the breast cancer cell lines like HC1806, MDA-MB-468, MDA-MB-231, BT549, and the breast metastatic cell line MDA-MB-231-BRM cells are killed at up to picomolar concentrations of QUAD-DM1. MDA-MB-231 tumors growing in mammary pads of athymic mice responded significantly to QUAD-DM1 given intravenously; QUAD recognizes murine receptors similarly to human. Thus, QUAD-DM1 is a novel type of a multivalent drug conjugate for the treatment of breast cancer and its brain metastases, which is applicable, but not exclusively, to TNBC.
EXTH-20. A MOUSE MODEL REVEALS VULNERABILITY OF IDH1-MUTATED GLIOMA TO FERROPTOSIS
Authors: Mela Angeliki , Dovas Athanassios , Mahajan Aayushi , Humala Nelson , Nguyen Trang , Kanangat Smriti , Upadhyayula Pavan , Sprinzen Lisa , Argenziano Michael , Huang Dennis , Guo Jia , Casaccia Patrizia , Siegelin Markus , Stockwell Brent , Bruce Jeffrey , Canoll Peter
Published: November 2023

The molecular classification of gliomas is currently based on the presence of IDH1 mutation, which is associated with better prognosis and longer survival. The hallmark of the IDH1 mutation is the production of D-2-Hydroxyglutarate with subsequent effects that are not fully understood. Ferroptosis, an iron-dependent mechanism of non-apoptotic cell death, is mostly triggered through blocking system Xc- or suppressing the antioxidant enzyme glutathione peroxidase 4 (GPX-4). In this study, we generated a mouse model of glioma harboring the IDH1(R132H) mutation in heterozygous condition, in combination with p53-deletion induced by the expression of PDGFA. We show that IDH1(R132H)-expressing mice survive longer compared to their wild-type counterparts, while histological analysis reveals characteristics of low-grade diffuse gliomas. We generated cell lines from primary tumors and analyzed their metabolic profile and response to mitochondrial stress and Ferroptosis. We treated them in vitro with RSL3, a GPX-4 inhibitor, alone or in combination with Cysteine and Methionine restriction. We show that IDH1(R132H)-expressing cells are far more sensitive to Ferroptosis in vitro. Finally, we show that convection-enhanced delivery of RSL3 in combination with dietary Cysteine and Methionine restriction in vivo, significantly prolongs survival of the IDH1(R132H)-expressing mice. Our findings suggest that Ferroptosis provides promising therapeutic potential worth exploring further and our mouse model could be used to test the efficacy of different treatments for IDH1(R132H) gliomas.
EXTH-23. EFFECT OF EVOGLIPTIN AND TEMOZOLOMIDE COMBINATION THERAPY FOR THE TREATMENT OF GLIOBLASTOMA, IN VITRO AND IN VIVO
Authors: Yang Seung Ho , Lee Keun Soo , Lee Jung Eun
Published: November 2023

A recent study showed that high dipeptidyl-peptidase IV (DPP4) expression affects glioma progression. The purpose of this study is to investigate the synergistic effect of a DDP4 inhibitor, evogliptin and temzolomide (TMZ) combination therapy for glioblastoma (GBM) in vitro and in vivo. U87, U252, and A172 cells were treated with 50, 250, and 500 uM TMZ or with 5, 10, and 20 mM evogliptin for 24, 48 and 72 hrs. For in vivo experiment, GBM xenograft models were used. Three groups (n=5 mice) were treated with TMZ(15mg/kg/day), evogliptin (2mg/25g/day), and combination of TMZ and evogliptin via i.p. injection for 4 weeks. For evaluating the relevant mechanism, Affymetrix miRNA arrays are used. The MTT assay revealed that the combination treatment had higher cytotoxicity against U87, U251, and A172 cells than the monotherapy had after 48 and 72-hr treatment. mRNA DDP4 levels were much more decreased after combination administration. The median survival of each group was 43.6, 55.2, 53.2, 65.2, and 71.3 days in the control, evogliptin, TMZ, the first combination therapy with low-dose evogliptin (2mg/25g/day) and TMZ, and the second combination therapy with high-dose evogliptin (10mg/25g/day) and TMZ, respectively. In Affymetrix miRNA arrays, miR-1246, miR-149-3p, miR-3148, miR-4440, miR-4484, miR-4535, miR-6126, miR-6780b-5p, and miR-7110-5p were increased after evogliptin treatment. miR-149-5p, miR-23a-5p, miR-3195, miR-4330, miR-4497, miR-4669, miR-671-3p, and miR-744-5p were decreased. miR-4440 and miR-6780b-5p were also increased following combination therapy. In the TCGA dataset, the survival of glioma patients with low DPP4 expression is longer than that in patients with high DPP4. A DDP4 inhibitor, evoglipin regulates miRNA in GBM cell lines. The combination of evogliptin and TMZ had a moderate effect on the treatment of GBM in vitro and in vivo. miR-4440 and miR-6780b-5p could be associated with inhibiting the proliferation of GBM cells by targeting DPP4.
EXTH-28. ISOCITRATE DEHYDROGENASE MUTATIONS PREDICT SENSITIVITY TO HISTONE DEACETYLASE INHIBITION AND ENHANCED HISTONE ACETYLATION DYNAMICS ONLY IN THE CONTEXT OF GLIOMA
Authors: Sears Thomas , Drumm Michael , Wang Wenxia , Horbinski Craig
Published: November 2023

Isocitrate dehydrogenase 1/2 mutations (IDHmut) define a subtype of glioma with profound epigenetic dysregulation through genomic hypermethylation. IDHmut gliomas are incurable and fatal, demonstrating new treatments are needed. These mutations are common in other solid tumors, including chondrosarcoma (CS) and intrahepatic cholangiocarcinoma (ICC). Histone deacetylase (HDAC) enzymes compose a class of epigenetic drug targets utilized clinically to treat cancer, but their potential against IDHmut gliomas has not been extensively studied. We previously showed that IDHmut glioma cultures exhibit pronounced sensitivity to the effects mediated by the FDA-approved HDAC inhibitor (HDACi) panobinostat. Here, we integrate proliferation and cytoxicity data to show that this effect is unique to gliomas. In the context of histone H3 acetylation (H3KAc), panobinostat increased H3KAc, on average, by 7.6-fold and 30.5-fold in IDHwt and IDHmut glioma cultures, respectively (p< 0.001). This difference in HDACi-mediated H3KAc based on IDH status was not significant for CS and ICC. IDHmut gliomas are more sensitive two other FDA-approved HDACis: belinostat and vorinostat. RNA-Seq analysis showed that panobinostat more greatly affected gene expression in IDHmut glioma cells, particularly in the context of gene downregulation. Similarly, H3KAc ChIP-Seq showed a decrease in promoter histone acetylation moreso in IDHmut glioma cultures treated with panobinostat: there is an average loss of 1,236 and 14,759 H3KAc peaks at gene promoters in IDHwt and IDHmut cultures, respectively. This suggests that IDHmut gliomas exhibit enhanced histone acetylation dynamics in response to HDACi. Furthermore, using a PDX glioma model, we show that only mice engrafted with IDHmut glioma exhibit a significant survival increase in response to the HDACi belinostat: median survival was extended by 14 days in IDHmut glioma-bearing mice (p= 0.01), whereas belinostat extended median survival by 4 days in IDHwt glioma-bearing mice (p= 0.11). These results suggest that HDACi may be an effective in treating IDHmut gliomas.
EXTH-44. ENHANCING GLIOBLASTOMA CLEARANCE: EMPOWERING ANTI-EGFRVIII CAR T CELLS WITH A PARACRINE SIRPΓ-DERIVED CD47 BLOCKER
Authors: Martins Tomas , Tatari Nazanin , Kaymak Deniz , Bartoszek Ewelina M , Hogan Sabrina , Buck Alicia , Ritz Marie-Françoise , Wieboldt Ronja , McDaid Marta , Gerber Alexandra , Shekarian Tala , Hedad Hayget Mohamed Seid , Schmassmann Philip , Weiss Tobias , Laeubli Heinz , Hutter Gregor
Published: November 2023

A major challenge for chimeric antigen receptor (CAR) T cell therapy against glioblastoma (GBM) is the immunosuppressive microenvironment (iTME), which is densely populated by protumoral glioma-associated microglia and macrophages (GAMs). Blockade of CD47, a “don’t-eat-me” signal overexpressed by GBM cells, disrupts the CD47-SIRPα axis, and regulates the phagocytic function of GAMs. However, systemic anti-CD47 monotherapy has been ineffective against human solid tumors to date. Here, we combined local CAR T therapy with paracrine GAM modulation to synergistically eliminate GBM. We engineered an armored CAR T cell against EGFRvIII that constitutively secretes a SIRPγ-related protein (SGRP) with high affinity to CD47. Anti-EGFRvIII-SGRP CAR T cells eliminated EGFRvIII+ GBM in vitro, and eradicated EGFRvIII-heterogeneous (EGFRvIII+ and EGFRvIII- mosaic) orthotopically xenografted tumors by locoregional application in vivo. This resulted in significant tumor-free long-term survival, followed by partial tumor control upon re-challenge. Combination of anti-CD47 antibodies with anti-EGFRvIII-CAR T cells failed to achieve synergy, pointing towards the importance of sustained paracrine GAM conversion. Paracrine SGRP enhanced CAR T infiltration, tumor clearance and GAM reconversion to an antitumor phenotype as shown by multidimensional brain immunofluorescence microscopy and in-depth spectral flow cytometry multiplexing. Moreover, the plasma of anti-EGFRvIII-SGRP CAR T-treated mice displayed a distinct signature of innate immune activation including TNFα and CCL3. Validation of the anti-EGFRvIII-SGRP CAR T in human explants is ongoing. Furthermore, armoring anti-CD19 CAR T cells with SGRP resulted in superior efficacy in a peripheral lymphoma mouse model compared to anti-CD19 CAR T treatment alone, most problably due to innate immune activation. Thus, local anti-EGFRvIII-SGRP CAR T cell therapy combines the potent antitumor effect of engineered T cells with the modulation of the surrounding innate iTME, inducing a synergistic clearance of GBM in a manner that overcomes known mechanisms of CAR T therapy evasion, such as tumor immune suppression and antigen escape.
EXTH-49. A NOVEL MULTIVALENT DRUG CONJUGATE FOR HIGH-GRADE GLIOMA TREATMENT
Authors: Debinski Waldemar , Fink Kaitlin N , Herpai Denise , Rossmeisl John
Published: November 2023

Interleukin 13 receptor alpha 2 (IL-13RA2), EphA2, EphA3 and EphB2 receptors are over-expressed collectively in almost all patients with glioblastoma (GBM), and also in spontaneous canine gliomas, the most faithful model of human disease. The four receptors are widely present in various compartments of GBM tumors, including tumor core, infiltrating cells, tumor neovasculature and tumor-associated macrophages. Thus, the four receptors are expressed in several GBM compartments involved in tumor progression and/or resistance to therapies, covering almost 100% of the tumor microenvironment. In first-of-a-kind approach, we performed Phase I clinical trial in dogs with gliomas using a cocktail of cytotoxins targeting IL-13RA2 and EphA2 receptor. The cocktail was administered loco-regionally through convection-enhanced delivery, using anti-reflux catheters and real-time MRI monitoring of drugs distribution. We observed prominent anti-tumor responses, including several near complete regressions, prolongation of survival and excellent quality of life, although we did not achieve dose-limiting toxicity (Neuro-Oncol 2021;23(3):422-434). Encouraged by these exceptional results, we pursued the novel idea of targeting the four GBM-associated receptors with one pharmaceutical compound. To this end, we designed, produced, and tested a multivalent ligand binding to all four receptors of our interest, termed QUAD, including murine and canine receptors. However, we found that a conjugate of QUAD with DM1, a microtubule-disrupting agent, demonstrated an extremely high (in low picomolar range) and specific killing potency on GBM cells. The IC50s of QUAD-DM1 are ~50 times higher than that for all other QUAD-based drug conjugates tested thus far, having a favorable toxicity profile in rodents when injected either intracranially or intravenously. QUAD-DM1 has already produced up to 95% tumor reduction in dogs with spontaneous brain tumors. QUAD-DM1 is a highly promising agent for the treatment of human and canine high-grade gliomas.
EXTH-53. VEGFR2-SPECIFIC CAR-T CELLS SHOW IMPROVED TUMOR INFILTRATION IN SYNGENEIC MOUSE GLIOMA MODELS
Authors: Mastall Maximilian , Dunkel Gina , Silginer Manuela , Okada Naoki , Weiss Tobias , Weller Michael , Weigelin Bettina , Roth Patrick
Published: November 2023

BACKGROUND

Chimeric antigen receptor (CAR-)T cell therapy, a powerful immunotherapy against hematological malignancies, has so far limited efficiency in solid tumors. Also in glioblastoma, a major obstacle remains limited infiltration of CAR-T cells into the tumor. Vessel-targeting CAR-T cells have been shown to infiltrate solid tumors more efficiently. Vascular endothelial growth factor receptor 2 (VEGFR2) is expressed in the glioma vasculature and VEGFR2-specific CAR-T cells prolong the survival of xenograft glioma-bearing mice. In this study, we investigated the efficacy of murine VEGFR2-specific CAR-T cells against syngeneic experimental gliomas and assessed the CAR-T cell infiltration of this approach.

METHODS

VEGFR2-CAR-T cells were generated by retroviral transduction to express a second generation CAR construct. Their activity was assessed in co-culture assays in vitro against murine endothelial and glioma cells, respectively. Syngeneic orthotopic mouse glioma models were used to explore the infiltration of intravenously administered CAR-T cells by in vivo fluorescence molecular tomography (FMT), ex vivo flow cytometry as well as ex vivo 3D light-sheet fluorescence microscopy (LSFM).

RESULTS

VEGFR2-CAR-T cells showed anti-endothelial and anti-glioma activity in vitro. Intravenous treatment with fluorescently labeled CAR-T or mock-transduced T cells of tumor-bearing mice resulted in a higher FMT signal at the tumor site. This was confirmed by ex vivo flow cytometry, wherein CAR-T cells represented a larger fraction of all T cells within the tumor (26.5% CAR versus 5.4% Mock, p = 0.0013) resulting in a higher donor T cell to tumor cell ratio. Similarly, significantly more VEGFR2-CAR-T cells were detected at the tumor site compared to tumor-targeting (but not vessel-targeting) control CAR-T cells. Currently, VEGFR2-CAR-T cell infiltration patterns as well as vasculature density are further investigated and visualized by LSFM.

CONCLUSION

VEGFR2-CAR-T cells show improved glioma infiltration in syngeneic mouse models. Therefore, VEGFR2 might be a relevant target that could improve CAR-T cell infiltration in glioblastoma.
EXTH-63. MTA-COOPERATIVE PRMT5 INHIBITORS ARE EFFICACIOUS IN MTAP-DELETED MALIGNANT PERIPHERAL NERVE SHEATH TUMOR MODELS
Authors: Borcherding Dana , Zhang Xiaochun , Zhang Minjie , Bhatia Himanshi , Lyu Yang , He Kevin , Yang Liuzhan , Yang Kuangying , DiBenedetto Heather , Tsai Alice , Huang Alan , Maxwell John , Cottrell Kevin , Briggs Kimberly , Hirbe Angela
Published: November 2023

OBJECTIVES

Malignant peripheral nerve sheath tumors (MPNST) are highly aggressive sarcomas with limited treatment options and poor survival rates, necessitating the development of novel therapeutics. Approximately 25-50% of MPNST harbor loss of the enzyme methylthioadenosine phosphorylase (MTAP) due to a passenger deletion driven by loss of the proximal tumor suppressor gene, CDKN2A. PRMT5 was identified as a selective dependence in MTAP-deleted cells due to the accumulation of the substrate methylthioadenosine (MTA), which is itself an endogenous PRMT5 inhibitor. TNG908 and TNG462 are clinical stage MTA-cooperative PRMT5 inhibitors that demonstrate selectivity for MTAP-deleted cells over MTAP-intact cells of 15X and 45X, respectively. Previous reports show both molecules drive durable tumor regressions in xenograft models of various MTAP-deleted cancer histologies. Here, our objectives are to examine the activity of TNG908 and TNG462 in preclinical MPNST models.

METHODS

The proliferation effects of MTA-cooperative PRMT5 inhibitors, TNG908 or TNG462, and a SAM-cooperative PRMT5 inhibitor, GSK3326595, on MTAP-deleted and MTAP-intact MPNST cell lines were determined using CellTiter-Glo (CTG) assays. TNG908 and TNG462 were further profiled in two MTAP-deleted MPNST patient-derived xenograft (PDX) models, WU-356 and WU-386.

RESULTS

Incubation with the MTA-cooperative PRMT5 inhibitors, TNG908 and TNG462, selectively decreased the proliferation of MTAP-deleted MPNST cell lines relative to MTAP-intact MPNST cell lines. TNG908 and TNG462 drove dose-dependent antitumor activity including tumor regressions in the MTAP-deleted MPNST PDX models, WU-356 and WU-386, at well-tolerated doses.

CONCLUSIONS

The clinical stage MTA-cooperative PRMT5 inhibitors TNG908 (NCT05275478) and TNG462 (NCT05732831) are efficacious in MPNST models in vitro and in vivo and are therefore promising therapeutic agents for patients with MTAP-deleted MPNST.
EXTH-64. ESTABLISHING A CLINICALLY RELEVANT MOUSE MODEL OF MESENCHYMAL GLIOBLASTOMA FOR STUDYING TME TARGETING TREATMENTS
Authors: Connor Kate , White Kieron , Clerkin James , Shiels Liam , Sweeney Kieron , Van Brussel Thomas , Arijs Ingrid , Lambrechts Diether , Shankar Gautam , de Smet Frederik , Zopf Dieter , Maher Stephen , Marignol Laure , Dicker Patrick , Prehn Jochen , O'Brien David , Byrne Annette
Published: November 2023

Historically, pre-clinical GBM models have largely failed to predict response in the clinical setting. Here, we establish a more clinically faithful model using the syngeneic NFpp10a-Luc2 mesenchymal-GBM cell line to study response to resection and temozolomide (TMZ), adjuvant/neo-adjuvant anti-PD1 and Regorafenib (REGO) therapy. Cells were orthotopically implanted in C57BL/6-mice. Response to surgical and therapeutic interventions was assessed using bioluminescence imaging (BLI). Murine Microenvironment cell-population (mMCP)-counter, GSEA and multiple iteractive labelling by antibody neodeposition (MILAN, high-dimensional single-cell multiplex analysis) were employed to characterise treatment-related TME effects. We observed survival advantage in aged mice undergoing resection (resection:33.5 days vs non-resection:18 days; p = 0.0166). TMZ/anti-PD1 had no impact on tumour growth (TMZ: p = 0.9001, anti-PD1: p = 0.7933) or survival (TMZ:p = 0.3035, anti-PD1-:p = 0.6328). Neo-adjuvant anti-PD1 also conferred no survival advantage in young mice (33 vs 35 days; p = 0.9429). REGO/REGO+TMZ treatment conferred no survival benefit in young mice (REGO:p = 0.0735 and REGO+TMZ:p = 0.3945). mMCP-counter (which estimates the abundance of TME-cell populations from gene-expression data) showed resection upregulated B-cells and mast-cells, whereas TMZ caused a decreased abundance of vessels. Anti-PD1 treatment caused an enrichment of B-cells, mast-cells, and CXCR3 expression (p = 0.0045). REGO/TMZ+REGO treatment upregulated cytotoxic-lymphocyte populations. MILAN analysis showed resection increased cytotoxic-T-cells (20.3% vs pre-resection:7%). In contrast, TMZ/REGO monotherapy increased tumour-cells and decreased cytotoxic-T-cells. Anti-PD1 decreased macrophage abundance (39.8% vs control:14.5%). Likewise, TMZ+REGO decreased macrophages (11.3% vs control:35.3%) but upregulated B-cells and vessels. Overall, we have characterised response of the NFpp10a mouse model to resection, TMZ, anti-PD1 and REGO. We have shown that the model is insensitive to chemotherapy and TME-targeting therapies, mirroring patient-response patterns. Nevertheless, we observe transcriptomic and proteomic changes following TME-targeting treatments. Further analyses of these TME-associated resistance properties may help guide novel combinatorial treatment regimens. Overall, the NFpp10a model of mesenchymal GBM may be employed in future pre-clinical studies to accurately guide future clinical trials.
EXTH-67. LP-184, AN MGMT-AGNOSTIC SMALL MOLECULE, HAS POTENT SYNERGY WITH SPIRONOLACTONE TO EFFECTIVELY INHIBIT ORTHOTOPIC GBM XENOGRAFT TUMORS
Authors: Lal Bachchu , Kulkarni Aditya , McDermott Joseph , Lopez-Bertoni Hernando , Bhatia Kishor , Sharma Panna , Laterra John
Published: November 2023

Temozolomide (TMZ) is currently the most effective standard-of-care chemotherapy based on its ability to extend survival of patients with newly diagnosed MGMT-methylated glioblastoma (GBM). Blood-brain barrier (BBB) permeable agents effective against TMZ-resistant GBMs (i.e. recurrent GBM, MGMT-unmethylated GBM) are needed. Lantern Pharma is advancing LP-184, an acylfulvene prodrug activated by the enzyme PTGR1. In MGMT-expressing TMZ-resistant GBM cultures, LP-184 was found to be ~5000X more potent than TMZ with LP-184 IC50s ranging from 20-200 nM. DNA damage induced by acylfulvenes is primarily repaired via transcription-coupled nucleotide excision repair (TC-NER) mediated by ERCC complexes. ERCC3 is proteolytically degraded in response to the FDA approved BBB permeable diuretic, spironolactone (SP). We found that SP induces rapid ERCC3 degradation by up to 95% in GBM cells and validated that SP-induced ERCC3 loss led to substantial increases in LP-184 responses (DNA damage, tumor cell death) in vitro and in subcutaneous (s.c.) tumor xenografts. Co-treatment of GBM cells with LP-184 and SP resulted in a 3-6 fold decrease in LP-184 IC50s in PDX-derived (M1123 and Mayo39) and cell line (U87) cultures in vitro. Systemic SP sensitized pre-established s.c. and orthotopic (i.c.) GBM xenografts to LP-184 therapy. Pre-established s.c. U87 tumors recurred after initial regression in 5/5 animals following treatment with LP-184 alone whereas tumors showed durable complete regression without recurrence in 4/5 animals following treatment with LP-184 + SP. Pre-established M1123 i.c. xenografts treated with LP-184 + SP were ~3-fold smaller than those treated with LP-184 alone. LP-184 is a promising agent with potential clinical translation in GBM patients. Our results indicate that LP-184 is MGMT-agnostic and effective in TMZ-resistant preclinical GBM models. The first-in-human LP-184 dose escalation Phase 1A trial enrolling solid tumor patients including GBM is planned to launch Q3 2023.
EXTH-69. REGULATION OF N1/N2 NEUTROPHIL PHENOTYPE BY A MANZAMINE-DERIVED COMPOUND FOR BRAIN TUMOR TREATMENT
Authors: Lin Ya-Jui , Huang Chiungyin , Wei Kuo-Chen , Chen Pin-Yuan
Published: November 2023

In cancer microenvironment, the presence of neutrophils is associated with tumor proliferation, invasion and immunomodulation. The tumor associated neutrophils (TAN) can be polarized toward N1 (anti-tumor) or N2 (pro-tumor) phenotypes. Therefore, modulating neutrophil phenotype may serve as brain tumor treatment strategy. We use immunosuppressive and normal mice bearing brain tumor cell xenograft to study the role of TANs in tumor progression. A manzamine-derived compound 1-(9’-propyl-3’-carbazole)-1, 2, 3, 4-tetrahydro-β-carboline (PCTC) was used to treat brain tumor mice. In brain tumor tissue, flowcytometry study revealed the amount of pro-tumor N2 TAN is significantly greater than anti-tumor N1 subtype. While PCTC was intracranial administrated into brain tumor, the ratio of N1/N2 is reversed. Immunochemical staining showed increasing neutrophils in tumor at day 1 post treatment, followed by subsequent T cell and macrophage gathering at day 5. Cytokine array results revealed the expression level of CXCL9/CXCL10 were upregulated in PCTC treatment glioma cells and brain tumor tissues. Cell study also demonstrated T cell migration ability was significantly increased when co-cultured with neutrophil and PCTC treated glioma cells. In mice tumor model, NU/NU mouse lack of T cell represented no response to PCTC treatment, while significant tumor shrunken was observed in B6 mice. Compensation study by intravenous inoculation of T cell and PCTC to NU/NU glioma mice showed flavor response to animal survival. In this study, we demonstrated the N1/N2 ratio of TAN can be regulated by PCTC, and be beneficial to glioma treatment. Furthermore, PCTC acts on tumor cells, together with TAN to attract T cell by increase CXCL9/CXCL10. Anti-tumor N1 and subsequent T cell gathering both contribute to tumor cell killing. As a conclusion, neutrophil phenotype can be modulated, and cooperated with T cells to serve as a new glioma treatment strategy.
EXTH-73. IN VIVO EFFECTS OF EPCAM-DIRECTED CAR T CELLS IN COMBINATION WITH PD-1 CHECKPOINT BLOCKADE IN LUNG CANCER BRAIN METASTASIS
Authors: Blobner Jens , Dengler Laura , Eberle Constantin , Herold Julika J , Xu Tao , Teske Nico , Karschnia Philipp , Ishikawa-Ankerhold Hellen , Subklewe Marion , Thon Niklas , Tonn Joerg-Christian , Buchholz Veit , von Baumgarten Louisa
Published: November 2023

BACKGROUND

Metastatic lung cancer is incurable once it spreads to the brain. Chimeric antigen receptor (CAR) T cells show promise in hematologic malignancies but face challenges in solid tumors, particularly in brain tumors, due to a highly immunosuppressive tumor microenvironment (TME), tumor antigen (TA) heterogeneity and impeded infiltration and persistence at the tumor site. To test the efficacy of CAR T cells and to find strategies for potentially enhancing its efficacy, CAR T cells were applied with and without checkpoint-blockade to treat lung cancer brain metastasis.

METHODS

We used an immunocompetent syngeneic orthotopic cerebral metastasis model combined with a chronic cranial window and repetitive intracerebral two-photon laser scanning microscopy (TPLSM). This allowed us to observe fluorescent tumor cells and CAR T cells in vivo at a single cell level over time. We injected red fluorescent EpCAM-transduced Lewis Lung carcinoma cells (EpCAM-LL/2tdT) into the brain tissue, followed by injection of EpCAM-directed or mock CAR T cells. Animals received anti-PD-1 and the respective isotype control via intraperitoneal injections.

RESULTS

EpCAM-directed CAR T cells were generated and showed substantial anti-tumor effects in vitro. Local injection into EpCAM-LL/2 tumor-bearing mice led to intratumoral accumulation of CAR T cells, resulting in reduced tumor growth compared to undirected CAR T cells translating into long-term survival in a fraction of animals. However, intratumoral CAR T cell numbers decrease over time pointing towards insufficient persistence. Interestingly, anti-PD-1 treatment did not enhance intratumoral CAR T accumulation, persistence and anti-tumor efficacy.

CONCLUSION

Our findings demonstrate the great potential of cell-based treatment approaches for the treatment of lung cancer brain metastases and underlines the necessity of further investigations to enhance infiltration and persistence in solid tumors.
EXTH-80. A SYSTEMIC COMPARISON OF CAR T CELLS, CAR NK CELLS AND CAR MACROPHAGES FOR GLIOMA TREATMENT
Authors: Look Thomas , Fazio Serena , Binder Niklas , Sentman Charles L , Roth Patrick , Arrieta Cesar Nombela , Sankowski Roman , Pascolo Steve , Weller Michael , Weiss Tobias
Published: November 2023

Adoptive transfer of engineered immune cells expressing chimeric antigen receptors (CAR) is an emerging cancer immunotherapy that is also being investigated for glioblastoma. Many separate studies focus on either CAR T or CAR NK cells, and CAR macrophages are in early stages of development. However, a systemic cross-comparison of engineered immune effector cells against solid tumors, including glioblastoma, is lacking. Here, we generated second-generation NKG2D CAR mouse and human T cells, NK cells and macrophages and characterized them in vitro in co-culture assays with glioma cells and in vivo in orthotopic glioma mouse models. In vitro, mouse and human CAR T cells and CAR NK cells exhibited the highest tumor-killing activity. In contrast, in vivo, only CAR T cells exhibited anti-tumor activity in two immunocompetent orthotopic glioma-bearing mouse models, whereas CAR NK cells and CAR macrophages failed to prolong survival. More in-depth characterizations using flow cytometry, in vivo imaging and 3D microscopy, revealed that CAR T cells had the best tumor migration properties upon i.v. administration with distinct spatial distribution within the tumor compared to CAR NK cells and CAR macrophages. To profile the effects on bystander immune cells within the tumor microenvironment, we employed flow cytometry and single-cell RNA sequencing. This revealed effector cell-specific effects on the tumor microenvironment and provided insights into why the effective in vitro activity did not translate to in vivo. To unleash the anti-tumor potential of CAR immune effector cells, we engineered them to co-express the pro-inflammatory cytokines IL-12/IFNα2. This improved the in vivo anti-tumor activity of all effector cells and led to the highest fraction of long-term surviving mice with CAR NK cells. This study offers the first cross-comparison of different CAR immune effector cells against gliomas, providing valuable insights for the design of future adoptive cell therapies targeting malignant brain tumors.
EXTH-84. INTRATUMORAL IL-12 DELIVERY VIA MESENCHYMAL STEM CELLS COMBINED WITH PD-1 BLOCKADE LEADS TO LONG-TERM ANTITUMOR IMMUNITY IN A MOUSE GLIOBLASTOMA MODEL
Authors: Ahn Stephen
Published: November 2023

Although PD-1 blockade is effective for treating several types of cancer, the efficacy of this agent in glioblastoma is largely limited. To overcome non-responders and the immunosuppressive tumor microenvironment, combinational immunotherapeutic strategies with anti-PD-1 need to be considered. Here, we developed IL-12-secreting mesenchymal stem cells (MSC_IL-12) with glioblastoma tropism and evaluated the therapeutic effects of anti-PD-1, MSC_IL-12, and their combination against glioblastoma using an immunocompetent mouse orthotopic model. Anti-PD-1 and MSC_IL-12 showed complete tumor remission in 25.0% (4/16) and 23.1% (3/13) of glioblastoma-implanted mice, respectively, and their combination yielded synergistic antitumor efficacy indicated by 50.0% (6/12) of complete tumor remission. Analyses of tumor-infiltrating lymphocytes using immunofluorescent imaging revealed that anti-PD-1 increased CD8+ T cells, while MSC_IL-12 led to infiltration of CD4+ T cells and NK cells. Both therapies reduced frequencies of Tregs. All these aspects observed in each monotherapy group were superimposed in the combination group. Notably, no tumor growth was observed upon rechallenge in cured mice, indicating long-term immunity against glioblastoma provoked by the therapies. Single-cell RNA-seq of mouse brains confirmed these results and revealed that the combined treatment led to immune-favorable tumor microenvironment–CD4+, CD8+ T cells, effector memory T cells, and activated microglia were increased, whereas exhausted T cells, Tregs, and M2 polarized microglia were reduced. Taken together, anti-PD-1 and MSC_IL-12 monotherapies show long-term therapeutic responses, and their combination further enhances antitumor efficacy against glioblastoma via inducing immune-favorable tumor microenvironment.
EXTH-85. EPHA3 CART: DUAL TARGETING OF GLIOBLASTOMA AND TUMOR MICROENVIRONMENT
Authors: Ruff Michael , Ogbodo Ekene , Siegler Elizabeth , Sakemura Leo , Sarkaria Jann , Kenderian Saad
Published: November 2023

BACKGROUND

In GBM, effective chimeric antigen receptor T-cell (CART) therapy remains a challenge; immunosuppressive components within the tumor microenvironment (TME) inhibit CART cells. EphA3 is a receptor tyrosine kinase with low expression in adult tissues but is highly expressed in tumor neovasculature and tumor stromal cells in GBM and other solid tumors.

METHODS

We performed RNA sequencing and Immunohistochemical staining for of EphA3 in a clinically annotated GBM PDX biobank and M01 M1 and M2 polarized macrophages. We then investigated the suppressive capability of M2 macrophage on EphA3-CART in an SNB-19 GBM cell co-culture. We tested the antiantitumor potential of EphA3-CART against luciferase+ SNB-19 GBM cells in vivo with flank and orthotopically engrafted NOD-SCID-ɣ-/- (NSG) mice. Engraftment was confirmed by bioluminescent imaging (BLI) and vernier caliber (flank) for 7-14 days post-injection. Mice were randomized to be treated with EphA3-CART or untransduced T-cells (UTD). Subsequently tumor size and mouse survival was monitored to determine the antitumor effect.

RESULTS

EphA3 was highly expressed on GBM PDX models as well as M2 macrophages. Compared to M0 and M1 macrophages, M2 macrophages significantly suppressed EphA3-CART However, despite the suppressive activity of the M2 macrophage, EphA3-CART exhibited significant antitumor activity . In both flank and orthotopically implanted mouse models, there was an observed reduction in tumor volume with EphA3-CART treated model compared to the UTD counterpart. EphA3-CART treatment resulted in significantly improved survival of the treated models compared to UTD models (hazard ratio = 0.053 **p = 0.005).

CONCLUSION

We demonstrate that EphA3 is expressed on GBM cells as well as on M2 macrophages. EphA3 CART is able to overcome and ameliorate the effect of a major component of the tumor microenvironment (TME), M2 macrophages. EphA3 CART appears effective in flank and orthotopic mouse models of GBM.
QLTI-09. INTEGRATION OF NEURO-ONCOLOGY CLINICAL PATHWAYS IN PROVIDENCE SOUTHERN CALIFORNIA CLINICAL RESEARCH NETWORK: UPDATED INFO AFTER 17 MONTHS OF UTILIZATION
Authors: Bott Thomas , Parseghian Nanor , Babcock Trisha , Sharma Akanksha , Wagle Naveed , Carrillo Jose , Juarez Tiffany , Kesari Santosh
Published: November 2023

INTRODUCTION

ClinicalPath is an evidence-based oncology decision support and analytics tool for cancer care. ClinicalPath’s treatment recommendations are prioritized based on efficacy, toxicity, and cost, by a nationwide committee of oncologists. The pathways are updated quarterly with the most recent evidenced-based treatment options that healthcare providers choose for adoption to help standardize therapy, improve quality, and decrease cost. The pathway system also allows for local clinical trial mapping to promote clinical trial awareness and help increase enrollment. ClinicalPath provides clinical pathways delivering personalized, evidence-based oncology guidance at the point of care. ClinicalPath’s network in North America serves more than 2,000 cancer physicians, within 54 practices in 31 states (15 academic medical centers, 29 hospital systems, and 9 community practices). Population: Our population is derived from multiple hospitals in Southern California within the Providence Health System. Methodology: Medical oncologists and Advanced Practice Providers received training on ClinicalPath before go-live. ClinicalPath was integrated into the Epic EHR in multiple Southern CA hospitals in a single month in Jan 2022.

RESULTS

On reviewing the utilization data within our Southern California region from Jan 2022-May 2023, 2681 treatment decisions were made across all cancers, with 86.7% of cancer patients treated on pathway. Of these decisions, 114 were made within the neuro-oncology specialty, and 70.2% of those cancer patients were treated on pathway.

CONCLUSION

We successfully integrated and initiated ClinicalPath in a multiple hospital-affiliated community oncology clinical trial network which included a strong neuro-oncology presence. We are actively working across our Southern California Region to map locally available clinical trials to promote awareness and increase enrollment. Provider utilization and patient on-pathway rates are actively monitored and will be updated.
QOL-16. GLIOBLASTOMAS LOCATED IN THE RIGHT INFERIOR PARIETAL LOBE CAUSE A POOR POSTOPERATIVE PERFORMANCE LEVEL
Authors: Nakada Mitsutoshi , Nakajima Riho , Kinoshita Masashi
Published: November 2023

OBJECTIVE

Managing quality of life has become more important for patients with glioblastoma (GBM). Maintaining independence levels should be given attention while treating GBM. Postoperatively, non-dominant hemispheric GBMs often decrease the Karnofsky Performance Status (KPS) score. This study aimed to investigate the factors that lead to poor KPS scores after tumor resection in non-dominant hemispheric GBM.

METHODS

Forty-one patients newly diagnosed GBM in the right cerebral hemisphere who underwent resection were included. Brain functions were assessed preoperatively and postoperatively. First, the KPS scores before and after surgery were compared. Second, univariate and multiple regression analyses and voxel-based lesion-symptom mapping (VLSM) were performed to analyze the functions and brain regions related to KPS, respectively. Third, factors associated with prognosis were analyzed using the log-rank test.

RESULTS

Compared with the preoperative status, KPS significantly decreased after the surgery (81.0% vs. 73.6%, p = 0.020). Brain functions affecting KPS include general cognitive function, processing speed, attention, memory, visuospatial cognition, emotion recognition, and executive function. Among these, multiple regression analysis revealed visuospatial cognition and emotion recognition to be significantly influenced KPS in the chronic postoperative phase (p = 0.030 and 0.048, respectively). VLSM demonstrated that resection of the inferior parietal lobe caused a significant decline in KPS. Visuospatial cognition and emotion recognition were impaired with a higher probability (p = 0.035 and 0.048, respectively) in patients with tumors located in the inferior parietal lobe. In addition, lesions in the inferior parietal lobe were associated with shorter overall survival (p = 0.046).

CONCLUSIONS

GBMs in the right inferior parietal lobe are more likely to result in poor postoperative KPS due to impairment of visuospatial cognition and emotion recognition, which relate to a poor prognosis.