bluuebunny/crossref_metadata_2025 huggingface dataset:
EXTH-43. TARGETING THE DNA DAMAGE RESPONSE THROUGH COMBINATION MDM2 AND AKT INHIBITOR THERAPY IMPROVES TEMOZOLOMIDE EFFECTIVENESS IN CHEMO-RESISTANT GLIOBLASTOMA
Authors: Koenig Jenna , Bailey Barbara , Alfonso Anthony , Saadatzadeh M Reza , Bijangi-Vishehsaraei Khadijeh , Pandya Pankita , Damayanti Nur , Dobrota Erika , Young Courtney , Shannon Harlan , Pollok Karen
Published: November 2023

Temozolomide remains the lone pharmacotherapeutic option for glioblastoma (GBM), yet the development of resistance to temozolomide has been a major challenge contributing to the persistent median < 2-year survival for patients after diagnosis. Tumor heterogeneity and induction of treatment response networks, such as the DNA damage response (DDR), are major contributors to temozolomide resistance in GBM. Targeting DDR treatment response networks, such as the MDM2/p53/p73 and PI3K/AKT/mTOR networks, with small-molecule inhibitors (SMIs) presents an opportunity to disrupt resistance mechanisms and enhance temozolomide efficacy. We utilized a triple drug combination of clinically relevant concentrations of the blood-brain-barrier penetrant SMIs of AKT (ipatasertib; GDC-0068) and MDM2 (idasanutlin; RG7388) with temozolomide to evaluate this targeted strategy using the recurrent, temozolomide-resistant, p53wt GBM10 xenoline. Proliferation studies demonstrated dose-related additive to synergistic inhibition of proliferation at clinically relevant concentrations of ipatasertib and idasanutlin. Further, IncuCyte live-cell imaging demonstrated dose-and time-related growth inhibition of these GBM cells and apoptosis marked by increased cleaved caspase 3 expression following the temozolomide+idasanutlin+ipatasertib triple combination treatment. Cells treated with temozolomide+idasanutlin+ipatasertib also displayed senescence phenotypes, with increased cell cycle arrest and elevated expression of SPiDER β-Gal expression and cell-cycle inhibitors such as p53 and p21. Experiments are in progress to determine the extent to which the effects of temozolomide+idasanutlin+ipatasertib combination therapy are dependent on p53 using siRNA knockdown of p53. In the present study, targeting the temzolomide-induced DNA damage response with idasanutlin+ipatasertib increased the effectiveness of temozolomide. These results indicate that this triple combination may be a promising approach to improving patient outcomes in temozolomide-resistant GBM.
EXTH-47. TUMOUR-TARGETED PAN-RAS INHIBITION AS A NOVEL THERAPY FOR DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG)
Authors: Sbergio Stefanie-Grace , Liang Peter , Beilhartz Greg , Patel Palak , Vadivel Arun Anguraj , Melnyk Roman , Hawkins Cynthia
Published: November 2023

INTRODUCTION

Diffuse Intrinsic Pontine Glioma (DIPG) has a median survival of 9 months following diagnosis in children 7-9 years old. Current therapeutic options are limited to radiation and thus tumour specific vulnerabilities are the subject of ongoing research. One such vulnerability is RAS signalling due to its upregulation in DIPG. RAS regulates cellular proliferation and survival making it an attractive target. Based on diphtheria toxin (DT), we have developed a molecular chimera which selectively binds a DIPG cell surface receptor and releases a RAS cleaving peptidase (RRSP). We hypothesize that using a DIPG targeted RRSP conjugated chimera will reduce tumour viability and improve survival in DIPG models.

METHODS

Viability of SU-DIPG XIII, XVII, XXV, 36 and 50 cell lines treated with RRSP-DTB, and a DIPG targeted RRSP conjugated chimera was measured using CellTiterGlo Luminescent Assay. Proteomic analysis and single-cell RNA sequencing was used to identify a cell surface receptor upregulated on tumour cell populations from patient samples. SU-DIPG 36 orthotopic xenograft mice were treated with our DIPG targeted RRSP conjugated chimera or vehicle for one week delivered into the pons via osmotic pump and monitored using bioluminescent imaging.

RESULTS

RRSP-DTB successfully reduces DIPG cell viability in vitro with an EC50 between 0-3 picomolar, demonstrating successful toxicity mediated by RRSP. This is supported by ablation of RAS verified on Western Blot. ANTXR1 receptor was identified as upregulated in tumour cell populations, and a TEM8 conjugated RRSP chimera was developed. RRSP-TEM8 has an EC50 of 5-70 picomolar in vitro and significantly improves survival in vivo with a median survival of 68 days (n = 14) compared to the vehicle control (n = 14) 57 days (p = 0.02). Our results present a successful novel therapeutic as our RRSP chimera, RRSP-TEM8, effectively targets DIPG cells and reduces cell viability to improve survival.
EXTH-54. GB13 IS A POTENT TREATMENT FOR IL13RA2-EXPRESSING GBM AND DMG AND IMPROVES STANDARD-OF-CARE THERAPY
Authors: Rechberger Julian , Zhang Liang , Laukhuff Harrison , Woodruff Maija , Sarkaria Jann , Daniels David , Schrecengost Randy
Published: November 2023

GB13 is a novel biologic therapy in the final stages of preclinical development for the treatment of glioblastoma (GBM) and H3 K27-altered diffuse midline glioma (DMG) that has received Orphan Drug Designation by the Food and Drug Administration for treatment of malignant gliomas. GB13 targets a specific tumor-restricted receptor of interleukin 13 called interleukin 13 receptor alpha 2 (IL13Rα2). IL13Rα2 is highly expressed in malignant gliomas and, importantly, is not expressed on non-cancerous cells of the brain. GB13 consists of an engineered proprietary mutant of IL13, which binds exclusively to IL13Rα2, and is fused to a highly cytotoxic exotoxin molecule. In vitro data demonstrate that GB13 potently kills IL13Rα2+ cancer cells while sparing non-cancerous cells. These characteristics make GB13 an attractive agent for safe and efficacious targeting of tumor cells expressing IL13Rα2 in upcoming clinical trials. In the current studies, we employed patient-derived GBM and DMG cell and animal models to provide key conclusions that support GB13 as an effective treatment option for gliomas in the clinic. First, we demonstrated that single acute infusions of GB13 by enhanced delivery (CED) is effective at decreasing orthotopic tumor volumes and increasing animal survival and that a long-term infusion can more significantly extend animal survival. Second, we determined that IL13Rα2 is requisite for GB13 activity as tumors that do not express the receptor are insensitive to the cytotoxic effects of GB13, demonstrating a precise and clear biomarker for clinical trial patient selection. Finally, we determined that GB13 works in concert with clinical standard-of-care radiation therapy to increase cell death, compared to radiation alone. Based on this work, we and our clinical collaborators are confident that the current work confirms GB13 has many important characteristics as an exciting therapy, which continues development towards a Phase I clinical trial for both GBM and pediatric DMG.
EXTH-55. ALL-IN-ONE GENETIC CONSTRUCT TO KNOCKDOWN MIR-21 REDUCES GLIOMA PROLIFERATION IN VITRO
Authors: Nieland Lisa , Vrijmoet Anne , de Reus Alexandra , Kleinsteiver Benjamin , Broekman Marike , Breakefield Xandra , Abels Erik
Published: November 2023

Glioma, the most aggressive tumor of the CNS has poor patient outcome with limited effective treatments. CRISPR-CAS technology recently opened a new avenue for gene therapy and has been previously used to target non-coding RNAs, including microRNA-21, an oncogene associated with glioma progression. Here we show that an all-in-one construct containing both Staphylococcus Aureus Cas9 (SaCas9) guided by a single-guide RNA (sgRNA) specifically targeting miR-21 resulted in a deletion causing a downregulation of miR-21 expression levels and reduced proliferation in glioma cell lines. Here, we aim to design a single adeno-associated vector (rAAV) vector platform that express both saCas9 and sgRNA to target miR-21 in a glioma syngeneic mouse model. With the future goal to engineer a single AAV that can achieve therapeutic genome editing outcomes.
EXTH-56. CSF PENETRATION COMPARISON OF TWO ORAL FORMULATIONS OF APL-101 IN A PRE-CLINICAL NON-HUMAN PRIMATE MODEL
Authors: Cabanas Natalia Corvalan , McCully Cynthia Lester , Peer Cody , Gross Andrea , Glod John , Figg William , Shankarappa Priya , Warren Katherine , Widemann Brigitte
Published: November 2023

Vebreltinib (APL-101) is a potent c-Met inhibitor which has shown efficacy in murine pre-clinical models and is under clinical trial evaluation for several cancer types, including adult high-grade glioma. The capsule formulation (APL-101-Cap) was reformulated as a pill (APL-101-Pill) with the expectation of increasing bioavailability. We determined and compared the plasma pharmacokinetics (PK) and cerebrospinal fluid (CSF) penetration of APL-101-Cap and APL-101-Pill in a non-human primate (NHP) model. METHODS: Seven animals, previously developed as serial CSF access models, were utilized across all studies. One NHP was studied with both formulations. Both formulations were administered orally as a single drug/single dose in serial studies, followed by serial plasma and CSF sample collections from 0-96 hours. Dosages: APL-101-Cap 3.25 mg/kg (n = 3) or 6.5 mg/kg (n = 4) and APL-101-Pill 5 mg/kg (n = 4). The resulting plasma concentrations from each formulation were quantified by LC-MS/MS. PK parameters were calculated via noncompartmental methods, and results were analyzed to assess CNS penetration (AUCCSF:AUCPlasma) and compare formulations. RESULTS: Mean (range) for plasma and CSF PK exposure [AUCLAST (hr*ng/mL)] reported. APL-101-Cap plasma exposure, regardless of dose, was more variable than APL-101-Pill. APL-101-Pill had lower exposure in both plasma (AUC 1893.0 (841-2865)] and CSF [AUC 27.7 (5.0-65.0)] than APL-101-Cap regardless of dose [(3.25 mg/kg): plasma AUC 9621.0 (1331-23132) and CSF AUC 688.0 (24-1352); 6.5 mg/kg: plasma AUC 6208.0 (1424-19800) and CSF AUC 606.0 (34-1179)]. CNS penetrance was higher with APL-101-Cap (3.2% [0.5-5.8%] at 3.25mg/kg; 4.2% (2.4-6%) at 6.5 mg/kg), but also more variable when compared to APL-101-Pill (1.2% [0.6-2.3%]). For APL-101-Cap, one animal at 3.25 mg/kg and two animals at 6.25 mg/kg had undetectable CSF concentrations. CONCLUSION: In this NHP model, single-dose oral administration of APL-101-Pill resulted in lower, but less variable plasma and CSF exposure compared to APL-101-Cap. APL-101-Cap CSF exposure was unaffected by dose escalation.
EXTH-58. USING MEK INHIBITOR TO ENHANCEMENT 5-ALA MEDIATED SONODYNAMIC THERAPEUTIC EFFECT: A PRECLINICAL STUDY
Authors: Huang Chiungyin , Wei Kuo-Chen
Published: November 2023

The potential of sonodynamic therapy (SDT) using sono-sensitive molecules such as 5-aminolevulinic acid to treat brain tumor is highly noted for glioma treatment. However, the accumulation of 5-ALA in glioma cells is limited by the heterogeneous cell types of GBM. MEK inhibitor is known to be effective on enhance the accumulation of 5-ALA in glioma cells, therefore, we aim to study the effect of MEK inhibition on sonodynamic therapy. MEK inhibitor trametinib were systemically administered to animals bearing subcutaneous tumor xenograft 24 hours prior to treatment. Subsequently, the effects of 5-ALA-mediated sonodynamic therapy were determined by measuring the volume of tumor xenografts and the bodyweights animals. Glioma cells and tissue samples were collected, and the effect on MEK signaling pathway were evaluated by immunohistochemistry/PCR/Western blotting. For tumor growth data, comparison across multiple groups was performed with repeated measures two-way analysis of variance (ANOVA). Animals were divided into 5 groups: control, focused ultrasound (0.35 MPa.duty10%.10min), trametinib (1mg/kg), 5ALA (180mg/Kg) +FUS, trametinib(1mg/Kg)+5ALA(180mg/Kg) +FUS (n = 5 for each group). Following treatment, tumor growth was monitored by digital caliper twice a week. As compared with control group, the tumor size of trametinib+5ALA+FUS group is significantly less than control group (p = 0.0085, 0.0001 and 0.0255 at day 4, 7 and 11). No significant difference was observed in other groups verse control. The daily mice body weight records revealed no significant change, demonstrated no major toxicity was induced by the MEK inhibitor/5-ALA/sonodynamic combination treatment. Our study demonstrates that suppression of MEK pathway by MEK inhibitor trametinib significantly increase the accumulation of PpIX. In tumor animal models, mice pretreated with MEK inhibitor presented favorable response to 5-ALA mediated sonodynamic therapy. Our finding may suggest a new strategy to enhance the effect of sonodynamic therapy.
EXTH-59. IDENTIFICATION OF GROWTH HORMONE RECEPTOR AS A RELEVANT TARGET FOR PRECISION MEDICINE IN LOW-EGFR EXPRESSING GLIOBLASTOMA
Authors: Verreault Maite , Vilchis Irma Segoviano , Rosenberg Shai , Lemaire Nolwenn , Schmitt Charlotte , Guehennec Jeremy , Royer-Perron Louis , Thomas Jean-Leon , Lam Tukiet T , Dingli Florent , Loew Damarys , Ducray Francois , Paris Sophie , Carpentier Catherine , Marie Yannick , Laigle-Donadey Florence , Rousseau Audrey , Pigat Natascha , Boutillon Florence , Bielle Franck , Mokhtari Karima , Frank Stuart J , de Reynies Aurelien , Hoang-Xuan Khe , Sanson Marc , Goffin Vincent , Idbaih Ahmed
Published: November 2023

New therapeutic approaches are needed to improve the prognosis of Glioblastoma (GBM) patients. With the objective of identifying alternative oncogenic mechanisms to abnormally activated EGFR signaling, one of the most common oncogenic mechanisms in GBM, we performed a comparative analysis of gene expression profiles in a series of 54 human GBM samples. We identified that Growth Hormone Receptor (GHR) signaling defines a distinct molecular subset of GBMs devoid of EGFR overexpression. GHR overexpression was detected in one third of patients and was associated with low levels of SOCS2 expression due to SOCS2 promoter hypermethylation. In GBM patient-derived cell lines, GHR signaling modulates the expression of proteins involved in cellular movement, promotes cell migration, invasion and proliferation in vitro, and promotes tumorigenesis, tumor growth and tumor invasion in vivo. GHR genetic and pharmacological inhibition reduced cell proliferation and migration in vitro. GHR signaling pathway thus emerges as an oncogenic signaling pathway in low EGFR-expressing GBMs and as a promising therapeutic target. This study pioneers a new field of investigation to improve the prognosis of GBM patients.
EXTH-60. OVERCOMING THE LEPTOMENINGEAL SEEDING OF MEDULLOBLASTOMA BY TARGETING HSP70
Authors: Choi Seung Ah , Ha Saehim , Kim Seung-Ki , Hwang Do Won , Heung Sekhoeun , Phi Ji Hoon
Published: November 2023

Purpose The development of leptomeningeal seeding (LMS) through the cerebrospinal fluid (CSF) is a common in medulloblastoma (MB) and a major cause of treatment failure. The mechanism of MB LMS remains unclear and effective treatment options are urgently required. This study aimed to discover molecules that can specifically target seeding cells by making a cellular model of MB LMS and analyzing their specific genetic and functional characteristics. METHODS: By repeated transplantation, separation, culture, seeding and non-seeding MB cells were isolated. The cellular characteristics of each group were compared and differentially expressed genes (DEGs) were determined through gene expression profiling. The therapeutic effect of the selected inhibitor on the selected protein was tested in vitro and in vivo. RESULTS: We separated seeding and non-seeding cells triply, with the DEGs analysis indicating that heat shock protein 70 (HSP70) was in the highest rank in the expression profile of the seeding cells, and pathway enrichment analysis revealed that the metabolism was the main pathway enriched in seeding cells. The proliferation of seeding cells (S3) was slower than that of non-seeding cells (N3), but there was no significant difference in viability. Notably, the wound-healing of S3 was delayed, but the adhesion ability on collagen was higher than N3. We tested the effect of HSP70 suppression. Among the six HSP70 inhibitors, VER155008 was efficiently sensitive to S3, and suppression of MRP proteins with HSP70 was observed. Importantly, the treatment of VER155008 reduced LMS along the spinal cord in vivo. In addition, a synergistic effect was observed in the combination treatment of VER155008 with 4-hydroperoxycyclophosphamide. CONCLUSION: Our study suggests that targeting HSP70 can be a promising treatment option to suppress the LMS of MB.
EXTH-61. A MULTI-TARGETED APPROACH TO EVALUATE THERAPEUTIC SELECTION AND EFFICACY IN PRECLINICAL GBM MODELS
Authors: Eastwood Emily , Carapia Bianca , Rodriguez Javier , Buck Kristen , Corcoran Bridget , Chien Yuan-Hung , Andrews Warren , Do Long , Nakashima Jonathan , Sperry Jantzen
Published: November 2023

Glioblastoma (GBM) is a devastating primary brain cancer with approximately 10,000 new US diagnoses annually. The current standard of care for GBM includes surgical resection followed by radiation therapy (RT) and temozolomide (TMZ), however there is near universal recurrence and development of resistance after treatment. Relapse in disease is tightly linked with dynamic changes in gene expression during tumor evolution, highlighting the need for stronger preclinical GBM models. Here we report developing a pair of patient-derived xenograft (PDX) models from surgical resections obtained from initial GBM incidence in a patient (CRT00433) and subsequent recurrence following treatment (CRT00435) in order to study disease progression and novel treatment strategies. Recent studies have suggested the utilization of combination therapy approaches for GBM patients to address TMZ resistance. To this end, Certis has developed a personalized, AI-based approach to predict and test combination therapies for CRT00433/435. Accuracy of the predicted sensitivities to treatment was then evaluated in vivo using both subcutaneously and orthotopically engrafted mouse modeling. Luciferase-tagged CRT00433 and CRT00435 spheroid cell lines were transduced with firefly luciferase and implanted intracranially by stereotactic surgery for orthotopic monitoring. Optical bioluminescence imaging (BLI) and MRI were used to assess therapeutic response of AI-predicted combination therapies and standard of care (RT and/or TMZ). Both in-life imaging and terminal histologic analysis of the tumors confirmed high fidelity to several of the therapies tested. In all, these results demonstrate a novel, combinatorial platform with which to assess therapeutic efficacy in GBM and exploit the overall ability of this deadly disease to adapt to an ever-changing molecular and genetic landscape.
EXTH-71. AUTOMATED AND MULTIPLEXED COMBINATORIAL DRUG SCREENING OF FDA-APPROVED DRUGS IDENTIFIES POTENTIAL SYNERGISTIC DRUG PARTNERS FOR THE TREATMENT OF AGGRESSIVE MENINGIOMAS
Authors: Jungwirth Gerhard , Braun Viktor , Warta Rolf , Abdollahi Amir , Unterberg Andreas , Herold-Mende Christel
Published: November 2023

The goal of combinatorial therapy is to improve the effectiveness of treatment by targeting multiple aspects of cancer cells or by overcoming resistance to single drugs. In search of effective synergistic drug combinations for the treatment of aggressive meningiomas, we performed an automated and multiplexed combinatorial drug screening of 166 FDA-approved anticancer drugs in three grade 3 meningioma cell lines. Three anaplastic meningioma cell lines (NCH93, IOMM-Lee, and KT21-MG1) were stably transduced with blue, green, and red fluorescence proteins. The cell lines were multiplexed into 384-well plates and treated in 5x5 dose-response matrices (1 to 1000 nmol/L) for 48 hours by the automated liquid handler Hamilton MicroLAB STAR®. The drug library consisted of 166 FDA-approved anticancer drugs. To demultiplex cell viability from a single well, fluorescence as a surrogate marker for viability was measured before adding an ATP-based end-point viability assay, which served as an independent combined result of all cell lines (combined group). Synergism was calculated by the ZIP Synergy model and was defined as a ZIP score over 10. This drug screening effort generated 13695 unique drug-drug combinations per cell line. Most synergistic combinations were observed in the combined group (n = 188, 1.37%), followed by IOMM-Lee (n = 157, 1.14%), and KT21-MG1 (n = 122, 0.88%). The lowest number of synergistic combinations was observed in NCH93 (n = 75, 0.54%). Interestingly, 86 combinations were uniquely found in IOMM-Lee, 54 in KT21-MG1, and 20 in NCH93, indicating specific tumor vulnerabilities. 19 drug combinations were observed in all cell lines. Of those, the drugs Temsirolimus, Gemcitabine, and Romidepsin were highly enriched. For example, mTORi Temsirolimus concordantly showed strong synergism with the androgen receptor antagonist Darolutamide in all cell lines (ZIP score: 27.75, P< .0001). This comprehensive combinatorial drug screening identified synergistic drug-drug partners for the treatment of aggressive meningiomas. Validation studies in patient-derived meningioma organoids are ongoing.
EXTH-75. A MACROPHAGE-BASED DRUG DELIVERY PLATFORM FOR GLIOMA TREATMENT
Authors: Sun Miaomiao , Bialasek Maciej , Rygiel Tomasz , Weller Michael , Krol Magdalena , Weiss Tobias
Published: November 2023

There is an urgent need for more effective treatment strategies against gliomas. Even though various drugs have potent anti-tumor activity in vitro, their application in vivo is limited by ineffective delivery and systemic toxicity. Therefore, novel strategies are needed to deliver these drugs effectively and safely to the tumor site. Here, we developed an adoptive transfer strategy against malignant brain tumors utilizing monocyte-derived macrophages that are loaded with ferritin-protein cages containing drugs or other proteins and transfer these nanocarriers effectively to cancer cells for intracellular release and cancer cell killing. Using flow cytometry and microscopy, we observed a high transfer efficiency of ferritin-cages from loaded macrophages into human and mouse glioma cells in vitro in co-culture assays. We also confirmed the transfer of ferritin-cages from macrophages to glioma cells in vivo upon intravenous or intratumoral treatment of GL-261 or CT-2A glioma-bearing mice using in vivo imaging and ex vivo flow cytometry and microscopy. To study the anti-glioma activity with therapeutically active payloads, we loaded murine/human macrophages with ferritin cages carrying cytotoxic auristatin. Co-culture of these loaded macrophages with murine or human glioma cells in vitro revealed a time- and concentration-dependent cytotoxicity to glioma cells. In vivo, intravenous or intratumoral administration of ferritin-drug protein cages was tolerated without toxicities and conferred a survival benefit in two orthotopic murine glioma models (GL-261 and CT-2A) leading to a large fraction of long-term surviving mice. Interactome studies of ferritin-cage-binding proteins revealed phagocytic and cytoskeleton re-arrangement pathways to be involved in uptake and transfer of ferritin-cages from macrophages to glioma cells. This ‘Trojan Horse’ approach based on macrophages-ferritin-protein cages constitutes a promising platform to deliver cytotoxic drugs effectively and safely to gliomas and provides a rationale for clinical translation.
EXTH-77. EXTENDED HALF-LIFE IL-2 SYNERGIZES WITH Α-PD-1 FOR TREATMENT OF PRECLINICAL MURINE GLIOBLASTOMA MODELS
Authors: Owens Carley , Tritz Zachariah , Ayasoufi Katayoun , Wolf Delaney , Parney Ian , Hanson Michael , Fang Jin , Johnson Aaron , Campian Jian , Fain Cori , Himes Benjamin , Malo Courtney , Goddery Emma , Yokanovich Lila , Wang Chensu , Vile Richard , Moynihan Kelly , Irvine Darrell J , Mercano Rosa , Wittrup Dane , Maynes Mark
Published: November 2023

α-PD-1 checkpoint blockade is a promising immunotherapeutic approach for many solid tumors; however, this strategy is minimally effective for GBM patients as a monotherapy. One potential reason why α-PD-1 checkpoint blockade is ineffective is the tumor microenvironment and systemic derangements of the immune system which are prevalent in GBM patients. We have successfully modeled peripheral immune derangements in experimental murine GBM models. These include low peripheral blood CD4 T cell counts, reduced MHC class II expression on monocytes, and atrophy of primary immune organs in animals harboring gliomas. We therefore hypothesized that extended half-life IL-2, a potent cytokine which promotes the proliferation, differentiation, and killing activity of T cells, could overcome immune derangements and could potentially synergize with α-PD-1 checkpoint blockade therapy. In cohorts of C57Bl/6 mice, we supplemented α-PD-1 checkpoint blockade with multiple bio-engineered extended half-life IL-2 molecules to treat GL261 and CT2A orthotopic glioma models which are normally resistant to monotherapy. We observe a statistically significant increase in survival in GL261-bearing animals receiving the combination of extended half-life IL-2 reagents and αPD-1 therapy relative to control-treated mice. Some animals receiving this combination therapy had a reduction in tumor burden to levels below detection. These long-term survivors underwent a rechallenge experiment with a second inoculation of GL261-Luc and effectively cleared tumor without further therapeutic intervention. This intervention causes a significant shift in the immune profile, including the formation of mature T cell responses, as well as restoring the diminished peripheral immune cell counts in GL261-bearing animals. Finally, combining extended half-life IL-2 with α-PD-1 checkpoint blockade is effective independently of the CD8 T cell response. Together, these data suggest that combination immunotherapies employing extended half-life IL-2 fusion proteins are translational to the clinic and do not require the identification of tumor specific antigens for efficacy
EXTH-78. CRISPROFF EPIGENOME EDITING AND FUNCTIONAL GENOMICS DEFINE MEDIATORS OF CHEMOTHERAPY RESISTANCE IN GLIOBLASTOMA
Authors: Lin Katie , Goudy Laine , Pak Joanna , Foster Kyla , Payne Emily , Ozawa Tomoko , de Groot John , Vasudevan Harish , Raleigh David , Gilbert Luke , Berger Mitchel , Liu John
Published: November 2023

Alkylating chemotherapies exhibit survival benefit for patients with glioblastoma (GBM). CRISPRoff is a programmable epigenetic memory writer that stably and heritably silences genes through DNA methylation. Epigenetic silencing of MGMT via promoter methylation predicts response to chemotherapy and is prognostic for overall survival. Here, we performed epigenome editing using CRISPRoff to stably silence MGMT through induced promoter methylation as a therapeutically tractable approach for potentiating GBM to chemotherapy. We then used genome-wide CRISPR interference (CRISPRi) screens to broadly define novel chemosensitizing targets of GBM cells. Epigenome editing was performed through electroporation of CRISPRoff mRNA and sgRNAs into MGMT hypomethylated GBM cell lines (LN18 and T98G) and primary GBM cells. Whole genome bisulfite sequencing, RT-qPCR, and western blot assessed gene silencing. Cell viability assays measured drug sensitivity. GBM xenografts with CRISPRoff-induced silencing of MGMT were intracranially transplanted in mice and treated with temozolomide. Genome-wide functional genomics screens were performed using CRISPR interference. CRISPRoff against MGMT reduced MGMT mRNA and protein levels by 99.97%, generating up to 150-fold sensitization to temozolomide and 9-fold sensitization to lomustine in GBM cells. Silencing remained stable and heritable in clonally isolated GBM cells at 145 days after transient delivery of CRISPRoff, and gene repression and drug sensitization were equivalent to Cas9-mediated homozygous deletion of MGMT in vitro and in vivo. CRISPRoff of MGMT in intracranial xenografts exhibited significant reduction in tumor growth with temozolomide treatment compared to temozolomide treatment with control CRISPRoff (p = 0.0047). CRISPRi screens validated MGMT and defined 266 and 238 additional modifiers of temozolomide and lomustine response, respectively, including the ATR (BRCA2), DNA repair (REV1), cell cycle (PSMD13), and Fanconi anemia pathways (FANCI, FANCD2). In summary, we integrate targeted epigenome editing with unbiased genome-wide approaches to establish a novel discovery and therapeutic platform against glioblastoma.
QLTI-03. FRACTIONATED PREOPERATIVE VS POSTOPERATIVE STEREOTACTIC RADIOTHERAPY FOR PATIENTS WITH MELANOMA BRAIN METASTASES: A COST UTILITY ANALYSIS
Authors: Keister Alexander , Vignolles-Jeong Joshua , Kreatsoulas Daniel , Damante Mark , Elder J Bradley
Published: November 2023

INTRODUCTION

Stereotactic radiosurgery (SRS) followed by surgical resection is an emerging treatment paradigm for brain metastases. Preoperative SRS may improve outcomes such as rates of radiation necrosis (RN) and leptomeningeal disease (LMD) compared to postoperative SRS. However, the impact of this paradigm shift on metrics such as cost of care and hospital length of stay is unclear. In this study, we sought to categorize these metrics for melanoma metastases, specifically.

METHODS

A retrospective analysis identified patients who underwent surgical resection and fractionated stereotactic radiation therapy (FSRT) for melanoma brain metastases. Demographics, medical history, systemic and local treatment modalities, imaging, and postoperative course were collected. Perioperative cost of care was analyzed beginning two weeks preoperatively and concluded at four-weeks postoperatively. Continuous variables were analyzed via non-parametric two-sided t-tests and ANOVAs. Categorical variables were analyzed via Chi-squared tests.

RESULTS

Forty-two patients underwent 43 craniotomies for melanoma metastases. The mean age at surgery was 59.6 years-old and the male predominance was 65.1%. Total cost of perioperative care was more expensive among those treated with neoadjuvant (n = 11) FSRT compared to those who underwent postoperative (n = 32) FSRT ($262,072 vs $174,646; p = 0.0254). Mean length of stay for craniotomies was similar between groups (p = 0.1674), although trending down among the neoadjuvant FSRT group (4.5 days) among the neoadjuvant FSRT group versus the postoperative FSRT group (7.0 days).

CONCLUSIONS

In this study, neoadjuvant FSRT had an increased cost of care in the perioperative period, and similar lengths of hospital stay for craniotomy. Preoperative FSRT for melanoma metastases may result in shorter LOS, however, comes with an increased cost of care. Further investigation of itemization of healthcare costs to identify areas of improvement for neoadjuvant therapy is warranted.
QLTI-04. LINKING DATA FROM A BRAIN CANCER CLINICAL REGISTRY (BRAIN) WITH THE STATE-BASED REGISTRY OF BIRTHS DEATHS MARRIAGES: IMPROVING THE QUALITY OF CLINICAL REGISTRY SURVIVAL DATA
Authors: Smith Samuel , Drummond Kate , Dowling Anthony , Bennett Iwan , Freilich Ronnie , Phillips Claire , Ahern Elizabeth , Reeves Simone , Campbell Robert , Collins Ian , Johns Julie , Dumas Megan , Gibbs Peter , Gately Lucy
Published: November 2023

BACKGROUND

Real-world data (RWD) collected routinely in clinical care forms the basis of cancer clinical registries. These registries are inclusive and provide valuable research outcomes, however missing data particularly survival compromise the accuracy of RWD. Here we explore the utility of data linkage to state-based registries to enhance the capture of survival outcomes.

METHODS

We reviewed prospectively collected data from consecutive patients with brain tumours in the Brain Tumour Registry Australia Innovation and Translation (BRAIN) database and included those treated in Victoria with no recorded date of death and no follow-up the preceding 6 months. Full name and birthdate were used to match patients in the BRAIN registry to those in the Victorian Births, Deaths and Marriages (BDM) Registry. Survival outcomes were compared, pre- and post-data linkage (DL).

RESULTS

Of the 7735 patients contained in BRAIN, 5435 patients (70.3%) met eligibility criteria and had no recorded date of death. 1611 (30%) of patients were matched with a date of death in BDM. More matches were found in tumours of highest malignant potential such as grade 4 glioma (67.2%), brain metastases (63.9%) and primary cerebral lymphoma (50.5%), compared with good-prognostic tumours such as meningioma (8.7%) and schwannoma (3.2%). Compared to post-DL, survival outcomes were significantly overestimated pre-DL for the entire cohort (30.3m vs 17m, p< .0001). This difference was most pronounced for Grade-3 glioma (93.7m vs. 38.1 p = 0.008) but significant differences were seen across all tumour types.

CONCLUSION

Using an Australian brain-tumour population, this is the first study to demonstrate the importance of improved RWD accuracy through linking state-based registries to comprehensive cancer registries. This missing death data significantly compromises the potential quality of audit and research projects, driving a repeated over-estimate of survival. Routine periodic DL to pertinent registries should be considered to ensure accurate reporting and interpretation of RWD.
QLTI-05. COST TOXICITY OF ORAL CHEMOTHERAPY IN PRIMARY BRAIN TUMOR PATIENTS
Authors: Patel Mallika , Affronti Mary L , Buckley Evan , Herndon James , Lipp Eric , Mackowsky Emma , Johnson Margaret O , Friedman Henry , Ashley David , Kim Jung-Young , Peters Katherine
Published: November 2023

BACKGROUND

Costs associated with cancer treatments in the United States continue to rise as new therapies are approved. Financial toxicity describes both the quantifiable costs associated with cancer as well as the distressful effects related to the costs of treatment.

METHODS

The goal of this study is to better understand the financial burden of oral chemotherapies on patients with primary brain tumors from their perspective. Following one cycle of oral chemotherapy, we contacted patients per IRB-approved protocol to participate in a 20-question survey (COST-FACIT and other questions relevant to insurance and cost). With descriptive statistics, we summarized survey responses overall and within strata defined by on-label or off-label oral medication use.

RESULTS

Sixty surveys were completed (58 total patients; 2 completed surveys for a second treatment). Most surveys (n = 53, 88%) reflected on-label therapy use, with only 7 patients (12%) on off-label therapies. The mean overall financial toxicity score was 23.1 (range: 1 – 44); the lower the financial toxicity score, the greater the financial distress of study participants. When asked if their provider discussed treatment cost before initiation, 21 patients (35%) stated that they did, and 39 patients (65%) said they did not discuss cost or did not recall a discussion. However, in the off-label therapies cohort, all 7 patients stated that their provider discussed cost before prescribing. Majority of surveys (70%) noted patient copays associated with these medications. Nine patients (17%) in the on-label group and three patients (43%) in the off-label group had chemotherapy-associated costs that caused negative effects on quality of life.

CONCLUSIONS

Although the groups are disproportionate, a higher percentage of financial distress occurred in the off-label therapy group. While cost discussions are challenging, they remain an important part of therapy initiation that may decrease undue stress; this will be an area of improvement.
QLTI-08. THE COLUMBIA NEURO-ONCOLOGY RESEARCH DASHBOARD: A WEB-BASED TOOL TO ASSESS CLINICAL TRIAL RECRUITMENT AND ACCRUAL METRICS
Authors: Welch Mary , Pan Peter , Haggiagi Aya , Donovan Laura , Diaz Maria , Iwamoto Fabio , Lassman Andrew
Published: November 2023

BACKGROUND

Insufficient trial participation is a recognized barrier to drug development. Research has focused on patient and physician-associated factors, yet few institutions assess the impact of trial availability, referral patterns, and patient eligibility. Screening logs provide a rough estimate of candidate pools but tell us nothing about patients who are not screened, let alone why. To better understand site-specific barriers and effectively assess efforts to overcome them, real-time, data-driven metrics are essential.

METHODS

To address this need, we created The Columbia Neuro-Oncology Clinical Research Dashboard (CRD), a web-based tool designed to capture all patients presenting to our faculty practice with newly diagnosed or recurrent CNS tumors and track their participation -- or lack thereof -- in interventional trials. From 7/2022 - 9/2022, we experimented with several iterations of the CRD, adjusting the platform and variables in response to user feedback. To pilot the final design, we started with a limited sample of high-grade glioma patients seen at Columbia University Irving Medical Center's Neuro-Oncology Faculty Practice from 9/1/2022 - 1/1/2023. During this period, 62 patients were tracked, allowing for further refinements to improve functionality and data capture. When populated, the CRD was easily queried for important quality improvement metrics including accrual rates, time from presentation to study initiation and grounds for screen failure. It also captured the percentage of patients who were not offered a trial and the cited reasons. Inclusion of demographics and referral patterns provided additional dimensions to the data. NEXT STEPS: The CRD has met its preliminary aims. It provides a user friendly and accessible interface for data capture. With appropriate staffing and implementation processes in place, it has real potential to inform our efforts to improve patient accrual and diversity with real-time metrics. Subsequent efforts will focus on these aspects of the project.
QLTI-11. TIMELINE FROM INITIAL MRI TO INTERVENTION IN NEWLY DIAGNOSED HIGH GRADE GLIOMA
Authors: Cevering Colby , Kaur Maninder
Published: November 2023

OBJECTIVE

Prompt treatment of high-grade glioma is crucial for prolonging life. In an attempt to identify factors that lead to delays in treatment, we evaluated the amount of time between initial MRI and treatment start date for our patients with newly diagnosed high grade glioma.

METHODS

This was a retrospective chart review study. Adults over the age of 18 years of age with newly diagnosed high grade glioma were included if they were seen by the neuro-oncology department at Loma Linda University Medical Center. Reviewed charts were dated from November 2020 to August 2022. We evaluated the amount of time between initial MRI and several important milestones in the diagnosis and treatment of high grade glioma, including resection; biopsy results; neuro-oncology consult; radiation-oncology consult; date that chemotherapy was ordered, received by the patient, and initiated; and radiation therapy start date.

RESULTS

Twenty-two patients with new diagnosis of high-grade glioma were identified. Six patients were excluded due to complicated treatment courses involving outside facilities. Sixteen patients were included in the study. Thirteen patients (81%) had a diagnosis of glioblastoma, 2 (12%) had a diagnosis of diffuse midline glioma, and 1 (6%) had a diagnosis of anaplastic astrocytoma. The mean number of days between initial MRI and chemotherapy start date was 88. Prolonged timelines were seen in all analyzed metrics.

CONCLUSIONS

There is a significant delay in chemotherapy initiation for patients with high grade glioma at our facility. We also provide a framework for other institutions to evaluate their system processes in order to improve care delivery.
QLTI-13. RETROSPECTIVE REVIEW OF THE DIAGNOSTIC YIELD OF CEREBROSPINAL FLUID (CSF) ANALYSIS IN DIAGNOSIS OF CENTRAL NERVOUS SYSTEM (CNS) LYMPHOMA IN A COMMUNITY NEURO ONCOLOGY CENTER
Authors: Lu-Emerson Christine , Lawlor Donna , Deborah Cushing , Rughani Anand , Christman Robert , Florman Jeffrey
Published: November 2023

Central nervous system (CNS) lymphoma can be a challenging disease to diagnose. Both primary and secondary CNS lymphoma often result in poor outcomes rendering early diagnosis and treatment essential. Traditionally, diagnostic modalities include surgery, cerebral spinal fluid (CSF) cytologic analysis, vitrectomy, and chorioretinal biopsy. Radiographic and clinical presentation can widely vary between patients, further enhancing diagnostic dilemma. We present a retrospective study from a community neuro oncology center analyzing the utility of CSF analysis in the diagnosis of CNS lymphoma. Between 2018-2022, 26 CNS lymphoma patients were identified of which 22 (85%) were primary CNS lymphoma patients. Median age of diagnosis was 68.5 years, and 21 (81%) of the patients were immunocompetent. 13 (50%) of the patients underwent CSF analysis, including cytology and flow cytometry), prior to biopsy and none (0%) yielded a positive diagnosis of CNS lymphoma. While mean CSF volume for cytology was slightly more than 3 cc of fluid, patients who had 5-10 cc of fluid sent for cytology also yielded a negative result for CNS lymphoma. For all patients, median duration from presentation of symptoms to surgery was 10.5 days. However, when divided between patients who proceeded straight to biopsy (CSFsecond) versus those who underwent CSF analysis prior to biopsy (CSFfirst), the duration from presentation of symptoms to surgery was 6 days versus 11 days, respectively. 10 patients in the CSFfirst group were not on steroids at the time of lumbar puncture whereas only 4 patients in the CSFsecond group were not on steroids at time of biopsy suggesting that steroid use did not seem to influence the yield of either diagnostic modalities. Our experience suggests that CSF analysis in community settings should be reserved only for staging and that surgical biopsy should be pursued as soon as the diagnosis of CNS lymphoma is considered.
QLTI-14. CAN VARIANT ALLELIC FREQUENCIES OF DRIVER MUTATIONS PREDICT FALSE NEGATIVE MGMT PYROSEQUENCING RESULTS IN ADULT-TYPE DIFFUSE GLIOMAS?
Authors: McCord Matthew , Jamshidi Pouya , Thirunavu Vineeth , Santana-Santos Lucas , Vormittag-Nocito Erica , Parker Stephanie , Baczkowski Joseph , Jennings Lawrence , Walshon Jordain , McCortney Katy , Galbraith Kirstyn , Zhang Hui , Lukas Rimas , Stupp Roger , Dixit Karan , Kumthekar Priya , Heimberger Amy , Snuderl Matija , Horbinski Craig
Published: November 2023

MGMT promoter methylation predicts favorable temozolomide (TMZ) response in gliomas. Accurate test results depend on adequate tumor cellularity in analyzed samples, which is usually estimated (with sub-optimal accuracy) via light microscopy. We evaluated driver mutation variant allelic frequency (VAF) as a quantitative metric for tumor cellularity in MGMT promoter methylation testing. In a cohort of 691 adult-type diffuse gliomas, MGMT promoter methylation was tested by either pyrosequencing (N = 445) or DNA methylation array (N = 246). VAF of TERT and IDH driver mutations was quantified by next generation sequencing (NGS). We compared frequency of methylated (positive) and unmethylated (negative) results (Fisher’s exact test) and promoter methylation levels (unpaired t-test) according to VAF. We correlated MGMT promoter methylation, VAF, visually estimated tumor cellularity, and cellularity inferred from VAF via linear regression. We assessed survival (Log-Rank test) for 201 patients with IDH-wildtype GBM treated with TMZ. In samples with VAF <0.325 (identified by CutoffFinder), pyrosequencing yielded fewer positive results (37% versus 56%, p < 0.0001) and lower methylation levels (13% versus 19%, p < 0.0001) than samples with VAF≥0.325. Methylation array showed less frequent positive results at low VAF for IDH-mutant astrocytoma, but not for IDH-wildtype GBM. Microscopic examination tended to overestimate tumor cellularity, especially when VAF was low (R2 = 0.558). GBMs with unmethylated MGMT by pyrosequencing and TERT VAF <0.145 showed better responses to TMZ versus cases with VAF≥0.145 (median survival = 16.8 versus 13.3 months). Twelve pyrosequencing samples were re-tested by DNA methylation array and droplet digital PCR (ddPCR). RESULTS: changed for 2/6 samples with TERT VAF≤0.1, and 0/6 samples with VAF >0.1. Driver mutation VAF is useful for quality assurance in MGMT promoter methylation testing. Tumor samples with low VAF are at greater risk of false-negative results by pyrosequencing, which can be corrected by DNA methylation array and ddPCR.
QOL-03. PATIENT-PARTNER RELATIONSHIPS AND QUALITY OF LIFE IN BRAIN TUMOR PATIENT
Authors: Boccia Maria , Fonkem Ekokobe , Frye Nick , Murillo Jennifer , Anyanda Elizabeth , Tamimi Adam , Bradshaw Eva
Published: November 2023

As cancer treatment has advanced, quality of life (QoL) has become a significant consideration in patient and survivor care. The 2005 Institute of Medicine Cancer Survivorship Care Planning guide requires the inclusion of information on the possible effects of cancer on relationship satisfaction and sexual functioning associated with QoL. Guided by the cognitive-transactional model of chronic illness, this study explored the extent to which relationship satisfaction and sexual dysfunction was associated with QoL. Thirty patients and their partners were recruited from a neuro-oncology practice and given a QoL questionnaire (FACT-Br) and measures of relationship satisfaction (Couple Satisfaction Index) and sexual functioning. Women were given the Female Sexual Function Index (FSFI). Men were given scales to assess premature ejaculation (PE), and erectile dysfunction (ED). In addition, information about site and type of tumor and treatment (surgery, radiation, chemotherapy) was collected. Descriptive statistics as well as T-tests and regression models were used to analyze the data. Relationship satisfaction varied across participants and was significantly related to QoL for patients. There was significant sexual dysfunction as was previously reported by our team. QoL and relationship satisfaction were correlated with sexual dysfunction. Our capacity to address the relationships of patients is dependent on our understanding the types of difficulties encountered. Specifically, partners are often also engaged in the role of primary caregiver, understanding these relationships and how to ensure their health can be critical for QoL and outcomes for brain tumor patients.