bluuebunny/crossref_metadata_2025 huggingface dataset:
CTNI-66. DECODING GLIOBLASTOMA SURVIVAL: UNRAVELING THE PROGNOSTIC POTENTIAL OF OLFACTORY FUNCTION IN A PROSPECTIVE OBSERVATIONAL STUDY
Authors: Oster Christoph , Hummel Thomas , Hattingen Elke , Schmidt Teresa , Lazaridis Lazaros , Jokisch Daniel , Jokisch Martha , Agkatsev Sarina , Ahmadipour Yahya , Sure Ulrich , Stuschke Martin , Kleinschnitz Christoph , Scheffler Björn , Deuschl Cornelius , Kebir Sied , Glas Martin
Published: November 2023

BACKGROUND

Olfactory impairment is a common neurologic deficit among glioblastoma patients. We have previously shown that glioblastoma patients with reduced smell sensitivity had lower overall survival rates compared to those with normal olfactory function. A notable limitation in that study was the unequal distribution of prognostic factors between the two groups, and the absence of continuous olfactory assessments during treatment to investigate if therapy-associated neurotoxicity could be a contributing factor to diminished olfactory acuity. Question: Can Olfactory Function Serve as an Independent Prognostic Indicator in Glioblastoma Patients?

METHODS

This prospective, multicenter study is set to recruit 64 glioblastoma patients alongside 64 healthy controls. Stratification of participants will be based on prognostically relevant variables such as resection status, MGMT promoter methylation status, radiographic involvement of olfactory brain areas, olfactory function, age, and Karnofsky performance status scale. We will utilize Sniffing Sticks to evaluate olfactory function through identification and threshold tests, and this assessment will be carried out longitudinally throughout the therapy starting from tumor diagnosis. Infiltration of the olfactory brain areas will be scrutinized using coronal T2 and T1 MRI sequences. MRI images will be independently reviewed by two board-certified radiologists from distinct institutions, who are blinded to the patients' olfactory function status. Furthermore, quality of life data, neuropsychological testing, and psychosomatic screening will be performed at specific intervals throughout the study. Also, we'll examine next-generation sequencing results to investigate potential genetic associations with hyposmia in glioblastoma patients.

RESULTS

The first participant was enrolled in May 2023. Plans are underway to open a second study site in 2024, with the aim to complete recruitment by December 2025. Follow-up assessments will continue until December 2027. We anticipate that the final results of the study will be available in 2028.
CTNI-70. RADIOTHERAPY QUALITY ASSURANCE IN THE ROAM/EORTC1308 ATYPICAL MENINGIOMA RANDOMISED CONTROLLED TRIAL: PROSPECTIVE REVIEW IMPROVES RADIOTHERAPY QUALITY AND CONSISTENCY
Authors: Jenkinson Michael , Mayles Helen , Weber Damien , Haylock Brian ,   ROAM/EORTC1308 Trial Management Group
Published: November 2023

OBJECTIVE

ROAM/1308 is an international randomised controlled phase III trial comparing radiotherapy (60Gy in 30 fractions) to observation following complete surgical resection of atypical meningioma. We embedded prospective radiotherapy quality assurance (RTQA) within the trial with the aim of ensuring consistent radiotherapy planning and delivery.

METHODS

The radiotherapy protocol described the consensus contouring/planning guidelines. Pre-trial assessment included benchmark cases (outlining/planning) and a technology ‘Dummy Run’. Individual case reviews were undertaken. Non-conformities were classed as ‘major’ (undertreatment of dural margins/over treatment of brain or organs at risk) or ‘minor’ (for education). Resubmissions were mandated for all major non-conformities. All plans were approved before radiotherapy delivery.

RESULTS

The UK RTQA group coordinated European sites. The Australian RTQA group (TROG) reviewed their sites and provided all data to the UK for review. Four radiation oncologists reviewed contours and physicists/dosimetrists reviewed plans. All sites (20 UK, 25 EORTC, 11 TROG) undertook the benchmark/’Dummy Run’ cases prior to opening. Resubmissions were: UK (1 contour, 0 plans), EORTC (2 contours, 6 plans) and TROG (1 contour, 3 plans). Trial communications and outlining workshops were used to provide feedback. Radiotherapy was delivered to 30, 26 and 7 patients at 11 UK, 12 EORTC and 5 TROG sites, respectively. Overall, 25 (40%) patient cases needed resubmitting: 23 (37%) sets of outlines (2 cases twice) and 9 (14%) treatment plans (1 plan twice).

CONCLUSIONS

Prospective quality assurance and case review are essential to ensure consistent high-quality radiotherapy and benchmark/’Dummy Run’ alone is not sufficient. RTQA should be used for future trials in rare tumours where centres may only treat a few patients. The consistent high-quality radiotherapy in ROAM/EORTC1308 ensures the primary outcome (progression free survival: to report 2026) will be a robust assessment and any difference between treatment arms cannot be attributed to variation in radiotherapy planning or delivery.
CTNI-75. EFFICACY AND SAFETY OF LAROTRECTINIB IN PATIENTS WITH TROPOMYOSIN RECEPTOR KINASE (TRK) FUSION PRIMARY CENTRAL NERVOUS SYSTEM (CNS) TUMORS: AN UPDATED ANALYSIS
Authors: Perreault Sébastien , Doz François , Geoerger Birgit , Italiano Antoine , Lassen Ulrik , Nilsson Anna , Nysom Karsten , Spano Jean-Philippine , Norenberg Ricarda , Bernard-Gauthier Vadim , de la Cuesta Esther , Drilon Alexander , Laetsch Theodore , van Tilburg Cornelis
Published: November 2023

BACKGROUND

Larotrectinib is a highly selective TRK inhibitor approved for tumor-agnostic use in patients with various tumor types, including primary CNS tumors. Here, we report the independent central review and updated data on patients with TRK fusion-positive primary CNS tumors.

METHODS

Patients with TRK fusion primary CNS tumors enrolled in two clinical trials (NCT02637687, NCT02576431) were included. Responses were independent review committee (IRC)-assessed.

RESULTS

As of July 2022, 41 patients were eligible for response assessment by IRC. The median age at enrollment was 11 years (range 1-79). Tumor histologic groups included: high-grade glioma (HGG; n=25), low-grade glioma (LGG; n=9), and other (n=7). Sixteen (39%) patients had received ≥ 2 prior systemic therapies. For all patients, objective response rate (ORR) was 22% (95% CI 11–38): one complete response, eight partial response, 20 stable disease, and 12 progressive disease. For pediatric patients (n=28), the ORR was 29% (95% CI 13–49). For pediatric patients with HGG and LGG, ORRs were 14% (95% CI 2–43) and 57% (95% CI 18–90), respectively. The disease control rates at 24 weeks were 54% (95% CI 37–69) and 71% (95% CI 51–87) for all patients and pediatric patients, respectively. Medians for time to response, duration of response, progression-free survival, and overall survival (OS) were 1.9 months, 12.2 months (95% CI 3.7–not estimable), 11.1 months (95% CI 3.6–19.8), and not reached, respectively. The 48-month OS rate was 52%. Treatment duration ranged from 1 to 50+ months. Treatment-related adverse events (TRAEs) were mostly Grade 1/2. No patients discontinued treatment due to TRAEs.

CONCLUSION

Larotrectinib demonstrated rapid, durable responses and a manageable safety profile in patients with TRK fusion primary CNS tumors. This supports the wider adoption of next-generation sequencing panels that include NTRK gene fusions when testing patients with CNS tumors.
CTNI-76. EFFICACY OF BRAF INHIBITOR PLIXORAFENIB (FORE8394) IN RECURRENT, PRIMARY CENTRAL NERVOUS SYSTEM TUMORS (PCNST)
Authors: de la Fuente Macarena , Butowski Nicholas , Taylor Jennie , Yaeger Rona , Tsai Frank Yung-Chin , Janku Filip , Allen Carl , Ammakkanavar Natraj , Michelson Glenn , Jiang Ping , Paz Michael , Tussay-Lindenberg Alexia , Wang Kongming , Shepherd Stacie Peacock , Kline Irina , Sherman Eric , Rodon Jordi
Published: November 2023

Plixorafenib, a selective potent BRAFi, is uniquely designed to disrupt BRAF dimers and evade paradoxical MAPK pathway activation. Thus, it inhibits both V600 and non-V600 BRAF alterations and may be less prone to toxicities and resistance typical of approved BRAFi. An approved BRAFi, when used with MEKi, has ORR 33% with mDOR 13.6=months and ORR=50% with DOR of 6-29 months in V600+ HGG and LGG, respectively (dabrafenib US Prescribing Information, 2023). Phase 1/2a is a single-arm study (NCT02428712) in patients (n=113) with BRAF-altered advanced tumors to assess safety, PK, and efficacy of oral plixorafenib 900-3600 mg/day alone or with cobicistat (CYP3A4/P-gp inhibitor). Symptomatic TEAEs (rash, pyrexia, myalgia) were low grade and infrequent relative to approved BRAFi. This pre-specified analysis (31Mar2023) was in MAPKi-naïve adults with BRAFV600+ PCNST. 22 patients with PCNST received plixorafenib: 9 LGG, 1 glioneuronal tumor (LGG/GNT; 5 V600+), 12 HGG (10 V600+). Treatment-emergent AEs (TEAEs, ≥ 20%) were limited to LFT changes, G1 increased creatinine, fatigue, headache, and nausea. Only one G3 event (increased ALT) occurred at the RP2D (n=7) showing better tolerability than dabrafenib. 10 BRAFV600+ MAPKi-naïve adults with PCNST (median age 45 yrs, 6 females, 9 non-Hispanic) were efficacy evaluable: 6 HGG (4 glioblastoma, 1 epithelioid glioblastoma, 1 anaplastic astrocytoma); 4 LGG/GNT (1 each: ganglioglioma, pilocytic astrocytoma, xanthoastrocytoma, neuroepithelial tumor). Prior anti-cancer treatments included surgery (8/10), radiotherapy (8/10), and systemic therapy (8/10, including temozolomide [n=8], bevacizumab [n=2], carboplatin [n=1], dendritic cell vaccine [n=1]). 1 was treatment-naïve (unresectable; declined radiation/chemotherapy). ORR=60% (6/10) including HGG=67% (4/6), LGG/GNT=50% (2/4); median time to response=1.94 months; 4/6 responders with DOR > 9 months; mPFS=34.1 months; median follow-up=10.3 months; 4/10 ongoing. Plixorafenib has a benign safety profile and leads to a high ORR and durable response in MAPKi-naïve BRAFV600+ PCNST. A phase 2 study is ongoing to confirm these findings (NCT05503797).
CTNI-81. REAL-WORLD TREATMENT RESULTS OF RELAPSED PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA TREATED BY MEDICAL THERAPIES
Authors: Nagane Motoo , Sasaki Nobuyoshi , Yamagaishi Yuki , Saito Kuniaki , Kobayashi Keiichi , Nakatomi Hirofumi
Published: November 2023

Recurrence of primary central nervous system lymphoma (PCNSL) is a condition which often leads to morbidity and mortality. Consensus regarding the optimal treatment regimen for relapsed PCNSL has not been achieved due to the rarity of the disease. In this study, we conducted a retrospective, single-institution study to investigate real world treatment results of relapsed PCNSL treated by several medical therapeutic regimens. Relapsed PCNSL patients treated at the authors’ institution were identified, and progression-free survival (PFS), overall survival (OS) were analyzed among patients treated by medical therapies. Patients treated by radiotherapy, treated for intraocular or systemic relapses, or best supportive care, were excluded from the survival analysis. 83 patients with first, 44 with second, 25 with third relapse were identified. Upon each relapse, number of patients who received medical therapies for CNS lesions, radiotherapy, treatment for intraocular or systemic relapse, and best supportive care were 48 (57.8%), 5(6%), 4(4.8%), 26(31.3%) (first relapse), 31(70.5%), 3(6.8%), 1(2.3%), 9(20.5%) (second relapse), 13(52.0%), 0, 1(4%), 11(44.0%) (third relapse), respectively. A total of 101 CNS relapses were treated by medical therapies, and PFS (months), OS (months) of the four groups of treatments (rituximab, methotrexate, procarbazine and vincristine [R-MPV], methotrexate [MTX], tirabrutinib, and others) were as follows. PFS: 13.0, 4.5, 2.7, 3.0, and OS: 70.0, 26.4, 51.2, 9.7 (all relapse). PFS: 12.7, 7.0, 3.0, 3.2, and OS: 58.9, 33.1, not reached(n/r), 16.1 (first relapse). PFS: 34.3, 3.9, 25.3, 1.5, and OS: n/r, 28.1, 25.5, 7.5 (second relapse). PFS: 10.1, 3.9, 2.4, 2.9, and OS: 14.9, 22.3, n/r, 8.1 (third relapse). In relapsed PCNSL, favorable PFS was observed in patients treated by R-MPV. Favorable OS was also observed in tirabrutinib, which might suggest that tirabrutinib failure were effectively salvaged by R-MPV. R-MPV might confer better prognosis in relapsed PCNSL.
CTNI-85. GBM AGILE PLATFORM TRIAL FOR NEWLY DIAGNOSED AND RECURRENT GBM: RESULTS OF FIRST EXPERIMENTAL ARM, REGORAFENIB
Authors: Wen Patrick , Alexander Brian , Berry Donald , Buxton Meredith , Cavenee Webster , Colman Howard , de Groot John , Ellingson Benjamin , Gordon Gary , Hyddmark Emma , Khasraw Mustafa , Lim Michael , Mellinghoff Ingo , Mikkelsen Tom , Perry James , Powell Ashley , Sulman Erik , Tanner Kirk , Weller Michael , Yung W K Alfred , Blondin Nicolas , Brenner Andrew , Butt Omar , de la Fuente Macarena , Drappatz Jan , Iwamoto Fabio , Kim Lyndon , Lee Eudocia , Mantica Megan , Nabors Burt , Newton Herbert , Schiff David , Walbert Tobias , Weathers Shiao-Pei , Cloughesy Timothy , Lassman Andrew
Published: November 2023

GBM AGILE (NCT03970447;https://www.gcaresearch.org/research/gbm-agile) is a phase 3 Bayesian adaptive platform trial that efficiently tests multiple arms against common control, with 6 arms included to date. Primary endpoint is overall survival (OS). Stage 1 experimental arms are adaptively randomized against other arms. Demonstrated efficacy in stage 1 leads to fixed randomization stage 2. Stages 1 and 2 are combined for registration. Control randomization is fixed. Regorafenib, a multikinase-inhibitor, entered into GBM AGILE as the first arm and therefore was equally randomized against control. Regorafenib showed OS benefit in recurrent disease (RD) in randomized phase 2 REGOMA trial. METHODS: Patient subtypes in GBM AGILE are newly diagnosed unmethylated (NDU), RD, and—not considered for regorafenib—ND methylated (NDM). Arm indications (signatures) are combinations of subtypes. Control is temozolomide (ND) and lomustine (RD). Efficacy is assessed by OS hazard ratio(HR), arm/control. Efficacy is demonstrated when Bayesian probability of benefit (HR< 1.00) ≥ 98% (roughly analogous P-value: 0.02). Futility occurs at any monthly analysis when Bayesian predictive power (PP) is < 25% for all signatures. Follow-up continues for 12 months after arm’s accrual stops. RESULTS: for regorafenib: When PP for all 3 pre-defined signatures was < 25%, regorafenib’s accrual was stopped for futility. Regorafenib/control sample sizes were 49/51, 126/128, 175/179 for signatures NDU, RD, and both. Respective PPs: 0.138, 0.030, 0.025—none close to 0.25. Respective mean HRs: 1.26, 1.25, 1.23. Probabilities of benefit (HR< 1.00): 0.35, 0.18, 0.17. At final analysis, mean HRs were 1.07, 1.12, 1.10 with final probabilities of benefit (HR< 1.00) equal to 0.43, 0.24, 0.24—none close to 0.98. CONCLUSION: GBM AGILE efficiently and compellingly addressed regorafenib’s role in GBM, in RD and NDU. These findings are germane as they fail to confirm the REGOMA results in RD. GBM AGILE continues to efficiently assess other therapies, including utilizing concurrent and previously accrued controls.
DNAR-03. A ROLE FOR THE INTERACTION BETWEEN DNA-DEPENDENT PROTEIN KINASE (DNA-PK) AND TAZ IN INDUCING GLIOMA STEM-LIKE CELL (GSC) RADIO-RESISTANCE
Authors: Tang Tiffany , Katayama Hiroshi , Bhat Krishna
Published: November 2023

Glioblastoma (GBM) is a primary brain tumor that is virtually incurable. Previous studies have shown that glioma stem-like cells (GSCs) are a particularly resistant subpopulation of GBM. Thus, a greater understanding of the mechanisms underlying therapy resistance in GSCs is required. TAZ is a transcriptional cofactor highly expressed in about 70% of GBMs. TAZ and its paralog YAP are oncogenic drivers of brain tumor progression. Our group has shown that GSCs overexpressing TAZ undergo a proneural to mesenchymal subtype transition, which is accompanied by aggressive phenotypes such as increased grade and treatment resistance in GSC xenografts. However, the molecular mechanisms of TAZ-mediated cell fate transition and GBM treatment resistance remain elusive. Previously, our group identified a novel interaction between DNA-dependent protein kinase (DNA-PK) and TAZ in response to exposure to ionizing radiation (IR) in GSCs. Here, we extend our previous findings by contextualizing the significance of this novel interaction in altering sensitivity to IR in GSCs. We demonstrate that prolonged culture of GSCs treated with etoposide increases TAZ expression. Furthermore, si-RNA knockdown of TAZ increases the number of γH2AX foci post-IR. Intriguingly, knocking down both TAZ/YAP does not increase the number of γH2AX foci post-IR in comparison to single knockdown of TAZ. Additionally, DNA-PK inhibitor treatment in GSCs reduces the half-life of TAZ. In contrast, GSCs treated with IR increases the half-life of TAZ compared to mock-irradiated cells. A combination of IR and DNA-PK inhibitor treatment in GSCs reduces the half-life of TAZ compared to GSCs treated with IR and DMSO, implicating the role of the recruitment of TAZ to DNA damage breaks and its resulting interactions with DNA-PK to induce radio-resistance. Overall, this study reports how interaction of DNA-PK with TAZ globally induces a GSC radio-resistant phenotype, highlighting the potential role of TAZ as a therapeutic target for GBM.
DDEL-02. CLINICAL BENEFIT OF BEVACIZUMAB AND IRINOTECAN (BEV+IRI) IN PATIENTS WITH RELAPSED/REFRACTORY GLIOBLASTOMA (R/RGBM) AND ITS POTENTIAL PREDICTORS
Authors: Park Ji Hyun , Cho Kyung Rae
Published: November 2023

BACKGROUND/AIM: Bevacizumab-containing chemotherapy constitutes an important salvage treatment for recurrent/refractory glioblastoma(r/rGBM). Patients and methods: We retrospectively collected the data of r/rGBM patients treated with the combination of bevacizumab and irinotecan (BEV+IRI) as their salvage treatment from July 2013 and December 2021 in Konkuk Medical Center of Korea. Patients with available results from molecular diagnostic tests were eligible, and markers of interest were examined including the presence of MGMT methylation, IDH1/2 mutation, or 1p/19q co-deletion. Efficacy of BEV+IRI and its potential biomarker was explored. RESULTS: Among 21 patients, 38.1% demonstrated European Cooperative Oncology Group-Performance scale (ECOG-PS) ≥3. The majority (71.4%) received BEV+IRI as their second-line chemotherapies, and the median dose was 5 (range=1-25). Objective response rate (ORR) was 33.3% and disease-control rate (DCR) was 85.7%. Irrespective of objective response, early clinical response was achieved in 14(66.7%) patients. During the median follow-up of 16.4 months for survivors, median progression-free survival (PFS) and overall survival (OS) were 3.6 and 6.8 months, respectively. ECOG PS≥3 and TP53 loss were independent predictors of an unfavorable OS, while prompt clinical improvement could predict favorable OS. Any molecular aberration was associated with OS or PFS in the study. CONCLUSION: Salvage BEV+IRI treatment in r/rGBM conferred comparable clinical benefit. ECOG PS ≥3, TP53 loss, and lack of prompt clinical improvement after the treatment were significantly associated with an unfavorable OS.
DDDR-11. IDENTIFYING NEW VULNERABILITIES TO TARGET PEDIATRIC LOW-GRADE GLIOMA
Authors: Borgenvik Anna , Misek Sean , Maile Jens , Novikov Dana , Bahadur Sher , Apfelbaum April , Morin Eric , Condurat Alexandra , Gonzales Elizabeth , Zhou Kevin , Goodale Amy , Abid Tanaz , Kalani Zohra , Piccioni Federica , Ligon Keith , Beroukhim Rameen , Persky Nicole , Jones David , Root David , Bandopadhayay Pratiti
Published: November 2023

Pediatric low-grade gliomas (pLGGs) are the most common solid tumors in children and are associated with devastating lifelong morbidities and mortality. Recent genomic profiling efforts have revealed that these tumors are largely driven by single-driver events that activate MAPK signaling. These insights have led to early clinical trials evaluating the role of MAPK inhibitors for these children with promising initial results. However, pLGGs are not cured by MAPK inhibitors, and tumors often rapidly rebound upon cessation of treatment. Therefore, continuous dosing of these inhibitors is required throughout a child’s development–often with significant and potentially permanent toxicities. In addition, 30-40% of tumors do not respond to MAPK inhibition, indicating primary resistance. We hypothesized that pediatrlc low-grade gliomas may also harbor additional dependencies beyond the MAPK pathway that may represent potential therapeutic targets. To address this, we generated isogenic neural stem cell models that expressed pLGG relevant oncogenes (BRAF family members, FGFR family members and MYB transcription factors, and subjected them to genome-scale CRISPR-cas9 screens. Compared to vector controls, pLGG models exhibited genetic dependencies on pathways that included regulators of cell-cycle and differentiation, in addition to genes involved in regulating the mTOR and MAPK pathways. Cell lines expressing MYB family transcription factors also harbored dependencies on genes involved in the DREAM complex. Together, these genes and pathways represent potential targets for combination treatments with MAPK pathway inhibitors for the treatment of pediatric low-grade gliomas.
DDDR-18. SINGLE-CELL FUNCTIONAL GENOMIC ANALYSIS OF PHARMACOLOGIC RESPONSES IN NF1 MUTANT GLIOBLASTOMA REVEALS DISTINCT MECHANISMS OF ACTION FOR MEK AND SHP2 INHIBITION
Authors: Pan Sixuan , Liu John , Mirchia Kanish , Payne Emily , Pak Joanna , Seo Kyounghee , Ozawa Tomoko , Raleigh David , Berger Mitchel , Abate Adam , Vasudevan Harish
Published: November 2023

BACKGROUND

Glioblastomas harbor recurrent mutations in NF1 that activate Ras/Raf/MEK signaling, motivating pharmacologic approaches targeting downstream (MEK) or upstream (SHP2) of Ras signaling. However, the mechanisms underlying therapeutic response remain unclear. Here, we integrate genome wide CRISPRi screens and single cell sequencing in cell lines and mouse xenografts to identify functional genomic mechanisms underlying responses to the MEK inhibitor selumetinib or the SHP2 inhibitor RMC-4550.

METHODS

Human NF1 mutant GBM43 cells expressing CRISPRi machinery were used for CRISPRi screens with selumetinib or RMC-4550. Intracranial xenografts were established with GBM43 cells and treated with selumetinib or RMC-4550. Tumor growth kinetics were measured with bioluminescent imaging.

RESULTS

Genome-wide CRISPRi screens with selumetinib or RMC-4550 in NF1 mutant human GBM43 cells identified 39 genes (14 sensitivity, 25 resistance) mediating selumetinib response and 327 genes (51 sensitivity, 276 resistance) mediating RMC-4550 response. While both selumetinib and RMC-4550 hits were enriched for components of Ras/Raf/MEK, hits sensitizing RMC-4550 response were uniquely enriched for PI3K signaling and focal adhesion components while hits mediating resistance were enriched for cell cycle genes. In NF1 mutant GBM43, RMC-4550 significantly reduced tumor volume (p=0.02) while selumetinib did not. Single cell RNA-sequencing (scRNA-seq) analysis of 90,782 tumor cells from NF1 mutant GBM43 xenografts treated with selumetinib or RMC-4550 identified 12 clusters across all samples. RMC-4550, but not selumetinib, resulted in significant depletion of cells expressing an epithelial-mesenchymal transition (EMT) signature marked by expression of focal adhesion genes mediating RMC-4550 sensitivity, suggesting this signature comprises a distinct mechanism of action in response to RMC-4550 but not selumetinib.

CONCLUSIONS

In NF1 mutant glioblastoma in vitro and in vivo models, cellular response to both upstream (SHP2) and downstream (MEK) inhibition are mediated by Ras/Raf/MEK signaling while RMC-4550 alone uniquely regulates a focal adhesion network associated with EMT and demonstrates improved efficacy in vivo.
DDDR-21. A TEMOZOLOMIDE-INDUCED LONG NONCODING RNA, LINC02454, REGULATES CHEMOSENSITIVITY IN GLIOBLASTOMA VIA MODULATION OF CXCR4
Authors: Yuan Edith , Tsung Kathleen , Han Jane , Lu Wange , Attenello Frank
Published: November 2023

INTRODUCTION

Chemoresistance is one of the primary factors influencing the poor prognosis in glioblastoma (GBM) patients. Long noncoding RNAs (lncRNAs) are a novel class of RNAs representing up to 80% of the genome, and noted to induce profound alterations in transcriptional regulation and phenotype, including chemotherapy response. We therefore set out to identify novel lncRNAs induced by chemotherapy that regulate GBM chemosensitivity. We further evaluated the mechanism by which a candidate chemoresistance-associated lncRNA exerts function.

METHODS

We evaluated gene expression following temozolomide treatment in multiple glioma lines (via RNA-seq). Candidate lncRNAs demonstrating significant expression upon TMZ treatment were assessed for association with patient survival. We further evaluated the effect of knockdown of candidate lncRNAs upon resulting TMZ sensitivity and downstream gene expression.

RESULTS

Linc02454 was among the most highly upregulated genes following TMZ treatment. Linc02454 resides on chromosome 12q14 within a locus of genes amplified in 10% of GBM patients. Elevated linc02454 expression was associated with decreased survival in TCGA data, while linc02454 knockdown reduced in vitro GBM cell viability in response to TMZ. RNA-seq identified CXC-chemokine receptor 4 (CXCR4) among the most heavily downregulated genes following lncRNA knockdown. Finally, TMZ induces similar increases in linc02454 and CXCR4, while CXCR4 KD chemosensitivity phenotypes closely parallel linc02454 KD phenotypes.

CONCLUSION

TMZ-induced increases in long noncoding RNAs, particularly in linc02454, regulate expression of well-known and previously targeted chemokines, including CXCR4. Subsequent studies, evaluating the manner by which chemotherapy increases linc02454, and the manner by which linc02454 affects CXCR4 and treatment sensitivity may improve GBM temozolomide sensitivity.
DDDR-23. COMBINATION THERAPY WITH PACLITAXEL, CARBOPLATIN, AND LOW-INTENSITY ULTRASOUND FOR RECURRENT GLIOBLASTOMA: RATIONALE FOR ONGOING PHASE II CLINICAL TRIAL
Authors: Habashy Karl , Dmello Crismita , Chen Li , Arrieta Victor , Kim Kwang-Soo , Gould Andrew , Bouchoux Guillaume , Canney Michael , Stupp Roger , Sonabend Adam
Published: November 2023

We recently participated in phase 1/2 clinical trials where patients with recurrent glioblastoma received surgery for tumor resection followed by implantation of an ultrasound device into a skull window for subsequent repeated blood-brain barrier opening and concomitant delivery of chemotherapy (Sonabend et al., Lancet Oncology). Intraoperative experiments demonstrated a 3.7 to 5.9-fold increase in the brain concentration of paclitaxel (NCT04528680) and carboplatin (NCT03744026). Building on the pharmacokinetics and safety of these trial results, and the historical use of paclitaxel and carboplatin as a combination in other cancers, we investigated the efficacy of this combination in glioblastoma models. First, we analyzed the cytotoxicity of both drugs in vitro against five human cell lines and six patient-derived xenografts as monotherapy and in combination at concentrations derived from our human intraoperative pharmacokinetic studies. Cell lines exhibited little overlap in susceptibility to the drugs, with 27% being exclusively susceptible to one of the two drugs tested. The combination covered 81% of cell lines, compared to 54% covered with monotherapy. We also assessed for synergy using the Loewe model and recorded synergy in 55% of cells. We then evaluated the benefit of this combination in vivo in two xenograft models (MES83 and GBM6) where drugs were administered with ultrasound. Combination therapy proved more effective than monotherapy with either of the drugs, led to distinct effects on cell cycle progression and enhanced DNA damage and apoptosis. We conclude that the addition of carboplatin to paclitaxel may be more effective than monotherapy with paclitaxel, which we performed in our phase 1 trial. This combination is supported by its efficacy in other cancers, and the synergy and independent susceptibility to each drug in glioma models. The safety and efficacy of this approach are currently under investigation in an ongoing phase II trial for patients with recurrent GBM (NCT04528680).
DDDR-24. SINGLE-CELL FUNCTIONAL TISSUE PROFILING IDENTIFIES PROMISING CANDIDATES FOR DRUG REPURPOSING AGAINST GLIOBLASTOMA
Authors: Weiss Tobias , Lee Sohyon , Buehler Marcel , Mena Julien , Lottenbach Zuzanna , Wegmann Rebekka , Bihl Michael , Sun Miaomiao , Goetze Sandra , van Drogen Audrey , Vasella Flavio , Wollscheid Bernd , Snijder Berend , Weller Michael
Published: November 2023

There remains an unmet need for novel treatment strategies against glioblastoma that are more effective than the current standard of care. However, the complex tumor microenvironment and genetic heterogeneity of these tumors require novel technologies enabling high-throughput assessment of cellular responses to treatments on a functional level in complex tumor samples with an intact cellular microenvironment. Here, we used a novel single-cell functional tissue profiling platform based on high—throughput microscopy followed by computer vision and machine learning algorithms to screen 70 clinically-approved drugs with good blood-brain-barrier penetration in 35 glioblastoma patient samples that were freshly obtained from surgery. This revealed prognostically relevant subtypes of glioma cell morphologies and promising candidates for drug repurposing. Among the drugs with potent anti-glioma activity, we identified the antidepressant Vortioxetine, that had strong anti-glioma activity across patients independent of the promoter methylation status of O6-methylguanine-DNA methyltransferase (MGMT). Complementrary in vitro studies using patient-derived glioma cell lines and orthotopic glioma xenograft mouse models confirmed the strong anti-glioma activity of Vortioxetine, leading to a notable fraction of long-term surviving mice. Mechanistically, multiplexed transcriptomics and proteomics unveiled that Vortioxetine induced an upregulation of the Activator protein 1 (AP-1) transcription factor family, along with the B-cell translocation gene (BTG) tumor suppressor genes. These findings serve as the cornerstone for future clinical applications of the single-cell functional tissue profiling platform and the potential clinical translation of Vortioxetine as a promising drug-repurposing candidate for glioblastoma patients.
DDDR-26. INHIBITION OF RAD52 ACTIVITY ENHANCES THE RADIOSENSITIVITY IN DIPG
Authors: Uchida Eita , Ishi Yukitomo , Watanabe Jun , Wang Lu , Abdala-Valencia Hiam , Gadd Samantha , Hashizume Rintaro
Published: November 2023

Diffuse intrinsic pontine glioma (DIPG) is one of the most devastating childhood cancers that limited response to radiation therapy, resulting in median overall survival of approximately 10 months. There is a critical need for new therapeutics that enhance the radiation effect while enabling the use of lower doses of radiation to limit long-term side effects in young patients. We, therefore, tested the hypothesis that targeting RAD52 activity sensitizes the radiation response of DIPG. Genome-wide CRISPR/Cas9 screening identified RAD52 as potential therapeutic target in DIPG cells. RAD52 inhibition, using shRNA mediated RAD52 depletion and treatment with RAD52 inhibitor, D-I03, suppressed DIPG cell proliferation. Importantly, RAD52 inhibition in combination with radiation therapy further increased radiosensitivity of DIPG cells. Immunocytochemistry of DNA double-strand breaks (DSB) marker γH2AX and repair marker 53BP1 showed that RAD52 inhibition sustained DNA damage with high levels of γH2AX at 24 hours following radiation while the level of 53BPI was decreased, thereby inhibiting DNA DSB repair. Western blotting also revealed that RAD52 inhibition causes a sustained level of phosphorylated Rad50 and γH2AX in irradiated DIPG cells. DNA repair assay showed that RAD52 inhibition suppressed DNA DSB repair through a homologous recombination pathway. RNA sequencing showed that RAD52 inhibition downregulated genes associated with the DNA repair pathway. Finally, the combination therapy of D-I03 RAD52 inhibitor and radiation inhibited tumor growth and significantly increased survival of mice bearing DIPG patient-derived xenografts, outperforming either monotherapy. Together, these results highlight RAD52 inhibitor as a potential radiosensitizer and provide a rationale for developing combination therapy with radiation in the treatment of DIPG.
EPID-09. ASSOCIATION BETWEEN VIRAL INFECTIONS AND GLIOMA RISK: A TWO-SAMPLE BI-DIRECTIONAL MENDELIAN RANDOMIZATION ANALYSIS
Authors: Yang Wenzhuo , Zhong Sheng , Xie Haoqun , Zhang Zhiyun , Sai Ke , Mou Yonggao
Published: November 2023

BACKGROUND

Glioma is one of the leading causes of brain tumors, but few etiologic factors of primary gliomas were identified. Previous observational research has shown an association between viral infection and glioma risk. Here, we sought to use Mendelian Randomization (MR) analysis to explore the direction and magnitude of the causal relationship between viral infections and glioma.

METHODS

We conducted a two-sample bi-directional MR analysis using Genome-Wide Association Study (GWAS) data. Summary statistics data of glioma were collected from the most extensive meta-analysis GWAS involving 12,488 cases and 18,169 controls. Single Nucleotide Polymorphisms (SNPs) associated with the exposures were used as instrumental variables to estimate the causal relationship between glioma and twelve types of viral infections from corresponding GWAS data. In addition, sensitivity analyses were performed.

RESULTS

After correcting for multiple tests and sensitivity analysis, we detected that genetically predicted VZV infection significantly decreased the risk of lower-grade glioma (LGG) development (OR=0.85, 95% CI: 0.76-0.96, P=0.0066, FDR=0.0396). No causal effects of the other eleven viral infections on glioma and reverse causality were detected.

CONCLUSIONS

Our research is one of this field's first and most significant studies. We showed robust evidence supporting that genetically predicted VZV infection reduces the risk of LGG. The findings from our research are a big step forward in understanding the etiology of glioma.
EPID-13. DATA-DRIVEN MACHINE LEARNING MODELS AS PROGNOSTIC TOOL FOR PREDICTING SURVIVAL OUTCOMES IN PEDIATRIC PATIENTS WITH GLIOMA OF THE OPTIC APPARATUS
Authors: Brown Nolan , Kuo Cathleen , Gendreau Julian
Published: November 2023

Optic pathway gliomas (OPG) are low-grade lesions arising from the astrocytes of the visual pathway and diencephalon. For most patients, observation appears to be the treatment of choice, but it remains unclear how frequently serial imaging should be obtained and at what point lesions can be deemed to have become quiescent. There is therefore an ongoing need for prognostication tools that can accurately predict the behavior of OPG to help identify those lesions meriting therapeutic intervention. In the present study, we leverage population-level data from the Surveillance, Epidemiology, and End. RESULTS: program (SEER) database to develop a predictive calculator for overall survival (OS) in pediatric OPG. Accordingly, we extracted all available patient-level data from the SEER database. Training and testing datasets were established. Cox proportional hazards regressions were then used to identify independent predictors of survival, and model validation was performed. A total of 1,052 pediatric patients met inclusion criteria. Most were between 5 to 9 years old (45.7%), males (51.6%), white (85.6%), non-Hispanic (82.1%), and 232 patients (22.1%) came from houses with a median income less than $54,999, while 111 patients (10.6%) lived in a rural county. Nearly 90% of patients did not undergo surgical debulking. Twenty-three patients (2.2%) received radiotherapy and 294 (27.9%) received chemotherapy. Additionally, univariate and multivariate analyses were performed to identify variables associated with OS. Median household income and subtotal resection were found to be predictors of OS on univariate analysis. Furthermore, on multivariate analysis, median household income greater than $55,000 and subtotal resection were predictive of higher OS. Age at diagnosis, sex, rural versus urban setting, benign versus malignant behavior, and use of chemotherapy or radiotherapy did not appear to affect OS. Finally, we created a calculator (https://spine.shinyapps.io/optic_glioma/) using our model to estimate 5-,10-, and 1-year OS probability and other survival outcomes.
EPID-30. DYSPHAGIA-RELATED HEALTHCARE UTILIZATION AMONG OLDER PATIENTS WITH PRIMARY AND METASTATIC BRAIN TUMORS: A NATIONAL STUDY OF MEDICARE BENEFICIARIES
Authors: Leiman David A , Parish Alice , Cohen Seth M , Niedzwiecki Donna , Johnson Margaret O
Published: November 2023

BACKGROUND

Swallowing dysfunction is common among older adults and the presence of a malignant brain tumor (primary or metastatic) may compound the existing burden of dysphagia in this population. We aimed to characterize the dysphagia-specific healthcare utilization among Medicare beneficiaries with malignant brain tumors.

METHODS

Using a Medicare 5% limited dataset (2013-2018) and ICD-9/10 codes, we identified beneficiaries (≥ 65 years) with primary malignant brain tumors (PMBTs) as well as the five most common solid tumors metastasizing to the brain (lung, breast, melanoma, renal, and colorectal). Those with disorders predisposing to dysphagia were excluded. Healthcare utilization was quantified using CPT codes for hospitalizations, gastroenterology services (endoscopy [EGD]), nutrition consultation, speech language management, radiographic testing, and enteral feeding access, occurring after cancer diagnosis. Comparisons of utilization by dysphagia status were made using chi-square and Wilcoxon rank-sum tests.

RESULTS

Among 79,926 beneficiaries, we identified 3,184 (4.0%) with malignant PBTs and 1,033 (1.3%) with brain metastases. Of the total cohort, 4.7% (n=3,777) experienced dysphagia. Whereas, 11.0% (n=349) of those with PMBTs and 7.9% (n=82) with brain metastases experienced dysphagia. Those with PMBTs were diagnosed with dysphagia significantly earlier in their disease course compared to other groups (median 20 vs. 36 vs. 58 days for PMBTs, brain metastases, and no brain metastases, respectively; p< 0.01). Speech pathology services use was highest among PMBT patients compared other groups (36.1%; n=126; p< 0.001). Gastroenterology services utilization overall was high among all groups and enteral feeding tube placement was significantly higher among PMBTs (p< 0.001).

CONCLUSIONS

Dysphagia increases with age and older patients with brain malignancies are at particularly high risk. Those with PMBTs experience dysphagia earlier in their disease course and dysphagia-related healthcare utilization is higher when compared to other cancers. Our findings have important implications as the number of Medicare beneficiaries is expected to increase.
EPCO-13. CNMF-SNS, A FRAMEWORK FOR UNSUPERVISED INTEGRATION OF MULTIOMICS DATA, IDENTIFIES INVASION AND RECURRENCE ASSOCIATED PROGRAMS IN GBM
Authors: Verhey Theodore , Seo Heewon , Morrissy Sorana
Published: November 2023

Glioblastoma (GBM) is an aggressive cancer of the brain for which novel therapies are urgently needed. Heterogeneity in GBM underlies tumor evolution and resistance to therapy and involves genetic diversity of tumor cells, spatially distinct niches harbouring stem-like cells, and immune cells spanning anti- and pro-tumor states. No single profiling methodology can capture all these facets of tumor biology in the same space and time, necessitating multi-omics data collection and computational methods suited for multi-omic integration across and within cohorts. We therefore set out to develop a generalizable framework for integration that can bridge across cohorts and data types. Using consensus non-negative matrix factorization (cNMF), we discover gene expression programs (GEPs) corresponding to cell types and/or states in an unsupervised fashion. Rather than choosing a single rank (number of programs), we identify both high and low-resolution programs for each dataset, and then integrate programs from all datasets and ranks into a solution network space (SNS) on which graph algorithms identify communities of highly similar GEPs identified in all or some datasets. These communities are characterized by gene set enrichment analyses and association with sample metadata. SNS communities can be used to transfer sample metadata across datasets, enabling multi-omics and multi-cohort integration, even in the absence of shared samples or cells. We showcase the utility of cNMF-SNS in integrating multiomics datasets of GBM from single-cell to bulk RNA-Seq and mass spectrometry proteomics. We further demonstrate the power of cNMF-SNS to define and cross-annotate programs identified in 5 complementary mass spectrometry datasets of GBM, layering on survival, driver gene mutation status, clinical features, and imaging features. We demonstrate robust mapping of biologically and clinically relevant processes, highlighting how programs for tumor cell invasion and therapy resistance can be mined for novel therapeutic targets. cNMF-SNS is available at https://github.com/MorrissyLab/cNMF-SNS.
EPCO-14. IDENTIFYING EPIGENETIC VULNERABILITIES OF MINIMAL RESIDUAL DISEASE IN GLIOBLASTOMA USING IN VIVO CRISPR SCREENS
Authors: Mitchell Kelly , Mihalas Anca , Arora Sonali , Paddison Patrick , Patel Anoop
Published: November 2023

Therapy for glioblastoma (GBM) includes surgical resection, radiation, and chemotherapy, which functionally reduces tumor burden to a state of minimal residual disease (MRD). However, recurrence over time is universal. Large-scale longitudinal studies of GBM patient samples did not identify selection pressure for specific DNA mutations in recurrent disease, highlighting the importance of epigenetic mechanisms during relapse. In this study, we aim to model MRD and the functional and transcriptional effects of epigenetic perturbations in GBM patient derived xenografts (PDXs). We developed an in vivo inducible genome editing system by engineering 827 GBM stem cells to express doxycycline inducible Cas9 and a pool of 14 CRISPR sgRNAs targeting 5 epigenetic factors (readers/erasers of H3K27me3 and H4 acetyltransferase KAT5) and controls. Tumor cells are implanted orthotopically and mice are followed by serial MRIs until tumor volumes reach 2mm3, after which in vivo editing is induced by administration of doxycycline. Cells are harvested for scRNA-sequencing and targeted amplification of sgRNA libraries, allowing for assignment of sgRNAs to individual cells. Genome editing efficiencies ranged from 50-90% in vivo. Knockout of core Polycomb (PcG) complex members led to dysregulated expression of genes involved in therapeutic resistance and altered cell state distributions. Current directions include optimization of sgRNA targeting and recovery of CRISPR-edited cells from tumors for scaling up screens. In addition, we have developed a “standard of care” treatment regimen in GBM PDX models whereby temozolomide and radiation therapy is dose optimized to achieve a latent state that mimics MRD followed by eventual tumor recurrence. Future experiments will combine MRD modeling in PDXs with in vivo CRISPR screening to characterize functional dependencies of MRD in GBM. This data provides proof of concept for utilizing these tools for studying genotype to phenotype connections in a complex GBM model system.
EPCO-15. DETECTING HISTOLOGIC & CLINICAL GLIOBLASTOMA PATTERNS OF PROGNOSTIC RELEVANCE
Authors: Baheti Bhakti , Rai Sunny , Innani Shubham , Mehdiratta Garv , Guntuku Sharath Chandra , Nasrallah MacLean P , Bakas Spyridon
Published: November 2023

BACKGROUND

Glioblastoma is the most common adult primary brain tumor. Limited improvement in patient prospects over the last 20 years reflects our limited disease understanding. Robust prognostic patient stratification from whole slide images (WSI) & clinical data using interpretable computational methods could improve disease understanding and patient management.

MATERIAL AND METHODS

The TCGA-GBM and TCGA-LGG data collections were reclassified according to the 2021 WHO classification criteria, identifying 188 glioblastoma (IDH-wt, Gr.4) cases and stratifying them to short- (< 9 months) and long-survivors ( > 13 months). H&E-stained WSI were comprehensively curated to remove artifactual content. An interpretability mechanism based on weakly-supervised attention-based multiple-instance-learning was employed. The prognostic relevance of associated clinical data was also evaluated both independently and integratively, using XGBoost and ‘SHapely Additive exPlanations’. Late fusion amalgamates the advantage of WSI patterns with clinical features by averaging the output probabilities of two distinct models at the decision level. Quantitative performance evaluation was based on a 10-fold monte carlo cross-validation, with training (80%), validation (10%), and test (10%) sets.

RESULTS

Our imaging, clinical, and integrative multi-modal models revealed AUCTest of 0.68/0.72/0.75 respectively. The imaging analysis revealed correctly predicted long-survivors associated with histologically malignant areas, including necrosis, hypercellularity, atypia, infiltration, and proliferation. Correctly classified short survivors highlighted influence by aggressive infiltrative features, including leptomeningeal involvement. The clinical analysis revealed age, mutation count, and TERT promoter status as the top three features contributing to stratification, in the XGBoost model.

CONCLUSION

Our findings support data-driven histology & data interpretation of algorithmic decisions contribute to further understanding of glioblastoma by identifying morphology patterns & clinical patterns of prognostic relevance. Integration of multiple modalities can be a powerful approach for improving the performance of AI models.
EPCO-50. THE TRANSCRIPTIONAL LANDSCAPE OF KEY INNATE DNA SENSORS WITHIN PRIMARY BRAIN TUMORS
Authors: Mangoli Avani , Bowie Michelle , Ashley David , Low Justin , Stevenson Kevin , Chandramohan Vidya , Hariharan Seetha
Published: November 2023

Primary brain tumors are notoriously resistant to immunotherapy. The efficacy of these treatments potentially requires normal expression of DNA innate sensors within both the immune and tumor compartments. Recently, we found that STING1, involved in the CGAS/STING pathway, is epigenetically silenced in the neoplastic cells of primary brain tumors. This silencing can be traced back to the normal brain. We and others have shown that rescue of STING1 expression can be modulated with epigenetic treatments. The mechanism by which DNA damage in cancer leads to an inflammatory response sheds light on the significance of other DNA sensors. We hypothesize that innate immune silencing within the tumor contributes to immunotherapy resistance and the addition of epigenetic treatments could increase efficacy. We evaluated the transcriptional landscape of DNA innate sensors within normal adult brain and in patient derived tumors including glioblastoma, pilocytic astrocytoma, and diffuse midline gliomas, H3K27M mutant. We found low expression of additional cytosolic DNA sensors including cGAS, AIM2, ZBP1 in normal neuronal as well as tumor cells. Since epigenetic silencing is modulated during normal development, we compared the transcriptional innate profiles from normal cortex brain development to primary brain cancers. DNA innate immune sensor expression correlates with pre-oligodendrocyte progenitor cells and oligodendrocyte progenitor cells. These results suggest the innate immune suppression of these key cytosolic DNA sensors is established early in fetal brain development and retained in the context of primary brain tumors. We are currently exploring the epigenetic profiles of fetal brain and brain tumors to determine how these innate immune expression patterns affect tumorigenesis and response to immunotherapy treatment.