Exploring the role of cerebrospinal fluid as analyte in neurologic disorders

The cerebrospinal fluid (CSF) is a clear ultrafiltrate of blood that envelopes and protects the central nervous system while regulating neuronal function through the maintenance of interstitial fluid homeostasis in the brain. Due to its anatomic location and physiological functions, the CSF can provide a reliable source of biomarkers for the diagnosis and treatment monitoring of different neurological diseases, including neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and primary and secondary brain malignancies. The incorporation of CSF biomarkers into the drug discovery and development can improve the efficiency of drug development and increase the chances of success. This review aims to consolidate the current use of CSF biomarkers in clinical practice and explore future perspectives for the field.

Binned Data Provide Better Imputation of Missing Time Series Data from Wearables

The presence of missing values in a time-series dataset is a very common and well-known problem. Various statistical and machine learning methods have been developed to overcome this problem, with the aim of filling in the missing values in the data. However, the performances of these methods vary widely, showing a high dependence on the type of data and correlations within the data. In our study, we performed some of the well-known imputation methods, such as expectation maximization, k-nearest neighbor, iterative imputer, random forest, and simple imputer, to impute missing data obtained from smart, wearable health trackers. In this manuscript, we proposed the use of data binning for imputation. We showed that the use of data binned around the missing time interval provides a better imputation than the use of a whole dataset. Imputation was performed for 15 min and 1 h of continuous missing data. We used a dataset with different bin sizes, such as 15 min, 30 min, 45 min, and 1 h, and we carried out evaluations using root mean square error (RMSE) values. We observed that the expectation maximization algorithm worked best for the use of binned data. This was followed by the simple imputer, iterative imputer, and k-nearest neighbor, whereas the random forest method had no effect on data binning during imputation. Moreover, the smallest bin sizes of 15 min and 1 h were observed to provide the lowest RMSE values for the majority of the time frames during the imputation of 15 min and 1 h of missing data, respectively. Although applicable to digital health data, we think that this method will also find applicability in other domains.

Case Report of AdAPT-001-Mediated Sensitization to a Previously Failed Checkpoint Inhibitor in a Metastatic Chordoma Patient

Chordoma is a rare, but aggressive bone tumor with a high recurrence rate that primarily arises at the cranial and caudal ends of the axial skeleton. Systemic chemotherapies are not effective against the tumor, and outside of surgical resection and radiation, no approved options are available. Prognosis depends on the extent of surgical resection, with the more the better, and adjuvant radiotherapy. Herein is presented the first-ever case of a recurrent chordoma patient that responded to the combination of one dose of an experimental TGF-beta trap carrying oncolytic adenovirus, known as AdAPT-001, followed by immune checkpoint inhibitor therapy, despite prior progression on an anti-PD-1. This case report highlights the potential of AdAPT-001 as a treatment modality in combination with checkpoint inhibition for recurrent chordoma.

Handgrip Strength Is Related to Hippocampal and Lobar Brain Volumes in a Cohort of Cognitively Impaired Older Adults with Confirmed Amyloid Burden

BACKGROUND

Strength and mobility are essential for activities of daily living. With aging, weaker handgrip strength, mobility, and asymmetry predict poorer cognition. We therefore sought to quantify the relationship between handgrip metrics and volumes quantified on brain magnetic resonance imaging (MRI).

OBJECTIVE

To model the relationships between handgrip strength, mobility, and MRI volumetry.

METHODS

We selected 38 participants with Alzheimer's disease dementia: biomarker evidence of amyloidosis and impaired cognition. Handgrip strength on dominant and non-dominant hands was measured with a hand dynamometer. Handgrip asymmetry was calculated. Two-minute walk test (2MWT) mobility evaluation was combined with handgrip strength to identify non-frail versus frail persons. Brain MRI volumes were quantified with Neuroreader. Multiple regression adjusting for age, sex, education, handedness, body mass index, and head size modeled handgrip strength, asymmetry and 2MWT with brain volumes. We modeled non-frail versus frail status relationships with brain structures by analysis of covariance.

RESULTS

Higher non-dominant handgrip strength was associated with larger volumes in the hippocampus (p = 0.02). Dominant handgrip strength was related to higher frontal lobe volumes (p = 0.02). Higher 2MWT scores were associated with larger hippocampal (p = 0.04), frontal (p = 0.01), temporal (p = 0.03), parietal (p = 0.009), and occipital lobe (p = 0.005) volumes. Frailty was associated with reduced frontal, temporal, and parietal lobe volumes.

CONCLUSION

Greater handgrip strength and mobility were related to larger hippocampal and lobar brain volumes. Interventions focused on improving handgrip strength and mobility may seek to include quantified brain volumes on MR imaging as endpoints.

Association of Autologous Tumor Lysate-Loaded Dendritic Cell Vaccination With Extension of Survival Among Patients With Newly Diagnosed and Recurrent Glioblastoma: A Phase 3 Prospective Externally Controlled Cohort Trial

Importance

Glioblastoma is the most lethal primary brain cancer. Clinical outcomes for glioblastoma remain poor, and new treatments are needed.

Objective

To investigate whether adding autologous tumor lysate-loaded dendritic cell vaccine (DCVax-L) to standard of care (SOC) extends survival among patients with glioblastoma.

Design, Setting, and Participants

This phase 3, prospective, externally controlled nonrandomized trial compared overall survival (OS) in patients with newly diagnosed glioblastoma (nGBM) and recurrent glioblastoma (rGBM) treated with DCVax-L plus SOC vs contemporaneous matched external control patients treated with SOC. This international, multicenter trial was conducted at 94 sites in 4 countries from August 2007 to November 2015. Data analysis was conducted from October 2020 to September 2021.

Interventions

The active treatment was DCVax-L plus SOC temozolomide. The nGBM external control patients received SOC temozolomide and placebo; the rGBM external controls received approved rGBM therapies.

Main Outcomes and Measures

The primary and secondary end points compared overall survival (OS) in nGBM and rGBM, respectively, with contemporaneous matched external control populations from the control groups of other formal randomized clinical trials.

Results

A total of 331 patients were enrolled in the trial, with 232 randomized to the DCVax-L group and 99 to the placebo group. Median OS (mOS) for the 232 patients with nGBM receiving DCVax-L was 19.3 (95% CI, 17.5-21.3) months from randomization (22.4 months from surgery) vs 16.5 (95% CI, 16.0-17.5) months from randomization in control patients (HR = 0.80; 98% CI, 0.00-0.94; P = .002). Survival at 48 months from randomization was 15.7% vs 9.9%, and at 60 months, it was 13.0% vs 5.7%. For 64 patients with rGBM receiving DCVax-L, mOS was 13.2 (95% CI, 9.7-16.8) months from relapse vs 7.8 (95% CI, 7.2-8.2) months among control patients (HR, 0.58; 98% CI, 0.00-0.76; P < .001). Survival at 24 and 30 months after recurrence was 20.7% vs 9.6% and 11.1% vs 5.1%, respectively. Survival was improved in patients with nGBM with methylated MGMT receiving DCVax-L compared with external control patients (HR, 0.74; 98% CI, 0.55-1.00; P = .03).

Conclusions and Relevance

In this study, adding DCVax-L to SOC resulted in clinically meaningful and statistically significant extension of survival for patients with both nGBM and rGBM compared with contemporaneous, matched external controls who received SOC alone.

Trial Registration

ClinicalTrials.gov Identifier: NCT00045968.

A Review of Persistent Post-COVID Syndrome (PPCS)

Persistent post-COVID syndrome, also referred to as long COVID, is a pathologic entity, which involves persistent physical, medical, and cognitive sequelae following COVID-19, including persistent immunosuppression as well as pulmonary, cardiac, and vascular fibrosis. Pathologic fibrosis of organs and vasculature leads to increased mortality and severely worsened quality of life. Inhibiting transforming growth factor beta (TGF-β), an immuno- and a fibrosis modulator, may attenuate these post-COVID sequelae. Current preclinical and clinical efforts are centered on the mechanisms and manifestations of COVID-19 and its presymptomatic and prodromal periods; by comparison, the postdrome, which occurs in the aftermath of COVID-19, which we refer to as persistent post-COVID-syndrome, has received little attention. Potential long-term effects from post-COVID syndrome will assume increasing importance as a surge of treated patients are discharged from the hospital, placing a burden on healthcare systems, patients' families, and society in general to care for these medically devastated COVID-19 survivors. This review explores underlying mechanisms and possible manifestations of persistent post-COVID syndrome, and presents a framework of strategies for the diagnosis and management of patients with suspected or confirmed persistent post-COVID syndrome.

MTAP loss: a possible therapeutic approach for glioblastoma

Glioblastoma is the most lethal form of brain tumor with a recurrence rate of almost 90% and a survival time of only 15 months post-diagnosis. It is a highly heterogeneous, aggressive, and extensively studied tumor. Multiple studies have proposed therapeutic approaches to mitigate or improve the survival for patients with glioblastoma. In this article, we review the loss of the 5'-methylthioadenosine phosphorylase (MTAP) gene as a potential therapeutic approach for treating glioblastoma. MTAP encodes a metabolic enzyme required for the metabolism of polyamines and purines leading to DNA synthesis. Multiple studies have explored the loss of this gene and have shown its relevance as a therapeutic approach to glioblastoma tumor mitigation; however, other studies show that the loss of MTAP does not have a major impact on the course of the disease. This article reviews the contrasting findings of MTAP loss with regard to mitigating the effects of glioblastoma, and also focuses on multiple aspects of MTAP loss in glioblastoma by providing insights into the known findings and some of the unexplored areas of this field where new approaches can be imagined for novel glioblastoma therapeutics.

Clinical Course of Two Patients with COVID-19 Respiratory Failure After Administration of the Anticancer Small Molecule, RRx-001

Two critically ill COVID-19 infected patients, who had exhausted all available treatment options, were treated with the small-molecule RRx-001 with subsequent improvement. RRx-001, a first-in-class small molecule with anti-inflammatory, vascular normalizing and macrophage-repolarizing properties, has been safely administered 300+ patients in clinical trials. This is the first report of RRx-001 treatment of COVID-19.

Phase 2 study of AV-GBM-1 (a tumor-initiating cell targeted dendritic cell vaccine) in newly diagnosed Glioblastoma patients: safety and efficacy assessment

Background

Vaccine immunotherapy may improve survival in Glioblastoma (GBM). A multicenter phase II trial was designed to determine: (1) the success rate of manufacturing the Aivita GBM vaccine (AV-GBM-1), (2) Adverse Events (AE) associated with AV-GBM-1 administration, and (3) survival.

Methods

Fresh suspected glioblastoma tissue was collected during surgery, and patients with pathology-confirmed GBM enrolled before starting concurrent Radiation Therapy and Temozolomide (RT/TMZ) with Intent to Treat (ITT) after recovery from RT/TMZ. AV-GBM-1 was made by incubating autologous dendritic cells with a lysate of irradiated autologous Tumor-Initiating Cells (TICs). Eligible patients were adults (18 to 70 years old) with a Karnofsky Performance Score (KPS) of 70 or greater, a successful TIC culture, and sufficient monocytes collected. A cryopreserved AV-GBM-1 dose was thawed and admixed with 500 μg of Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) before every subcutaneous (s.c.) administration.

Results

Success rates were 97% for both TIC production and monocyte collection. AV-GBM-1 was manufactured for 63/63 patients; 60 enrolled per ITT; 57 started AV-GBM-1. The most common AEs attributed to AV-GBM-1 were local injection site reactions (16%) and flu-like symptoms (10%). Treatment-emergent AEs included seizures (33%), headache (37%), and focal neurologic symptoms (28%). One patient discontinued AV-GBM-1 because of seizures. Median Progression-Free Survival (mPFS) and median Overall Survival (mOS) from ITT enrollment were 10.4 and 16.0 months, respectively. 2-year Overall Survival (OS) is 27%.

Conclusions

AV-GBM-1 was reliably manufactured. Treatment was well-tolerated, but there were numerous treatment-emergent central nervous system AEs. mPFS was longer than historical benchmarks, though no mOS improvement was noted.

Trial registration

NCT, NCT03400917, Registered 10 January 2018,

Differentiation of Subjective Cognitive Decline, Mild Cognitive Impairment, and Dementia Using qEEG/ERP-Based Cognitive Testing and Volumetric MRI in an Outpatient Specialty Memory Clinic

BACKGROUND

Distinguishing between subjective cognitive decline (SCD), mild cognitive impairment (MCI), and dementia in a scalable, accessible way is important to promote earlier detection and intervention.

OBJECTIVE

We investigated diagnostic categorization using an FDA-cleared quantitative electroencephalographic/event-related potential (qEEG/ERP)-based cognitive testing system (eVox® by Evoke Neuroscience) combined with an automated volumetric magnetic resonance imaging (vMRI) tool (Neuroreader® by Brainreader).

METHODS

Patients who self-presented with memory complaints were assigned to a diagnostic category by dementia specialists based on clinical history, neurologic exam, neuropsychological testing, and laboratory results. In addition, qEEG/ERP (n = 161) and quantitative vMRI (n = 111) data were obtained. A multinomial logistic regression model was used to determine significant predictors of cognitive diagnostic category (SCD, MCI, or dementia) using all available qEEG/ERP features and MRI volumes as the independent variables and controlling for demographic variables. Area under the Receiver Operating Characteristic curve (AUC) was used to evaluate the diagnostic accuracy of the prediction models.

RESULTS

The qEEG/ERP measures of Reaction Time, Commission Errors, and P300b Amplitude were significant predictors (AUC = 0.79) of cognitive category. Diagnostic accuracy increased when volumetric MRI measures, specifically left temporal lobe volume, were added to the model (AUC = 0.87).

CONCLUSION

This study demonstrates the potential of a primarily physiological diagnostic model for differentiating SCD, MCI, and dementia using qEEG/ERP-based cognitive testing, especially when combined with volumetric brain MRI. The accessibility of qEEG/ERP and vMRI means that these tools can be used as adjuncts to clinical assessments to help increase the diagnostic certainty of SCD, MCI, and dementia.

MODL-17. SEGMENTATION OF PRE AND POST-TREATMENT GLIOMA TISSUE TYPES INCLUDING RESECTION CAVITIES

PURPOSE

Measuring gliomas is a time-intensive process with significant inter-rater variability in post-surgical residual tumor and resection cavities. This likely contributes to the delayed assessment of progression and in-field recurrences from radiation. Automated segmentation of pre and post-treatment gliomas could reduce inter-rater variability and increase workflow efficiency for routine longitudinal radiographic assessment and treatment planning. We evaluated whether a 3D neural network is comparable to expert assessment of pre and post-treatment diffuse gliomas tissue types and resection cavities.

METHODS

A retrospective cohort of 647 MRIs of patients with diffuse gliomas (average 55.1 years, 45% female, 396 pre-treatment and 251 post-treatment, median 237 days post-surgery) from The Cancer Imaging Archive were stratified by operation status and tumor grade and randomly split into training (536) and testing (111) samples. T1, T1-post-contrast, T2, and FLAIR images were registered, skull-stripped, and interpolated to 1x1x1. Four classes — edema/infiltrative/post-treatment changes (ED), enhancing tissue (ET), necrotic core (NCR), and resection cavities (RC) — were manually segmented by an expert neuroradiologist. Using these segmentations and the four input image modalities, a nnU-Net, a state-of-the-art 3D U-Net convolutional neural network, was trained to predict segmentations of the four classes.

RESULTS

Segmentation performance in the test set for the ED, ET, and RC classes was at the level of inter-rater reliability with median Dice scores ranging from 0.85 to 1 and relative volume errors ranging from -0.05 to 0.02. There was a near-perfect correlation between manually segmented and predicted total lesion volumes (r2 values ranging from 0.95 to 0.98 among classes).

CONCLUSIONS

Accurate, automated volumetric quantification of diffuse glioma tissue volumes may improve response assessment in clinical trials and reduce provider burden and errors in measurement.

INNV-19. THE DETECTION OF DISSEMINATED PINEAL PARENCHYMAL TUMOR OF INTERMEDIATE DIFFERENTIATION (PPTID) IN CEREBROSPINAL FLUID (CSF) USING CELL CAPTURE AND IMMUNOCYTOCHEMISTRY

BACKGROUND

Pineal parenchymal tumors of intermediate differentiation (PPTID) account for 21% to 54% of pineal parenchymal tumors and may be complicated by cerebrospinal dissemination (most commonly at time of reoccurrence; up to 4-10 years post resection). The integral membrane protein synaptophysin is expressed in neuroendocrine cells and virtually all neuraxial neurons that contribute to synaptic transmission. PPTID frequently demonstrates synaptophysin independently of other neural differentiation markers. Cerebrospinal fluid (CSF) cell capture assays have demonstrated utility for assessing disseminated intracranial neoplasms, thus we explore this technology for monitoring a patient with PPTID.

METHODS

A 30-year-old female patient with PPTID diagnosed two years prior was suspected for intracranial dissemination and underwent five CSF collections over the course of 64 days. Per collection, approximately 7 mL of CSF was submitted for each cytology and cell capture. Cytology was performed at Providence Saint John’s Health Center. The CNSide™ platform (Biocept, Inc.) was used to capture and stain cells for DAPI, synaptophysin, and CD45. Multiple capture antibody cocktails (termed 1986, 1822, and gTP1—originally developed for use in carcinoma, melanoma, and glioma) were tested. Cells of interest (COI) were defined by positive immunoreactivity for both DAPI and synaptophysin and no immunoreactivity for CD45. Results were quantified and compared longitudinally.

RESULTS

CSF analysis on days 0, 9, 21, 36, and 64 demonstrated negative results by cytology and 51, 96, 170, 130, and 43 COI/mL by the CNSide platform, respectively. Cumulative mean capture rates for cocktails 1986, 1822, and gTP1 were 47, 14, and 36 COI/mL/sample, respectively.

DISCUSSION

A significant amount of PPTID patients will develop cerebrospinal dissemination. The importance of craniospinal control in this setting has been previously demonstrated. Our work suggests that cell capture assays paired with immunocytochemistry can be used as sensitive means to monitor disseminated PPTID and may impact treatment decisions.

INNV-06. DETECTION OF MUTANT P53 POSITIVE GLIOBLASTOMA CELLS IN CEREBROSPINAL FLUID (CSF) USING A MICROFLUIDIC BASED IMMUNOASSAY

BACKGROUND

Metastatic involvement of the CSF by non-CNS neoplasms surpasses that of primary brain tumors, although conventional glioblastoma (GBM) can occasionally be identified in the CSF. Here, we apply Biocept’s CNSide test to examine a patient CSF sample with GBM, verified with an antibody against mutant p53. The p53 pathway is deregulated in 84% of glioblastoma patients and point mutations lead to expression of mutant p53 protein.

METHODS

A CSF sample from 65-year-old male patient, with GBM diagnosed by MRI & CT, and prior identified p53 mutation on R273C by NGS was collected into Biocept’s CSF collection tubes at Providence Saint John’s Health Center. CSF-cells were incubated, 2 days post collection, with a proprietary antibody cocktail, including anti-CD9, followed with a biotinylated secondary, which enables enrichment of capture antibody labeled cells in a streptavidin coated microfluidic device. Cells were fixed and permeabilized immunofluorescence was performed against mutant p53, CD45, fluorescently labeled streptavidin, for capture antibody detection, and DAPI. Microfluidic chips were scanned and analyzed on a Bioview system. The specificity of the mutant p53 antibody was verified using the same test on tumor cells with either wildtype p53 vs various p53 mutations.

RESULTS

CSF analysis by the CNSide platform detected 3 tumor cells / mL. Immunofluorescence confirmed strong expression of mutant p53 protein on about 1/3 of cells identified as tumor cells. Besides the patient R273C mutation, we demonstrated detection of P223L/V274F, E285K and Q331R mutations on tumor cell lines.

DISCUSSION

Our work suggests that a microfluidic based GBM capture test paired with appropriate biomarkers can be used as sensitive means to detect GBM cells in CSF and may be useful for diagnostics and treatment monitoring. Further, we demonstrated the utility of a mutant p53 antibody to identify tumor cells. Technical and clinical studies are needed to substantiate this hypothesis.

EPCO-10. SYSTEMS BIOLOGY-BASED THERAPEUTIC PREDICTIONS WITH GBMSYGNAL AND CLINICAL CORRELATES IN THE REAL-WORLD LONGITUDINAL OUTCOMES REGISTRY XCELSIOR

Glioblastoma is an aggressive disease with multiple disrupted signaling networks in the same tumor, demanding the development of personalized combination regimens. Using SYstems Genetics Network AnaLysis we analyzed TCGA multiomics datasets for 422 glioblastoma patients to generate a predictive disease network model (gbmSYGNAL). This model seeks to uncover how subsets of mutations causally modulate regulators (transcription factors, miRNAs, etc.) that mechanistically regulate gene modules (“regulons”) associated with disease progression. Using the real-world registry XCELSIOR (NCT03793088), we identified 55 anti-cancer therapies utilized in glioblastoma treatment (N = 354 patients) and associated them with positive or negative regulon activity within individual patients across the TCGA cohort. A median of 12 regulons were targeted by each drug. Interestingly, nilotinib targeted only 5 regulons but they were found to be active in 38% of patients and regulons overactive in &gt;35% of patients were targeted by repurposed anti-cancer drugs including celecoxib, hydroxychloroquine, and tocilizumab. Standard-of-care treatments lomustine and bevacizumab were predicted to be active in only 28% and 23% of patients, respectively. Using gbmSYGNAL, we then prioritized drugs for 12 additional patients from the XCELSIOR registry. Median overactive regulons per patient was 110 (range 55-254) represented by a median 28 molecular targets (range 17-37). Surprisingly, regulons targeted by metformin were predicted to be overactive in all patients. Certain regulons displayed a binary pattern (high “on” activity or completely “off” per patient) including those targeted by pemetrexed, pembrolizumab, and valproic acid while others showed a gradient of activity across patients including selinexor, panobinostat, palbociclib, and alpelisib. Systems biology analysis of commercially available NGS data combined with the XCELSIOR direct patient engagement platform yielded therapeutically actionable insights for glioblastoma patients in real time. Correlation with clinical outcomes is ongoing for ~50 additional patients and will be presented at the meeting.

QLTI-26. INTEGRATION OF NEURO-ONCOLOGY CLINICAL PATHWAYS IN PROVIDENCE SOUTHERN CALIFORNIA CLINICAL RESEARCH NETWORK

INTRODUCTION

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

RESULTS

After 3 months of utilization within our Southern California region, 342 treatment decisions were made across all cancers, and 85.1% of cancer patients were treated on pathway. Of which, 7 treatment decisions were made within the neuro-oncology specialty, and 85.7% of those cancer patients were treated on pathway.

CONCLUSION

We successfully integrated and initiated ClinicalPath in a multiple hospital-affiliated community oncology clinical trial network. We are actively working across our Southern California Region to map locally available clinical trials to promote awareness and increase enrollment. Provider utilization and patient on-pathway rates are actively monitored and will be updated.

NCMP-07. CASE SERIES OF REGULARLY SCHEDULED MANNITOL INFUSIONS SHOWING WITH PROLONGED CLINICAL BENEFIT FOR MANAGEMENT OF CEREBRAL EDEMA IN GLIOMAS

Gliomas account for the vast majority of malignant primary tumors arising in the central nervous system. Elevated intracranial pressure (ICP) may be a potentially devastating complication of brain tumors and hydrocephalus. Brain tumors may occupy significant space causing displacement and compression of delicate structures within a finite intracranial compartment. The compliance relationship is nonlinear and decreases as the combined volume of the intracranial contents increases. When these compensatory mechanisms have been exhausted, significant increases in pressure develop with relatively small increases in volume. The diagnosis of elevated ICP is generally based on clinical findings and corroborated by imaging studies and the patient's medical history. The best therapy for intracranial hypertension (ICH) is the resolution of the proximate cause of elevated ICP such as the evacuation of a blood clot, resection of a tumor, or cerebrospinal fluid (CSF) diversion in the setting of hydrocephalus. If these modalities have been exhausted or unavailable, osmotic diuretics such as mannitol can be utilized. This medication reduces brain volume by drawing free water out of the tissue and into the circulation, where it is excreted by the kidneys, thus dehydrating brain parenchyma. The common belief is that effects are usually present within minutes, peak at approximately one hour, and last 4 to 24 hours. We report a series of 33 patients treated for a minimum of 1 month of regularly scheduled maintenance infusions of Mannitol 1g/kg every two weeks, 64% showed improved clinical outcomes or stabilization of edema clinical symptoms. Patients expressed improvements in headaches, dizziness, and cognitive ability. This supports the bi-weekly maintenance use of Mannitol in glioma patients with symptomatic cerebral edema. A controlled trial should be supported. This series also suggest a mechanism of action with a more durable response than osmotic diuresis.

INNV-26. EMERGENCE OF VIRTUAL TUMOR BOARD [VTB] IN NEURO-ONCOLOGY: OPPORTUNITIES AND CHALLENGES

INTRODUCTION

Virtual tumor board [VTB] platforms are an important aspect of cancer management. They enable easier access to a multidisciplinary team of experts. In order to deliver high-quality cancer care, it is necessary to coordinate numerous therapies and providers, and maintain open lines of communication among all professionals involved. Design/

METHODS

We performed a systematic search of all VTBs incorporating a platform designed for this specific role. We reviewed the records of Genomet, Medical University of South Carolina[MUSC] and Xcures virtual tumor boards. Summary data examined include year of launch, demographics, characteristics of cases, average response time, advantages, and how they handle protected health information.

RESULTS

30% of VTBs examined launched in 2017. All had a HIPAA compliant online environment. Xcures records reveals median age of female patients was 57yrs and the median age of male patients was 55 years. The data showed that 44% with a confirmed treatment preferred VTB integrated option. 76% of patients in Xcures registry consist of primary CNS tumors. There are at least 556 patients in the tumor registry which included 46% Glioblastoma cases [96% primary, 4% secondary]. MUSC VTB shows 112 thoracic tumor cases and 9 neuro-Oncology cases. Genomet VTB data shows age range from 6 months to 84 years [mean age 44.5 years] with 69.6% males and 30.4% females, 43.5% glioblastoma, 8.7% adenocarcinoma, 8.7% infratentorial tumor. Average response time observed in all cases was ≤ 24 hours.

CONCLUSION

VTBs allow for quicker expert analysis of cases. More studies are needed to gain additional insight into user engagement metrics.

CTNI-51. FEASIBILITY AND SAFETY OF NEUROSURGICAL RESECTION AND INTRA-OPERATIVE RADIATION THERAPY USING THE XOFT AXXENT ELECTRONIC BRACHYTHERAPY SYSTEM AND BEVACIZUMAB IN RECURRENT GLIOBLASTOMA

Glioblastoma (GBM) is the most common and aggressive primary brain tumor. External beam radiation therapy (EBRT) is widely recognized as an effective treatment for primary GBM. EBRT applied after GBM resection is associated with an increase in overall survival. Beyond upfront therapy with radiation and temozolomide chemotherapy, there is no standard therapy that has been proven effective. Re-irradiation with ERBT is minimally effective and with significant comorbidities. Our study uses IORT at the time of re-resection in patients who have recurrent, operable GBM after failure of who received primary EBRT and temozolamide in their first course of treatment. IORT allows the delivery of a large effective radiation dose applied directly to the tumor bed at the time of resection. This affords direct radiation to be delivered to the micro- and macroscopic tumor remnants in the vicinity of the resection cavity immediately following gross resection. In contrast, the more distant, surrounding brain tissue does not receive high radiation exposure. This Phase II study continues to accrue subjects with the primary endpoint of overall survival and several secondary endpoints that includes progression free survival, quality of life, and adverse events/safety. To date, five patients have been treated on this protocol. The technical feasibility and safety of administering intraoperative radiation with the Xoft System has been established in this cohort. Preliminary GLIOX Trial findings demonstrate the safety and feasibility of using the Xoft Axxent® Electronic Brachytherapy System to administer intracranial radiation during resection of recurrent glioblastomas. We will report new and expansive study results to include these early findings.

QLTI-22. IMPROVING BRAIN CANCER PATIENT ACCESS TO CLINICAL TRIALS ACROSS SEVEN COMMUNITY HOSPITALS, THE PROVIDENCE SOUTHERN CALIFORNIA CLINICAL RESEARCH NETWORK

Despite current FDA approved treatments for glioblastoma (GBM), prognosis remains poor. The rare patient population and limited access to clinical trials are factors in this poor prognosis. Clinical trials need to increase enrollment of patients with glioblastoma and other brain cancers to more rapidly develop more effective treatments. Clinical trials are featured on NCCN guidelines, and are considered “Standard of Care” by many experts. Multiple studies have shown that access to clinical trials is associated with improved survival in GBM, however, less than 25% of patients have access or are offered clinical trials. Access to clinical trials can be even more limited in community hospitals, while a large proportion of brain tumors are treated in smaller centers. Community hospitals care for a significant number of brain tumors annually. We have developed a Clinical Research Network for Neuro-Oncology within the Providence Network involving seven hospitals to date. In the past 3 years, we have grown the number of clinical trials available in outlying cities and counties spanning a distance of 60 miles. Between the seven hospitals in our network, we have 15 clinical trials currently open for brain cancer patients, of which, 3 trials were phase I studies. Over the past 2 years, we have enrolled 104 GBM patients in clinical trials. The ability to enhance access to clinical trials by Neuro-Oncologists treating patients in the community is feasible and promising.

BIOS-03. REAL WORLD CLINICAL OUTCOMES OF PATIENTS WITH DIFFUSE MIDLINE GLIOMA IN A LONGITUDINAL OUTCOMES REGISTRY

We utilized the longitudinal clinical outcomes registry XCELSIOR (NCT03793088) to understand real world outcomes and treatment patterns among patients with diffuse midline glioma. A total of 74 patients were identified with a diagnosis of diffuse midline glioma by pathology or imaging (36 pediatric and 38 adult patients). Median age at diagnosis was 20 years. As of 6/1/2022, 45 patients had expired. Median overall survival (mOS) of the entire cohort was 16.2 months. Cox proportional hazard ratio analysis identified age as the only significant covariate for OS (pediatric HR = 1.59, p=0.04). Pediatric patients had a mOS of 12.9 months and adult patients a mOS of 18.9 months from diagnosis. Frequency of primary tumor location in this dataset was brainstem (35%), thalamus (23%), and pons (20%). Pons location was associated with worst survival (mOS 11.4 months, n=15 patients). The most common anti-cancer interventions among all patients were ONC201 (39 patients), temozolomide (37 patients), bevacizumab (23 patients), panobinostat (8 patients), and immune checkpoint inhibitors (3 patients each, pembrolizumab and nivolumab). In this dataset, no interventions were statistically significant in a Cox proportional hazard model, but both immune checkpoint inhibitors (HR = -1.24, p=0.11) and ONC201 (HR = -0.38, p=0.27) trended toward benefit in the entire population. The subpopulation of patients treated with ONC201 whose tumor also harbored a TP53 mutation displayed a tendency toward activity (n=8); TP53-mutant patients treated with ONC201 had a mOS of 25.0 months vs. TP53 wild-type patients treated with ONC201 had a mOS of 20.3 months. Annotation of data for additional patients is ongoing and updated analyses will be presented at the meeting.

BIOM-43. THE GENOMIC, TRANSCRIPTOMIC, AND EPIGENOMIC LANDSCAPE OF ISOCITRATE DEHYDROGENASE WILD TYPE GLIOBLASTOMA ACROSS THE AGE CONTINUUM

BACKGROUND

Older age is a poor prognostic factor for glioblastoma (GBM) patients. We tested whether the intrinsic molecular landscape of the tumor may contribute to this poor prognosis.

METHODS

In accordance with the 2021 WHO classification scheme, we included only isocitrate dehydrogenase (IDH) wild type GBM. Based on published literature, we defined older as age &gt; 65. RNA expression, gene amplification, tumor mutational burden (TMB) and mutational profiles were analyzed in three unique datasets: Tempus (n = 1,410), Caris (n = 1,432), and TCGA (n = 557). Comparison were made between &lt; 65 and ³ 65 year olds using Pearson’s Chi-squared tests, Fisher’s exact tests, or Wilcoxon rank-sum where appropriate.

RESULTS

From our evaluable gene sets, TERT promoter mutations were more prevalent in patients ³ 65 years old (Caris 82.64 vs 77.27%, p = 0.016; Tempus 58.0 vs 49.0%, p = 0.002). There were no significant differences in PDCD1, CD274, CD3E, TNFRSF18, CD40, CD8A, TNFRSF4, CTLA4, HAVCR2, TNFSF9, CD274, or CDKN2A; PDL-1 (by IHC); dMMR/MSI-H, TMB; CDK6 amplification, EGFR amplification, EGFR, EGFRvIII, EGFR fusions, MET fusions, PTEN, TP53, or NF-1. MGMT promoter methylation (Caris data) was more common in the older group (49.73 v 34.14%, p &lt; 0.001). TGCA data demonstrated that gene expression, TMB, and methylation did not change significantly with age. Additionally, PCOLCE2 and SLC10A4 were differentially methylated, and missense mutations, of any type, were more common in the older group (p=0.006).

CONCLUSION

Despite worse survival outcomes for older patients with IDHwt GBM as compared to younger counterparts, the molecular landscape is similar at the genomic, transcriptomic and epigenomic levels. The key exception is TERT promoter mutations that are more common in older GBM patients. Poorer survival is therefore not likely to be attributable solely to intratumoral factors.

BIOM-05. THE HER2 FLIP: HER2 AMPLIFICATION OF TUMOR CELLS IN THE CEREBROSPINAL FLUID (CSF-TCS) OF PATIENTS WITH SOLID TUMOR LEPTOMENINGEAL METASTASIS

INTRODUCTION

Patients with leptomeningeal metastasis (LM) have limited treatment options and a poor outcome. However, they may benefit from targeted therapy. LM patients with HER2-positive primary breast cancer treated with IT trastuzumab demonstrated clinical benefit (Malani, 2020), and improved PFS (Figura, 2019). HER2 amplification in the primary and metastatic tumors can be divergent. Biocept’s CNSideTM is a CLIA validated test that can detect CSF tumor cells (CSF-TCs) and interrogate those cells with FISH and NGS. We analyzed HER2 amplification on CSF-TCs in LM patients with breast cancer, non-small cell lung cancer (NSCLC) and upper GI cancer.

METHODS

CSF was collected from patients with suspected or confirmed LM with breast cancer (N =134 patients), NSCLC (Nf28 patients) or upper GI cancer (Nf2 patients). CSF TCs were tested for HER2 amplification by FISH using CNSide.

RESULTS

HER2 amplification in CSF-TCs was detected in 46% (76/164) of all patients. Of the breast cancer patients, 37% (49/134) flipped HER2 status in the LM tumor, 38% (41/108) switched from a HER2 negative or equivocal primary tumor to HER2 positive CSF-TCs, and 27% (7/26) from a HER2 positive primary tumor to HER2 negative CSF-TCs. For the NSCLC patients, 50% (14/28) showed HER2 amplification on the CSF-TCs. For the upper GI cancer patients, HER2 amplification in CSF-TCs was detected in both patients, one patient had an equivocal HER2 primary tumor and HER2 positive CSF-TCs.

CONCLUSION

HER2 amplification was detected in a substantial fraction of CSF-TCs from patients with LM from breast, upper GI, and NSCL cancers. This finding may have important therapeutic (justifying the use of intra-CSF trastuzumab), prognostic (HER2 positivity in NSCLC is associated with poorer prognosis and a higher frequency of CNS metastases) and pathophysiologic implications (a potential role of HER2 amplification in the genesis of CNS metastases). Additional investigations are underway.