BACKGROUND:Immunotherapy has yet to make significant gains in glioblastoma (GBM) treatment, due in part to GBM-mediated immune suppression. Increasing evidence points to critical roles for tumor-derived extracellular vesicles (EVs) and immunosuppressive myeloid cells as key factors in this process. METHODS:Immunophenotyping of the tumor-immune microenvironment was performed using ultrasonic aspirate collected during GBM resection by high-dimensional flow cytometry. EVs collected from patient-derived GBM cell lines were used to condition myeloid cells collected from healthy donors to generate immunosuppressive myeloid cells. siRNA was used to knockdown TIGIT and/or NLRP3 expression prior to EV conditioning. T cell co-culture studies were performed with donor-matched T cells. RESULTS:Immune phenotyping of the tumor microenvironment and EV-conditioned myeloid cells revealed similar immunomodulatory protein expression across myeloid cell populations, with particularly elevated TIGIT expression. Knockdown of TIGIT reduced the immunosuppressive polarization of myeloid cells, resulting in improved T cell function. This finding proceeded in an NLRP3-dependent manner, with substantial co-expression of TIGIT and NLRP3 expression prior to knockdown, and concomitant knockdown of NLRP3 abrogating the effect of TIGIT knockdown. TIGIT expression correlated with increased IL-13 expression, and IL-13 blockade unmasked a pro-inflammatory myeloid cell phenotype. CONCLUSION:TIGIT expression in myeloid cells in the GBM microenvironment is a functional marker of immunosuppressive activity, with TIGIT knockdown reducing IL-13 expression and unmasking the pro-inflammatory activity of NLRP3. This study bolsters our understanding of the immunosuppressive complexities of the GBM microenvironment and supports attenuation of immunosuppressive myeloid cell activity as a strategy to restore immune function in GBM.

Abstract Standard of care (SOC) for ndGBM begins with maximal safe resection followed by adjuvant radiotherapy and temozolomide, and maintenance temozolomide. IGV-001 is an autologous biologic-device combination immunotherapy for the treatment of ndGBM that consists of autologous GBM tumor cells and an antisense oligonucleotide against IGF-1R mRNA, irradiated and administered via biodiffusion chambers implanted in the abdomen. In a phase 1b study, IGV-001 was well tolerated without unexpected adverse events in subjects with ndGBM. Multiple efficacy signals were observed, including significant improvements in progression-free survival (PFS), overall survival (OS), radiographic evidence of tumor response, and changes in immune response biomarkers. Here, we present early safety data from the phase 2b randomized, multicenter, double-blind, placebo-controlled study (NCT04485949) designed to assess efficacy and safety of IGV-001 in subjects with ndGBM across 20 sites in the United States. After surgical resection, subjects were randomized 2:1 and treated with IGV-001 or placebo followed by SOC. The primary outcome is PFS, defined as the time from randomization to first progression, as determined by blinded central radiology review, or death. Secondary outcomes include OS, defined as the time from randomization to death due to any cause, and safety. As of May 22, 2024, 99 subjects were randomized and 95 implanted with IGV-001 or placebo plus SOC. A total of 39/45 (86.7%) subjects had sufficient follow-up time after initiated treatment with concurrent radiation and temozolomide. Nine of 72 randomized (12.5%) discontinued treatment, including 7 who stopped during the SOC treatment period. None ceased treatment for adverse events, protocol deviations, or death. A total of 11/72 (15.3%) randomized subjects discontinued the study after randomization. A review of blinded safety data did not show any emerging risk and supports no change to the benefit-risk profile of IGV-001 versus placebo. Updated data will be presented.

Abstract The tumor microenvironment (TME) of glioblastoma (GBM) is populated by cells that foster immunosuppression. Reversing immunosuppression and promoting tumor surveillance by T cells that recognize the antigens generated by tumor-specific mutations (neoantigens) is critical to eliminating the tumor cells. In a phase 1 clinical trial of newly diagnosed GBM (NCT03223103), patients were treated with personalized neoantigen vaccines (PNV) combined with standard of care (resection, radiotherapy, temozolomide chemotherapy, and TTFields). The neoantigens were identified using the OpenVax computational pipeline. Primary endpoints included safety and feasibility, and the secondary endpoints included PFS, OS, TME analysis, and immunogenicity assays. The study enrolled 12 patients, ages 32-84, between December 2017 - July 2020. With a feasibility endpoint of one successful PNV administration, all patients got at least 6. All developed PNV-related injection site reactions, and flu-like symptoms grade 1-2. Concomitant use with TTFields did not increase toxicity. None of the patients exhibited dose-limiting toxicity within 30 days of receiving the PNV. However, one developed grade 3 SAE, consisting of seizures, neck pain, and progressive neurological deficits, after vaccine 10, culminating in a grade 5 SAE and brain demyelination 10 months later. Assays performed on this subject showed induction of neoantigen-specific responses with PNV. PNV induced CD4+ and CD8+ T cells reactive against multiple vaccine peptide sequences with CD8+ T cell cross-reactivity against one wild-type epitope. Other patients had immunogenicity against the vaccinated peptides. Overall, the 6 months PFS was 100%, with 67% 2-year and 58% 3-year survival. Although the mutation burden is low in GBM, neoantigens were detected in all tumors, and PNV were manufactured for all patients. PNV with synthetic long peptides combined with standard care treatment may help improve outcomes in GBM. Cross-reactivity may potentially be responsible for post-vaccination T-cell demyelination. Further evidence is needed to substantiate a direct effect. Funding: CRI - V Foundation CLIP (#3680)

2068 Background: Epidermal growth factor receptor ( EGFR) gene is the most frequently altered oncogenic driver in glioblastoma (GBM). In-frame deletion alterations (e.g., EGFRvIII) and missense mutations co-occur in the setting of EGFR gene amplification and are characterized as a hallmark of disease pathogenesis in GBM. BDTX-1535 is an oral, highly potent, brain penetrant, selective, irreversible 4th generation tyrosine kinase inhibitor that targets EGFR alterations in GBM and NSCLC. Preliminary results of the Phase 1 dose escalation study (NCT05256290) of patients with recurrent GBM (rGBM) are presented here. Methods: BDTX-1535-101 is a first-in-human study that enrolled patients with either rGBM harboring EGFR alterations following standard of care or patients with locally advanced or metastatic EGFR mutated NSCLC that progressed on prior EGFR TKIs. Using an adaptive Bayesian optimal interval design in the Phase 1 part, patients were enrolled at increasing dose cohorts and were treated daily for 21-day cycles until treatment discontinuation. The primary objective was to determine the BDTX-1535 recommended Phase 2 dose based on the overall safety, PK, pharmacodynamics, and preliminary antitumor activity. Results: Twenty-seven patients with rGBM were enrolled in the Phase 1 cohort that consisted of 54 patients in total including 27 patients with NSCLC. Patients were treated across seven dose levels (15mg – 400mg QD). The mean age of patients with rGBM was 58.7 years (range 41-85) with 96% of patients with previous temozolomide (TMZ) treatment and a median of 2 lines of prior therapy (range 1-4). The most common all-grade treatment-related AEs across all cohorts were rash (78%), diarrhea (41%), fatigue (15%), stomatitis (11%), decreased appetite (11%), nausea (11%) and paronychia (11%). Gr 3 TRAEs ≥ 10% included rash (19%) reported at 300 or 400 mg QD doses. Plasma exposure of BDTX-1535 increased dose proportionally and had a half-life of ~15h, supporting once daily dosing. The maximum tolerated dose (MTD) is 300 mg QD. Among 19 evaluable patients for response based on RANO criteria, 1 confirmed partial response was observed and 8 patients achieved stable disease. Five patients remained on BDTX-1535 with stable disease for an extended period (>5 months) who previously performed poorly on TMZ with short treatment duration, and 1 patient continues on BDTX-1535 after 16 months of treatment. Conclusions: BDTX-1535 was well-tolerated up to 300mg daily, which is the MTD, and promising preliminary clinical activity was observed in patients with rGBM after relapse on standard of care treatment. Given the inability to reconfirm EGFR status at the time of treatment with BDTX-1535 in this Phase 1 trial, further exploration of BDTX-1535 in a “window of opportunity” study is ongoing (NCT06072586). Clinical trial information: NCT05256290 .

Background: Clinical, histopathological, and imaging variables have been associated with prognosis in patients with glioblastoma (GBM). We aimed to develop a multiparametric radiogenomic model incorporating MRI texture features, demographic data, and histopathological tumor biomarkers to predict prognosis in patients with GBM. Methods: In this retrospective study, patients were included if they had confirmed diagnosis of GBM with histopathological biomarkers and pre-operative MRI. Tumor segmentation was performed, and texture features were extracted to develop a predictive radiomic model of survival (<18 months vs. ≥18 months) using multivariate analysis and Least Absolute Shrinkage and Selection Operator (LASSO) regularization to reduce the risk of overfitting. This radiomic model in combination with clinical and histopathological data was inserted into a backward stepwise logistic regression model to assess survival. The diagnostic performance of this model was reported for the training and external validation sets. Results: A total of 116 patients were included for model development and 40 patients for external testing validation. The diagnostic performance (AUC/sensitivity/specificity) of the radiomic model generated from seven texture features in determination of ≥18 months survival was 0.71/69.0/70.3. Three variables remained as independent predictors of survival, including radiomics (p = 0.004), age (p = 0.039), and MGMT status (p = 0.025). This model yielded diagnostic performance (AUC/sensitivity/specificity) of 0.77/81.0/66.0 (training) and 0.89/100/78.6 (testing) in determination of survival ≥ 18 months. Conclusions: Results show that our radiogenomic model generated from radiomic features at baseline MRI, age, and MGMT status can predict survival ≥ 18 months in patients with GBM.

While immune checkpoint inhibitors (ICI) have had success with various malignancies, their efficacy in brain cancer is still unclear. Retrospective and prospective studies using PD-1 inhibitors for recurrent glioblastoma (GBM) have not established survival benefit. This study evaluated if ICI may be effective for select patients with recurrent GBM. This was a single-center retrospective study of adult patients diagnosed with first recurrence GBM and received pembrolizumab or nivolumab with or without concurrent bevacizumab. Archival tissue was used for immunohistochemistry (IHC) and targeted DNA next-generation sequencing (NGS) analysis. Median overall survival (mOS) from initial diagnosis was 24.5 months (range 10–42). mOS from onset of ICI was 10 months (range 1–31) with 75

Abstract BACKGROUND Treatment options for GBM remain limited, and novel approaches are required. One of them, Tumor Treating Fields (TTFields) therapy, is a non-invasive treatment modality that delivers low intensity, intermediate frequency, alternating electrical fields and increases survival through multiple mechanisms, including disrupting cell mitosis, triggering tumor cell death, and expanding CD8+ cytotoxic lymphocytes. METHODS In this prospective study, adult patients with ndGBM underwent standard-of-care treatment with maximal resection, followed by radiotherapy and temozolomide. Use of TTFields therapy, with a recommended daily use of ≥ 18 hours/day, throughout adjuvant temozolomide treatment and with immunotherapy, was investigated. RESULTS Eight patients received TTFields therapy. Use of TTFields was 2, 5, 6, 6, 8, 8, 10, and 16 months with an average of 10.2 months. The patient with the lowest use developed a grade 1 papulopustular scalp rash and discontinued use. Monthly average daily use ranged from 0% to 87%. Average daily use over treatment was 39%, 47%, 48%, 53%, 67%, 69%, 78%, and 83%. None of the patients achieved the goal for daily use every month. Four patients had a daily use ≥ 80% for at least one month of treatment. Except for one patient, whose daily use increased from 72% in the first month to 79% in the last month, all other patients down-trended in TTFields use. Six patients completed EORTC-QLQ-C30 surveys throughout the study. 3/8 had an overall increase in their global quality of life scale, 3 patients had a decrease, and 2 patients did not complete the survey. DISCUSSION In this study, the use of TTFields was suboptimal. We presume that with multiple treatments in the adjuvant phase including 6 cycles of temozolomide and optional TTFields use, patients did not recognize the potential therapeutic benefit of continued TTField therapy use and opted to remain only in the immunotherapy treatment.

One-way ANOVA analysis comparing expression of cytokines between Avelumab treated and Avelumab combined with Bevacizumab

Supplementary Data 1 ELIGIBILITY CRITERIA. Supplementary Data 2 HYPOFRACTIONATED STEREOTACTIC RADIOTHERAPY PLANNING. Supplementary Data 3 MRI ACQUISITION PARAMETERS AND PROCESSING. Supplementary Data 4 Nanostring-based Tissue Correlates Methods. Supplementary Data 5 Number of patients experiencing Grades 3-5 treatment-related toxicities. Supplementary Data 6 Univariate analysis of DSC MR perfusion and diffusion MRI. Supplementary Data 7 NEUROPSYCHOLOGICAL TEST Z-SCORES, QUALITY OF LIFE, DEPRESSION AND FATIGUE SCORES OVER TIME.

Purpose:The treatment of glioblastoma (GBM) poses challenges. The use of immune checkpoint inhibition (ICI) has been disappointing as GBM is characterized by low mutational burden and low T-cell infiltration. The combination of ICI with other treatment modalities may improve efficacy.Patient and Methods:Patients with recurrent GBM were treated with avelumab, a human IgG1 antibody directed against PD-L1 (part A), or avelumab within a week after laser interstitial thermal therapy (LITT) and continuation of avelumab (part B). Bevacizumab was allowed to be combined with ICI to spare steroid use. The primary objective was to characterize the tolerability and safety of the regimens. The secondary objectives included overall survival, progression-free survival (PFS), signatures of plasma analytes, and immune cells.Results:A total of 12 patients (median age 64; range, 37–73) enrolled, five in part A and seven in part B. Two serious adverse events occurred in the same patient, LITT treated, not leading to death. The median survival from enrollment was 13 months [95% confidence interval (CI), 4–16 months] with no differences for part A or B. The median PFS was 3 months (95% CI, 1.5–4.5 months). The decrease in MICA/MICB, γδT cells, and CD4+ T cell EMRA correlated with prolonged survival.Conclusions:Avelumab was generally well tolerated. Adding bevacizumab to ICI may be beneficial by lowering cytokine and immune cell expression. The development of this combinatorial treatment warrants further investigation. Exploring the modulation of adaptive and innate immune cells and plasma analytes as biomarker signatures may instruct future studies in this dismal refractory disease.Significance:Our phase I of PD-L1 inhibition combined with LITT and using bevacizumab to spare steroids had a good safety profile for recurrent GBM. Developing combinatory treatment may help outcomes. In addition, we found significant immune modulation of cytokines and immune cells by bevacizumab, which may enhance the effect of ICI.

Supp. Fig.1. CONSORT Flow Diagram Supp. Fig.2. MRI Perfusion Parameters Supp. Fig. 3. Immunohistochemistry Supp. Fig. 4. Gene Expression Profile Supp. Table 1. Adverse Events Supp. Table 2. Pharmacokinetic Data Supp. Table 3. Molar Drug Levels Supplemental Methods

Chromogenic multiplex expression analysis of different biomarkers in formalin-fixed paraffin-embedded tissue of a patient's tumor when diagnosed with glioblastoma (34369), before treated with LITT (34370) and after treatment with LITT and avelumab (34371) and quantitative analysis using Halo® Image Analysis Platform.

Table S1. Representativeness of Study Participants

Purpose: The T2-FLAIR mismatch sign has shown promise in determining IDH mutant 1p/19q non-co-deleted gliomas with a high specificity and modest sensitivity. To develop a multi-parametric radiomic model using MRI to predict 1p/19q co-deletion status in patients with newly diagnosed IDH1 mutant glioma and to perform a comparative analysis to T2-FLAIR mismatch sign+. Methods: In this retrospective study, patients with diagnosis of IDH1 mutant gliomas with known 1p/19q status who had preoperative MRI were included. T2-FLAIR mismatch was evaluated independently by two board-certified neuroradiologists. Texture features were extracted from glioma segmentation of FLAIR images. eXtremeGradient Boosting (XGboost) classifiers were used for model development. Leave-one-out-cross-validation (LOOCV) and external validation performances were reported for both the training and external validation sets. Results: A total of 103 patients were included for model development and 18 patients for external testing validation. The diagnostic performance (sensitivity/specificity/accuracy) in the determination of the 1p/19q co-deletion status was 59%/83%/67% (training) and 62.5%/70.0%/66.3% (testing) for the T2-FLAIR mismatch sign. This was significantly improved (p = 0.04) using the radiomics model to 77.9%/82.8%/80.3% (training) and 87.5%/89.9%/88.8% (testing), respectively. The addition of radiomics as a computer-assisted tool resulted in significant (p = 0.02) improvement in the performance of the neuroradiologist with 13 additional corrected cases in comparison to just using the T2-FLAIR mismatch sign. Conclusion: The proposed radiomic model provides much needed sensitivity to the highly specific T2-FLAIR mismatch sign in the determination of the 1p/19q non-co-deletion status and improves the overall diagnostic performance of neuroradiologists when used as an assistive tool.

(1) Background: Gliomas are the most common primary brain neoplasms accounting for roughly 40–50% of all malignant primary central nervous system tumors. We aim to develop a deep learning-based framework for automated segmentation and prediction of biomarkers and prognosis in patients with gliomas. (2) Methods: In this retrospective two center study, patients were included if they (1) had a diagnosis of glioma with known surgical histopathology and (2) had preoperative MRI with FLAIR sequence. The entire tumor volume including FLAIR hyperintense infiltrative component and necrotic and cystic components was segmented. Deep learning-based U-Net framework was developed based on symmetric architecture from the 512 × 512 segmented maps from FLAIR as the ground truth mask. (3) Results: The final cohort consisted of 208 patients with mean ± standard deviation of age (years) of 56 ± 15 with M/F of 130/78. DSC of the generated mask was 0.93. Prediction for IDH-1 and MGMT status had a performance of AUC 0.88 and 0.62, respectively. Survival prediction of <18 months demonstrated AUC of 0.75. (4) Conclusions: Our deep learning-based framework can detect and segment gliomas with excellent performance for the prediction of IDH-1 biomarker status and survival.

Background Patients with glioblastoma (GBM) have a poor prognosis and limited effective treatment options. Bevacizumab has been approved for treatment of recurrent GBM, but there is questionable survival benefit. Based on preclinical and early clinical data indicating that CD105 upregulation may represent a mechanism of resistance to bevacizumab, we hypothesized that combining bevacizumab with the anti-CD105 antibody TRC105 may improve efficacy in recurrent GBM. Methods Phase I dose-escalation/comparative randomized phase II trial in patients with GBM. During phase I, the maximum tolerated dose (MTD) of TRC105 in combination with bevacizumab was determined. In phase II, patients were randomized 1:1 to TRC105 and bevacizumab or bevacizumab monotherapy. Patients receivedTRC105 (10 mg/kg) weekly and bevacizumab (10 mg/kg) every 2 weeks. Efficacy, as assessed by progression-free survival (PFS), was the primary endpoint; safety, quality of life, and correlative outcomes were also evaluated. Results In total, 15 patients were enrolled in phase I and 101 in phase II; 52 patients were randomized to TRC105 with bevacizumab and 49 to bevacizumab monotherapy. The MTD was determined to be 10 mg/kg TRC105 weekly plus bevacizumab 10 mg/kg every 2 weeks. An increased occurrence of grade >= 3 adverse events was seen in the combination arm, including higher incidences of anemia. Median PFS was similar in both treatment arms: 2.9 months for combination versus 3.2 months for bevacizumab monotherapy (HR = 1.16, 95% CI = 0.75-1.78, P = .51). Quality of life scores were similar for both treatment arms. Conclusions TRC105 in combination with bevacizumab was well tolerated in patients with recurrent GBM, but no difference in efficacy was observed compared to bevacizumab monotherapy.

2004 Background: Novel T cell-enabling therapies plus checkpoint inhibition may improve OS in GBM. INO-5401 (synthetic DNA plasmid encoding hTERT, WT-1, PSMA) plus INO-9012 (synthetic DNA plasmid encoding IL-12), with cemiplimab (PD-1 inhibitor), was given to patients with newly diagnosed GBM with MRD to evaluate tolerability, efficacy, and immunogenicity. Median OS and immunogenicity at 18 months (OS18) are reported. Methods: This is a phase I/II, single arm, two cohort (A: unmethylated MGMT and B: methylated MGMT) study. Primary endpoint is safety; efficacy and immunogenicity are secondary. Nine mg INO-5401 plus 1 mg INO-9012 (4 doses Q3W, then Q9W) was given IM with EP in combination with cemiplimab (350 mg IV Q3W). Hypofractionated RT (40 Gy over 3 weeks) with TMZ was given to all patients, followed by maintenance (Cohort B only), which was a novel therapeutic approach. Immunogenicity was assessed by quantifying INO-5401-specific peripheral cellular immune responses via IFN-g ELISpot and flow cytometry. Intra-tumoral gene expression was analyzed by RNA-Seq of FFPE GBM tissue. Differences in gene expression were analyzed using the Wilcoxon rank sum test. Results: Fifty-two subjects were enrolled: 32 in Cohort A; 20 in Cohort B (35% women; median age 60 years [range 19-78 years]). The adverse event profile was consistent with known single-agent (INO-5401, INO-9012, EP or cemiplimab) events; most events were ≤Grade 2 and no related events were Grade ≥4. Median OS durations in Cohorts A and B were 17.9 months (95% CI 14.5-19.8) and 32.5 months (95% CI 18.4-not reached), respectively. Flow cytometry revealed activated, antigen specific CD4+CD69+PD1+ and CD8+CD69+PD1+ T cells, the latter with lytic potential as defined by presence of perforin and granzyme A. Both subsets exhibited HR < 1.0 and p < 0.05 when accounting for a 0.1% T cell frequency change, translating to a 23% and 28% reduced risk of death, respectively. Gene expression levels in pre-treatment tissues were similar between alive and deceased groups for INO-5401 antigens and immune cell markers; however, the alive group displayed significantly reduced expression of genes associated with anti-apoptosis, pro-proliferation, and immune response suppression. Post-treatment tumor tissue displayed altered gene expression for immune-related markers versus pre-treatment tissue, including markers of T cell infiltration, activation, and lytic potential. Conclusions: INO-5401 + INO-9012 has an acceptable risk/benefit profile and elicits robust immune responses that correlate with enhanced survival when administered with cemiplimab and RT/TMZ to newly diagnosed GBM patients. Pre-treatment gene expression signatures in MGMT-unmethylated patients were statistically associated with OS18. Overall, INO-5401 elicits antigen-specific T cells that can infiltrate GBM tumors. Clinical trial information: NCT03491683.