Checkpoint blockade only works in 10-20% of patients. Consequently, investigators are testing checkpoint inhibitors in combination with drugs like the class I histone deacetylase inhibitor, entinostat (ENT). Unfortunately, the combination of ENT and checkpoint blockade fared poorly in patients with breast or ovarian cancer, despite promising pre-clinical results. Here we show that ENT enhances CD8+ T cell responses by maintaining a progenitor-like population of CD8+ T cells that supplies activated effector T cells to tumors for prolonged periods. Surprisingly, the anti-tumor effects of ENT are only experienced when delivered during a narrow window that occurs after T cell activation and before T cell exhaustion-a window that is likely closed in most patients. However, by first "jump-starting" the T cell response using an oncolytic virus, the anti-tumor activity of ENT and PD1 blockade is restored. These data establish a general paradigm, independent of tumor type, to rationally manipulate anti-tumor immunity.

BACKGROUND Postoperative seizures can occur secondary to cortical irritation from malignant glioma resection or from direct electrical stimulation of the cortical surface during intraoperative brain mapping. A paucity of literature exists with regards to the use of appropriate seizure risk-reduction strategies for this patient population. The objective of the study was to identify primary risk factors for early and late postoperative seizures following intraoperative brain mapping. METHODS The authors performed a case-control study with 30 patients who had postoperative clinical seizures within 6 months following craniotomies with intraoperative mapping for glioma resection from 2013 to 2021 at a single academic institution. An unmatched control population of all patients (n=52) who had undergone craniotomies with ICM during the same period and had no clinical seizures within 6 months following their operation were used for comparative analysis. Primary endpoint was any postoperative seizure within 6 months of surgery. Outcomes were analyzed both via frequentist and Bayesian statistical approaches. RESULTS Bayesian analysis using non-informative priors demonstrated that the probability of an odds ratio (OR) > 1 for prior history of seizures being a risk factor for postoperative seizures is 73%. The probability that OR < 1 for a patient with post op seizures who underwent motor mapping was 91%. If patients experienced an intraoperative seizure during mapping, the probability of having a postoperative seizure was 84%. Probability that awake mapping is protective of post op seizure when compared to asleep mapping is 88%. Complex anti-epileptic drug (AED) regimen (increasing dose + adding additional AEDs or 2 dose adjustments) had 64% probability of protection from late postoperative seizures. CONCLUSION Patients with a preoperative history of seizures may be at higher risk for postoperative seizures. More aggressive perioperative seizure prophylaxis may provide a protective benefit from postoperative seizures in patients who undergo intraoperative mapping.

Purpose Adjuvant radiation therapy for atypical meningiomas (AMs) aids in local control following surgery and salvage after recurrence. The role of fractionated stereotactic radiosurgery (FSRT) in this population remains an area of active study with many unanswered clinical questions. This single-institution retrospective study evaluates the local control, marginal control, and toxicity of FSRT in treating AM. Methods Between 2009 and 2022, 39 patients with WHO grade 2 AM underwent FSRT via marginless, frameless volumetric-modulated arc therapy (VMAT) at doses of 27.5-30 Gy in five fractions. Local recurrence was defined as an increase of 20% in the greatest cross-sectional diameter on MRI or CT, following RECIST criteria. Cavity and marginal recurrences were defined as any new lesion outside the prescription volume but within the resection cavity or within 2 cm of the resection cavity, respectively. High-grade toxicity was defined per Common Terminology Criteria for Adverse Events (CTCAE) v5. Resection for radionecrosis with viable residual tumor was considered a local failure. Results Twenty-six AMs were treated post-subtotal resection (STR), 16 post-gross total resection (GTR) with recurrence, and five treated definitively. Patient characteristics included a mean age of 54 years, 20 (51%) male patients, and 31 (79%) patients with ECOG 0-1. The three-year local control rate was 84.0%. Larger tumors were more likely to fail locally (p > 0.001). Two (5%) patients experienced high-grade toxicity necessitating resection. The three-year marginal control rate was 92.3%, and recurrent tumors post-GTR failed marginally more often compared to those treated after STR (p = 0.009). One (4%) tumor treated after STR failed marginally, while four (33%) tumors treated after GTR recurrence failed marginally. The three-year control rate of the unirradiated cavity was 88%. Conclusion The rate of high-grade toxicity in AM patients receiving FSRT was low. Local control appeared comparable to historical rates, which may suggest the potential need for dose escalation with longer-term follow-up. Recurrent tumors were more prone to marginal failures. Further investigation is needed to determine which patients may benefit from whole-cavity treatment, additional CTV margin, or prolonged fractionated dose schedules. Newer imaging studies, including DOTATATE PET, should be explored to assess whether improvements in targeting accuracy can enhance outcomes.

Glioblastoma multiforme (GBM) is an aggressive brain tumor characterized by poor prognosis and frequent recurrence. The tumor microenvironment (TME) plays a crucial role in GBM progression, with extracellular matrix (ECM) components like Fibronectin (FN1) supporting tumor growth and invasion. This study investigated the impact of FN1 on microvascular alterations in GBM. Patient-derived specimens and mouse glioma models were classified as ECM-high or ECM-low based on FN1 expression. Histopathological and immunofluorescence analyses were performed on formalin-fixed, paraffin-embedded (FFPE) tumor sections. The results showed the FN1-high tumors exhibited more aggressive features, including palisading necrosis, mesenchymal regions, and enhanced vascular proliferation. FN1-high tumors showed elevated pericyte (SMA+) and endothelial cells (CD31+) proliferation, reinforcing their aggressive phenotype. Additionally, FN1-high tumors showed enrichment of astrocytes with GFAP+ expression surrounding the perivascular niche (PVN) but not tumors with low FN1 expression. Histopathological evaluation of FN1-high gliomas also showed a higher density of defined Vascular Garland and Glomeruloid vascular proliferation patterns compared to FN1-low tumors, which displayed less malignant vascular patterns like Microvascular Sprouting and Vascular Cluster. These results suggest that GBM cells overexpressing FN1 are associated with more malignant microvascular patterns and increased pericyte and endothelial proliferation. This study highlights the potential of glioma-secreted FN1 components as pathological biomarkers and therapeutic targets for mitigating GBM malignancy.

Rationale: Developing novel pre-operative and intraoperative imaging approaches for glioblastoma multiforme (GBM) could aid therapeutic intervention while sparing healthy normal brain, which remains a significant clinical challenge. 5-aminolevulinic acid (5-ALA) is the only intraoperative imaging agent approved to aid the resection of GBM. Matrix metalloproteinase 14 (MMP14), which is overexpressed in GBM, is an attractive target for preoperative and intraoperative imaging of GBM. Prior studies have shown the feasibility of near-infrared fluorescence (NIRF) imaging and positron emission tomography (PET) imaging of GBM xenografts in mice using MMP-14 targeted peptide probes. The present studies assessed the tumor-specific localization and contrast of these MMP-14 targeted peptides relative to 5-ALA in GBM models. Methods: Fluorescence and PET imaging was performed after i.v. injection of 5-ALA and the MMP-14 targeted peptide probes (non-labeled or radiolabeled with 64Cu) in mice bearing human GBM orthotopic xenografts (U87, D54). Imaging signals were correlated to MMP-14 expression determined by immunofluorescence. Tumor-to-normal brain ratio (TBR) and Dice similarity coefficient (DSC) relative to tumor defined by ex vivo pathology or in vivo magnetic resonance imaging were determined for each imaging agent. Results: NIRF signals from the MMP-14 targeted peptide probes showed comparable TBR (p < 0.05) but significantly higher DSC (p < 0.05) relative to 5-ALA. NIRF signals from the peptide probes significantly correlated with MMP-14 expression (p < 0.05). MMP-14 binding peptide labeled with 64Cu showed moderate DSC (0.45) while PET signals significantly correlated (p < 0.05) with NIRF signals from a co-injected MMP-14 substrate peptide. NIRF and PET signals localized in residual tumor regions in the resection cavity during in situ resection. Conclusions: MMP-14 targeted peptides showed favorable TBR and higher tumor localization than 5-ALA in GBM orthotopic models. Further development of MMP-14 targeted peptide probes could lead to improved pre-operative and intraoperative management of GBM.

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) present unique challenges due to their heterogeneity and limited treatment options. Oncolytic virotherapy has emerged as a promising therapeutic for other NETs and thus, we sought to investigate the potential of an engineered oncolytic herpes simplex virus (oHSV), M002, for GEP-NETS. We employed an established long-term passage GEP-NET cell line and a unique, human pediatric patient-derived xenograft GEP-NET line. We found the virus to effectively infect, replicate within, and kill both cell lines in vitro. Similar effects were noted in vivo, with M002 decreasing tumor growth and improving overall survival in mice bearing tumors from both the established cell line and human GEP-NET PDX. Overall, these studies provide an evaluation of an oncolytic HSV in GEP-NETs, highlighting its therapeutic potential and considerations for clinical translation.

Symptoms of depression are highly prevalent among patients with glioblastoma and have been associated with poor outcomes. In addition to managing depression symptoms, preclinical and clinical studies suggest that antidepressants may inhibit glioblastoma progression However, the effect of antidepressants on survival is unknown and results from existing studies are conflicting. We conducted a systematic review and meta-analysis to investigate the effect of antidepressant therapy on glioblastoma survival. We queried PubMed, Embase, Scopus, PsycINFO, and Web of Science from inception to March 2024 for studies investigating the overall survival of patients with glioblastoma treated with antidepressants. Results were combined using a restricted maximum-likelihood estimation random effects model. We identified 6 observational studies meeting inclusion criteria with 8,269 patients. Of these, 1,093 (13%) were treated with antidepressant therapy at some point after their glioblastoma diagnosis. Antidepressant therapy was not significantly associated with overall survival (HR 1.27, 95% CI 0.90-1.79, P = .17). In a subanalysis of studies that specified whether selective serotonin reuptake inhibitors were utilized, SSRI usage specifically was also not associated with overall survival (HR 1.08, 95% CI 0.58-2.03, P = .81). We observed considerable heterogeneity (I2 = 92.7%, P < .001). Antidepressants were not significantly associated with overall survival in patients with glioblastoma. However, our meta-analysis was limited by significant heterogeneity observed across studies. The effect of antidepressants on outcomes in patients with glioblastoma remains uncertain. We observed conflicting results in the literature, with some studies suggesting decreased survival. Therefore, the role of antidepressants in patients with glioblastoma warrants further investigation.

Glioblastoma (GBM) is the most prevalent and lethal primary malignant brain tumor in adults. Oncolytic viruses have emerged as a promising immunotherapy to treat GBM. However, the temporal impact on tumor cells and the tumor microenvironment, and the nature of sustained anti-tumor immunity post-therapy remain largely unclear. We have recently identified CD4+ T-cells as the critical cellular component that is responsible for oncolytic herpes simplex virus (oHSV)-mediated durable control of tumor in syngeneic immunocompetent murine models of GBM. oHSV treatment upregulates MHCII on residual tumor cells that is important for programmed polyfunctional CD4+ T-cells to control tumor and to form memory responses. Single-cell RNA sequencing analysis further revealed that oHSV treatment expanded a subset of CD4+ T-cells that displayed a unique signature and had distinct expanded T-cell receptor clonotypes. Flow cytometry analysis confirmed its kinetic expansion after treatment. Importantly, adoptive transfer of this subset prolonged survival in mice bearing GBM. In addition, spatial transcriptomics analysis of human GBM tissues collected from tumor infiltrative regions pointed a close localization relationship of this CD4+ T-cell subset with dendritic cells (DC) in the non-malignant areas. CellChat analysis also showed that the interactions of DC and this subset were increased in oHSV-treated mice compared to vehicle controls. In sum, this CD4+ T-cell subset, characterized by specific spatiotemporal regulation, may serve as a new prognostic biomarker for GBM patients and a response predictor for GBM patients receiving oHSV therapy, suggesting strategies to improve oHSV therapeutic efficacy and to develop new modalities to improve outcomes for patients with GBM.

Purpose:Radiosurgery plan safety is commonly estimated by volumes receiving specific doses (ie, 12 Gy/1 fraction [fx]), which are evaluated postplan generation. However, automated treatment planning can produce highly consistent and thus predictable plans. Thus, we hypothesized that HyperArc (HA) automated stereotactic radiosurgery (SRS) planning enables clinical decision-making prior to plan generation, such as selecting the appropriate SRS fractionation scheme. Methods and Materials:All previously treated single-isocenter HA plans at our institution were queried, totaling 3361 marginless targets without bridging at the 50% isodose level (1495 plans), making this the largest single-institutional SRS dosimetry study to the authors' knowledge. Eight isodose volumes (IDVs; 50.00%-97.60%) were calculated for all HA targets, each corresponding to the ratio of a High Dose per Fraction, Hypofractionated Treatment Effects in the Clinic (HyTEC) brain toxicity dose level and a common prescription dose (eg, 50.00% = 12 Gy/24 Gy). Power law relationships of IDV and target volume ( I D V = a V t a r g e t b ) were generated from a training data set of 361 targets (10.7%) and validated on the remaining 3000 targets (89.3%), allowing grade 1 to 3 brain toxicity rates to be predicted from target volume. Results:Models resulted in high R² values when applied to the validation cohort (≥0.982), allowing targets to be classified as either above or below the HyTEC thresholds (IDV = 5 cm3, 10 cm3, and 20 cm3) with high accuracy (≥97.6%) and precision (≥99.3%). As an example, the 50.0% IDV model predicted that target volumes/diameters of 1.00 cm3/1.24 cm, 2.34 cm3/1.65 cm, and 5.51 cm3/2.19 cm correlate with 3.6%, 4.8%, and 8.6% grade 1 to 3 brain toxicity rates, respectively, when prescribing 24 Gy/1 fx. Conclusion:The resulting models enabled accurate and precise prediction of target volumes/diameters, resulting in 3.6%, 4.8%, and 8.6% brain grade 1 to 3 toxicity rates, according to HyTEC toxicity estimates. Leveraging relative IDVs rather than prescription doses enabled all 3361 targets to be used for modeling 9 common SRS prescriptions (1 fx: 24 Gy, 20 Gy, 18 Gy, 16 Gy, and 15 Gy; 3 fx: 27 Gy and 24 Gy; 5 fx: 30 Gy and 25 Gy), enabling clinicians to estimate brain toxicity a priori via an open-source calculator.

Identification of isocitrate dehydrogenase (IDH) mutations has uncovered the crucial role of metabolism in gliomagenesis. Oncolytic herpes virus (oHSV) initiates direct tumor debulking by tumor lysis and activates anti-tumor immunity, however, little is known about the role of glioma metabolism in determining oHSV efficacy. Here we identify that oHSV rewires central carbon metabolism increasing glucose utilization towards oxidative phosphorylation and shuttling glutamine towards reductive carboxylation in IDH wildtype glioma. The switch in metabolism results in increased lipid synthesis and cellular ROS. PKC induces ACSL4 in oHSV treated cells leading to lipid peroxidation and ferroptosis. Ferroptosis is critical to launch an anti-tumor immune response which is important for viral efficacy. Mutant IDH (IDHR132H) gliomas are incapable of reductive carboxylation and hence ferroptosis. Pharmacological blockade of IDHR132H induces ferroptosis and anti-tumor immunity. This study provides a rationale to use an IDHR132H inhibitor to treat high grade IDH-mutant glioma patients undergoing oHSV treatment.

Abstract BACKGROUND Glioblastoma (GBM) is the most common primary brain malignancy. Despite recent progress in treatments, prognosis for patients remain poor. Recent literature has suggested the association of GBM outcomes and socioeconomic status. However, there is limited evidence regarding the association of neighborhood-level socioeconomic status on GBM outcomes. OBJECTIVE To investigate the impact of neighborhood-level socioeconomic status on GBM outcomes. METHODS We retrospectively reviewed all adult GBM patients at a single institution from 2008 to 2023. Patient addresses underwent geospatial analysis and Area Deprivation Index (ADI) was extracted. Univariable and multivariable survival analyses were performed. A Cox proportional hazards model was used to assess the effect of ADI and other socioeconomic variables while controlling for a priori selected clinical variables with known relevance to survival. RESULTS In total, 1492 patients met inclusion criteria. The average age at diagnosis was 62±14.2 years with a median overall survival of 12.1 [Interquartile Range (IQR) 5-22] months. The median ADI was 66 (IQR 46-84). Patients with high socioeconomic deprivation (ADI>75) were less likely to receive chemotherapy (92% vs 96%, p=.03), and had worse overall survival compared to patients with low socioeconomic deprivation (10 vs 13 months, p=.001). In the multivariable model, patients with high ADI had worse overall survival (hazard ratio [HR], 1.42; 95% confidence interval [CI], 1.16-1.73, p<.001). To account for changes in WHO guidelines, we implemented the model on patients diagnosed between 2017-2023 and findings were consistent (HR 1.34, 95%CI 1.07-1.68, p=.011). CONCLUSIONS We present the largest study reporting the effect of neighborhood-level socioeconomic status on overall survival of GBM patients. Neighborhood-level socioeconomic status provides the most accurate capture of the patient-level socioeconomic determinants of health. Patients with higher ADI have worse overall survival after controlling for other socioeconomic and clinical variables. These results suggest significant association between neighborhood-level socioeconomic status and overall survival in GBM patients.

Abstract Pediatric high-grade gliomas (HGGs) represent a significant clinical challenge with poor survival rates. Engineered oncolytic herpes simplex virus (oHSV) has shown potential in several clinical trials at targeting HGGs through their direct lytic effect and induction of an immune response. We have learned from our clinical trial experience (NCT02457845) that a critical barrier to more durable response is augmenting and sustaining the anti-tumor immune response generated by oHSV. LB-100, a protein phosphatase 2A (PP2A) inhibitor, is known to enhance T-cell activity. We hypothesized that LB-100 with anti-PD-1 therapy would overcome the immunosuppressive barriers, enhancing the immunotherapeutic effects of oHSV and improve survival in an immunocompetent murine model. We investigated the therapeutic impact of clinically available, next-generation oHSV, M002, which expresses murine interleukin-12, combined with LB-100 and PD-1 inhibition compared to M002 with LB-100 or anti-PD-1 antibody, each therapy alone, or control by measuring median survival and changes in the tumor immune microenvironment. The triple combination of M002, LB-100, and anti-PD-1 antibody significantly extended median survival compared to control (45 days vs 22.5 days, P=0.001) or each treatment alone, and compared to M002 and LB-100 (44 days vs 28 days, P=0.017) or M002 and anti-PD-1 (45.5 days vs 41 days, P=0.023). This increase in survival was correlated with a robust increase in CD45+ immune cell infiltration and a reduction in T-regulatory cells. We will further investigate the changes in the tumor microenvironment to better understand the specific contributions of different immune cell populations. These data support the hypothesis that LB-100 enhances the efficacy of oHSV by amplifying T-cell-mediated immune responses against tumor cells. This combination therapy demonstrates a promising strategy that warrants further exploration and potential clinical application, emphasizing the critical role of targeting multiple aspects of immune regulation to enhance the efficacy of oncolytic virotherapy in pediatric tumors.

IntroductionMalignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas with unacceptably low cure rates occurring often in patients with neurofibromatosis 1 defects. To investigate oncolytic Herpes Simplex Virus (oHSV) as an immunotherapeutic approach, we compared viral replication, functional activity, and immune response between unarmed and interleukin 12 (IL-12)-armed oncolytic viruses in virus-permissive (B109) and -resistant (67C-4) murine MPNSTs.MethodsThis study compared two attenuated IL-12-oHSVs with γ134.5 gene deletions (Δγ134.5) and the same transgene expression cassette. The primary difference in the IL-12-oHSVs was in their ability to counter the translational arrest response in infected cells. Unlike M002 (Δγ134.5, mIL-12), C002 (Δγ134.5, mIL-12, IRS1) expresses an HCMV IRS1 gene and evades dsRNA activated translational arrest in infected cells.Results and discussionOur results show that oHSV replication and gene expression results in vitro were not predictive of oHSV direct oncolytic activity in vivo. Tumors that supported viral replication in cell culture studies resisted viral replication by both oHSVs and restricted M002 transgene expression in vivo. Furthermore, two IL-12-oHSVs with equivalent transcriptional activity differed in IL-12 protein production in vivo, and the differences in IL-12 protein levels were reflected in immune infiltrate activity changes as well as tumor growth suppression differences between the IL-12-oHSVs. C002-treated tumors exhibited sustained IL-12 production with improved dendritic cells, monocyte-macrophage activity (MHCII, CD80/CD86 upregulation) and a polyfunctional Th1-cell response in the tumor infiltrates.ConclusionThese results suggest that transgene protein production differences between oHSVs in vivo, in addition to replication differences, can impact OV-therapeutic activity.

Early indicators of the response to imunovirotherapy are currently limited due to the novelty of the therapies and unpredictability of responses. We propose using the persistent tumor index (PTI) derived from diffusion and perfusion MRI as a predictor of treatment response. In 10 high grade glioma patients treated with imunovirotherapy, only the baseline PTI measure was associated with progression free survival whereas other known imaging biomarkers of survival were not.