Glioblastoma in the oldest old: Clinical characteristics, therapy, and outcome in patients aged 80 years and older

Background

Incidence rates of glioblastoma in very old patients are rising. The standard of care for this cohort is only partially defined and survival remains poor. The aims of this study were to reveal current practice of tumor-specific therapy and supportive care, and to identify predictors for survival in this cohort.

Methods

Patients aged 80 years or older at the time of glioblastoma diagnosis were retrospectively identified in 6 clinical centers in Switzerland and France. Demographics, clinical parameters, and survival outcomes were annotated from patient charts. Cox proportional hazards modeling was performed to identify parameters associated with survival.

Results

Of 107 patients, 45 were diagnosed by biopsy, 30 underwent subtotal resection, and 25 had gross total resection. In 7 patients, the extent of resection was not specified. Postoperatively, 34 patients did not receive further tumor-specific treatment. Twelve patients received radiotherapy with concomitant temozolomide, but only 2 patients had maintenance temozolomide therapy. Fourteen patients received temozolomide alone, 35 patients received radiotherapy alone, 1 patient received bevacizumab, and 1 took part in a clinical trial. Median progression-free survival (PFS) was 3.3 months and median overall survival (OS) was 4.2 months. Among patients who received any postoperative treatment, median PFS was 3.9 months and median OS was 7.2 months. Karnofsky performance status (KPS) ≥70%, gross total resection, and combination therapy were associated with better outcomes. The median time spent hospitalized was 30 days, accounting for 23% of the median OS. End-of-life care was mostly provided by nursing homes (n = 20; 32%) and palliative care wards (n = 16; 26%).

Conclusions

In this cohort of very old patients diagnosed with glioblastoma, a large proportion was treated with best supportive care. Treatment beyond surgery and, in particular, combined modality treatment were associated with longer OS and may be considered for selected patients even at higher ages.

Marizomib for patients with newly diagnosed glioblastoma: a randomized phase 3 trial

BACKGROUND

Standard treatment for patients with newly diagnosed glioblastoma includes surgery, radiotherapy (RT) and temozolomide (TMZ) chemotherapy (TMZ/RT→TMZ). The proteasome has long been considered a promising therapeutic target because of its role as a central biological hub in tumor cells. Marizomib is a novel pan-proteasome inhibitor that crosses the blood brain barrier.

METHODS

EORTC 1709/CCTG CE.8 was a multicenter, randomized, controlled, open label phase 3 superiority trial. Key eligibility criteria included newly diagnosed glioblastoma, age > 18 years and Karnofsky performance status > 70. Patients were randomized in a 1:1 ratio. The primary objective was to compare overall survival (OS) in patients receiving marizomib in addition to TMZ/RT→TMZ with patients receiving only standard treatment in the whole population, and in the subgroup of patients with MGMT promoter-unmethylated tumors.

RESULTS

The trial was opened at 82 institutions in Europe, Canada and the US. A total of 749 patients (99.9% of planned 750) were randomized. OS was not different between the standard and the marizomib arm (median 17 vs 16.5 months; HR=1.04; p=0.64). PFS was not statistically different either (median 6.0 vs. 6.3 months; HR=0.97; p=0.67). In patients with MGMT promoter-unmethylated tumors, OS was also not different between standard therapy and marizomib (median 14.5 vs 15.1 months, HR=1.13; p=0.27). More CTCAE grade 3/4 treatment-emergent adverse events were observed in the marizomib arm than in the standard arm.

CONCLUSIONS

Adding marizomib to standard temozolomide-based radiochemotherapy resulted in more toxicity, but did not improve OS or PFS in patients with newly diagnosed glioblastoma.

Prognostic Role of Ventricular Size and Its Dynamics in Patients With Leptomeningeal Metastasis From Solid Tumors

BACKGROUND AND OBJECTIVES

Hydrocephalus is a common radiologic sign in patients with leptomeningeal metastasis (LM) from solid tumors which can be assessed using the Evans index (EI). Here, we explored the prognostic value of ventricular size in LM.

METHODS

We identified patients with LM from solid tumors by chart review at 3 academic hospitals to explore the prognostic associations of the EI at diagnosis, first follow-up, and progression.

RESULTS

We included 113 patients. The median age was 58.3 years (interquartile range [IQR] 46.1-65.8), 41 patients (36%) were male, and 72 patients (64%) were female. The most frequent cancers were lung cancer (n = 39), breast cancer (n = 36), and melanoma (n = 23). The median EI at baseline was 0.28 (IQR 0.26-0.31); the EI value was 0.27 or more in 67 patients (59%) and 0.30 or more in 37 patients (33%). Among patients with MRI follow-up, the EI increased by 0.01 or more in 16 of 31 patients (52%), including 8 of 30 patients (30%) without and 10 of 17 patients (59%) with LM progression at first follow-up. At LM progression, an increase of EI of 0.01 or more was noted in 18 of 34 patients (53%). The median survival was 2.9 months (IQR 1-7.2). Patients with a baseline EI below 0.27 had a longer survival than those with an EI of 0.27 or more (5.3 months, IQR 2.4-10.8, vs 1.3 months, IQR 0.6-4.1) (HR 1.70, 95% CI 1.135-2.534, p = 0.0099). The median survival was 3.7 months (IQR 1.4-8.3) with an EI below 0.30 vs 1.8 months (IQR 0.8-4.1) with an EI of 0.30 or more (HR 1.40, 95% CI 0.935-1.243, p = 0.1113). Among patients with follow-up scans available, the overall survival was 9.4 months (IQR 5.6-21.0) for patients with stable or decreased EI at first follow-up as opposed to 5.6 months (IQR 2.5-10.5) for those with an increase in the EI (HR 1.08, 95% CI 0.937-1.243; p = 0.300).

DISCUSSION

The EI at baseline is prognostic in LM. An increase of EI during follow-up may be associated with inferior LM progression-free survival. Independent validation cohorts with larger sample size and evaluation of confounding factors will help to better define the clinical utility of EI assessments in LM.

Zotiraciclib (TG02) for newly diagnosed glioblastoma in the elderly or for recurrent glioblastoma: The EORTC 1608 STEAM trial

BACKGROUND

Zotiraciclib (TG02) is an oral multi-cyclin dependent kinase (CDK) inhibitor thought to inhibit tumor growth via CDK-9-dependent depletion of survival proteins such as c-MYC and MCL-1 which are frequently overexpressed in glioblastoma.

METHODS

EORTC 1608 (NCT03224104) (STEAM) had a three parallel group (A,B,C) phase Ib, open-label, non-randomized, multicenter design in IDH wild-type newly diagnosed glioblastoma or anaplastic astrocytoma. Groups A and B explored the maximum tolerated dose (MTD) of TG02 in elderly patients, in combination with hypofractionated radiotherapy alone (group A) or temozolomide alone (group B), according to O6-methylguanine DNA methyltransferase promoter methylation status determined centrally. Group C explored single agent activity of TG02 at first relapse after temozolomide chemoradiotherapy with a primary endpoint of progression-free survival at 6 months (PFS-6). Tumor expression of CDK-9, c-MYC and MCL-1 was determined by immunohistochemistry.

RESULTS

The MTD was 150 mg twice weekly in combination with radiotherapy alone (group A) or temozolomide alone (group B). Two dose-limiting toxicities were observed at 150 mg: one in group A (grade 3 seizure), one in group B (multiple grade 1 events). Main toxicities included neutropenia, gastrointestinal disorders and hepatotoxicity. PFS-6 in group C was 6.7%. CDK-9, c-MYC and MCL-1 were confirmed to be expressed and their expression was moderately cross-correlated. High protein levels of MCL-1 were associated with inferior survival.

CONCLUSIONS

TG02 exhibits overlapping toxicity with alkylating agents and low single agent clinical activity in recurrent glioblastoma. The role of CDK-9 and its down-stream effectors as prognostic factors and therapeutic targets in glioblastoma warrants further study.

A phase Ib/II randomized, open-label drug repurposing trial of glutamate signaling inhibitors in combination with chemoradiotherapy in patients with newly diagnosed glioblastoma: the GLUGLIO trial protocol

BACKGROUND

Glioblastoma is the most common and most aggressive malignant primary brain tumor in adults. Glioblastoma cells synthesize and secrete large quantities of the excitatory neurotransmitter glutamate, driving epilepsy, neuronal death, tumor growth and invasion. Moreover, neuronal networks interconnect with glioblastoma cell networks through glutamatergic neuroglial synapses, activation of which induces oncogenic calcium oscillations that are propagated via gap junctions between tumor cells. The primary objective of this study is to explore the efficacy of brain-penetrating anti-glutamatergic drugs to standard chemoradiotherapy in patients with glioblastoma.

METHODS/DESIGN

GLUGLIO is a 1:1 randomized phase Ib/II, parallel-group, open-label, multicenter trial of gabapentin, sulfasalazine, memantine and chemoradiotherapy (Arm A) versus chemoradiotherapy alone (Arm B) in patients with newly diagnosed glioblastoma. Planned accrual is 120 patients. The primary endpoint is progression-free survival at 6 months. Secondary endpoints include overall and seizure-free survival, quality of life of patients and caregivers, symptom burden and cognitive functioning. Glutamate levels will be assessed longitudinally by magnetic resonance spectroscopy. Other outcomes of interest include imaging response rate, neuronal hyperexcitability determined by longitudinal electroencephalography, Karnofsky performance status as a global measure of overall performance, anticonvulsant drug use and steroid use. Tumor tissue and blood will be collected for translational research. Subgroup survival analyses by baseline parameters include segregation by age, extent of resection, Karnofsky performance status, O6-methylguanine DNA methyltransferase (MGMT) promotor methylation status, steroid intake, presence or absence of seizures, tumor volume and glutamate levels determined by MR spectroscopy. The trial is currently recruiting in seven centers in Switzerland.

TRIAL REGISTRATION

NCT05664464. Registered 23 December 2022.

Improved prognostic stratification of patients with isocitrate dehydrogenase-mutant astrocytoma

Prognostic factors and standards of care for astrocytoma, isocitrate dehydrogenase (IDH)-mutant, CNS WHO grade 4, remain poorly defined. Here we sought to explore disease characteristics, prognostic markers, and outcome in patients with this newly defined tumor type. We determined molecular biomarkers and assembled clinical and outcome data in patients with IDH-mutant astrocytomas confirmed by central pathology review. Patients were identified in the German Glioma Network cohort study; additional cohorts of patients with CNS WHO grade 4 tumors were identified retrospectively at two sites. In total, 258 patients with IDH-mutant astrocytomas (114 CNS WHO grade 2, 73 CNS WHO grade 3, 71 CNS WHO grade 4) were studied. The median age at diagnosis was similar for all grades. Karnofsky performance status at diagnosis inversely correlated with CNS WHO grade (p < 0.001). Despite more intensive treatment upfront with higher grade, CNS WHO grade was strongly prognostic: median overall survival was not reached for grade 2 (median follow-up 10.4 years), 8.1 years (95% CI 5.4-10.8) for grade 3, and 4.7 years (95% CI 3.4-6.0) for grade 4. Among patients with CNS WHO grade 4 astrocytoma, median overall survival was 5.5 years (95% CI 4.3-6.7) without (n = 58) versus 1.8 years (95% CI 0-4.1) with (n = 12) homozygous CDKN2A deletion. Lower levels of global DNA methylation as detected by LINE-1 methylation analysis were strongly associated with CNS WHO grade 4 (p < 0.001) and poor outcome. MGMT promoter methylation status was not prognostic for overall survival. Histomolecular stratification based on CNS WHO grade, LINE-1 methylation level, and CDKN2A status revealed four subgroups of patients with significantly different outcomes. In conclusion, CNS WHO grade, global DNA methylation status, and CDKN2A homozygous deletion are prognostic in patients with IDH-mutant astrocytoma. Combination of these parameters allows for improved prediction of outcome. These data aid in designing upcoming trials using IDH inhibitors.

Custom order entry for Parkinson's medications in the hospital improves timely administration: an analysis of over 31,000 medication doses

Background

Patients with Parkinson's disease (PD) are at increased risk for hospital acquired complications. Deviations from home medication schedules and delays in administration are major contributing factors. We had previously developed a protocol to ensure adherence to home medication schedules using "custom" ordering. In this study we are assessing the impact this order type may have on reducing delays in PD medication administration in the hospital.

Material and methods

We reviewed 31,404 orders placed for PD medications from January 2, 2016 to April 30 2021. We evaluated the orders to determine if they were placed in a Custom format or using a default non-custom order entry. We further evaluated all orders to determine if there was a relationship with the order type and timely administration of medications. We compared medications that were administered within 1 min, 15 min, 30 min and 60 min of due times across custom orders vs. non-custom default orders. We also evaluated the relationship between ordering providers and type of orders placed as well as hospital unit and type of orders placed.

Results

14,204 (45.23%) orders were placed using a custom schedule and 17,200 (54.77%) orders were placed using non-custom defaults. The custom group showed a significantly lower median delay of 3.06 minutes compared to the non-custom group (p<.001). Custom orders had a significantly more recent median date than non-custom default orders (2019-10-07 vs. 2018-01-06, p<0.001). In additional analyses, medication administration delays were significantly improved for custom orders compared to non-custom orders, with likelihoods 1.64 times higher within 1 minute, 1.40 times higher within 15 minutes, and 1.33 times higher within 30 minutes of the due time (p<0.001 for all comparisons).

Conclusion

This is the largest study to date examining the effects of order entry type on timely administration of PD medications in the hospital. Orders placed using a custom schedule may help reduce delays in administration of PD medications.

Chimeric antigen receptor T cell-based targeting of CD317 as a novel immunotherapeutic strategy against glioblastoma

BACKGROUND

Chimeric antigen receptor (CAR) T cell therapy has proven to be successful against hematological malignancies. However, exploiting CAR T cells to treat solid tumors is more challenging for various reasons including the lack of suitable target antigens. Here, we identify the transmembrane protein CD317 as a novel target antigen for CAR T cell therapy against glioblastoma, one of the most aggressive solid tumors.

METHODS

CD317-targeting CAR T cells were generated by lentivirally transducing human T cells from healthy donors. The anti-glioma activity of CD317-CAR T cells toward various glioma cells was assessed in vitro in cell lysis assays. Subsequently, we determined the efficacy of CD317-CAR T cells to control tumor growth in vivo in clinically relevant mouse glioma models.

RESULTS

We generated CD317-specific CAR T cells and demonstrate strong anti-tumor activity against several glioma cell lines as well as primary patient-derived cells with varying CD317 expression levels in vitro. A CRISPR/Cas9-mediated knockout of CD317 protected glioma cells from CAR T cell lysis, demonstrating the target specificity of the approach. Silencing of CD317 expression in T cells by RNA interference reduced fratricide of engineered T cells and further improved their effector function. Using orthotopic glioma mouse models, we demonstrate the antigen-specific anti-tumor activity of CD317-CAR T cells, which resulted in prolonged survival and cure of a fraction of CAR T cell-treated animals.

CONCLUSIONS

These data reveal a promising role of CD317-CAR T cell therapy against glioblastoma, which warrants further evaluation to translate this immunotherapeutic strategy into clinical neuro-oncology.

Immune checkpoint inhibitors induced side effects of the peripheral nervous system

PURPOSE OF REVIEW

This review highlights recent knowledge on the diagnosis and treatment of immune checkpoint inhibitor-induced neurological side effects (irNAE) focussing on the neuromuscular system.

RECENT FINDINGS

irNAEs mainly resemble sporadic neuromuscular autoimmune diseases and paraneoplastic neurological syndromes. However, neurological symptoms may be unspecific (muscle weakness, fatigue) in the oncological setting and carry the risk of misdiagnosis and delayed therapeutic intervention. The role of disease-specific neuromuscular autoantibodies in the diagnosis is controversial as preexisting autoantibodies may otherwise be present before immune checkpoint inhibitor (ICI) treatment without clinical symptoms and may not develop in case of irNAE manifestation. A new necrotising form of myositis (irMyositis) has been described presenting with facial weakness and ptosis mimicking myasthenia gravis. It comes along with a high rate of severe myocarditis accounting for a triad overlap syndrome (myasthenia/myositis/myocarditis). The role of modern biologicals in the treatment of irNAEs has to be determined.

SUMMARY

irNAEs are rare but carry the risk of permanent morbidity and mortality. Early suspicion and diagnosis are key to prevent neurological sequelae. Beyond interruption of ICI administration, treatment corresponds to sporadic autoimmune diseases. The myasthenia/myositis/myocarditis overlap syndrome deserves special attention as it carries the highest risk of mortality. The role of neurotoxic pretreatment regimens, preexisting subclinical neurological autoimmune diseases and the risk of ICI-re-challenge after irNAEs has to be further investigated.

Bridging the age gap: a review of molecularly informed treatments for glioma in adolescents and young adults

Gliomas are the most common primary central nervous system (CNS) tumors and a major cause of cancer-related mortality in children (age <15 years), adolescents and young adults (AYA, ages 15-39 years), and adults (age >39 years). Molecular pathology has helped enhance the characterization of these tumors, revealing a heterogeneous and ever more complex group of malignancies. Recent molecular analyses have led to an increased appreciation of common genomic alterations prevalent across all ages. The 2021 World Health Organization (WHO) CNS tumor classification, 5th edition (WHO CNS5) brings forward a nomenclature distinguishing "pediatric-type" and "adult-type" gliomas. The spectrum of gliomas in AYA comprises both "pediatric-like" and "adult-like" tumor entities but remains ill-defined. With fragmentation of clinical management between pediatric and adult centers, AYAs face challenges related to gaps in medical care, lower rates of enrollment in clinical trials and additional psychosocial and economic challenges. This calls for a rethinking of diagnostic and therapeutic approaches, to improve access to appropriate testing and potentially beneficial treatments to patients of all ages.

The manganese carbonyl complex [Mn(CO)3(tqa-κ3N)]Br: A novel antimicrobial agent with the potential to treat avian pathogenic Escherichia coli (APEC) infections

The development of alternatives to antibiotics is essential for the treatment of animal infections and as a measure to reduce the selective pressure on antibiotics that are critical for human medicine. Metal complexes have been highlighted for their antimicrobial activity against several bacterial pathogens. In particular, manganese carbonyl complexes have shown efficacy against multidrug-resistant Gram-negative pathogens, and relatively low cytotoxicity against avian macrophages and in wax moth larval models. They are thus potential candidates for deployment against Avian Pathogenic Escherichia coli (APEC), the aetiological agent of avian colibacillosis, which results in severe animal welfare issues and financial losses worldwide. This study aimed to determine the efficacy of [Mn(CO)3(tqa-κ3N)]Br in Galleria mellonella and chick models of infection against APEC. The results demonstrated in vitro and in vivo antibacterial activity against all antibiotic-resistant APEC test isolates screened in the study.

A T-cell antigen atlas for meningioma: novel options for immunotherapy

Meningiomas are the most common primary intracranial tumors. Although most symptomatic cases can be managed by surgery and/or radiotherapy, a relevant number of patients experience an unfavorable clinical course and additional treatment options are needed. As meningiomas are often perfused by dural branches of the external carotid artery, which is located outside the blood-brain barrier, they might be an accessible target for immunotherapy. However, the landscape of naturally presented tumor antigens in meningioma is unknown. We here provide a T-cell antigen atlas for meningioma by in-depth profiling of the naturally presented immunopeptidome using LC-MS/MS. Candidate target antigens were selected based on a comparative approach using an extensive immunopeptidome data set of normal tissues. Meningioma-exclusive antigens for HLA class I and II are described here for the first time. Top-ranking targets were further functionally characterized by showing their immunogenicity through in vitro T-cell priming assays. Thus, we provide an atlas of meningioma T-cell antigens which will be publicly available for further research. In addition, we have identified novel actionable targets that warrant further investigation as an immunotherapy option for meningioma.

Long-term survival with IDH wildtype glioblastoma: first results from the ETERNITY Brain Tumor Funders' Collaborative Consortium (EORTC 1419)

BACKGROUND

Median survival with glioblastoma remains in the range of 12 months on population levels. Only few patients survive for more than 5 years. Patient and disease features associated with long-term survival remain poorly defined.

METHODS

European Organization for Research and Treatment of Cancer (EORTC) 1419 (ETERNITY) is a registry study supported by the Brain Tumor Funders Collaborative in the US and the EORTC Brain Tumor Group. Patients with glioblastoma surviving at least 5 years from diagnosis were identified at 24 sites in Europe, US, and Australia. In patients with isocitrate dehydrogenase (IDH) wildtype tumours, prognostic factors were analysed using the Kaplan-Meier method and the Cox proportional hazards model. A population-based reference cohort was obtained from the Cantonal cancer registry Zurich.

RESULTS

At the database lock of July 2020, 280 patients with histologically centrally confirmed glioblastoma (189 IDH wildtype, 80 IDH mutant, 11 incompletely characterised) had been registered. In the IDH wildtype population, median age was 56 years (range 24-78 years), 96 patients (50.8%) were female, 139 patients (74.3%) had tumours with O6-methylguanine DNA methyltransferase (MGMT) promoter methylation. Median overall survival was 9.9 years (95% confidence interval [95% CI] 7.9-11.9). Patients without recurrence experienced longer median survival (not reached) than patients with one or more recurrences (8.92 years) (p < 0.001) and had a high rate (48.8%) of MGMT promoter-unmethylated tumours.

CONCLUSIONS

Freedom from progression is a powerful predictor of overall survival in long-term survivors with glioblastoma. Patients without relapse often have MGMT promoter-unmethylated glioblastoma and may represent a distinct subtype of glioblastoma.

Diagnosis and management of complications from the treatment of primary central nervous system tumors in adults

Central nervous system (CNS) tumor patients commonly undergo multimodality treatment in the course of their disease. Adverse effects and complications from these interventions have not been systematically studied, but pose significant challenges in clinical practice and impact function and quality of life, especially in the management of long-term brain tumor survivors. Here, the European Association of Neuro-Oncology (EANO) has developed recommendations to prevent, diagnose, and manage adverse effects and complications in the adult primary brain CNS tumor (except lymphomas) patient population with a specific focus on surgery, radiotherapy, and pharmacotherapy. Specifically, we also provide recommendations for dose adaptations, interruptions, and reexposure for pharmacotherapy that may serve as a reference for the management of standard of care in clinical trials. We also summarize which interventions are unnecessary, inactive or contraindicated. This consensus paper should serve as a reference for the conduct of standard therapy within and outside of clinical trials.

Prognostic assessment in patients operated for brain metastasis from systemic tumors

BACKGROUND

Established models for prognostic assessment in patients with brain metastasis do not stratify for prior surgery. Here we tested the prognostic accuracy of the Graded Prognostic Assessment (GPA) score model in patients operated for BM and explored further prognostic factors.

METHODS

We included 285 patients operated for brain metastasis at the University Hospital Zurich in the analysis. Information on patient characteristics, imaging, staging, peri- and postoperative complications and survival were extracted from the files and integrated into a multivariate Cox hazard model.

RESULTS

The GPA score showed an association with outcome. We further identified residual tumor after surgery (p = 0.007, hazard ratio (HR) 1.6, 95% confidence interval (CI) 1.1-2.3) steroid use (p = 0.021, HR 1.7, 95% CI 1.1-2.6) and number of extracranial metastasis sites (p = 0.009, HR 1.4, 95% CI 1.1-1.6) at the time of surgery as independent prognostic factors. A trend was observed for postoperative infection of the subarachnoid space (p = 0.102, HR 3.5, 95% CI 0.8-15.7).

CONCLUSIONS

We confirm the prognostic capacity of the GPA score in a cohort of operated patients with brain metastasis. However, extent of resection and steroid use provide additional aid for the prognostic assessment in these patients.

Targeted delivery of tumor necrosis factor in combination with CCNU induces a T cell-dependent regression of glioblastoma

Glioblastoma is the most aggressive primary brain tumor with an unmet need for more effective therapies. Here, we investigated combination therapies based on L19TNF, an antibody-cytokine fusion protein based on tumor necrosis factor that selectively localizes to cancer neovasculature. Using immunocompetent orthotopic glioma mouse models, we identified strong anti-glioma activity of L19TNF in combination with the alkylating agent CCNU, which cured the majority of tumor-bearing mice, whereas monotherapies only had limited efficacy. In situ and ex vivo immunophenotypic and molecular profiling in the mouse models revealed that L19TNF and CCNU induced tumor DNA damage and treatment-associated tumor necrosis. In addition, this combination also up-regulated tumor endothelial cell adhesion molecules, promoted the infiltration of immune cells into the tumor, induced immunostimulatory pathways, and decreased immunosuppression pathways. MHC immunopeptidomics demonstrated that L19TNF and CCNU increased antigen presentation on MHC class I molecules. The antitumor activity was T cell dependent and completely abrogated in immunodeficient mouse models. On the basis of these encouraging results, we translated this treatment combination to patients with glioblastoma. The clinical translation is ongoing but already shows objective responses in three of five patients in the first recurrent glioblastoma patient cohort treated with L19TNF in combination with CCNU (NCT04573192).

Immunological and tumor-intrinsic mechanisms mediate the synergistic growth suppression of experimental glioblastoma by radiotherapy and MET inhibition

The hepatocyte growth factor (HGF)/MET signaling pathway has been proposed to be involved in the resistance to radiotherapy of glioblastoma via proinvasive and DNA damage response pathways.Here we assessed the role of the MET pathway in the response to radiotherapy in vitro and in vivo in syngeneic mouse glioma models. We find that the murine glioma cell lines GL-261, SMA-497, SMA-540 and SMA-560 express HGF and its receptor MET and respond to exogenous HGF with MET phosphorylation. Glioma cell viability or proliferation are unaffected by genetic or pharmacological MET inhibition using tepotinib or CRISPR/Cas9-engineered Met gene knockout and MET inhibition fails to sensitize glioma cells to irradiation in vitro. In contrast, the combination of tepotinib with radiotherapy prolongs survival of orthotopic SMA-560 or GL-261 glioma-bearing mice compared with radiotherapy or tepotinib treatment alone. Synergy is lost when such experiments are conducted in immunodeficient Rag1^-/- mice, and, importantly, also when Met gene expression is disrupted in the tumor cells. Combination therapy suppresses a set of pro-inflammatory mediators including matrix metalloproteases that are upregulated by radiotherapy alone and that have been linked to poor outcome in glioblastoma. Several of these mediators are positively regulated by transforming growth factor (TGF)-β, and pSMAD2 levels as a surrogate marker of TGF-β pathway activity are suppressed by combination treatment. We conclude that synergistic suppression of experimental syngeneic glioma growth by irradiation and MET inhibition requires MET expression in the tumor as well as an intact immune system. Clinical evaluation of this combined strategy in newly diagnosed glioblastoma is warranted.

Structural and biochemical insights into His-tag-induced higher-order oligomerization of membrane proteins by cryo-EM and size exclusion chromatography

Structural and functional characterization of proteins as well as the design of targeted drugs heavily rely on recombinant protein expression and purification. The polyhistidine-tag (His-tag) is among the most prominent examples of affinity tags used for the isolation of recombinant proteins from their expression hosts. Short peptide tags are commonly considered not to interfere with the structure of the tagged protein and tag removal is frequently neglected. This study demonstrates the formation of higher-order oligomers based on the example of two His-tagged membrane proteins, the dimeric arginine-agmatine antiporter AdiC and the pentameric light-driven proton pump proteorhodopsin. Size exclusion chromatography revealed the formation of tetrameric AdiC and decameric as well as pentadecameric proteorhodopsin through specific interactions between their His-tags. In addition, single particle cryo-electron microscopy (cryo-EM) allowed structural insights into the three-dimensional arrangement of the higher-order oligomers and the underlying His-tag-mediated interactions. These results reinforce the importance of considering the length and removal of affinity purification tags and illustrate how neglect can lead to potential interference with downstream biophysical or biochemical characterization of the target protein.

Safety and anti-tumor activity of lisavanbulin administered as 48-hour infusion in patients with ovarian cancer or recurrent glioblastoma: a phase 2a study

PURPOSE

 Lisavanbulin (BAL101553) is the prodrug of avanbulin (BAL27862), a microtubule-destabilizing agent. The goal of this study (NCT02895360) was to characterize the safety, tolerability and antitumor activity of lisavanbulin administered as a 48-hour intravenous (IV) infusion at the recommended Phase 2 dose (RP2D) of 70 mg/m². Results from the Phase 1 dose-escalation portion of the study identifying the RP2D have been previously reported. Here, we present the findings from the Phase 2a portion of this study. Methods. This multi-center, open-label study included patients with ovarian, fallopian-tube, or primary peritoneal cancer that was either platinum-resistant or refractory (11 patients), or with first recurrence of glioblastoma (12 patients). Lisavanbulin was administered as a 48-hour IV infusion on Days 1, 8, and 15 of a 28-day cycle. Results. Lisavanbulin was well tolerated in both patient cohorts. Thirteen patients (56.5%) developed 49 adverse events assessed as related to study treatment. The majority were mild or moderate; four were grade 3/4. Sixteen SAEs were reported in nine patients (39.1%), with none considered related to study treatment. No AEs led to permanent treatment discontinuation. Three patients in the ovarian cancer cohort had stable disease with lesion size reductions after two cycles of treatment; in the glioblastoma cohort, one patient showed partial response with a > 90% glioblastoma area reduction as best response, and one patient had stable disease after eight cycles of treatment. Conclusion. This study demonstrated a favorable safety and tolerability profile of 48-hour continuous IV infusion of lisavanbulin in patients with solid extracranial tumors or glioblastoma. Clinicaltrials.gov registration: NCT02895360.

Radiotherapy combined with nivolumab or temozolomide for newly diagnosed glioblastoma with unmethylated MGMT promoter: An international randomized phase III trial

BACKGROUND

Addition of temozolomide (TMZ) to radiotherapy (RT) improves overall survival (OS) in patients with glioblastoma (GBM), but previous studies suggest that patients with tumors harboring an unmethylated MGMT promoter derive minimal benefit. The aim of this open-label, phase III CheckMate 498 study was to evaluate the efficacy of nivolumab (NIVO) + RT compared with TMZ + RT in newly diagnosed GBM with unmethylated MGMT promoter.

METHODS

Patients were randomized 1:1 to standard RT (60 Gy) + NIVO (240 mg every 2 weeks for eight cycles, then 480 mg every 4 weeks) or RT + TMZ (75 mg/m2 daily during RT and 150-200 mg/m2/day 5/28 days during maintenance). The primary endpoint was OS.

RESULTS

A total of 560 patients were randomized, 280 to each arm. Median OS (mOS) was 13.4 months (95% CI, 12.6 to 14.3) with NIVO + RT and 14.9 months (95% CI, 13.3 to 16.1) with TMZ + RT (hazard ratio [HR], 1.31; 95% CI, 1.09 to 1.58; P = .0037). Median progression-free survival was 6.0 months (95% CI, 5.7 to 6.2) with NIVO + RT and 6.2 months (95% CI, 5.9 to 6.7) with TMZ + RT (HR, 1.38; 95% CI, 1.15 to 1.65). Response rates were 7.8% (9/116) with NIVO + RT and 7.2% (8/111) with TMZ + RT; grade 3/4 treatment-related adverse event (TRAE) rates were 21.9% and 25.1%, and any-grade serious TRAE rates were 17.3% and 7.6%, respectively.

CONCLUSIONS

The study did not meet the primary endpoint of improved OS; TMZ + RT demonstrated a longer mOS than NIVO + RT. No new safety signals were detected with NIVO in this study. The difference between the study treatment arms is consistent with the use of TMZ + RT as the standard of care for GBM.ClinicalTrials.gov NCT02617589.

European Association of Neuro-Oncology (EANO) guidelines for treatment of primary central nervous system lymphoma (PCNSL)

The management of primary central nervous system (PCNSL) is one of the most controversial topics in neuro-oncology because of the complexity of the disease and the limited number of controlled studies available. In 2021, given recent advances and the publication of practice-changing randomized trials, the European Association of Neuro-Oncology (EANO) created a multidisciplinary task force to update the previously published evidence-based guidelines for immunocompetent adult patients with PCNSL and added a section on immunosuppressed patients. The guideline provides consensus considerations and recommendations for the treatment of PCNSL, including intraocular manifestations and specific management of the elderly. The main changes from the previous guideline include strengthened evidence for the consolidation with ASCT in first-line treatment, prospectively assessed chemotherapy combinations for both young and elderly patients, clarification of the role of rituximab even though the data remain inconclusive, of the role of new agents, and the incorporation of immunosuppressed patients and primary ocular lymphoma. The guideline should aid the clinicians in everyday practice and decision making and serve as a basis for future research in the field.

Diabetes insipidus and Guillain-Barré-like syndrome following CAR-T cell therapy: a case report

BACKGROUND

Immune effector cell-associated neurotoxicity syndrome (ICANS) is a common adverse event of CD19-directed chimeric antigen receptor (CAR) T cell therapy. Other neurological adverse events, however, have not methodically been described and studied. Furthermore, safety data on CAR-T cell therapy in patients with central nervous system (CNS) lymphoma remain limited.

MAIN BODY

We here report occurrence of a Guillain-Barré-like syndrome (GBS) and central diabetes insipidus (cDI) following tisagenlecleucel therapy for relapsed high-grade lymphoma with CNS involvement. Both complications were refractory to standard treatment of ICANS. Weakness of respiratory muscles required mechanical ventilation and tracheostomy while cDI was treated with desmopressin substitution for several weeks. Muscle-nerve biopsy and nerve conduction studies confirmed an axonal pattern of nerve damage. T cell-rich infiltrates and detection of the CAR transgene in muscle-nerve sections imply a direct or indirect role of CAR-T cell-mediated inflammation. In line with current treatment guidelines for GBS, intravenous immunoglobulin was administered and gradual but incomplete recovery was observed over the course of several months.

CONCLUSIONS

This case report highlights the risk of rare but severe neurological adverse events, such as acute GBS or cDI, in patients treated with CAR-T cells. It further underlines the importance of appropriate patient surveillance and systematic reporting of rare complications to eventually improve treatment.

Differential roles of type I interferon signaling in tumor versus host cells in experimental glioma models

Despite multimodal treatment approaches including surgery, radiotherapy and chemotherapy, the median survival for patients with glioblastoma remains in the range of one year and thus poor. Type I interferons (IFN) are involved in immune responses to viral infection and exhibit anti-tumor activity in certain cancers. Here we explored the biological relevance of constitutive type I IFN signaling in murine glioma models in vitro and in vivo. CT-2A, GL-261, SMA-497, SMA-540 and SMA-560 murine glioma cells expressed IFN type I receptors IFNAR1 and IFNAR2 and were responsive to exogenous IFN stimulation. CRISPR/Cas9-mediated deletion of IFNAR1 decreased the baseline expression of type I IFN response genes in GL-261 cells, but neither in CT-2A nor in SMA-560 cells. IFNAR1 deletion slowed growth in GL-261 and SMA-560, but not in CT-2A cells. However, only the growth of IFNAR1-depleted GL-261 tumors and not that of SMA-560 tumors was delayed in vivo upon orthotopic tumor cell implantation into syngeneic mice. This survival gain was no longer detected when the IFNAR1-depleted GL-261 cells were inoculated into IFNAR1-deficient mice. Altogether these data suggest that constitutive type I IFN signaling in gliomas may be pro-tumorigenic, but only in a microenvironment that is proficient for type I IFN signaling in the host.

Vaccination with Designed Neopeptides Induces Intratumoral, Cross-reactive CD4+ T-cell Responses in Glioblastoma

PURPOSE

The low mutational load of some cancers is considered one reason for the difficulty to develop effective tumor vaccines. To overcome this problem, we developed a strategy to design neopeptides through single amino acid mutations to enhance their immunogenicity.

EXPERIMENTAL DESIGN

Exome and RNA sequencing as well as in silico HLA-binding predictions to autologous HLA molecules were used to identify candidate neopeptides. Subsequently, in silico HLA-anchor placements were used to deduce putative T-cell receptor (TCR) contacts of peptides. Single amino acids of TCR contacting residues were then mutated by amino acid replacements. Overall, 175 peptides were synthesized and sets of 25 each containing both peptides designed to bind to HLA class I and II molecules applied in the vaccination. Upon development of a tumor recurrence, the tumor-infiltrating lymphocytes (TIL) were characterized in detail both at the bulk and clonal level.

RESULTS

The immune response of peripheral blood T cells to vaccine peptides, including natural peptides and designed neopeptides, gradually increased with repetitive vaccination, but remained low. In contrast, at the time of tumor recurrence, CD8+ TILs and CD4+ TILs responded to 45% and 100%, respectively, of the vaccine peptides. Furthermore, TIL-derived CD4+ T-cell clones showed strong responses and tumor cell lysis not only against the designed neopeptide but also against the unmutated natural peptides of the tumor.

CONCLUSIONS

Turning tumor self-peptides into foreign antigens by introduction of designed mutations is a promising strategy to induce strong intratumoral CD4+ T-cell responses in a cold tumor like glioblastoma.

IMMU-27. SIMULTANEOUS TARGETING OF THE PD-L1 AND THE TGF-Β PATHWAYS WITH BINTRAFUSP ALFA IN EXPERIMENTAL GLIOMAS

Currently, immunotherapy is one of the most promising research areas in oncology, but immunotherapeutic strategies do not have proven clinical activity against glioblastoma so far. The immunosuppressive microenvironment of gliomas limits an appropriate anti-tumor immune response and represents a major challenge in the context of immunotherapy. Therefore, novel therapeutic strategies that reactivate the immune system and allow for potent anti-glioma immune responses are needed. Bintrafusp alfa is a bifunctional fusion protein that is composed of the extracellular domain of human transforming growth factor-beta receptor type II (TGF-βRII) and a human IgG1 monoclonal antibody blocking programmed death-ligand 1 (PD-L1). It is designed to target the TGF-β and the PDL-1 pathways simultaneously by specifically localizing to the tumor via the anti-PD-L1 moiety and sequestering TGF-β within the tumor microenvironment. We analyzed interrelations between the immunosuppressive factors TGF-β and PD-L1 in glioblastoma samples from patients and observed a significant correlation that points towards a co-regulation of both targets as part of a gene expression network. Next, we assessed the activity of bintrafusp alfa in human and murine glioma cell lines in vitro and observed interference with TGF-β-induced Smad2 phosphorylation as a bona fide response marker of TGF-β pathway activation and an increase in immune cell-mediated glioma cell killing. In vivo, bintrafusp alfa prolonged the survival of glioma-bearing immunocompetent mice, whereas the survival benefit was absent in immunodeficient Rag1-/- mice lacking T and B cell populations. Characterization of the tumor microenvironment by immunohistochemistry and high-dimensional flow cytometry confirmed the immune-activating effects of bintrafusp alfa. In summary, these encouraging results demonstrate that novel treatment options such as bintrafusp alfa may have the potential to overcome the lack of immunogenicity and reinvigorate anti-tumor immune responses to efficiently combat glioblastoma.

EPID-10. SEIZURE CONTROL BY BEVACIZUMAB IN GLIOBLASTOMA PATIENTS

Seizures are a frequent symptom in patients with glioblastoma and bear a relevant impact on quality of life. Likewise, anti-epileptic treatment may affect patients’ well-being due to side effects. Here, we assessed whether owing to relieve from edema and intracranial pressure, treatment with bevacizumab for recurrent glioblastoma might contribute to seizure control.We retrospectively analyzed clinical data of adult patients with glioblastoma who were treated with bevacizumab versus a non-bevacizumab-containing regimen for first recurrence of glioblastoma in the Canton of Zurich between 2010 and 2014 and assessed occurrence and dynamics of seizures before and after first recurrence. Categorical and continuous variables were compared by the Chi-square and the Mann-Whitney U test, respectively. Associations of clinical parameters and seizures were analyzed by binary logistic regression.We identified 55 patients with glioblastoma who had received bevacizumab and 61 patients that received a non-bevacizumab-containing regimen at first recurrence. Seizures were noted in 42 of 111 patients (37.8%) during the 12 weeks preceding tumor recurrence. In the non-bevacizumab group, 23 patients (39.0%) still suffered from seizures 3 months after recurrence whereas only 4 patients (7.7%) in the bevacizumab group experienced seizures (p &lt; 0.001). Multivariable binary logistic regression analyses, including sex, age, performance status, extent of resection, O6-methylguanine DNA methyltransferase (MGMT) promoter methylation status and first-line treatment confirmed bevacizumab to be inversely associated with seizures in the 12 weeks after first recurrence (odds ratio (OR) 0.23, 95% confidence interval (CI) 0.06-0.94, p = 0.009).Bevacizumab may contribute to a reduction in seizure frequency in patients with recurrent glioblastoma.

CTIM-22. THE COMBINATION OF LOMUSTINE AND THE IMMUNOCYTOKINE L19TNF IS A PROMISING TREATMENT FOR RECURRENT GLIOBLASTOMA

Glioblastoma is the most aggressive primary brain tumor and adults and poorly immunogenic. Treatment options for recurrent glioblastoma after standard of care chemoradiation are limited Several immunotherapeutic strategies including peptide vaccination and immune checkpoint inhibition have so far failed to improve survival and except from potentially regorafenib, no other agent has demonstrated superior activity to lomustine. Therefore, there is an urgent need for more effective treatment strategies for recurrent glioblastoma. Here, we investigate a new treatment combination based on the alkylating chemotherapy lomustine and the tumor-stroma targeting antibody-cytokine fusion protein L19TNF in preclinical glioma models and patients with recurrent glioblastoma. The combination treatment with lomustine and L19TNF demonstrated strong synergistic anti-tumor activity in several immunocompetent orthotopic glioma models curing the majority of tumor-bearing mice, whereas other mono- or combination therapies for example with anti-PD1 had only limited anti-glioma activity. Investigations of the mechanism of action revealed that lomustine plus L19TNF led to intratumoral necrosis, DNA damage and triggered a strong local anti-tumor immune response with increased MHC-I expression, presentation of neoepitopes and increased abundance of tumor-infiltrating lymphoid cells. In the first patients treated within a phase I/II clinical trial (NCT04573192), the treatment was well tolerated, and durable objective tumor responses and disease stabilizations could be observed also in patients with an unmethylated MGMT promoter.

EXTH-45. TARGETING GLIOBLASTOMA BY NOVEL INTEGRIN-SPECIFIC CAR T CELLS

RATIONALE

Innovative treatment strategies are urgently needed to improve the prognosis of glioblastoma patients. Chimeric antigen receptor (CAR) T cell therapy has shown great success in hematological malignancies. However, it remains to be shown that CAR T cells are also active against solid tumors. αv integrins are overexpressed in gliomas and have already been used as therapeutic targets for small molecule inhibitors and antibodies. While these approaches were well tolerated, they did not exert meaningful clinical activity in glioblastoma patients. We aimed at exploiting the presence of αv integrins as targets for anti-glioma CAR T cell therapy.

METHODS

CAR T cells targeting specific integrin heterodimers (αvβ3, αvβ5 or αvβ8) were generated and their anti-glioma activity was determined in co-culture assays with different glioma cells. The efficacy of CAR T cells to control tumor growth in vivo was assessed in clinically relevant orthotopic mouse glioma models.

RESULTS

All newly generated integrin-targeting CAR T cells exerted strong anti-tumor activity in vitro. The highest lytic activity against glioma cells was observed for αvβ5 and αvβ8 integrin-specific CAR T cells. CAR T cells generated from patient-derived immune cells displayed strong lytic activity when tested against autologous tumors cells. Glioma cells with a CRISPR/Cas9-mediated knockout of the target antigen were resistant to CAR T cell-mediated cytotoxicity demonstrating their specificity. The in vivo activity of integrin-specific CAR T cells was tested in 2 orthotopic glioma models. Intratumoral treatment of glioma-bearing mice with αvβ5 or αvβ8 CAR T cells significantly prolonged their survival and cured a substantial fraction of these animals.

CONCLUSION

αvβ5- and αvβ8-specific CAR T cells exert strong and target-specific anti-glioma activity in vitro and prolong the survival of glioma-bearing mice. These data form the basis for a clinical evaluation of integrin-specific CAR T cells against glioblastoma.

Multifunctional mRNA-Based CAR T Cells Display Promising Antitumor Activity Against Glioblastoma

PURPOSE

Most chimeric antigen receptor (CAR) T-cell strategies against glioblastoma have demonstrated only modest therapeutic activity and are based on persistent gene modification strategies that have limited transgene capacity, long manufacturing processes, and the risk for uncontrollable off-tumor toxicities. mRNA-based T-cell modifications are an emerging safe, rapid, and cost-effective alternative to overcome these challenges, but are underexplored against glioblastoma.

EXPERIMENTAL DESIGN

We generated mouse and human mRNA-based multifunctional T cells coexpressing a multitargeting CAR based on the natural killer group 2D (NKG2D) receptor and the proinflammatory cytokines IL12 and IFNα2 and assessed their antiglioma activity in vitro and in vivo.

RESULTS

Compared with T cells that either expressed the CAR or cytokines alone, multifunctional CAR T cells demonstrated increased antiglioma activity in vitro and in vivo in three orthotopic immunocompetent mouse glioma models without signs of toxicity. Mechanistically, the coexpression of IL12 and IFNα2 in addition to the CAR promoted a proinflammatory tumor microenvironment and reduced T-cell exhaustion as demonstrated by ex vivo immune phenotyping, cytokine profiling, and RNA sequencing. The translational potential was demonstrated by image-based single-cell analyses of mRNA-modified T cells in patient glioblastoma samples with a complex cellular microenvironment. This revealed strong antiglioma activity of human mRNA-based multifunctional NKG2D CAR T cells coexpressing IL12 and IFNα2 whereas T cells that expressed either the CAR or cytokines alone did not demonstrate comparable antiglioma activity.

CONCLUSIONS

These data provide a robust rationale for future clinical studies with mRNA-based multifunctional CAR T cells to treat malignant brain tumors.

Postoperative progression of brain metastasis is associated with seizures

Seizures in patients with brain metastases have an impact on morbidity and quality of life. The influence of tumor growth on the risk of seizures in these patients is not well defined. In this cohort study, we evaluated adult patients from the University Hospital of Zurich following resection of brain metastases from solid tumors, with or without preoperative seizures, at 3, 6, 9, and 12 months postoperatively. Brain magnetic resonance imaging was assessed for tumor progression using the Response Assessment in Neuro-Oncology criteria. The quarterly risk of unprovoked seizures was modeled with mixed effects logistic regression. We analyzed 444 time frames in 220 patients. Progression of brain metastases was independently associated with seizures during the respective quarterly follow-up period (odds ratio = 3.9, 95% confidence interval = 1.3-11.3, p = .014). Complete resection of brain metastases was associated with a lower risk of seizures (odds ratio = .2, 95% confidence interval = .04-.7, p = .015). Postoperative progression of brain metastases quadrupled the risk of seizures; therefore, vigorous follow-up may be useful to identify tumor progression and gauge the risk of seizures. The identification of patients at high seizure risk may have implications for treatment decisions and influence aspects of daily life. Breakthrough seizures may indicate brain metastases progression.

Programmed death ligand 1 gene silencing in murine glioma models reveals cell line-specific modulation of tumor growth in vivo

Background

Glioblastoma is the most common brain tumor in adults and virtually incurable. Therefore, new therapeutic strategies are urgently needed. Immune checkpoint inhibition has not shown activity in various phase III trials and intra- as well as intertumoral expression of programmed death ligand 1 (PD-L1) varies in glioblastoma.

Methods

We abrogated constitutive PD-L1 gene expression by CRISPR/Cas9 in murine glioma models and characterized the consequences of gene deletion in vitro and in vivo.

Results

A heterogeneous expression of Pdl1 mRNA and PD-L1 protein was detected in the glioma cell panel in vitro and in vivo. PD-L1, but not PD-L2, was inducible by interferon β and γ. Co-culture with splenocytes induced PD-L1 expression in GL-261 and SMA-560, but not in CT-2A cells, in an interferon γ-dependent manner. Conversely, Pdl1 gene silencing conferred a survival benefit in CT-2A, but not in the other 2 models. Accordingly, PD-L1 antibody prolonged survival in CT-2A glioma-bearing mice. This activity required PD-L1 expression on tumor rather than host cells, and the survival gain mediated by PD-L1 loss was reproduced in immune-deficient RAG^−/− mice.

Conclusions

PD-L1 is expressed and interferon-inducible in murine glioma cell lines. PD-L1 has model-specific roles for tumor growth. Future studies need to determine which subset of glioblastoma patients may benefit from PD-L1 antagonism as part of a multimodality therapeutic approach to glioblastoma.

OS08.8.A Integrin-specific CAR T cells for the treatment of glioblastoma

Background

Current standard of care for glioblastoma patients has limited therapeutic efficacy and novel innovative treatment strategies are urgently needed. One such strategy is chimeric antigen receptor (CAR) T cell therapy that has shown great success in hematological malignancies. αv integrins are overexpressed in several neoplasms and have already been used as therapeutic targets for small molecule inhibitors and antibodies, which did not cause major toxicities. Herein, we propose αv integrins as an ideal target for CAR T cell therapy in glioblastoma.

Material and Methods

CAR T cells targeting specific heterodimers (αvβ3, αvβ5 or αvβ8) were generated by transducing primary human T cells from healthy donors with a lentiviral vector expressing a second-generation CAR. Activity and specificity of CAR T cells was determined by co-culture assays with different glioma cells. Efficacy of CAR T cells to control tumor growth in vivo was investigated in clinically relevant orthotopic xenograft glioma mouse models. Additionally, we generated CAR T cells from T cells from a glioblastoma patient and measured their activity against the patient’s autologous tumor cells.

Results

All newly generated integrin-targeting CAR T cells exerted strong anti-glioma activity in vitro. Long-term and repetitive killing assays as well as cytokine-release measurements demonstrated highest activity of αvβ5 and αvβ8 integrin-specific CAR T cells. Antigen specificity of these cells was confirmed, as glioma cells with a CRISPR/Cas9-mediated knockout of the target antigen were resistant to CAR T cell-mediated cytotoxicity. Intratumoral injection of αvβ5 or αvβ8 CAR T cells significantly prolonged the survival and cured a substantial fraction of glioma-bearing mice in two different xenograft models. When used in a patient-derived setting, matched CAR T cells exerted strong anti-glioma activity.

Conclusion

We show strong and integrin-specific anti-glioma activity of CAR T cells developed from healthy donor T cells and glioblastoma-patient-derived T cells in vitro. αvβ5- and αvβ8-specific CAR T cells exerted the best therapeutic activity in two different xenograft glioma models in vivo. These data support the evaluation of integrin-specific CAR T cells as a therapeutic strategy in clinical neuro-oncology.

OS08.7.A Lomustine and the immunocytokine L19TNF are a promising treatment combination for recurrent glioblastoma

Background

Treatment options for recurrent glioblastoma are limited and with the possible exception of regorafenib, no agent has demonstrated superior activity to lomustine. Therefore, there is an urgent need for more effective treatment strategies for recurrent glioblastoma. Here, we investigated different treatment combinations based on the tumor-stroma targeting antibody-cytokine fusion protein L19TNF in preclinical glioma models and translated the most effective treatment combination to patients with recurrent glioblastoma.

Material and Methods

Orthotopic immunocompetent mouse glioma models were used to study the anti-glioma activity of L19TNF in combination with anti-PD1, bevacizumab or lomustine. Tumor growth was monitored by MRI. Flow cytometry and microscopy were used to characterize tumor-infiltrating-immune cells. MHC immunoaffinity purification and mass spectrometry were used to characterize the MHC immunopeptidome. Genetic mouse models were used to study immune-dependent effects. Subsequently, we translated the most efficient treatment combination to patients with recurrent glioblastoma within a phase I/II clinical trial (NCT04573192).

Results

The combination of L19TNF and lomustine demonstrated strong synergistic anti-tumor activity in two immunocompetent orthotopic glioma models and cured a majority of tumor-bearing mice. In contrast, combinations with anti-PD-1 or bevacizumab had only limited anti-glioma activity. Furthermore, compared to the monotherapies, the combination of L19TNF and lomustine led to the strongest increase in tumor-infiltrating lymphoid cells as demonstrated by flow cytometry and microsopy and to the highest number of peptides presented in the context of MHC-I. The treatment effect was abrograted in different genetic immunodeficient mouse models. The treatment combination of L19TNF and lomustine was well tolerated in the first patients treated within a phase I/II clinical trial and we observed partial tumor responses also in patients with an unmethylated MGMT promoter.

Conclusion

The combination of L19TNF and lomustine demonstrated promising anti-glioma activity and patients are currently recruited within a phase I/II clinical trial for patients with recurrent glioblastoma.

P10.20.A Mechanisms of synergistic glioma growth suppression by radiotherapy and MET inhibition

Background

Glioblastoma remains to be one of the most lethal solid cancers. Despite multi-modal therapy including surgery as safely feasible, radiotherapy and chemotherapy with the alkylating agent temozolomide, the median survival of affected patients is still limited to approximately one year on a population level. Thus, novel therapies are urgently needed. There is increasing interest in the role of the HGF/MET pathway in the response of glioblastoma to radiotherapy since MET may be involved in radioresistance via proinvasive and DNA damage response pathways.

Material and Methods

Here we assessed the role of the MET pathway in the response to radiotherapy in vitro and in vivo in syngeneic mouse glioma models and explored potential modes of action responsible for the synergistic effects of MET pathway inhibition and irradiation on tumor growth in vivo.

Results

Murine glioma cells express HGF and MET and show increased MET phosphorylation upon exposure to exogenous HGF. In vitro, glioma cell viability and proliferation are not affected by pharmacological MET inhibition using tepotinib or genetic MET inhibition using CRISPR/Cas9-engineered Met gene knockout and sensitization to irradiation by MET inhibition is not seen. In vivo, the combination of MET inhibition with focal radiotherapy mediates prolonged survival of syngeneic orthotopic glioma-bearing mice compared with either treatment alone. Complementary studies demonstrate that synergy is lost when gliomas are established and treated in immunodeficient mice, but also if MET gene expression is disrupted in the tumor of wildtype mice. Combination therapy suppresses a set of pro-inflammatory mediators that are upregulated by radiotherapy alone and which are positively regulated by transforming growth factor (TGF)-β. In line with this data, ex vivo analysis of mouse brains reveal increased TGF-β pathway activity upon irradiation alone that is counteracted by concomitant MET inhibition.

Conclusion

In summary, we demonstrate synergistic suppression of syngeneic glioma growth by irradiation and MET inhibition that requires MET expression in the tumor as well as an intact immune system. Clinical evaluation of this combined treatment approach in newly diagnosed glioblastoma is warranted.

P10.19.B An immunotoxin targeting CD317 for the treatment of glioblastoma

Background

CD317 is an interferon-inducible cell surface receptor expressed in several solid cancer types. HM1.24-ETA’ is a small immunotoxin with a CD317 single-chain variable fragment (svFv) antibody fused to a truncated version of Pseudomonas aeruginosa exotoxin A (ETA’) that is explored as a novel therapeutic approach in CD317-expressing tumors.

Material and Methods

CD317 mRNA expression in human gliomas and its association with survival was analyzed using the database of the Cancer Genome Atlas (TCGA). CD317 protein levels in human gliomas were assessed by immunohistochemistry. CD317 mRNA expression was assessed by RT-PCR and CD317 protein levels by flow cytometry in 13 human glioma cell lines in vitro. Efficacy of HM1.24-ETA’ was analyzed in acute cytotoxicity assays in vitro. Finally, HM1.24-ETA’ was evaluated in the intracranial human LN-229 glioma xenograft nude mouse model after intravenous injection.

Results

Interrogation of the TCGA database showed that increased CD317 mRNA expression correlated with grade of malignancy among isocitrate dehydrogenase (IDH) wildtype and IDH-mutant gliomas. Enhanced CD317 mRNA expression was associated with inferior survival in glioblastoma and astrocytoma, IDH-mutant, WHO grade 4. Immunohistochemistry confirmed CD317 overexpression in human glioblastoma compared to lower grade astrocytomas. CD317 was expressed heterogeneously on mRNA and protein levels in glioma cell lines in vitro. HM1.24-ETA’ induced acute cytotoxicity in CD317-positive glioma cells in vitro. CD317 expression and susceptibility to HM1.24-ETA’-induced cell death were enhanced by interferon-β. HM1.24-ETA’ prolonged survival in the LN-229 xenograft nude mouse model.

Conclusion

These data define CD317 as a novel target for treatment of human gliomas with immunoconjugates.

Improving Patient Satisfaction in the Hispanic American Community

Hispanic Americans are the fastest growing ethnic group in the United States, with an ever-growing gap in the communicative capacity between patients and healthcare providers. This leads to linguistic marginalization and worse healthcare outcomes. There is an increasing need for Spanish literacy in healthcare professionals, including medical students. However, approximately half of medical schools don’t offer a Spanish elective. We performed a scoping review of the literature to assess the relationship between medical Spanish electives, verbal fluency, auditory comprehension, and student comfort. This study was conducted using PubMed and Google Scholar to evaluate articles on Spanish electives in medical schools. Nine articles met inclusion criteria. Almost all studies demonstrated benefit as per outcome measures assessed with statistical significance. The available literature supports the need for Spanish elective courses, with numerous advantages conferred, e.g. increased self-perceived knowledge about specific health issues in the Hispanic American community and reduction in inadvertent communication errors in the patient-provider-interpreter interaction. However, most of the reports analyzed exhibited numerous limitations that warrant future research studies in order to eliminate variables such as bias and issues with generalizability. The authors suggest that more medical schools offer virtual Spanish electives with a focus on empathetic language strategies and patient satisfaction.

Infigratinib in Patients with Recurrent Gliomas and FGFR Alterations: A Multicenter Phase II Study

PURPOSE

FGFR genomic alterations (amplification, mutations, and/or fusions) occur in ∼8% of gliomas, particularly FGFR1 and FGFR3. We conducted a multicenter open-label, single-arm, phase II study of a selective FGFR1-3 inhibitor, infigratinib (BGJ398), in patients with FGFR-altered recurrent gliomas.

PATIENTS AND METHODS

Adults with recurrent/progressive gliomas harboring FGFR alterations received oral infigratinib 125 mg on days 1 to 21 of 28-day cycles. The primary endpoint was investigator-assessed 6-month progression-free survival (PFS) rate by Response Assessment in Neuro-Oncology criteria. Comprehensive genomic profiling was performed on available pretreatment archival tissue to explore additional molecular correlations with efficacy.

RESULTS

Among 26 patients, the 6-month PFS rate was 16.0% [95% confidence interval (CI), 5.0-32.5], median PFS was 1.7 months (95% CI, 1.1-2.8), and objective response rate was 3.8%. However, 4 patients had durable disease control lasting longer than 1 year. Among these, 3 had tumors harboring activating point mutations at analogous positions of FGFR1 (K656E; n = 2) or FGFR3 (K650E; n = 1) in pretreatment tissue; an FGFR3-TACC3 fusion was detected in the other. Hyperphosphatemia was the most frequently reported treatment-related adverse event (all-grade, 76.9%; grade 3, 3.8%) and is a known on-target toxicity of FGFR inhibitors.

CONCLUSIONS

FGFR inhibitor monotherapy with infigratinib had limited efficacy in a population of patients with recurrent gliomas and different FGFR genetic alterations, but durable disease control lasting more than 1 year was observed in patients with tumors harboring FGFR1 or FGFR3 point mutations or FGFR3-TACC3 fusions. A follow-up study with refined biomarker inclusion criteria and centralized FGFR testing is warranted.

Venous thromboembolic events in glioblastoma patients: an epidemiological study

Background and purpose

Venous thromboembolic events (VTEs) are a major complication in cancer patients, and therefore, also in brain cancer patients, anticoagulants are considered appropriate in the treatment of VTEs.

Methods

Frequency, risk factors, and treatment of VTEs, as well as associated complications, were assessed in a population‐based cohort of glioblastoma patients in the Canton of Zurich, Switzerland. Correlations between clinical data and survival were retrospectively analyzed using the log‐rank test and Cox regression models.

Results

Four hundred fourteen glioblastoma patients with isocitrate dehydrogenase wild‐type status were identified. VTEs were documented in 65 patients (15.7%). Median time from tumor diagnosis to the occurrence of a VTE was 1.8 months, and 27 patients were diagnosed with VTEs postoperatively (within 35 days; 42.2%). History of a prior VTE was more common in patients who developed VTEs than in those who did not (p = 0.004). Bevacizumab treatment at any time during the disease course was not associated with occurrence of VTEs (p = 0.593). Most patients with VTEs (n = 61, 93.8%) were treated with therapeutic anticoagulation. Complications occurred in 14 patients (23.0%), mainly intracranial hemorrhages (n = 7, 11.5%). Overall survival did not differ between patients diagnosed with VTEs and those who had no VTE (p = 0.139). Tumor progression was the major cause of death (n = 283, 90.7%), and only three patients (1.0%) died in association with acute VTEs.

Conclusions

Venous thromboembolic events occurred early in the disease course, suggesting that the implementation of primary venous thromboembolism prophylaxis during first‐line chemoradiotherapy could be explored in a randomized setting.

Influence of calcium on the uptake of ingested strontium

Radioactive isotopes of strontium, mainly 90Sr, released into the environment due to nuclear accidents may contribute significantly to the internal radiation exposure of members of the public after ingestion of strontium with contaminated foodstuffs. The committed radiation dose is significantly dependent on the fraction of the ingested activity that crossed the gut wall (f1 value). The directive 96/29/EURATOM has adopted f1 values of 0.3 for adults. This study was aimed to investigate how far the calcium content of foodstuffs influences the uptake of ingested strontium. For aqueous solutions without calcium containing 1 mg strontium, f1 values of 0.62 ± 0.13 (mean ± SD) were obtained. However, the uptake of 1 mg Sr from milk, and respectively from solutions with calcium was lower than from aqueous solution (f1: = 0.32 ± 0.06, respectively f1: = 0.31 ± 0.06). The data obtained show a significant reduction of the uptake of ingested strontium from milk in comparison to aqueous solution. The calcium content of milk could explain this reduction.