bluuebunny/crossref_metadata_2025 huggingface dataset:
CTIM-26. PHASE I/II STUDY OF THE COMBINATION OF PEMBROLIZUMAB (MK-3475) AND LASER INTERSTITIAL THERMAL THERAPY (LITT) IN RECURRENT GLIOBLASTOMA
Authors: Campian Jian , Butt Omar , Ghinaseddin Ashley , Rahman Maryam , Chheda Milan , Johanns Tanner , Ansstas George , Huang Jiayi , Liu Jingxia , Talcott Grayson , Katumba Ruth , Zhou Alice , Leidig William , Dunn Gavin , Kim Albert , Leuthardt Eric , Tran David
Published: November 2021

BACKGROUND

The blood brain barrier (BBB) remains a potential barrier to central nervous system (CNS) penetration of novel immunotherapies in recurrent glioblastoma (rGBM). Laser interstitial thermal therapy (LITT) was recently demonstrated to induce BBB disruption. When combined with anti-PD1 blockade, LITT may therefore potentiate host T-cell mediated cytotoxicity. This phase I/II study aims to evaluate the safety and efficacy of combining LITT and the PD-1 inhibitor pembrolizumab for rGBM.

METHODS

Phase I treated eligible bevacizumab-naïve high grade glioma patients with LITT and the anti-PD1 inhibitor pembrolizumab at 3 dose levels (100, 150, and 200 mg IV Q3W; 3 patients at each level), while phase II was restricted to rGBM patients only with the recommended phase II dose (RP2D) of pembrolizumab. Phase II was initially designed to randomize rGBM to either pembrolizumab or pembrolizumab+LITT but was later amended to receive only pembrolizumab+LITT after 16 patients were randomized (10 pembrolizumab+LITT arm, 6 pembrolizumab-alone arm). Progression-free survival (PFS) and overall survival (OS) were evaluated using the Kaplan Meier method, and adverse events (AE) documented.

RESULTS

Phase I enrolled 9 patients (7 rGBM and 2 anaplastic astrocytomas, 33% IDH-mut, 44% MGMTp-methylated) with no dose limiting toxicities (DLT), prompting selection of 200mg Q3W as the RP2D. Phase II interim analysis included 34 rGBM patients (9% IDH-mut, 50% MGMTp-methylated; 6 receiving pembrolizumab alone and 28 pembrolizumab+LITT) plus two Phase I rGBM patients who received RP2D. On per-protocol analysis, pembrolizumab+LITT cohort had improved PFS (median PFS 10.5 months vs 2.1 months) and OS (median OS 11.4 months vs 5.2 months) than pembrolizumab alone. A single treatment-related grade 3 AE was noted (respiratory infection). CONCLUSION: LITT may be safely combined with pembrolizumab for rGBM with promising clinical outcomes on interim analysis. Enrollment for Phase II, correlative studies, and continued AE documentation are ongoing.

Clinical Trial ID

NCT02311582.
CTNI-01. A PHASE 1-2 CLINICAL TRIAL OF EO1001 (APL-122), A NOVEL IRREVERSIBLE PAN-ERBB INHIBITOR WITH PROMISING BRAIN PENETRATION
Authors: Frentzas Sophia , Richardson Gary , Bacha Jeffrey , Kanekal Sarath , Sankar Neil , Shen Wang , Redkar Sanjeev , Lai Chinglin , Yu Peony , Nisbet Ian , Skoff Kathy , Wheeler Helen , Pedersen Harry , Zhong Wang Zhen , Brown Dennis
Published: November 2021

CNS metastases are a prominent driver of cancer morbidity and mortality, especially as targeted therapies have improved systemic outcomes. Mutations in the ErbB/HER kinase family are known oncodrivers in many cancers. Extensive crosstalk among ErbB/HER receptors suggests that inhibition of multiple family members may benefit treatment and limit drug resistance. There is a desperate need for new agents that are more tolerable and effective in treating CNS metastases. EO1001 (APL-122) is a first-in-class, oral, irreversible pan-ErbB inhibitor targeting ErbB1, ErbB2 and ErbB4 with promising CNS penetration in preclinical models. Preclinical data suggests a favorable pharmacokinetic and safety profile and activity against ErbB-driven cancers in patient-derived xenograft models. We report on a first-in-human Phase 1-2 clinical trial in progress. Adult participants with confirmed ErbB-positive cancer, including patients with CNS involvement, who have progressed after standard-of-care, with adequate bone marrow, renal and liver function are eligible. ESCALATION: One subject per dose cohort is enrolled in an accelerated dose-escalation design until drug-related toxicity (≥G2) is observed in the first cycle, after which dose escalation will revert to a 3 + 3 design to determine the maximum tolerated dose (MTD). Cycle 1: Patients receive a single oral dose of EO1001 on day 1; single-dose pharmacokinetics are measured. Beginning on day 8, EO1001 is administered once daily for 21 days; multi-dose pharmacokinetics are measured. Cycles 2-6: EO1001 is administered once daily in continuous 28-day cycles for up to 20 weeks. EXPANSION: EO1001 will be administered once daily to 20 patients at the MTD in continuous 28-day cycles for up to 6 cycles to determine a recommended Phase 2 dose (RP2D) for further study. Toxicity is assessed based on NCI CTCAEv5 and tumor response is assessed by RECIST 1.1. CNS exposure is evaluated in patients via CSF collection with confirmed CNS disease involvement.
CTNI-23. A FIRST-IN-HUMAN PHASE 0/1 CLINICAL TRIAL OF 5-AMINOLEVULINIC ACID SONODYNAMIC THERAPY IN RECURRENT GLIOBLASTOMA
Authors: Sanai Nader , Tien An-Chi , Tovmasyan Artak , Chang Yu-Wei , Margaryan Tigran , Hendrickson Kristin , Eschbacher Jennifer , Yoo Wonsuk , Harmon Jocelyn , Quarles Christopher , Alhilali Lea , Barani Igor , Mehta Shwetal , Mirzadeh Zaman
Published: November 2021

5-Aminoleveulinic acid sonodynamic therapy (5-ALA SDT) is a drug-device strategy that exploits the metabolic liabilities of cancer. Following systemic administration of 5-ALA, aberrant tumor metabolism leads to accumulation of protoporphyrin-IX (PpIX). Activation of PpIX by non-invasive, non-ablative magnetic resonance-guided focused ultrasound (MRgFUS) induces reactive oxygen species and tumor cell death. This first-in-human Phase 0/1 study investigates the feasibility, safety, and biological effects of 5-ALA SDT in recurrent glioblastoma (GBM) patients. Six hours prior to SDT, adult patients with recurrent GBM are administered Sonala-001 (10mg/kg), an IV formulation of 5-ALA. In a Dose-Escalation Arm, 9-18 patients are assigned to one of three ascending acoustic energy doses of MRgFUS (200J/400J/800J, measured at transducer surface), followed by a four-day interval to planned tumor resection. In each patient, half the tumor volume, including Gadolinium-enhancing and nonenhancing tumor, is targeted with MRgFUS and the other half serves as an internal control. Using tumor pharmacodynamic endpoints, the Minimum Biological Dose (MBD) associated with 5-ALA SDT response is identified. In a subsequent Time-Escalation Arm, 12 patients are treated at the MBD and assigned to one of two time-intervals between SDT and resection. As of May 1, accrual to the 200J dose level (n=3) is complete without significant drug- or device-related adverse events. No cellular or radiographic changes to non-targeted tissue were detected. The median Cmax for 5-ALA and PpIX were 307 µM and 319 nM, respectively. The oxidative stress biomarkers 4-hydroxynonenal, glutathione, cysteine, and thiol were significantly elevated in treated tissue vs. control. Similarly, the apoptosis biomarker cleaved caspase-3 was increased in treated tumor vs. control (median, 48.6% vs. 29.6%, p=0.05). This first-in-human experience with a new therapeutic modality for recurrent glioblastoma patients demonstrates that 5-ALA SDT is safe at 200J. Sonodynamic therapy leads to targeted oxidative stress and tumor cell death in human glioblastoma tissue.
CTNI-49. PHASE 1 STUDY OF ST101, A FIRST-IN-CLASS PEPTIDE ANTAGONIST OF CCAAT/ENHANCER-BINDING PROTEIN ß, IN PATIENTS WITH ADVANCED SOLID TUMORS, WITH A PHASE 2 EXPANSION IN RECURRENT GLIOBLASTOMA MULTIFORME
Authors: Symeonides Stefan , Evans Jeff , Arkenau Hendrik-Tobias , McKean Meredith , Lakhani Nehal , Lim Emerson , Falchook Gerald , Rotolo Jim , Capiaux Gina , Michel Rob , Kaesshaefer Stephen , Bexon Alice
Published: November 2021

BACKGROUND

C/EBPβ is a transcription factor that is active during embryofetal development but held in an inactive state in most mature cells (Zahnow 2009). C/EBPβ is upregulated or overactivated in multiple cancers, where it inversely correlates with disease prognosis and survival due to activation of a gene signature that promotes tumor cell proliferation and survival. ST101 is a cell-penetrating peptide antagonist of C/EBPβ. ST101 exposure leads to selective tumor cell death in multiple human cancer cell lines, including GBM, without impacting normal cell viability. In vivo, ST101 displays rapid uptake into multiple organs, the ability to cross the blood-brain barrier, and a long plasma half-life due to its resistance to degradations. It has potent anti-tumor activity in multiple GBM models, as a single agent or in combination, which supported moving into clinical development.

TRIAL DESIGN

This phase 1-2 study is enrolling patients ≥ 18 years of age with advanced, unresectable metastatic solid tumors refractory to or intolerant of other therapeutic options. We began recruitment in August 2020. The primary objective of phase 1 is to evaluate safety and tolerability of ST101. Secondary objectives include the recommendation of a dose and regimen of ST101 for further evaluation, pharmacokinetics, several pharmacodynamic measures, and preliminary efficacy. Patients receive intravenous ST101 once weekly in a standard 3 + 3 design. Enrollment is ongoing, and by 21 May 2021, 15 patients have been recruited in four dose-escalation cohorts up to 4 mg/kg; a 5th cohort (6 mg/kg) is ongoing. The recommended phase 2 dose will be used in a 15-30 patient GBM expansion cohort, with a Simon 2-stage design, which requires one response or two patients with PFS6 in the first cohort to continue the study. Up to 120 patients are planned in a total of four expansion cohorts, which should be enrolling by Q3 2021.
DDRE-13. PROSTAGLANDIN E RECEPTOR 3 (PTGER3) REGULATES RESISTANCE TO TUMOR TREATING FIELDS (TTFields) IN GLIOBLASTOMA CELLS
Authors: Chen Dongjiang , Le Son , Hutchinson Tarun , Tran David
Published: November 2021

INTRODUCTION

TTFields, a novel approved therapy for GBM, employ alternating intermediate-frequency electric fields to disrupt mitotic macromolecules leading to chromosome mis-segregation and apoptosis. The addition of TTFields significantly improves survival. However, most patients eventually develop resistance to TTFields through an unknown mechanism.

METHODS

Multiple human GBM cell lines were treated with TTFields continuously using Inovitro, an in vitro TTFields system, until cells with relative resistance to killing by TTFields emerged. Temporal gene expression profiles were analyzed using NETZEN, an innovative deep-learning and gene network-based ranking computational algorithm, to identify resistance pathways, followed by experimental validation.

RESULTS

PTGER3, a Gαi-protein-coupled cell surface receptor, is the top ranked master regulator in the predicted resistance program, which is upregulated in GBM cells within 24 hrs of exposure to TTFields and further reinforced as resistance sets in. Forced expression of PTGER3 in sensitive GBM cells confers relative resistance to TTFields, while PTGER3 depletion in resistant cells re-sensitizes them to TTFields. Most importantly, pharmacological inhibition of PTGER3 using either aspirin to reduce prostaglandin E production or PTGER3-specific inhibitors effectively prevent resistance from developing. Mechanistically, PTGER3 is rapidly translocated from the plasma membrane to the nucleus after TTFields exposure, where it interacts with ZNF488, a stemness transcription factor tightly linked to PTGER3 in our predicted network to initiate and maintain the resistance program. Indeed, TTFields resistance is associated with a transition to glioma stem cells (GSCs) as determined by increased neurosphere formation and orthotopic tumorigenesis in immunocompromised mice, and PTGER3 inhibition alone reverses the GSC transition leading to improved tumor control and survival.

CONCLUSIONS

PTGER3 is at the apex of a novel pathway that indispensably regulates TTFields resistance through a unique mechanism involving the physical nuclear translocation of this 7-transmembrane receptor. PTGER3 and its pathway are thus potential therapeutic targets to enhance therapeutic efficacy of TTFields.
DDRE-41. TREATMENT OF REFRACTORY PITUITARY NEOPLASMS WITH TEMOZOLOMIDE IN THREE PATIENTS
Authors: Duncan Kelsey , Arafah Baha , Rogers Lisa
Published: November 2021

BACKGROUND

There is relatively little information regarding the efficacy of temozolomide (TMZ) for pituitary adenomas; less than 100 cases treated with TMZ are reported, with a variable response rate of 50-75%, depending on response criteria.

METHODS

Retrospective review of patients with pituitary tumors treated with TMZ at University Hospitals Cleveland Medical Center.

RESULTS

Three patients were identified. Patient age at the time of TMZ treatment was 20, 51, and 70 years. Two were female, one male. Histology was prolactinoma in two and Cushing’s disease in one. Each patient had undergone multiple surgeries and medical treatments with insufficient response or relapse. Two had received radiosurgery; it was withheld in a 20 year old male due to concerns of optic nerve radiation injury. A 5d q 28d regimen was used in each, beginning at 150mg/M2 daily for initial dose then increased to 200mg/M2 daily. Diplopia and headache improved in one patient, whose serum prolactin significantly declined (222.8 to 81.9 ng/ml). Headache resolved in another patient and prolactin remained stable. In the patient with Cushing’s disease, headaches improved and ACTH remained elevated but stable. The tumor remained stable on MRI in each patient. There were no adverse effects from TMZ used over 5 to 29 months.

CONCLUSIONS

Our clinical experience adds to the limited published information regarding the effectiveness of TMZ for pituitary adenomas. In our case series, clinical improvement was noted in each of 3 patients with pituitary adenomas that had failed or recurred after other therapies. Serum prolactin significantly declined in one patient. This data suggests a beneficial role for TMZ in treating pituitary adenomas.
DDRE-47. ASSESSMENT OF BRAIN PENETRANCE, BIODISTRIBUTION, AND EFFICACY OF PLATINUM (IV)-CONJUGATED FLUORINATED MACROCYCLIC CELL-PENETRATING PEPTIDES IN A MURINE GLIOBLASTOMA MODEL
Authors: Jimenez Macias Jorge , Lee Yen-Chun , Finkelberg Tomer , Zdioruk Mykola , Berger Gilles , Nowicki Michal , Cho Choi-Fong , Fedeles Bogdan , Loas Andrei , Pentelute Bradley , Lawler Sean
Published: November 2021

INTRODUCTION

Glioblastoma (GBM), an aggressive brain tumor with a poor prognosis, presents an average of 2% of patients surviving beyond 2 years after diagnosis. Therapies to effectively manage glioblastoma are hindered due to the presence of the blood-brain barrier (BBB). Previously, a cell-penetrating peptide, M13, was conjugated to a Pt(IV) cisplatin prodrug, via amide bond formation. The conjugated Pt(IV) releases active cisplatin upon intracellular reduction. Herein, we investigated the BBB-penetrance and biodistribution of M13 conjugated to Pt(IV), as well as its effectiveness against GBM in mouse models.

METHODS

M13 platinum-conjugate tumor cell killing capacity was assessed by luminescent cell viability assays in vitro. By using Inductively-Coupled Plasma Mass-Spectrometry for platinum detection, BBB penetration and bio-distribution studies were performed in a three-dimensional BBB spheroid in vitro model and in vivo in mouse brain, intracranial tumor, and peripheral organs. Dose-regime studies involved observations of symptomatology and weight variations after bi-weekly injections of platinum compounds at 2mg/kg and 5mg/kg.

RESULTS

The Pt(IV)-M13 conjugate possesses tumor cell killing effects similar to cisplatin when tested in GBM cell lines in vitro. Platinum increased by using Pt(IV)-M13 when compared to cisplatin in our in vitro BBB-spheroid model (20-fold, p-value=0.0033), in brain tissue (10-fold, p< 0.0001) and GBM tumor-bearing mice models (7.5-fold, p< 0.0001). Bio-distribution of platinum delivered by Pt(IV)-M13 in spleen, heart and blood was significantly different to cisplatin 5hrs. after intravenous injection (p< 0.001). Bi-weekly dose regimes of Pt(IV)-M13 are tolerable in nude mice without toxicity at a similar concentration to reported tolerable cisplatin doses at 5 mg/kg. Finally, Pt(IV)-M13 significantly increased survival in a murine glioblastoma xenograft model compared with controls (median 24 days vs. 29 days, p-value=0.0071).

CONCLUSION

Overall, our data support the further development of BBB-crossing peptide-drug conjugates for GBM treatment.
EPID-05. TREATMENT PATTERNS OF GLIOMAS: AN EPIDEMIOLOGICAL STUDY
Authors: Bajwa Mohammad Hamza , Imran Noor , Shah Mashal , Baig Erum , Laghari Altaf Ali , Bin-Anis Saad , Akhunzada Naveed Zaman , Gilani Jaleed , Jawed Noyan , Khalid Usman , Qadeer Namra , Lutfi Areeb , Tahir Izza , Bajwa Rameen , Rashid Huzaifa , Sadia Haleema , Ghazi Kinzah , Gillani Mishal , Consortium Pakistan Brain Tumor , Siddiqi Sameen , Enam Syed Ather
Published: November 2021

INTRODUCTION

Gliomas are the most common malignant brain tumors of the central nervous system in adults. Specialized treatment modalities have improved morbidity and mortality within high-income countries. In lower- and middle-income countries (LMICs), the overall mortality rate is still seen to be alarmingly high. As there is a shortage of statistical data available regarding the epidemiology of these tumors and their management within the country, the objective of this study is to define the landscape of treatment patterns and current epidemiological data regarding gliomas in Pakistan.

METHODS

As part of the Pakistan Brain Tumor Epidemiology Study (PBTES), data was collected from major neurosurgical centers across the country, consisting of 35 hospitals in all 4 provinces. Our retrospective study looked at patients who underwent surgical procedures for gliomas in 2019, where a surgical pathology was available. The data was collated and analyzed using appropriate statistical methods.

RESULTS

791 patients with gliomas were identified (61.8 % in public sector hospitals, 39.1% in private sector). The most common histopathological subtypes were glioblastoma (33.5%), followed by astrocytoma (18.8%) and oligodendroglioma (11.9%). Gender distribution was skewed towards men (65%). The most commonly performed initial surgical procedure was gross total resection (50% in public hospitals, 41% in private hospitals). Private institution hospitals performed surgical biopsies as the first surgical procedure (23%) more often than public hospitals (9%). Regarding adjuvant treatments, only 26% of patients were given chemotherapy, and there was no data regarding 53% of patients. Similarly, only 15% of patients received radiation therapy, and there was no data for 60% of patients.

CONCLUSIONS

Our study was able to identify the gaps in glioma management within Pakistan, particularly with regards to chemoradiotherapy. Identifying these unmet needs is the first step in developing comprehensive care for glioma patients.
EPID-27. GEOGRAPHIC BURDEN OF CNS TUMORS AND DENSITY OF NEURO-ONCOLOGISTS IN THE UNITED STATES
Authors: Gregory Timothy , Graber Jerome
Published: November 2021

CNS cancer care relies heavily on exam and imaging interpretation skills distinctive to a neurology-trained oncologist, and access to this subspecialty is increasingly more essential as targeted molecular therapies evolve. We sought to explore the supply of neuro-oncologists in terms of geographic CNS tumor incidence. Using the UCNS online directory, we generated a heat map representing the location (set to 75-mile radius) and density of active neuro-oncologists. We overlaid this data upon yearly incidence of CNS tumors per neuro-oncologist for each state using most recent CBTRUS data. We highlight the significant distance Americans outside of urban areas must travel for care and that isolation from academic centers and exclusion from clinical trials are substantial barriers to cancer care for a significant proportion of the population. Telemedicine may in part improve patient access to care and clinical trial participation, but significant state-to-state legal variability for providing telehealth services across state lines remains a national challenge. Short-term strategies for equitably meeting this subspecialty need may require policy changes that optimize employment of telemedicine, and long-term must ensure a robust fellowship pipeline with thoughtful incentivization and allocation of resources.
IMMU-03. IMMUNE CHECKPOINT INHIBITORS IN SMALL CELL LUNG CANCER PATIENTS DEVELOPING BRAIN METASTASES
Authors: Jessurun Charissa , Tewarie Ishaan , Hulsbergen Alexander , Broekman Marike , Smith Timothy , phillips John
Published: November 2021

INTRODUCTION

Small cell lung cancer (SCLC) is known for rapid growth, and about 40-50% of SCLC patients will develop brain metastases (BM). The addition of immune checkpoint inhibitors (ICI) to the standard chemotherapy, which is the current backbone of first-line therapy, has resulted in more prolonged survival than chemotherapy alone in SCLC patients.

PURPOSE

This study aimed to assess the effect of ICI before BM development in SCLC patients on time to BM development and survival.

METHODS

A single-institutional retrospective review of SCLC patients that underwent cranial radiation therapy between January 2014 and June 2020 was performed to assess the impact of ICI therapy on time to BM development, overall survival (OS), and time to failure of BM treatment (defined as local or distant BM recurrence) using a multivariable Cox Proportional Hazards model.

RESULTS

Among 197 included patients, 23 patients (11.7%) received ICI before BM development. Extensive stage of SCLC at diagnosis was observed in eighteen patients (78.2%) in the ICI group and 133 (76.4%) in the non-ICI group. In total, seventeen patients (8.6%) received prophylactic cranial irradiation, of which seven patients (30.4%) also received ICI. ICI were associated with prolonged time to BM in comparison with the non-ICI group (HR = 0.29, 95% CI: 0.18-0.47). ICI were also associated with an increased OS (HR = 0.56, 95% CI: 0.32-0.97) and prolonged time to BM treatment failure (HR = 0.32, 95% CI: 0.15-0.71) in comparison with patients who did not receive ICI.

CONCLUSION

The use of ICI before BM development was associated with a longer time to BM. Additionally, ICI therapy was associated with an increased OS and prolonged BM treatment failure. These results are a proof of concept of the potential benefit of ICI therapy in SCLC patients, and the presented results should be further validated in larger cohorts.
IMMU-13. COMBINED MODULATION OF THE TGF-Β PATHWAY AND GITR IMMUNE CHECKPOINT SIGNALING PROMOTES ANTI-TUMOR IMMUNITY IN SYNGENEIC GLIOMA MODELS
Authors: Lorizio Daniela , Weller Michael , Silginer Manuela , Epstein Alan , Roth Patrick
Published: November 2021

The profound local immunosuppressive microenvironment is one hallmark of glioblastoma, which results in resistance to most immunotherapeutic strategies that have been explored so far. Reverting this condition in order to reinvigorate anti-glioma immunity might be a promising therapeutic approach. Transforming growth factor (TGF)-β signaling is deregulated in different cancer types and contributes to the malignant phenotype of glioma cells. Glioma-derived TGF-β is also a major immunosuppressive factor in the tumor microenvironment. Furthermore, intratumoral regulatory T (Treg) cells and activated T effector cells express high levels of the co-stimulatory immune checkpoint glucocorticoid-induced tumor necrosis factor receptor (GITR). Agonistic anti-GITR antibodies have been explored in preclinical tumor models and are under investigation in clinical trials for the treatment of solid tumors. We evaluated the effect of TGF-β and GITR targeting on anti-tumor immune responses in syngeneic mouse glioma models. In co-culture settings, GITR modulation with a GITR ligand (GITRL)-Fc fusion protein, given alone or in combination with a pharmacological TGF-β receptor inhibitor, led to increased T cell activation. Furthermore, the combined targeting of the two pathways resulted in significantly higher immune cell-mediated tumor cell killing than either treatment alone. In vivo, TGF-β inhibition and GITR signaling modulation resulted in a higher fraction of long-term surviving glioma-bearing mice than single-agent treatment. Surviving mice were resistant to tumor re-challenge, suggesting adaptive immunity as an underlying mechanism. These data support the assumption that combined immunotherapeutic strategies may represent a promising approach for the treatment of glioma.
IMMU-16. CHARACTERISTICS OF EGFRVIII-DIRECTED CART CELL INFUSION PRODUCT ASSOCIATED WITH CLINICAL RESPONSE IN RECURRENT GLIOBLASTOMA
Authors: Tang Oliver , Binder Zev , Tian Lifeng , Chang Wan-Jung , Yoder Todd , Lacey Simon , Melenhorst Jos , O’Rourke Donald M
Published: November 2021

BACKGROUND

A therapeutic approach for chimeric antigen receptor T (CART) cell therapy in glioblastoma is targeting the epidermal growth factor receptor variant III (EGFRvIII), present in approximately 30% of glioblastomas. While earlier research demonstrated that phenotypic and genotypic characteristics in patient T cells and CART product may predict therapeutic success for hematologic malignancies, no study has investigated such determinants for clinical response in glioblastoma.

METHODS

We analyzed apheresis and infusion products for patients in the first-in-human trial of EGFRvIII-directed CART for recurrent glioblastoma (NCT02209376, n=9). Inherent T cell phenotypes were characterized by flow cytometry assay using a panel of 27 markers. Clinical response was quantified via engraftment in peripheral circulation and time-on-trial (ToT).

RESULTS

Mean area under the curve (AUC) peripheral CART engraftment for the study period was 213 log10 copies/μg (SD=173) and mean ToT was 134 days (SD=173). For the CAR+/CD4+ population in the infusion product, PD1 positivity was positively associated with AUC engraftment (r=0.753, P=0.012) and ToT (r=0.800, P=0.010). On immune checkpoint inhibitor analysis, CTLA-4, TIM3, and LAG3 did not exhibit significant associations with AUC engraftment or ToT. For activation markers, PD1/GRZB (r=0.794, P=0.011) and PD1/HLA-DR (r=0.769, P=0.016) were directly associated with ToT. PD1/GRZB was also predictive of AUC engraftment (r=0.794, P=0.011). For the CAR+/CD8+ population, PD1 positivity correlated with elevated AUC engraftment (r=0.639, P=0.047). In the CAR-/CD4+ population, PD1 remained positively correlated with AUC engraftment (r=0.690, P=0.027) and ToT (r=0.726, P=0.027). No significant associations were observed for apheresis products.

CONCLUSION

PD1 in CART infusion products predicted peripheral engraftment and ToT in recurrent glioblastoma. Double-positive cells for PD1 and activation markers also displayed a positive correlation, suggesting PD1 highlights a population of activated CAR T cells. Further characterization of predictors of EGFRvIII-directed CART treatment efficacy may improve selection of patients and starting T cell populations for clinical expansion.
IMMU-17. SYSTEMIC IMMUNOSUPPRESSION OF CD4+ T HELPER CELLS IN GLIOMA
Authors: Mohme Malte , Maire Cecile , Rünger Alessandra , Glau Laura , Tolosa Eva , Westphal Manfred , Lamszus Katrin
Published: November 2021

Cancer is a systemic disease. Due to the exceedingly rare occurrence of metastasis of cerebral glioma, systemic alterations have, however, not been considered to play a major role in disease progression of glioma. CD4+ T helper (TH) cells orchestrate the adaptive immune response in an antigen-specific, cytokine mediated manner. The aim of our study was to investigate how far cerebral glioma impacts the systemic CD4+ immune repertoire. We therefore analyzed the peripheral blood CD4+ TH cell phenotype and cytokine production in 100 patients with IDHwt, 30 IDHmut and 16 IDHmut 1p19q co-deleted gliomas in comparison with age-matched healthy donors (HD). We found a significant skewing of the peripheral phenotype in IDHwt glioma patients, showing a TH1 expansion and reduced numbers of T follicular helper cells (TFH), TH1* and mucosa associated invariant T (MAIT) cells, while TH2 and TH17 percentages remained stable compared to IDHmut and HD. Interestingly, although TH1 cells were dominant in IDHwt patients, intracellular cytokine staining showed a distinct reduction of IFNg and TNFa production after in vitro stimulation, while IL-4 was significantly increased compared to HD. No alterations between all groups were observed in IL-2, IL-10 or IL-17 production. Profiling of metabolic surface markers further revealed three distinct groups of CD4+ T cells which are altered in IDHwt patients, indicating a metabolic shift in the CD4+ repertoire compared to HD. Taken together, our results show a CD4+ TH cell type specific skewing of the peripheral immune repertoire in patients with IDHwt gliomas. Our data highlights the importance of considering malignant glioma as a systemic disease that fundamentally alters the immune repertoire in affected patients.
IMMU-20. HYDROGEL-CXCL9 VACCINE RESULTS IN MRNA DELIVERY TO DENDRITIC CELLS AND POTENT ANTI-TUMOR RESPONSES IN GBM
Authors: Dastmalchi Farhad , Karachi Aida , Mehkri Yusuf , O’Malley Ashley , Subramaniam Vignesh , Angelini Thomas , Mitchell Duane , Rahman Maryam
Published: November 2021

INTRODUCTION

Our group and others have shown mRNA-vaccines have significant anti-tumor efficacy in the treatment of brain tumors and are currently being tested in first-in-human trials. To further enhance mRNA delivery, a hydrogel platform was developed with the addition of CXCL9 to promote immune cell trafficking.

METHODS

We generated the vaccine by utilizing a hydrogel platform. CXCL9 and Nano-mRNA were loaded into the hydrogel. In vitro recruitment of DCs and NK was evaluated by fluorescence microscopy. In vivo recruitment of immune cells was analyzed by flowcytometry after collecting the fat pad, spleen, and tumor samples from KR158b-luc and Gl261-gp100 tumor-bearing animals 3, 5 and 10 days after vaccine delivery. The efficacy of the vaccine was evaluated by measuring overall survival, and tumor growth was measured by IVIS live-imaging.

RESULTS

Dendritic cells(DCs) and natural killer(NK) cells were able to efficiently migrate within the hydrogel-CXCL9 platform and uptake and express mRNA in vivo. In vitro, the hydrogel-CXCL9 was combined with nanoparticles loaded with total tumor RNA, and the vaccine was delivered to KR-158-luc and GL261-gp100 tumor-bearing animals via mammary fat pad SQ injection. Flow cytometry of the fat pad and draining lymph nodes demonstrated showed significant recruitment of endogenous DCs including inflammatory-DC(P= 0.0035), conventional-DC1(P= 0.0076), pDC(P=0.0028), NK(p= 0.0025 compared to the control group. In two different tumor models, a single dose of the vaccine resulted in significant survival benefits compared to control animals (n=10,P< 0.0001). SQ injection was superior to intracranial injection of the vaccine. Vaccinated animals showed an increased number of antigen-specific CD8 T cells in spleen(P= 0.0001) and tumor-microenvironment(P= 0.0070).

CONCLUSION

The hydrogel-CXCL9 platform results in efficient delivery of mRNA loaded nanoparticles to endogenous DCs and also causes an upregulation of NK cells with resultant improved survival in murine GBM models including the highly resistant KR158 model with a single dose. Further studies are ongoing.
IMMU-21. DIFFERENTIAL EXPRESSION OF ADHESION MOLECULES DEFINES MYELOID CELL INFILTRATION IN GLIOBLASTOMA AND COMPRISES A THERAPEUTIC TARGET
Authors: Bayik Defne , Bartels Cynthia , Lovrenert Katreya , Watson Dionysios , Kay Kristen , Lauko Adam , Scacheri Peter , Lathia Justin
Published: November 2021

A potently immunosuppressive tumor microenvironment facilitates progression of glioblastoma (GBM). Immunotherapies have had variable success in improving the outcome of GBM patients, suggesting that there is a need to gain insight into the mechanisms of immunosuppression. Myeloid-derived suppressor cells (MDSCs) associate with poor prognosis and treatment resistance of GBM patients, but the distinct role of individual populations is not well-defined. We previous showed that monocytic MDSCs (mMDSCs) accumulated in tumors of mice and patients, while granulocytic MDSCs (gMDSCs) mainly remained in the circulation. Furthermore, nonspecific targeting of mMDSCs with chemotherapies provided therapeutic benefit in preclinical models of GBM, suggesting that mMDSCs drive disease progression. To investigate the differential function of mMDSCs versus gMDSCs in GBM, we adoptively transferred bone marrow-derived MDSC subsets into tumor-bearing mice. Mice that received mMDSCs succumbed to disease sooner compared to control mice, which was not observed with gMDSC transfer. To determine the basis of this pro-tumorigenic activity of mMDSCs, we performed ATAC-sequencing and comparison of differentially accessible regions indicated that cell adhesion pathways were significantly upregulated in mMDSCs. Aligned with this epigenetic profile, mMDSCs from bone marrow and blood had significantly higher surface integrin β1 and integrin β7 expression compared to gMDSCs. To evaluate the role of integrins in MDSC behavior, we pre-treated mMDSCs with anti-integrin β1 prior to adoptive transfer. Blockade of integrin β1 interfered with the pro-tumorigenic role of mMDSCs compared to isotype controls. Similarly, blockade of integrin β1 and integrin β7 systemically extended the survival duration of tumor-bearing mice. Finally, high expression of integrin β1 and integrin β7 served as a poor prognostic indicator in GBM patients. Our findings indicate that modulation of immunosuppressive myeloid cells by leveraging differences in adhesion mechanisms represents a potential immunotherapeutic option for GBM.
IMMU-24. IMPROVING OUTCOMES IN OLDER ADULTS WITH GLIOBLASTOMA BY REVERSING AGE-RELATED CHANGES
Authors: Ladomersky Erik , Zhai Lijie , Bollu Lakshmi , Bell April , Lauing Kristen , Lukas Rimas , Wainwright Derek
Published: November 2021

Wild-type IDH glioblastoma (wtGBM) represents ≥90% of human GBM patient diagnoses with a median age of onset at 68-70 years of age. We previously found a decline of GBM patient survival with progressive age and that subjects ≥65 years of age had the poorest prognosis. We also showed an age-dependent enhancement of immune suppression in the brain that negatively affected immunotherapeutic efficacy in older adult mice with syngeneic brain tumors. Here, we extended those observations while studying C57BL/6 mice with intracranial CT-2A or GL261 between 80-110 weeks old - analogous to the age of a wtIDH GBM patient diagnosis. Overall survival of older adult mice with CT-2A or GL261 was significantly decreased when subjects were lymphopenic for CD4+ T cells as compared to an IgG Ab treatment group (n=12/group; p< 0.01). CD8+ T cell or NK cell leukopenia had no effect on survival outcomes. The negative effect of CD4+ T cell lymphopenia in older adults was not observed in younger mice with brain tumors. We also investigated the increased immunosuppression in the brain and its relationship to the accumulation of senescent cells and the treatment with standard of care radiation/temozolomide (RT/TMZ). p16INK4A, a marker for senescent cells, was increased in non-tumor cells of the brain during advanced age and its expression was increased after treatment with RT/TMZ. Older adult mice with brain tumors and treated with senolytics showed decreased p16INK4A levels after treatment with RT/TMZ. Senolytic treatment also improved the efficacy of combination therapy with RT, anti-PD-1 mAb, and IDO enzyme inhibitor in older adults as compared to senolytics alone or the triple immunotherapeutic cocktail alone (n=12-15/group; p< 0.01). Collectively, the results suggest that strategies aimed at reversing the effects of the aging combined with tumor eradication therapies may be particularly beneficial for older adult human patients with GBM.
IMMU-26. SAFETY AND EFFICACY OF PVSRIPO IN RECURRENT GLIOBLASTOMA: LONG-TERM FOLLOW-UP AND INITIAL MULTICENTER RESULTS
Authors: Desjardins Annick , Gromeier Matthias , Friedman Henry , Landi Daniel , Friedman Allan , Ashley David M , Curry William , Butowski Nicholas , Sloan Andrew , Wen Patrick , Cavaliere Robert , Gerstner Elizabeth , Berger Mitchel , Buerki Robin , Chiocca E Antonio , Sauvageau Eric , Kelly Andrea , Nichols W Garrett , Mixson Lori , Dickinson Adam , Orr Kristin , Learn Chris , Bigner Darell
Published: November 2021

BACKGROUND

Recurrent glioblastoma (rGBM) is rapidly fatal (median overall survival [mOS] of ~9 months; OS at 12 months [OS12] < 35%) with approved therapies (lomustine±bevacizumab). PVSRIPO is an intratumoral immunotherapy targeting CD155 on antigen-presenting and malignant cells of solid tumors. Preclinically, PVSRIPO delivers a systemic, tumor antigen-specific, polyfunctional T-cell mediated anti-tumor response. Interim, single-center, phase (Ph) 1 results showed greater long-term survival with PVSRIPO vs. criteria-matched external control rGBM patients (Desjardins 2018). Updates to Ph1 safety (at the Ph2 dose) and efficacy and interim multicenter (Ph2) results are presented.

METHODS

Adults with histologically-confirmed rGBM, Karnofsky performance status ≥ 70, and an active, supratentorial, contrast-enhancing lesion (1-5.5cm) received PVSRIPO (5x107 TCID50) intratumorally via convection-enhanced delivery on Day 1, with a planned follow-up of 24 months. Safety (treatment-emergent adverse events [TEAEs]), efficacy (reported as OS12, OS24, mOS), and blood/tissue were assessed.

RESULTS

149 patients (>90% with 1-2 prior progressions, including failure of SOC and patients with prior bevacizumab failure) received the Ph2 dose of PVSRIPO (n=30 received other doses in Ph1 with safety summarized previously). Follow-up durations for surviving patients were 51-74 months (Ph1) and 10-44 months (Ph2). No dose-limiting toxicities occurred; up to 97% of patients experienced mostly grade 1-2 related TEAEs; ≤ 23% patients experienced grade ≥ 3 related events. Neurologic symptoms related to peritumoral edema were most common ( > 90% patients) and were effectively managed with low-dose bevacizumab/corticosteroids. Survival estimates were: OS12: 54%, 50%; OS24: 18%, 17%; mOS: 12.3 (95% CI 10,15.3), 12 (10.6,13.7) months, for the Ph1 and Ph2 trials, respectively. Baseline correlates of longer survival included smaller lesions and methylated MGMT-promoter status.

CONCLUSIONS

The multicenter/Ph2 study replicated the single-center/Ph1 results. Relative to published data with approved therapies, PVSRIPO was associated with greater long-term survival and mOS in patients with rGBM and was generally well-tolerated.
IMMU-28. DECONVOLUTION OF SPATIALLY RESOLVED T CELL RECEPTOR PROFILING (SPTCR-seq) UNCOVERED REGIONAL ANTI-TUMOR IMMUNITY IN GLIOBLASTOMA
Authors: Benotmane Jasim Kada , Kückelhaus Jan , Joseph Kevin , Beck Jürgen , Schnell Oliver , Ravi Vidyha , Heiland Dieter Henrik
Published: November 2021

The diversity to T cell responses and clonality in spatially heterogeneous glioblastoma is of paramount importance to explore underlying mechanisms of anti-tumor immunity. Spatial transcriptomics, a novel technology to map the transcriptional architecture, is technically limited to discover T cell receptor (TCR) sequences as the 3' approach lacks sufficient coverage. Here, we established SPTCR-seq, a method to capture TCR sequences followed by long-read sequencing to enable full-length TCR reconstruction. We performed 10X Visium spatial transcriptomics on 9 primary and recurrent glioblastoma with both 3’-sequencing and SPTCR-seq. For SPTCR-seq, we target enriched T cell receptor sequences by capturing by hybridization followed by Oxford-Nanopore long-read sequencing. The on-target rate was above 80% for captured TCR genes and spatial barcode was successfully aligned in more than 60%. IgBlast and MixCR were used to reconstruct the TCR and map T cell clonality. Within our recent developed spatial transcriptomic analysis framework (SPATA2), we build a novel toolbox, SPATA-Immunology, which enables integration of stRNA-sequencing data and spatially resolved TCR sequencing. Our data showed that clonal evolution of T cells is limited to regional areas underpinned by significant spatial autocorrelation coefficient (0.6-0.95, padj< 0.001). In the surrounding tumor cell spots, the recently described transcriptional program “reactive immune” (RI), was significantly enriched. Using spotlight, a computational approach to project scRNA-sequencing into the spatial space, we found a local enrichment of CD163 positive macrophages exclusively in areas of large T cell clonality. Imaging mass cytometry of a consecutive section confirmed the spatial confluence of T-cell infiltration and CD163-positive macrophages. Through DeepTCR we uncovered potential epitopes which correlate with T cell clonality and might help to discover novel targets for CART therapy. Spatial profiling of TCR sequences through SPTCR-seq is a powerful tool to investigate anti-tumor immunity in glioblastoma and allows to discover general and personalized targets for immunotherapy.
IMMU-37. DISRUPTION OF PD-L1 BY ENHANCED TWO-SGRNAS CRISPR/CAS9 IN TREATMENT OF GLIOBLASTOMA
Authors: Fierro Javier , Perez joshua , Aguilar Rocio , Dipasquale Jake , Tran An , Factoriza Chris , Dou Huanyu
Published: November 2021

Anti-glioblastoma multiform (GBM) immunotherapy poses a great challenge due to immunosuppressive brain tumor environments and the blood brain barrier (BBB). Programmed death ligand 1 (PD-L1) plays a key role in GBM immunosuppression, vitality, proliferation, and migration. Targeting PD-L1 for immunotherapy is a promising new avenue for treating GBM. CRISPR/Cas9 gene editing can be used to knockout both membrane and cytoplasmic PD-L1, leading to an enhanced immunotherapeutic strategy. We identified two sgRNA sequences located on PD-L1 exon 3. The first sgRNA recognized the forward strand of human PD-L1 near the beginning of exon 3 and cuts at approximately base pair 82 (g82). The second sgRNA recognized the reverse strand of exon 3 and cuts at base pair 165 (g165). Two sgRNAs, g82 and g165, created an 83bp deletion in PD-L1 genomic sequence. Two sgRNAs combination with a homology-directed repair template (HDR) was designed to enhance PD-L1 knockout specificity and efficiency. Both g82 and g165 were cloned into one CRISPR/Cas9 plasmid, and was co-transfected with HDR. GFP tagged CRISPR/Cas9 plasmid containing of g82 and g165 (Cas9-g82/165) was loaded into Rhodamine labeled nanoparticles (Cas9-g82/165-NPs) and then treated to GBM U87 cells. The enhanced intracellular uptake and transfection of Cas9-g82/165-NPs were detected by a fluorescence microscopy. T7E1, qRT-PCR and western blot analysis determined that the dual sgRNA CRISPR/Ca9 system knocked out both endogenous (80%) and exogenous (64%) PD-L1 in U87 cells and PD-L1 overexpression U87 cells, respectively. Deletion of PD-L1 reduced U87 migration and proliferation, while PD-L1 overexpression promoted tumor growth and tumor-associated macrophage polarization. Together, deletion of both membrane and cytoplasmic PD-L1 altered the PD-L1-associated immunosuppressive environment and prevented tumor progression and migration. Thus, two-sgRNAs CRISPR/Cas9 gene-editing system is a promising avenue for anti-GBM immunotherapy.
IMMU-48. IMMUNOMODULATION WITH RESIQUIMOD REPOLARIZES THE IMMUNE MICROENVIRONMENT TO INHIBIT MEDULLOBLASTOMA PROGRESSION
Authors: Park Christopher , Del Mar Coral , Thang Morrent , Dismuke Taylor , Hwang Duhyeong , Lim Chaemin , Mirlekar Bhalchandra , Donson Andrew , Vibhakar Rajeev , Sokolsky Marina , Pylayeva-Gupta Yuliya , Gershon Timothy
Published: November 2021

BACKGROUND

New, non-cytotoxic treatments may improve outcomes for medulloblastoma, the most common malignant pediatric brain tumor. Sonic hedgehog (SHH) subgroup medulloblastoma, which includes subtypes with poor prognosis, can be modeled in immunocompetent, transgenic mice. These models are ideal for preclinical testing of immunotherapies. Here, we show that immune stimulation using resiquimod, a small molecule agonist of Toll-like receptor 7 and 8 (TLR 7/8), alters myeloid populations in medulloblastoma and significantly reduces tumor growth.

METHOD

We generated mice with medulloblastoma by interbreeding the hGFAP-Cre and SmoM2 mouse lines. The resultant hGFAP-Cre/SmoM2 (G-Smo) mice develop SHH medulloblastoma with 100% frequency. We analyzed myeloid populations and demonstrated TLR7/8 expression patterns in G-Smo tumors. We then compared survival of untreated G-Smo mice versus G-Smo mice treated with three doses of resiquimod at postnatal days 10, 12, and 14. We also assessed pharmacodynamic effects at progressive intervals after a single dose.

RESULTS

Approximately 10% of cells in G-Smo medulloblastomas were myeloid cells, and these cells were the only cells that expressed TLR7/8. Resiquimod slowed tumor growth and increased the survival of mice with medulloblastoma. Untreated median survival was 14.5 days (n=12), compared to resiquimod-treated median survival of 37 days (n=10; p=0.0003). All treated mice eventually demonstrated tumor progression. Immunohistochemistry for IBA1, a pan-macrophage marker, demonstrated significant increase in myeloid cells within the tumor by 24 hours after treatment (p=0.0178), however the IGF1+ fraction of myeloid cells decreased (p=0.0275).

CONCLUSION

Resiquimod prolongs survival in mice with SHH-driven medulloblastoma, demonstrating the potential for therapies that target myeloid cells to produce significant anti-tumor effects. Myeloid-derived IGF-1 has been shown to support tumor progression and resiquimod may act by disrupting this paracrine signaling.
INNV-07. TTFIELDS TREATMENT OF GLIOSARCOMA AND RECURRENT ANAPLASTIC OLIGODENDROGLIOMA
Authors: Blondin Nicholas , Fulbright Robert , Huttner Anita , Moliterno-Gunel Jennifer
Published: November 2021

INTRODUCTION

The Optune device delivers tumor treating fields (TTFields) and is considered as a standard of care for newly diagnosed and recurrent glioblastoma patients. The efficacy of Optune in other glioma subtypes, such as gliosarcoma and anaplastic oligodendroglioma, is still unclear. In this small case series, we present the clinical, pathologic and radiographic findings of two patients who utilized Optune and had improved outcomes compared to historical controls.

CASE 1

A 49 year old woman underwent resection of a right temporal lobe gliosarcoma in November 2017. She received conventional radiation therapy with concurrent temozolomide, which was complicated by significant thrombocytopenia and leukopenia. She initiated Optune as monotherapy six weeks after completing radiation, and used the device for 24 months. She still has not had a recurrence, now 3.5 years since her initial diagnosis.

CASE 2

A 46 year old woman underwent resection of a right frontal lobe oligodendroglioma, WHO Grade 2, in September 2011. She received one cycle of temozolomide in April 2014, complicated by thrombocytopenia, and no further chemotherapy was administered. In November 2017, she underwent resection of a new focus of enhancement at the margin of the resection cavity, which was confirmed to have transformed to WHO Grade 3. In August 2019, a radiographic progression of an enhancing nodule was observed. She initiated Optune as monotherapy in September 2019, and since that time, has had stable disease for 18 months. Optune treatment is still ongoing.

CONCLUSIONS

In a case of newly diagnosed gliosarcoma, Optune monotherapy has contributed to progression-free and overall survival of 3.5 years to date. In a case of recurrent anaplastic oligodendroglioma, Optune monotherapy has achieved stable disease for at least 18 months. These cases demonstrate that Optune can be safely utilized in these glioma subtypes and contributed to improved survival outcomes in these two patients.