Recurrent Glioblastoma Patients Research Articles

Efficacy and safety study of neoadjuvant efineptakin alfa (NT-I7) and pembrolizumab in recurrent glioblastoma.

TPS2085 Background: Glioblastoma (GBM) is the most common and aggressive form of brain tumor in adults. Despite maximal surgical resection, irradiation, and chemotherapy, median overall survival (OS) remains at only 30 weeks for recurrent GBM (rGBM) patients, emphasizing the need for novel treatments. GBM tumors are immunologically ‘cold,’ in that they have an immune-suppressive microenvironment with a low number of tumor-infiltrating lymphocytes (TIL). Interleukin 7 (IL-7) plays a key role in T cell development and survival. The physiological level of IL-7 increases to stimulate T cell expansion in lymphopenic condition. Previous studies have shown that lymphopenic GBM patients have shorter survival. However, their IL-7 levels are unexpectedly low. Efineptakin alfa (NT-I7), a long-acting IL-7, has been shown to increase effector CD8 T cells and reduce suppressor T-regulatory cells in murine GBM models, with subsequently improved OS. Further, we recently completed a Phase I study which showed that NT-I7 is safe, well- tolerated, and increased absolute lymphocyte counts (ALC) in newly diagnosed GBM patients. Phase II dosing was determined through this Phase I study reaching maximum tolerated dose. Thus, we hypothesized that NT-I7 may reverse GBM-associated immune suppression and potentiate the effect of an immune checkpoint inhibitor, leading to an increase in TILs and improved survival. Our preliminary data suggests that combining NT-I7 with pembrolizumab, an anti-PD-1 antibody, improves survival in murine glioma models. The purpose of this study is to evaluate the safety and efficacy of combining NT-I7 and pembrolizumab in rGBM patients. Methods: This is an open-label single arm one-stage Phase II study of NT-I7 and pembrolizumab as neoadjuvant and adjuvant therapy with surgery for adult patients with rGBM. We plan to enroll 30 evaluable patients, including a 6-patient safety run-in. Key eligibility criteria include candidates willing to undergo clinically indicated resection or biopsy, age ≥ 18 years, Karnofsky performance status ≥ 70, and dexamethasone dose > 2 mg/day ≤ 2 days prior to registration. The primary endpoint is a 9-month OS rate. Secondary endpoints include progression-free survival, objective response rate, changes in ALC, and adverse events profile. The correlative endpoints include studies to assess the anti-glioma immune response, changes in T cell subsets, T cell effector function, cytokine analysis, and immunohistochemical analysis of GBM tissue. Longitudinal cerebrospinal fluid proteomics is optional. This study opened on 1/20/2023. Two of the planned 30 patients had been enrolled by submission on 2/14/2023. Clinical trial information: NCT05465954 .

Clinical characterization of patients with recurrent glioblastoma in trials involving CED and non-CED treatment.

e18845 Background: Glioblastoma (GBM) is the most common and aggressive of the primary malignant brain tumors in adults. Bevacizumab (beva) remains the only currently approved therapeutic for recurrent GBM (rGBM) patients who progress on prior therapy. Despite advances in care, rGBM has a median expected progression-free survival (PFS) of < 4 months and overall survival (OS) of ~8 months. NCCN guidelines [Version 2.2022], and other oncology medical societies unanimously recommend patients seek treatment by entering a clinical trial. Since the late 1990’s a number of studies have explored the use of convection-enhanced delivery (CED) of drugs, a well-accepted and widely published delivery option for the treatment of rGBM. This analysis compares the demographics, medical history and survival outcome of patients enrolled into recently completed clinical trials with beva monotherapy to those entered into CED studies. Methods: Data for this analysis was sourced from the Medidata Enterprise Data Store (MEDS), comprised of over 28,000 historical clinical trials for de-identified aggregate patient-level analyses and from the study and patient-level data in the CED studies referenced in D’Amico [J Neurooncol 2021]. Aggregate summary statistics comparing beva and CED patients were based on combined study- and patient-level data using weighted (by sample size) means, incidence and overall survival (OS) rates and median of medians. Results: 163 rGBM beva patients were identified from MEDS. The CED cohort included 636 patients from MEDS and studies referenced in D’Amico. Cohort comparisons (beva vs CED) found median age: 56 vs 55 years; Caucasian race: 91% vs 93%; male sex: 68% vs 65%; not Hispanic or Latino ethnicity: 90% vs 94%; median OS: 7.9 vs 8.4 months. Over the last 2 decades there was a 23% increase in patients with ECOG Performance Status = 0 and 25% decrease in tumor area size at study enrollment, whereas there was no clear temporal OS trend. Conclusions: Patient demographics and most tumor attribute variables were similarly distributed between the beva and CED cohorts. While there is some indication that recent CED studies have enrolled healthier patients with smaller tumors; as expected, this does not appear to have translated to a consistent survival benefit.

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).

Effects of Reoperation Timing on Survival among Recurrent Glioblastoma Patients: A Retrospective Multicentric Descriptive Study.

Glioblastoma inevitably recurs, but no standard regimen has been established for treating this recurrent disease. Several reports claim that reoperative surgery can improve survival, but the effects of reoperation timing on survival have rarely been investigated. We, therefore, evaluated the relationship between reoperation timing and survival in recurrent GBM. A consecutive cohort of unselected patients (real-world data) from three neuro-oncology cancer centers was analyzed (a total of 109 patients). All patients underwent initial maximal safe resection followed by treatment according to the Stupp protocol. Those meeting the following criteria during progression were indicated for reoperation and were further analyzed in this study: (1) The tumor volume increased by >20-30% or a tumor was rediscovered after radiological disappearance; (2) The patient's clinical status was satisfactory (KS ≥ 70% and PS WHO ≤ gr. 2); (3) The tumor was localized without multifocality; (4) The minimum expected tumor volume reduction was above 80%. A univariate Cox regression analysis of postsurgical survival (PSS) revealed a statistically significant effect of reoperation on PSS from a threshold of 16 months after the first surgery. Cox regression models that stratified the Karnofsky score with age adjustment confirmed a statistically significant improvement in PSS for time-to-progression (TTP) thresholds of 22 and 24 months. The patient groups exhibiting the first recurrence at 22 and 24 months had better survival rates than those exhibiting earlier recurrences. For the 22-month group, the HR was 0.5 with a 95% CI of (0.27, 0.96) and a p-value of 0.036. For the 24-month group, the HR was 0.5 with a 95% CI of (0.25, 0.96) and a p-value of 0.039. Patients with the longest survival were also the best candidates for repeated surgery. Later recurrence of glioblastoma was associated with higher survival rates after reoperation.

Abstract LB127: VAL-083 in patients with recurrent glioblastoma treated under expanded access program

Abstract Current standard-of-care for glioblastoma (GBM) includes surgery followed by concurrent therapy with radiation and temozolomide (TMZ) and adjuvant TMZ. Almost all GBM patients experience recurrent/progressive disease despite upfront standard of care treatment, with a median overall survival of 3-9 mo. after recurrence. There are limited treatment options available upon progression of disease which may include potential participation in clinical trials. However, patients may not meet the strictly defined entry criteria to participate in these clinical trials. VAL-083 is a first-in-class bifunctional alkylating agent that acts independent of O6-methylguanine-DNA-methyltransferase (MGMT) methylation status. Under an Expanded Access (EA) program, we have treated 24 patients with recurrent GBM, who were not eligible to participate in clinical trials with VAL-083. Four (4/24; 17%) patients had leptomeningeal disease (LMD) at time of enrolment. While safety data was assessed for all patients, those without LMD (20 patients) were evaluated for efficacy. All patients evaluated for efficacy received chemoradiation with TMZ, and the mean number of adjuvant TMZ cycles was 5 (± 6.2). The median time from last progression to start of VAL-083 was 0.65 mo. (95%CI: 0.32-1.55) and median KPS was 80 (25-75P: 70-90). Eight (8/20; 40%) patients had 2 or more prior recurrences, 9/20 (45%) patients had multifocal disease, and 5/20 (25%) had prior lomustine. Eighteen (18/20; 90%) patients had unmethylated promoter status for MGMT and 18/20 (90%) were IDH wild type. All patients had at least 1 mutation, with 11/20 (55%) having 5 or more mutations, and one patient had hypermutator phenotype with MSH6 mutation. The most common mutations were, TERT 11/20 (55%), PTEN 9/20 (45%), and TP53 6/20 (30%). All patients started treatment with VAL-083 at 30 mg/m2 administered on 3 consecutive days every 21 days. Seven patients received bevacizumab concurrently with VAL-083. VAL-083 was well tolerated and the main adverse events were consistent with prior experience, i.e., thrombocytopenia and neutropenia. Eight (8/24; 33%) patients had a dose reduction, 7 of which were due to thrombocytopenia, and 1 due to neutropenia. Five patients with thrombocytopenia had prior lomustine. As of cut-off date (05 Jan, 2023), median progression free survival (mPFS) and median overall survival (mOS) from last disease progression was 5.9 mo (95%CI: 3.9-7.9) and 9.4 mo (95%CI: 3.0-14.3), respectively. In patients without multifocal disease mOS was even longer, 14.3 mo (95%CI: 3.9-14.3). Use of VAL-083 in this expanded access study showed benefit in the treatment of recurrent GBM patients even those who have had multiple recurrences and were not candidates for the treatment through clinical trial. Additional safety and efficacy measures will be presented at the meeting.Clincialtrials.gov Identifier: NCT03138629. All EA treatment requests and plans were approved by MD Anderson Cancer Center IRB. Citation Format: Carlos Kamiya-Matsuoka, Shiao-Pei Weathers, Rebecca A. Harrison, Nazanin K. Majd, Ashley E. Aaroe, Stephanie Knight, Teresa Hanna, Timothy A. Gregory, John Langlands, Dennis Brown, Vinay K. Puduvalli. VAL-083 in patients with recurrent glioblastoma treated under expanded access program [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB127.

Abstract 337: Antitumor effect of oncomagnetic therapy in glioblastoma

Abstract Background: Glioblastoma (GBM) is the most lethal primary malignant brain tumor with a median survival of 15-20 months. Concurrent temozolomide (TMZ) chemotherapy and radiation (XRT) remain the current standard of care (SOC) treatment for newly diagnosed GBM. The addition of tumor treating fields (TTFs) improves median survival from 16 to 20.9 months. This modest improvement underscores the urgent need to identify a new treatment modality as standalone therapy. We have reported recently that brief 2 - 6 h of daily brain stimulation with a new noninvasive, non-contact, magnetic stimulation device causes >30% reduction of contrast-enhanced tumor (CET) volume in an end-stage recurrent GBM patient after a ~30-day treatment. Purpose: The noninvasive Oncomagnetic device developed in our laboratory selectively kills glioblastoma (GBM) and other cancer cells while sparing normal developing neurons and astrocytes in vitro. The spinning oscillating magnetic field (sOMF) generated by this device disrupts electron transport in the mitochondrial respiratory chain leading to a marked increase in reactive oxygen species (ROS) and consequent cancer cell death. However, the downstream molecular mechanism of sOMF action is under investigation. We studied the cellular and molecular effects of sOMF treatment on GBM cell lines and investigated the response to Oncomagnetic monotherapy (OMT) in a syngeneic mouse model. We treated LN229 and U87 GBM cells with sOMF with and without a sub-therapeutic dose of TMZ in vitro. To study the anticancer effect of sOMF in vivo, we developed syngeneic GBM tumors in BALB/c mice by stereotactic intracranial injection of GL261WT cells. Tumor growth was monitored periodically by MRI scans. Results: Our results showed that sOMF significantly reduce cell proliferation and cell survival in vitro. We observed that sOMF induces DNA damage and arrests cells in G1 phase of cell cycle. OMT of tumor-bearing mice using a whole-body sOMF stimulation method caused a substantial retardation of tumor growth and reduction of the contrast-enhanced tumor volume in 9.4 T MRI scans. OMT also showed significant increase in overall survival in these mice. Conclusion: These experiments contribute to unraveling the mechanism of action underlying the response to OMT in GBM and provide a strong rationale for a standalone Oncomagnetic therapy for GBM. Citation Format: Arvind Pandey, Shashank Hambarde, David S. Baskin, Santosh A. Helekar. Antitumor effect of oncomagnetic therapy in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 337.

Longitudinal analysis of serum-derived extracellular vesicle RNA to monitor dacomitinib treatment response in EGFR-amplified recurrent glioblastoma patients.

Glioblastoma (GBM) is a highly aggressive and invasive brain tumor associated with high patient mortality. A large fraction of GBM tumors have been identified as epidermal growth factor receptor (EGFR) amplified and ~50% also are EGFRvIII mutant positive. In a previously reported multicenter phase II study, we have described the response of recurrent GBM (rGBM) patients to dacomitinib, an EGFR tyrosine kinase inhibitor (TKI). As a continuation of that report, we leverage the tumor cargo-encapsulating extracellular vesicles (EVs) and explore their genetic composition as carriers of tumor biomarker. Serum samples were longitudinally collected from EGFR-amplified rGBM patients who clinically benefitted from dacomitinib therapy (responders) and those who did not (nonresponders), as well as from a healthy cohort of individuals. The serum EV transcriptome was evaluated to map the RNA biotype distribution and distinguish GBM disease. Using long RNA sequencing, we show enriched detection of over 10 000 coding RNAs from serum EVs. The EV transcriptome yielded a unique signature that facilitates differentiation of GBM patients from healthy donors. Further analysis revealed genetic enrichment that enables stratification of responders from nonresponders prior to dacomitinib treatment as well as following administration. This study demonstrates that genetic composition analysis of serum EVs may aid in therapeutic stratification to identify patients with dacomitinib-responsive GBM.

Treatment of unmethylated MGMT-promoter recurrent glioblastoma with cancer stem cell assay-guided chemotherapy and the impact on patients' healthcare costs.

Glioblastoma (GBM) is a lethal disease. At least in part, the recurrence of GBM is caused by cancer stem cells (CSCs), which are resistant to chemotherapy. Personalized anticancer therapy against CSCs can improve treatment outcomes. We present a prospective cohort study of 40 real-world unmethylated Methyl-guanine-methyl-transferase-promoter GBM patients treated utilizing a CSC chemotherapeutics assay-guided report (ChemoID). Eligible patients who underwent surgical resection for recurrent GBM were included in the study. Most effective chemotherapy treatments were chosen based on the ChemoID assay report from a panel of FDA-approved chemotherapies. A retrospective chart review was conducted to determine OS, progression-free survival, and the cost of healthcare costs. The median age of our patient cohort was 53 years (24-76). Patients treated prospectively with high-response ChemoID-directed therapy, had a median overall survival (OS) of 22.4 months (12.0-38.4) with a log-rank P = .011, compared to patients who could be treated with low-response drugs who had instead an OS of 12.5 months (3.0-27.4 months). Patients with recurrent poor-prognosis GBM treated with high-response therapy had a 63% probability to survive at 12 months, compared to 27% of patients who were treated with low-response CSC drugs. We also found that patients treated with high-response drugs on average had an incremental cost-effectiveness ratio (ICER) of $48,893 per life-year saved compared to $53,109 of patients who were treated with low-response CSC drugs. The results presented here suggest that the ChemoID Assay can be used to individualize chemotherapy choices to improve poor-prognosis recurrent GBM patient survival and to decrease the healthcare cost that impacts these patients.

Compassionate use of recombinant human IL-7-hyFc as a salvage treatment for restoring lymphopenia in patients with recurrent glioblastoma.

Addressing lymphopenia in cancer patients has been suggested as a novel immunotherapeutic strategy. As interleukin-7 (IL-7) is necessary for proliferation of lymphocytes and to increase total lymphocyte count (TLC), IL-7 therapy has been attempted in various cancers. Here, we describe the clinical results of treatment of recurrent glioblastoma (GBM) with a long-acting engineered version of recombinant human IL-7 (rhIL-7-hyFc). This prospective case series based on compassionate use was approved by the Ministry of Food and Drug Safety in South Korea. Primary outcomes were safety profile and TLC. Secondary outcomes were overall survival (OS) and progression-free survival (PFS). Among the 18 patients enrolled, 10 received rhIL-7-hyFc with temozolomide, 5 received rhIL-7-hyFc with bevacizumab, 1 received rhIL-7-hyFc with PCV chemotherapy, and 2 received rhIL-7-hyFc alone. Mean TLC of the enrolled patients after the first rhIL-7-hyFc treatment increased significantly from 1131 cells/mm3 (330-2989) at baseline to 4356 cells/mm3 (661-22,661). Higher TLCs were maintained while rhIL-7-hyFc was repeatedly administered. Median OS and PFS were 378 days (107-864 days) and 231 days (55-726 days), respectively. Our study reports that IL-7 immunotherapy can restore and maintain TLC during treatment with various salvage chemotherapies in recurrent GBM patients without serious toxicity.

ACT-20 PHASE 1/2, PROSPECTIVE, INTERNATIONAL MULTI-CENTER STUDY TO ESTABLISH THE SAFETY AND FEASIBILITY OF BLOOD-BRAIN-BARRIER DISRUPTION COMBINED WITH CARBOPLATIN FOR RECURRENT GLIOBLASTOMA; FIRST CLINICAL EXPERIENCE IN JAPAN

Abstract The prognosis for glioblastoma is still very poor despite intensive treatment by surgery, radiation, and chemotherapy. One of the reasons for poor prognosis of glioblastoma is blood-brain-barrier (BBB), which limits the delivery of chemotherapeutic agents to the brain. Focused ultrasound (FUS) therapy is approved for essential tremor and Parkinson disease in Japan and preclinical studies suggest low-intensity focused ultrasound (LIFU) administered with microbubbles (MB) can disrupt BBB and can improve the delivery of chemotherapeutic agents. Thus, currently, focused ultrasound therapy has gained attention in neuro-oncology and a number of clinical trials using FUS for the treatment of glioblastoma are underway. Our institutions (Osaka University Hospital and Saito Yukoukai Hospital) are the first in Japan to join the international multicenter study to examine the safety and feasibility of BBB disruption by FUS and MB combined with intravenous carboplatin for the treatment of recurrent glioblastoma. We are planning to enroll one recurrent glioblastoma patient for this study soon. BBB disruption strategies using FUS and MB for the treatment of neuro-oncological disease has potentials to improve the outcome of patients and many clinical trials will be performed in future.

CTIM-08. A PILOT STUDY OF ABEMACICLIB WITH BEVACIZUMAB IN RECURRENT GLIOBLASTOMA PATIENTS WITH LOSS OF CDKN2A/B OR GAIN OR AMPLIFICATION OF CDK4/6

Abstract The recurrence rate for glioblastomas is essentially 100% and median overall survival (OS) for recurrent glioblastoma patients is usually poor, approximately 6-8 months from first recurrence. There is an unmet need in recurrent glioblastomas for novel therapeutic options with favorable safety profiles and potentially longer OS. PURPOSE The goal was to assess the impact of treating recurrent Glioblastoma patients whose tumors harbor loss of CDKN2A and/or CDKN2B, and/or copy gains or amplifications of CDK4 and/or CDK6 with dual therapy Abemaciclib with Bevacizumab. METHODS This was a single institution, pilot study (N = 10) of recurrent glioblastoma patients given the combination of Abemaciclib with Bevacizumab. Study patients received the combination of Abemaciclib at 150 mg po bid daily along with intravenous Bevacizumab at 10 mg/kg once every 2 weeks within a 28-day cycle. Staging brain MRIs with contrast were obtained every 8 weeks. Trial patients were removed from the study for significant treatment toxicities, clinical or MRI progression, patient choice, or death. RESULTS A total of 10 patients were enrolled in the study. There were 3 patients initially enrolled that were evaluated for safety followed by the additional 7 patients meeting clinical accrual from Jan. 2020-Sept. 2021. A total of 9 patients received at least one cycle (M = 6, F = 3). Preliminary findings revealed a median PFS of 14 weeks (range 5 weeks–25 weeks) and median OS of 20 weeks (range 5-70 weeks). CONCLUSION The combination of Abemaciclib with Bevacizumab compared to monotherapy Bevacizumab, surprisingly, had poorer outcomes. In a 2014 Bevacizumab study in recurrent glioblastomas, the median PFS was 13 weeks and OS 34.8 weeks compared to our combination therapy study of 14 weeks and 20 weeks, respectively. It is postulated that the use of Bevacizumab with Abemaciclib caused a drug-drug interaction that led to poor outcomes in our pilot study.

CTNI-44. A PHASE 0 ‘TRIGGER’ TRIAL OF PAMIPARIB IN NEWLY DIAGNOSED AND RECURRENT GLIOBLASTOMA PATIENTS

Abstract This study evaluates glioblastoma (GBM) pharmacokinetics (PK) and pharmacodynamics (PD) of pamiparib, a PARP1/2-selective inhibitor, graduating patients to a therapeutic expansion phase of drug plus radiotherapy. Newly-diagnosed (Arm A) and recurrent GBM (Arm B) patients received 4 days of pamiparib (60 mg BID) prior to planned resection at 2-4 or 8-12 hours following the final dose. Arm C included recurrent GBM patients who received 4 days of olaparib (200 mg BID). Tumor tissue cerebrospinal fluid (CSF), and plasma were collected. Total and unbound drug concentrations were measured using validated LC-MS/MS methods. A PK ‘trigger’, defined as unbound drug > 5-fold biochemical IC50 in nonenhancing tumor determined eligibility for the therapeutic expansion phase. PARP inhibition was assessed via ex vivo radiation and quantification of PAR levels compared to non-radiated control. All patients exceeding the PK threshold were eligible for an expansion phase of study drug plus radiotherapy followed by maintenance regimen. In Arms A (n = 20) and B (n = 15), the mean unbound concentrations of pamiparib in Gd-nonenhancing tumor region were 171.5 nM and 102.9 nM, respectively and in Arm C (n = 4) the mean unbound concentration of olaparib was 11.0 nM. All patients in Arms A and B, but only one in Arm C, exceeded the PK threshold to qualify for the expansion phase of the study. 12/20 (60%), 7/14 (50%), and 1/4 (25%) patients in Arms A, B, and C, respectively progressed to expansion phase. Radiation-induced PAR expression was 2.44 fold in untreated control vs 1.16 in Arm A, 0.82 in Arm B and 1.11 in Arm C patients, respectively. The median progression-free survival was 5.4 (Arm A) (n = 7), 5.0 months (Arm B) (n = 6), and 2.7 months (Arm C) (n = 1), respectively. Pamiparib was generally well-tolerated, achieved pharmacologically-relevant concentrations in nonenhancing GBM tissue and suppressed induction of PAR levels ex vivo post-radiation.

DDEL-13. ULTRASOUND-ENHANCED DELIVERY OF LIPOSOMAL DOXORUBICIN ACROSS THE BLOOD BRAIN BARRIER INDUCES AN IFN-GPHENOTYPE IN MICROGLIA, MACROPHAGES, AND T CELLS AND IMPROVES RESPONSE TO PD-1 BLOCKADE IN GLIOMAS

Abstract INTRODUCTION Given the limited drug penetration across the blood-brain barrier (BBB), the therapeutic potential of new and existing therapies has not been fully exploited for the benefit of glioblastoma (GBM) patients. METHODS Here we employed a novel drug delivery technology based on low-intensity pulsed ultrasound combined with intravenous microbubbles (LIPU/MB) that temporarily opens the BBB to deliver liposomal doxorubicin (DOX) and anti-PD-1 therapy (aPD-1) in mouse glioma models and 3 recurrent GBM patients. Immunological variables were evaluated in tumor and immune cells as well as efficacy in glioma-bearing mice treated with DOX delivered by LIPU. These included measurement of HLA ABC and HLA DR protein expression by tumor cells, microglia, and macrophages and IFN-g production by glioma-associated microglia and macrophages in mouse and human tumors. We also assessed efficacy of LIPU/MB enhanced combination therapy in glioma-bearing mice. RESULTS Upregulation of HLA ABC and HLA DR was observed in GBM cell lines at low concentrations of DOX. Tumor cells from GBM patients treated with DOX, aPD-1 and LIPU/MB showed increased expression of HLA ABC and HLA DR compared to paired pretreatment samples. In both mice and humans, LIPU/MB liposomal DOX increased absolute brain drug concentrations and elicited a specific IFN-g phenotype and MHC I expression in glioma-associated microglia and macrophages in mice and humans. Furthermore, LIPU/MB-mediated BBB opening increased brain concentrations of aPD-1 in mice and in peritumoral regions of GBM patients. Combined treatment with liposomal DOX and aPD-1 delivered with LIPU/MB resulted in long-term survival of glioma-bearing mice that relied on the activity of CD8+ T cells for its efficacy. CONCLUSIONS Overall, this translational study demonstrates the utility of LIPU/MB to stimulate intracranial immune responses in the context of treatment with DOX and aPD-1 for gliomas.

DDDR-36. VAL-083 IN PATIENTS WITH RECURRENT GLIOBLASTOMA TREATED UNDER EXPANDED ACCESS PROGRAM

Abstract Current standard-of-care for glioblastoma (GBM) includes surgery followed by radiation with concurrent and adjuvant temozolomide. There are limited treatment options available upon progression or recurrence of disease. Options often involve participation in clinical trials with promising new therapies. However, patients may not meet the strictly defined entry criteria to participate in these clinical trials. Under an Expanded Access (EA) program, we have treated 14 recurrent GBM patients with VAL-083, they were not eligible to participate in other clinical trials. The median time from last progression to start of VAL-083 was 1.0 month (95%CI:0.09-2.67). All patients had received chemoradiation with temozolomide. Five (5/14;36%) patients had ≥ 2 recurrences, 8/14 (57%) had multifocal disease, and the median KPS was 80 (95%CI:70-90). All patients had unmethylated MGMT promoter, 13/14 (93%) were IDH-WT, 9/14 (64%) had a TERT promoter mutation, 6/14 (43%) had a PTEN mutation, and 4/14 (28%) had an EGFR mutation. All patients received treatment with VAL-083 at 30 mg/m2 x 3 days every 21 days. Five patients with cerebral edema refractory to steroids received bevacizumab (BEV;10 mg/kg) concurrently with VAL-083, and 8 patients received dexamethasone (Dex; >4 mg/day) with VAL-083. This is the first report of the use of VAL-083 in combination with BEV (VAL-03/BEV).The main adverse event was thrombocytopenia consistent with prior experience. Four (4/14; 28%) patients had a dose reduction, 3 of which were due to thrombocytopenia. No patients had a dose reduction while receiving VAL-083/BEV. Two patients who progressed on VAL-083, were later treated with CCNU, and myelosuppression was not observed.Median progression-free survival (mPFS) and median overall survival (mOS) from last progression were 5.7 months (95%CI:1.3-7.9) and 8.3 months (95%CI:3.0-14.3), respectively. Additional treatment, safety and outcome data will be presented at the meeting.Clinicaltrials.gov Identifier: NCT03138629. EA treatment plans were approved by MD Anderson Cancer Center IRB.

EXTH-65. SYNERGISTIC ONCOLYTIC EFFECTS OF TEMOZOLOMIDE AND ONCOMAGNETIC THERAPIES IN GLIOBLASTOMA

Abstract The noninvasive Oncomagnetic device developed in our laboratory selectively kills glioblastoma (GBM) and other cancer cells while sparing normal developing neurons and astrocytes in vitro. We have reported that brief 2 – 6 h of daily Oncomagnetic brain stimulation causes >30% reduction of contrast-enhanced tumor (CET) volume in an end-stage recurrent GBM patient after a ~30-day treatment. We have evidence that the spinning oscillating magnetic fields (sOMF) generated by this device disrupts electron transport in the mitochondrial respiratory chain, at least in part by inhibiting the activity of Complex II succinate dehydrogenase, leading to a marked increase in reactive oxygen species (ROS) and consequent cancer cell death. Here, we further studied the cellular effects of sOMF treatment alone and in combination with Temozolomide (TMZ) on GBM cell lines with other methods and investigated the response to Oncomagnetic monotherapy (OMT) in a mouse GBM model. We treated LN229 and U87 GBM cells with sOMF with and without a sub-therapeutic dose of TMZ. To study the anticancer effect of sOMF in vivo, we developed syngeneic GBM tumors in BALB/c mice by stereotactic intracranial injection of GL261WT cells. Our results show that cytotoxic effects of sOMF or TMZ alone, as measured by the MTT assay and reduced cell survival, are significantly potentiated by combining the two treatments. OMT of tumor-bearing mice using a whole-body sOMF stimulation method causes substantial retardation of tumor growth and reduction of the CET volume in 9.4 T MRI scans. To study the molecular pathways involved in the treatment response we are mapping alterations in various key biomarkers in treated tumor tissues and comparing them with those in untreated controls. These experiments will unravel the molecular mechanism of action underlying the response to OMT in GBM and help develop a sound rationale for an effective therapeutic protocol.

BIOM-39. P-ERK ASSOCIATION WITH OVERALL SURVIVAL IN RECURRENT GBM PATIENTS TREATED WITH INTRACEREBRAL ADMINISTRATION OF PD-1 AND CTLA-4 BLOCKING ANTIBODIES

Abstract INTRODUCTION Anti-PD-1 immunotherapy induces clinical responses in a subset of glioblastoma (GBM) patients. We previously reported that ERK1/2 phosphorylation (p-ERK) in pre-treatment tumor samples is predictive of overall survival (OS) following adjuvant anti-PD-1 therapy in two independent cohorts of recurrent GBM patients. METHODS Following the Remark criteria for biomarker validation, we investigated p-ERK as a predictive of OS in 24 evaluable tumor samples of recurrent GBM patients from a clinical trial. These patients underwent intracerebral administration of immune checkpoint inhibitors as part of a phase I clinical trial where intracerebral administration of ipilimumab (10 mg) or ipilimumab (5 mg) and nivolumab (10 mg) followed by postsurgical intravenous nivolumab (10 mg) was evaluated (NCT03233152; Duerinck J, et al. JITC, 2021). We quantified cell density of p-ERK+ cells in tumor regions. For exploratory purposes, patients were divided in 3 groups (n=8 per group) bases on p-ERK cell density. RESULTS We observed an incremental OS with high p-ERK GBM patients exhibiting a median OS of 81.6 weeks (95% CI 33.86-NA), intermediate p-ERK median OS of 43.1 weeks (95% CI 33.14-NA), and low p-ERK group with a median OS of 19.3 weeks (95% CI 16.14-NA). A Cox proportional hazards model adjusted for age and IDH mutant status showed a trend for p-ERK association with favorable OS (HR= 0.77, 95% CI 0.6-=1.01, P=0.056). CONCLUSIONS While the number of patients analyzed is relatively small, this study suggests the potential predictive power of p-ERK in an independent prospective GBM cohort treated with an alternative and unique administration approach of immune checkpoint blockade.

CTNI-35. PHASE 0/1 TRIAL OF MYCOPHENOLATE MOFETIL COMBINED WITH CHEMORADIATION TO OVERCOME TREATMENT RESISTANCE IN NEWLY DIAGNOSED AND RECURRENT GLIOBLASTOMA BY TARGETING PURINE METABOLISM

Abstract BACKGROUND Purine metabolism promotes glioblastoma growth, stemness, invasiveness, and treatment resistance. The purine synthesis inhibitor, mycophenolate mofetil (MMF), improves radiation and temozolomide efficacy in preclinical glioblastoma models. This phase 0/1 trial (NCT04477200) aims to determine the maximum-tolerated dose of MMF combined with chemoradiation in glioblastoma. It also aims to quantify the levels of the active metabolite of MMF and the extent of purine synthesis inhibition in enhancing and non-enhancing tumor tissue. METHODS Key eligibility criteria are age ≥ 18 and KPS ≥ 60%. TITE-CRM dose-escalation is used for MMF dosing starting at 1000mg PO BID (range 500-2000mg BID). Thirty recurrent glioblastoma patients receive MMF one-week prior to and concurrently with re-irradiation (40.5 Gy in 15 fractions), with 28 days of dose-limiting toxicity (DLT) period. Thirty newly diagnosed glioblastoma patients receive MMF one-week prior to and concurrently with standard radiation with concurrent temozolomide and followed for 28 days for DLT1-period, then MMF is given days 0-5 of each adjuvant cyclic temozolomide using a separate dose-escalation with the first two cycles as the DLT2-period. In phase 0, eight recurrent glioblastoma patients receive MMF 500-2000mg PO BID one-week pre-operatively and tissues are analyzed using mass spectrometry. RESULTS Eighteen phase 1 subjects (11 recurrent, 7 new) have received study treatment with no DLT to date up to MMF 2000mg BID. Main toxicities are mild nausea, fatigue, and elevated liver enzymes. No notable study-related hematotoxicity nor opportunistic infection have been observed. The active metabolite of MMF accumulated to active concentrations in enhancing and non-enhancing tumor tissue and appeared to inhibit purine synthesis. CONCLUSION MMF combined with chemoradiation has been reasonably well tolerated in glioblastoma patients with preliminary evidence of intracranial target engagement of its active metabolite. This study will yield a recommended phase 2 dose and preliminary efficacy estimate for future randomized phase 2/3 trial.

RBIO-03. A MULTI-INSTITUTIONAL EXPERIENCE OF GAMMATILE BRACHYTHERAPY AS TREATMENT FOR RECURRENT GLIOBLASTOMAS

Abstract BACKGROUND Recurrent glioblastoma remains a disease without established standard of care. Here, we report the safety profile and survival outcome of recurrent glioblastoma patients treated with maximal safe resection followed by intraoperative placement of GammaTile (GT), a collagen tile-embedded Cs-131 brachytherapy platform. METHODS The study included isocitrate Dehydrogenase (IDH) wild-type glioblastoma patients who suffered tissue confirmed recurrence after concurrent temozolomide-radiation therapy. The series included consecutively patients treated at the University of Minnesota, Barrow Neurological Institute, Vidant Health, and Emory University Hospital. Survival results were stratified by methyl-guanine methyl transferase (MGMT) promoter methylation status RESULTS In total 48 patients were treated between 2019 and 2022 in this multi-institutional experience. The median days of hospitalization following the procedure was two (range: 1-15), with 72.5% of the GT implanted patients discharged home before postoperative day three. In terms of post-operative course, two patients suffered new-onset seizure post-surgery (4.0%). There was one (2%) 30-day mortality from intracranial hemorrhage secondary to heparinization for an ischemic limb. There were 13% readmission within 30 days, including hydrocephalus (n=2), urinary tract infection (n=1), deep venous thrombosis (n=1), failure to thrive (n=1), and infected wound (n=1). Of note, the patient with the infected wound had suffered a previous wound infection prior to the GT implantation and the pathogenic organism for both infections were the same (S. aureus). With a median follow-up of 250 days, twelve-month local control was 82%. Median overall survival (OS) from the time of diagnosis was 19 and 33 months for the MGMT unmethylated and methylated tumors, respectively. Select patients (n = 6) treated with adjuvant ketogenic diet in addition to GT and subsequent chemotherapy exhibited survival beyond expectation (> 14 mo, median survival not reached). CONCLUSION This multi-institutional experience supports further investigation of GT brachytherapy as a treatment for recurrent glioblastomas.

NIMG-34. QUANTIFICATION OF GLYCOLYTIC FLUX REDUCTION IN RECURRENT GLIOBLASTOMA AFTER EGFR INHIBITION USING MOLECULAR MR-PET

Abstract In recently published work, we demonstrated that acute inhibition of the EGFR – the most frequently altered oncogene in GBM – can rapidly reduce glycolysis in a subset of GBM. To quantify this effect, we propose a new combination metabolic MR-PET imaging biomarker that combines 18F-FDG PET, DSC perfusion MRI, diffusion MRI, and pH- and oxygen-sensitive amine CEST-SAGE-EPI. Specifically, this “glycolytic index” or GI, can be defined as elevated glucose uptake (18F-FDG standard uptake value), elevated tumor acidity (MTRasym@3ppm), and lower oxygen utilization (relative cerebral metabolic rate of oxygen, rCMRO2, defined as R2’ x rCBF/rCBV from oxygen-sensitive SAGE-EPI and DSC perfusion), normalized to cell density (using ADC from diffusion MRI). In the current study, we explored the use of Tagrisso® (Osimertinib or AZD9291), which has very high brain to plasma ratios (> 1) and has proven effective in CNS metastasis of EGFR mutant lung cancer, as a potential treatment for EGFR amplified recurrent GBM. We have conducted a clinical trial (NCT03732352) to determine whether we observe similar metabolic imaging changes in EGFR mutated or amplified recurrent glioblastoma patients after treatment with osimertinib. Consistent with prior in vitro and in vivo results, treated patients exhibited a reduced glycolytic flux as indicated by reduction in 18F-FDG PET uptake (-3% change in SUV), tumor acidity (-19% change in MTRasym@3ppm) on pH-weighted CEST MRI, and glycolytic index (GI) (-25% change) in EGFR amplified recurrent GBM within 24 hours of treatment. Preliminary data suggests early change in GI correlates with and predicts both PFS (Pearson correlation, R2=0.3463, P=0.0441; Log-rank, P=0.0467) and OS (R2=0.6368, P=0.0019; Log-rank, P=0.0192). These preliminary data establish the scientific premise that a “glycolytic index” created using 18F-FDG PET, DSC perfusion, diffusion MRI, and pH- and oxygen-weighted amine CEST-SAGE-EPI may be an important tool for quantifying and visualizing glycolytic flux in GBM.

Study protocol of the GLOW study: maximising treatment options for recurrent glioblastoma patients by whole genome sequencing-based diagnostics—a prospective multicenter cohort study

BackgroundGlioblastoma (GBM), the most common glial primary brain tumour, is without exception lethal. Every year approximately 600 patients are diagnosed with this heterogeneous disease in The Netherlands. Despite neurosurgery, chemo -and radiation therapy, these tumours inevitably recur. Currently, there is no gold standard at time of recurrence and treatment options are limited. Unfortunately, the results of dedicated trials with new drugs have been very disappointing. The goal of the project is to obtain the evidence for changing standard of care (SOC) procedures to include whole genome sequencing (WGS) and consequently adapt care guidelines for this specific patient group with very poor prognosis by offering optimal and timely benefit from novel therapies, even in the absence of traditional registration trials for this small volume cancer indication.MethodsThe GLOW study is a prospective diagnostic cohort study executed through collaboration of the Hartwig Medical Foundation (Hartwig, a non-profit organisation) and twelve Dutch centers that perform neurosurgery and/or treat GBM patients. A total of 200 patients with a first recurrence of a glioblastoma will be included. Dual primary endpoint is the percentage of patients who receive targeted therapy based on the WGS report and overall survival. Secondary endpoints include WGS report success rate and number of targeted treatments available based on WGS reports and number of patients starting a treatment in presence of an actionable variant. At recurrence, study participants will undergo SOC neurosurgical resection. Tumour material will then, together with a blood sample, be sent to Hartwig where it will be analysed by WGS. A diagnostic report with therapy guidance, including potential matching off-label drugs and available clinical trials will then be sent back to the treating physician for discussing of the results in molecular tumour boards and targeted treatment decision making.DiscussionThe GLOW study aims to provide the scientific evidence for changing the SOC diagnostics for patients with a recurrent glioblastoma by investigating complete genome diagnostics to maximize treatment options for this patient group.Trial registration: ClinicalTrials.gov Identifier: NCT05186064.