Concomitant Temozolomide Research Articles

SURG-08. A PHASE III RANDOMIZED TRIAL OF GROSS TOTAL RESECTION VERSUS POSSIBLE RESECTION OF FLAIR HYPERINTENSITY LESION ON MR IMAGE FOR NEWLY DIAGNOSED SUPRATENTORIAL GLIOBLASTOMA (JCOG2209)

Abstract BACKGROUND Complete resection of contrast-enhanced lesion (gross total resection: GTR) without severe neurological deficits has been generally accepted as the goal of surgery. However, it remains unclear if additional resection of surrounding FLAIR hyper-intense lesion combined with GTR (FLAIRectomy) has survival advantage of primary glioblastoma patients. Purpose: Multicenter, open-label, randomized phase III trial was commenced to confirm the superiority of FLAIRectomy to GTR alone followed by radiotherapy with concomitant and adjuvant temozolomide in terms of overall survival (OS) for primary glioblastoma IDH-wildtype patients. This trial investigates not only survival but also postoperative neurological and neurocognitive deficits in detail. METHODS We assumed a 2-year OS of 50% in the GTR arm and expected a 15% improvement in the FLAIRectomy arm. A total of 130 patients is required with a one-sided alpha of 5%, power of 70%, and will be accrued from 49 Japanese institutions in 4 years and follow-up will last 2.5 years. Patients 18-75 years of age will be registered and randomly assigned to each arm with 1:1 allocation. The primary endpoint is OS, and the secondary endpoints are progression-free survival, frequency of adverse events, proportion of Karnofsky performance status preservation, proportion of National Institutes of Health stroke scale preservation, proportion of mini-mental state examination preservation and proportion of health-related quality of life preservation. The Japan Clinical Oncology Group Protocol Review Committee approved this study protocol in May 2023. Ethics approval was granted by the National Cancer Center Hospital Certified Review Board. Patient enrollment began in July 2023. DISCUSSION If FLAIRectomy is superior to GTR alone, aggressive surgery will become a standard surgical treatment for glioblastoma with resectable contrast-enhanced lesion. Trial registration: Registry number: jRCT1031230245. Date of registration: 19/July/2023. Date of first participant enrollment: 28/July/2023. Funding for this study is provided by National Cancer Center Research and Development Fund (2023-J-03).

CTIM-16. SAFETY AND PRELIMINARY EFFICACY OF AZD1390 + RADIATION THERAPY FOR GLIOBLASTOMA

Abstract BACKGROUND Glioblastoma is an aggressive cancer; intensity-modulated radiation therapy (IMRT) with concomitant and adjuvant temozolomide is the first-line standard of care. AZD1390, an ataxia telangiectasia mutated kinase inhibitor, aims to augment the efficacy of IMRT without exacerbating neurotoxicity. AZD1390 is optimized for blood–brain barrier penetration, confirmed in healthy volunteers (NCT03215381) and patients with glioblastoma (Phase 0; NCT05182905). This Phase 1, open-label study (NCT03423628) evaluated safety and efficacy of AZD1390 and IMRT in patients with glioblastoma. METHODS Adult patients received escalating once-daily AZD1390 doses with IMRT 35 Gy in 10 fractions over 2 weeks (Arm A, recurrent glioblastoma) or IMRT 60 Gy in 30 fractions over 6 weeks (Arm C, newly-diagnosed O-6-methylguanine-DNA methyltransferase unmethylated glioblastoma). Patients received 2 additional weeks of adjuvant AZD1390 post-IMRT. Primary objective was safety; secondary objectives included efficacy and pharmacokinetics. RESULTS As of Feb 6, 2024, 115 patients (Arm A=75; Arm C=40) received AZD1390 10–900 mg/day. Pharmacokinetics were linear, with a slightly more-than dose-proportional increase and mean elimination half-life ~9–11 hours. Most patients had ≥1 treatment-emergent adverse event (AE), most commonly fatigue (51.3%), nausea (39.1%) and headache (38.3%). Grade ≥3 AZD1390-related AEs occurred in 18/115 patients. The maximum tolerated dose was 400 mg (Arm A) and 300 mg (Arm C). Dose-limiting toxicities included creatinine kinase elevation (Arm A) and radiation skin injury (Arm C). AEs led to AZD1390 discontinuation in 15/115 patients. Safety profiles were mostly consistent across Arms despite different radiation schedules. At target-engaging doses, median overall survival was 12.7 months (95% CI: 10.7–18.9; Arm A) and still maturing (Arm C). CONCLUSIONS Concurrent AZD1390 and IMRT demonstrated manageable safety at doses with known target engagement. Preliminary efficacy is encouraging (Arm A). AZD1390 can potentially act as a radiosensitizer for glioblastoma treatment. Clinical investigation is ongoing.

CTIM-08. FIRST IN HUMAN STUDY OF THE MRNA-BASED CANCER VACCINE CVGBM IN PATIENTS (PTS) WITH NEWLY-DIAGNOSED AND SURGICALLY RESECTED MGMT-UNMETHYLATED GLIOBLASTOMA (GBM): FIRST RESULTS FROM THE DOSE ESCALATION PHASE

Abstract INTRODUCTION CVGBM is an investigational therapeutic mRNA-based vaccine encoding 8 epitopes derived from tumor associated antigens with potential relevance in GBM. This is an ongoing, first-in-human study evaluating the safety of CVGBM in pts with newly-diagnosed MGMT-unmethylated GBM. METHODS HLA-A*02:01-positive pts with newly-diagnosed MGMT-unmethylated GBM (CNS WHO Grade [Gr] 4) who had a gross total or partial resection and completed radiotherapy ± concomitant temozolomide received CVGBM on Days 1, 8, 15, 29, 43, 57 and 71 + 6 optional doses at 6-week intervals. Primary endpoints are safety, tolerability and dose-limiting toxicities (DLTs). Immunogenicity is an exploratory endpoint. RESULTS As of 29/2/2024, 16 pts were enrolled in the dose-escalation part (Part A); 3 each in DL 1 (12 µg), DL 2 (25 µg), and DL 3 (50 µg), and 7 in DL 4 (100 µg). For all cohorts, mean time on study from 1st dose to last visit was 4.5 months (min: 1.5; max: 8). 109 doses were administered (mean: 6.8 doses per pt). All pts completed the 2-week DLT evaluation period without DLTs. Of 156 treatment-emergent adverse events (TEAEs), the majority (73%) were CTCAE Gr 1 (21% Gr 2, 6% Gr 3). The most common related TEAEs were chills (n=13), pyrexia (n=12), headache (n=12), fatigue (n=11) and malaise (n=5), mostly of mild to moderate severity. 7 pts had 9 ≥ Gr 3 AEs assessed as potentially related to CVGBM by the investigators outside the DLT period (cerebral edema [n=2], leukoencephalopathy, pseudoprogression with cerebral edema, structural epilepsy, ataxia, hypertension, malaise and fever [1 of each]), evenly distributed across cohorts. First immunogenicity data are planned to be presented. CONCLUSIONS CVGBM was generally well tolerated with an acceptable safety profile. The highest tolerated dose was not reached. Based on all available safety data, the selected dose for trial expansion was 100 µg. Previously presented at ESMO 2024, “FPN (Final Publication Number): 4400, Ghazaleh Tabatabai et al. - Reused with permission.

NCOG-50. LONG TERM-SURVIVAL OF AN ELDERLY PATIENT WITH GIANT CELL CEREBELLUM GLIOBLASTOMA (GBM)

Abstract INTRODUCTION Primary cerebellar glioblastoma (GBM) in adult is very rare and accounts for 1% of all GBM. Giant cell variant cerebellar GBM is even rarer. Because of the rarity, its molecular feature, the response to the standard treatment, and biological behavior of tumor progression are not well understood. CASE REPORT An 80 yo male presented with headache, nausea, vomiting and ataxia in 2019. Brain MRI was notable for a large enhancing cerebellar mass. Surgical resection was completed, and pathology was giant cell GBM. Molecular studies showed IDH-wildtype, CDKN2A/B copy number loss, positive TP53 G262V mutation as well as KIT and KDR amplification. The patient underwent standard 6-week concomitant temozolomide (TMZ) and radiation therapy. He only completed 3 cycles of low dose adjuvant temozolomide and two cycles of lomustine due to intolerance of both chemotherapy agents. After that the patient has been off treatment and received brain MRI surveillance over past 4 years. Two years later, his brain MRI showed new punctuate lesions in the radiation field. Suspecting the radiation necrosis; the patient underwent observation. Later, more nodular enhancing lesions developed at the outside region of the radiation field. Tumor progression was considered but the patient wished no biopsy or re-radiation. The new small nodular lesions on MRIs over past two years have behaved unusually with small fluctuations among mild progression, stabilization, or regression. His physical functions have been preserved with a Karnofsky Performance Status scale of 90% with normal cognition. DISCUSSION The patient, who is now 85 years old, has surpassed a 4.5-year survival mark, which is remarkable compared to the supratentorial and the cerebellar GBM with a few months’ survival mark in elderly patients. Our experience emphasizes the different behavior (good response) of a very rare giant cell cerebellar GBM to the standard treatment for newly diagnosed GBM.

PATH-31. COMPLETE TUMOR DISAPPEARANCE ON BRAIN MRI AFTER STANDARD CHEMORADIATION THERAPY FOR A MOLECULAR GLIOBLASTOMA

Abstract INTRODUCTION Glioblastoma (GBM) is the most aggressive brain tumor. The WHO CNS5 classification has newly incorporated three molecular criteria in diagnosing molecular GBM, including a concurrent gain of chromosome 7 and loss of chromosome 10 (+7/-10), TERT promoter mutation, or EGFR amplification. Despite new classification, the Stupp protocol remains the standard of care for all GBMs. However, it is unclear if the treatment response of the molecular GBM with low grade features is the same as the limited response of the traditional histopathological GBM. CASE REPORT A 74-year-old male presented in August of 2023 with new onset left-sided facial numbness. The numbness resolved spontaneously that day. Brain MRI was notable for a diffuse left frontal T2/Flair hyperintense lesion extending across the corpus callosum into the right frontal lobe without definite enhancement. Brain biopsy from 8 sites of the tumor demonstrated a subset of areas with mild hyper-cellularity, suggesting a low-density infiltrating glioma. However, TERT promoter mutation (-124C>T), was detected along with wild-type IDH1, supporting molecular GBM. Studies also found unmethylated MGMT gene promotor. Brain MRIs after 3 and 6 months showed no tumor progression. The patient has remained asymptomatic apart from baseline mild forgetfulness. He was started on the 6-week standard concomitant temozolomide and radiation therapy. Follow-up brain MRI after the above treatment showed complete imaging resolution of the tumor. DISCUSSION It is very rare for complete imaging resolution of GBM on brain MRI after standard 6-week chemoradiation therapy. Our case suggests that molecular GBM with low-grade features on imagine and pathology might have a better response to the standard treatment than traditional histopathological GBM even though the molecular GBM patient has unfavorable prognostic factors such as unmethylated MGMT and older age (>70 years old). Our experience emphasizes the heterogenous response of molecular GBM to the current standard treatment.

Efficacy of Adding Veliparib to Temozolomide for Patients With MGMT-Methylated Glioblastoma

The prognosis for patients with glioblastoma is poor following standard therapy with surgical resection, radiation, temozolomide, and tumor-treating fields. To evaluate the combination of veliparib and temozolomide in glioblastoma based on preclinical data demonstrating significant chemosensitizing effects of the polyadenosine diphosphate-ribose polymerase 1/2 inhibitor veliparib when combined with temozolomide. Patients with newly diagnosed glioblastoma with MGMT promoter hypermethylation who had completed concomitant radiation and temozolomide were enrolled between December 15, 2014, and December 15, 2018, in this Alliance for Clinical Trials in Oncology trial. The data for this analysis were locked on April 21, 2023. Patients were randomized and treated with standard adjuvant temozolomide (150-200 mg/m2 orally, days 1-5) combined with either placebo or veliparib (40 mg orally, twice daily, days 1-7) for 6 cycles. The primary end point for the phase 3 portion of the trial was overall survival (OS). There were 322 patients randomized during the phase 2 accrual period and an additional 125 patients randomized to complete the phase 3 accrual, for a total of 447 patients in the final phase 3 analysis. The median (range) age for patients was 60 (20-85) years and 190 patients (42.5%) were female. The median OS was 24.8 months (90% CI, 22.6-27.7) for the placebo arm and 28.1 months (90% CI, 24.3-33.3) for the veliparib arm (P = .17). The difference in survival did not meet the prespecified efficacy end point. However, there was a separation of the survival curves that favored the veliparib arm over 24 to 48 months of follow-up. The experimental combination was well tolerated with an acceptable elevation in grade 3 or 4 hematologic toxic effects. This trial found that adding veliparib to adjuvant temozolomide did not significantly extend OS in patients with newly diagnosed, MGMT-hypermethylated glioblastoma. ClinicalTrials.gov Identifier: NCT02152982.

Temozolomide Therapy in Management of Refractory Pituitary Adenomas: A Case Series of 39 Patients

ObjectiveThe management of refractory pituitary adenomas (RPAs) presents significant challenges. This study aimed to evaluate the long-term treatment outcomes of patients with RPA managed with temozolomide (TMZ) and to identify potential biomarkers for predicting TMZ treatment response. MethodsThis retrospective case series included patients with RPA who underwent trans-sphenoidal surgery (TSS) or craniotomy at a comprehensive medical center in China between January 2014 and December 2021. Results39 patients with RPA (median age 42 years; 23 males [59%]) were treated with TMZ for a median of 9 cycles. The median follow-up was 34.4 months. Complete response (CR) was observed in 2 patients, partial response (PR) in 11 patients, stable disease (SD) in 9, progressive disease (PD) in 11, and death in 6 patients. O6-methylguanine DNA methyltransferase levels were significantly lower in patients with CR, PR, or SD compared to those with PD or mortality, with mean values of 24.2% and 58.1, respectively. MutS homologs 6 levels were significantly higher in patients with CR, PR, or SD compared to those with PD or mortality, with mean values of 64.2% and 36.9%, respectively. Patients who received concomitant TMZ and external beam radiotherapy showed a significant tumor size reduction of 178,837 mm3 (P < .001) compared to those treated with TMZ alone. ConclusionsTMZ demonstrates promising efficacy in eliciting tumor responses in patients with PRA. O6-methylguanine DNA methyltransferase and MutS homologs 6 have emerged as potential biomarkers for predicting treatment response. Furthermore, radiation with concurrent TMZ may significantly improve outcomes in patients with RPA.

AB012. A phase III randomized trial of gross total resection versus possible resection of fluid-attenuated inversion recovery (FLAIR) hyperintensity lesion on magnetic resonance image for newly diagnosed supratentorial glioblastoma (JCOG2209).

Complete resection of contrast-enhanced lesions [gross total resection (GTR)] without severe neurological deficits has been generally accepted as the goal of surgery. However, it remains unclear if additional resection of surrounding fluid-attenuated inversion recovery (FLAIR) hyper-intense lesions combined with GTR (FLAIRectomy) has survival advantage of primary glioblastoma patients. Multicenter, open-label, randomized phase III trial was commenced to confirm the superiority of FLAIRectomy to GTR alone followed by radiotherapy with concomitant and adjuvant temozolomide in terms of overall survival (OS) for primary glioblastoma IDH-wildtype patients. This trial investigates not only survival but also postoperative neurological and neurocognitive deficits in detail. We assumed a 2-year OS of 50% in the GTR arm and expected a 15% improvement in the FLAIRectomy arm. A total of 130 patients is required with a one-sided alpha of 5%, power of 70%, and will be accrued from 49 Japanese institutions in 4 years and follow-up will last 2.5 years. Patients aged 18-75 years will be registered and randomly assigned to each arm with 1:1 allocation. The primary endpoint is OS, and the secondary endpoints are progression-free survival, frequency of adverse events, proportion of Karnofsky performance status preservation, proportion of National Institutes of Health stroke scale preservation, proportion of mini-mental state examination preservation and proportion of health-related quality of life preservation. The Japan Clinical Oncology Group Protocol Review Committee approved this study protocol in May 2023. Ethics approval was granted by the National Cancer Center Hospital Certified Review Board. Patient enrollment began in July 2023. If FLAIRectomy is superior to GTR alone, aggressive surgery will become a standard surgical treatment for glioblastoma with resectable contrast-enhanced lesion. Registry number: jRCT1031230245. Date of registration: 19/July/2023. Date of first participant enrollment: 28/July/2023.

Global post‑marketing safety surveillance of Tumor Treating Fields (TTFields) therapy in over 25,000 patients with CNS malignancies treated between 2011–2022

BackgroundTumor Treating Fields (TTFields) are alternating electric fields that disrupt cancer cell processes. TTFields therapy is approved for recurrent glioblastoma (rGBM), and newly-diagnosed (nd) GBM (with concomitant temozolomide for ndGBM; US), and for grade IV glioma (EU). We present an updated global, post-marketing surveillance safety analysis of patients with CNS malignancies treated with TTFields therapy.MethodsSafety data were collected from routine post-marketing activities for patients in North America, Europe, Israel, and Japan (October 2011–October 2022). Adverse events (AEs) were stratified by age, sex, and diagnosis.ResultsOverall, 25,898 patients were included (diagnoses: ndGBM [68%], rGBM [26%], anaplastic astrocytoma/oligodendroglioma [4%], other CNS malignancies [2%]). Median (range) age was 59 (3–103) years; 66% patients were male. Most (69%) patients were 18–65 years; 0.4% were < 18 years; 30% were > 65 years. All-cause and TTFields-related AEs occurred in 18,798 (73%) and 14,599 (56%) patients, respectively. Most common treatment-related AEs were beneath-array skin reactions (43%), electric sensation (tingling; 14%), and heat sensation (warmth; 12%). Treatment-related skin reactions were comparable in pediatric (39%), adult (42%), and elderly (45%) groups, and in males (41%) and females (46%); and similar across diagnostic subgroups (ndGBM, 46%; rGBM, 34%; anaplastic astrocytoma/oligodendroglioma, 42%; other, 40%). No TTFields-related systemic AEs were reported.ConclusionsThis long-term, real-world analysis of > 25,000 patients demonstrated good tolerability of TTFields in patients with CNS malignancies. Most therapy-related AEs were manageable localized, non-serious skin events. The TTFields therapy safety profile remained consistent across subgroups (age, sex, and diagnosis), indicative of its broad applicability.

HRQoL in patients with GBM: The impact of tumor treating fields.

e24049 Background: Glioblastoma (GBM) is the most common malignant glioma with a dismal prognosis. Patients experience a range of progressively worsening symptoms, including headaches, nausea, seizures, and cognitive deficits throughout their disease course. Initial treatment for newly diagnosed patients consists of maximal safe surgical resection followed by fractionated radiation treatment with concomitant temozolomide. Presently, there are two approved adjuvant treatment modalities following chemoradiation: temozolomide and tumor-treating fields (TTFields). In this poster, we explore the impact of TTFields on the quality of life, assessed through health-related quality of life (HRQoL), in patients with GBM. Methods: Using PubMed, Medline-indexed articles were collected using this structured query: Glioblastoma[MeSH] AND (("Electric Stimulation Therapy*"[MeSH]) OR ("Transcranial Direct Current Stimulation*"[MeSH]) OR "Tumor Treating Fields" OR "TTF") NOT "RAT" This yielded 233 results before the search date (2023). Collected sources were uploaded to Covidence to allow for multi-reviewer screening, review, and extraction. For completeness, limited forward and back citations using the ResearchRabbit tool and limited addition of non-Medline indexed articles via unstructured query yielded four additional results. Sources were filtered by study type and included/excluded based on accessibility, sample population, design, outcome measures, and interventions. Five randomized control studies remained. From this subset, bias, effect size, I2-index, and forest analysis with random effect model estimation were calculated. Results: Data analysis showed that TTFields therapy has demonstrated associations with increased progression-free survival and enhanced overall survival rates without negative effects on HRQoL. Some patients have reported improvement in mobility, self-care, and carrying out regular activities. One notable side effect observed in these patients was increased skin itchiness, which was expected due to the use of transducer arrays. Conclusions: This project identified a research gap in standardizing the assessment of quality of life in patients treated with TTFields. A significant limitation in research on TTFields is an overall lack of HRQoL data, often due to patients failing to follow-up with surveys. Future research should prioritize patient follow-up to obtain more comprehensive and precise longitudinal data on HRQoL while considering disease and treatment characteristics.

Alterations of the tumor microenvironment (TME) in recurrent glioblastoma following apatinib in combination with temozolomide.

e14018 Background: Glioblastoma (GBM) is the highly malignant primary central nervous system tumor. The standard treatment for glioblastoma is maximal surgical resection followed by concomitant radiotherapy and temozolomide chemotherapy, but patient’s survival still remains poor. At present, apatinib in combination with temozolomide (TMZ) has achieved reasonable clinical efficacy in the treatment of recurrent glioblastoma (rGBM), however, there are currently no clear biomarkers related to clinical efficacy or prognosis. Methods: This retrospective study was enrolled 22 rGBMs treated with apatinib in combination with TMZ and 6 patients who received standard radiotherapy combined with TMZ and experienced recurrence. At the same time, we collected their tissue samples for RNA transcriptome analysis by the Nanostring nCounter platform. In prognosis analysis, long survival benefit is defined as a PFS≥4.2 months, and short survival benefit is defined as a PFS&lt;4.2 months. This PFS threshold was primarily referenced from a Phase III study of bevacizumab combined with chemotherapy for rGBM. The study was approved by the institutional ethics committee of Sanbo Brain Hospital, Capital Medical University (SBNK-YJ-2021-010-02) and informed consent was also obtained from the patients. Results: The differential gene of pre and post standard chemoradiotherapy results suggest that standard treatment has reduced the expression of genes associated with tumor proliferation and up-regulated the expression of the genes associated with the immune response in rGBM. In apatinib combined TMZ patients, compared to the non-response group, the response group had significantly up-regulated expression of genes related to endothelial cells and apoptosis. Enrichment analysis revealed that signaling pathways related to cell proliferation were down-regulated in the response group. In terms of prognosis, compared with the short-survival benefit group (&lt; 4.2 months), four tumor progression-associated genes were down-regulated in response group (≥4.2 months). Hypoxia related-genes was significantly up-regulated in the long survival benefit group. Enrichment analysis showed that genes related to cell proliferation were also down-regulated in the long-survival benefit group, while the expression of signaling pathway genes related to cell activation, and immune response was significantly up-regulated. Conclusions: Our study suggests that the combination of apatinib and TMZ may potentially provide clinical benefits in treating rGBM by modulating genes associated with cell proliferation, promoting apoptosis, regulating hypoxia, and enhancing immune response within the tumor microenvironment. Clinical trial information: NCT04814329 .

Diffuse midline gliomas in children: Does changing strategies change results?

10045 Background: The prognosis of children with diffuse intrinsic pontine gliomas (DIPG)/diffuse midline glioma (DMG) is dismal. Radiotherapy (RT) is considered the standard of treatment. We previously published results of our center, where patients receiving temozolomide or other chemotherapy after radiotherapy (RT) had a better survival than those receiving RT alone (1). This study aims to evaluate a larger cohort of children with DMG in a single center. Methods: We retrospectively reviewed demographic, clinical characteristics and treatment outcome of children with DMG diagnosed and treated at Istanbul University, Oncology Institute between Feb1999-Feb 2023. We compared the groups that received only radiotherapy (Group 1, only RT, n=19), the ones that received RT with concomitant and adjuvant temozolomide po (Group 2-n= 38 TMZ 75 mg/m2/day for 6 weeks concomitant (c.) with RT, followed by TMZ (200 mg/m2/day) for 5 days every 28 days until progression or for 12 cycles), and the ones that received RT with c. TMZ, followed by other systemic agents (Group 3 n= 18 RT c.TMZ, followed by nimotuzumab containing regimens; Group 4 the rest 26 received other agents such as bevacizumab, CCNU, ONC201 and other). The ones that progressed on group 2, received nimotuzumab containing or other regimens. Results: 114 children (49 female, 65 male) with a mean age of 7± 4 years (6 months-16 years) were analyzed. The most frequent clinical findings were ataxia, strabismus and motor weakness. 108 had diffuse intrinsic pontine gliomas (DIPG). In total 106 patients received RT, 54-60 Gy to the tumor site. The overall survival (OS) in all patients at 2 years, 3 years and 5 years were 25.6%,15% and 11.5% respectively. The 2 years, 3 years and 5 years OS in group1 were 0.79%, 0% ,0% respectively; in group 2 they were 38.4%, 27.9%, 16%respectively ; in group 3 they were 17.6% , 0 % ,0% respectively, in Group 4 they were 10.3%, 0.34%, 0% respectively, The OS in Group 2 or3 or 4 were significantly higher than group 1 (only RT) (P =0.002, p=0.004, p&lt;0.001,respectively). There was no major side effect due to TMZ, nor nimotuzumab. Seven patients were re-irradiated at progression. The number of patients undergoing biopsies and molecular testing increased to 50% of the patients after 2016 versus only in two patients previously. Conclusions: In our series, the overall survival was significantly superior in patients who received RT with concurrent and adjuvant temozolomide and/or adjuvant nimotuzumab containing regimens or other adjuvant systemic treatment in comparison to patients that received RT alone, suggesting that adding systemic treatment after RT (poTMZ or iv nimotuzumab containing regimens or other) may help extend survival. Oral temozolomide may be easier to use as first line treatment after radiotherapy especially in resource limited settings, switching to nimotuzumab containing or other chemotherapy and/or re-radiotherapy at progression. 1. Kebudi R, 2013.

Personalized neoantigen-pulsed autologous dendritic cells vaccine as an adjuvant treatment for patients with newly-diagnosed glioblastoma multiforme: A phase I trial.

e14025 Background: Glioblastoma Multiforme (GBM) is the most common and aggressive primary brain malignancy in adults. We herein report a phase I trial using personalized neoantigen-pulsed autologous dendritic cells (nDC) vaccine as an adjuvant treatment for patients with newly-diagnosed GBM. Methods: It is a single-center, single-arm phase I trial, enrolling patients aged 18-75 years old, with newly-diagnosed GBM and tumor resection extent ≥90%. Tumor specimens were sequenced for identification of personalized neoantigens. A total of 3-10 neoantigen peptides were loaded into DC to generate the nDC vaccine. The vaccine was administered subcutaneously for 5-6 doses at 1×10^7 cells following concomitant radiotherapy plus temozolomide. The primary objective is safety. Secondary objectives include survival outcomes and T cell immune response against the neoantigens. Results: As of Dec. 31, 2023, eleven patients completed at least one dose of vaccination and were included in the safety analysis; eight patients completed planned doses and were included in the efficacy analysis. All the patients reported Treatment-emergent adverse events (TEAEs). Most TEAEs were grade 1 or 2. One patient reported two grade 3 TEAEs: decreased white blood cell count and decreased lymphocyte count. Pyrexia was considered as treatment-related adverse event (TRAE) that was reported in two (18.2%) patients. No treatment-related deaths occurred. Among eight efficacy-assessable patients, seven (87.5%) patients kept progression-free for at least 5.4-27.3 months; one patient progressed at 10.2 months after surgery and achieved complete remission after receiving anti-PD1 plus bevacizumab therapy; compared to the baseline level, a median 15-fold (3 to 506-fold) increase of neoantigen-specific cytotoxic T cells was detected in their peripheral blood samples post-vaccination, indicating strong anti-tumor T cell responses elicited by the nDC vaccine. Conclusions: The nDC vaccine, combined with the standard treatments for GBM, was well tolerated. Initial results from this ongoing study have exhibited encouraging survival outcome of the nDC vaccine for patients with newly-diagnosed GBMs. Clinical trial information: NCT04968366 . [Table: see text]

MGMT inhibition regulates radioresponse in GBM, GSC, and melanoma

Radiotherapy is the standard treatment for glioblastoma (GBM), but the overall survival rate for radiotherapy treated GBM patients is poor. The use of adjuvant and concomitant temozolomide (TMZ) improves the outcome; however, the effectiveness of this treatment varies according to MGMT levels. Herein, we evaluated whether MGMT expression affected the radioresponse of human GBM, GBM stem-like cells (GSCs), and melanoma. Our results indicated a correlation between MGMT promoter methylation status and MGMT expression. MGMT-producing cell lines ACPK1, GBMJ1, A375, and MM415 displayed enhanced radiosensitivity when MGMT was silenced using siRNA or when inhibited by lomeguatrib, whereas the OSU61, NSC11, WM852, and WM266-4 cell lines, which do not normally produce MGMT, displayed reduced radiosensitivity when MGMT was overexpressed. Mechanistically lomeguatrib prolonged radiation-induced γH2AX retention in MGMT-producing cells without specific cell cycle changes, suggesting that lomeguatrib-induced radiosensitization in these cells is due to radiation-induced DNA double-stranded break (DSB) repair inhibition. The DNA-DSB repair inhibition resulted in cell death via mitotic catastrophe in MGMT-producing cells. Overall, our results demonstrate that MGMT expression regulates radioresponse in GBM, GSC, and melanoma, implying a role for MGMT as a target for radiosensitization.

Abstract 1144: Glioblastoma cells increase expression of neurodevelopmental programs and synaptic connectivity in the tumor periphery

Abstract Glioblastoma remains one of the deadliest brain malignancies. First-line therapy consists of maximal surgical tumor resection, accompanied by concomitant and adjuvant temozolomide chemotherapy and radiotherapy. Malignant cells escape surgical resection by migrating into the brain parenchyma, where they give rise to the recurrent tumor. Based on gene expression, the tumor core can be subtyped into mesenchymal, proneural and classical areas, each being associated with differences in genetic alterations and cellular composition. In contrast, the tumor periphery where migrating tumor cells infiltrate brain parenchyma is less characterized in patients. Using spatial transcriptomics (n = 11), we show that specific malignant states colocalize in tumor core areas with necrosis and microvascular proliferation. Malignant cells within proneural or mesenchymal subtyped cores displayed, as expected, many differences in genetic expression, although such differences disappeared in the tumor periphery. Malignant cells residing in the tumor periphery had increased expression of genes related to neurodevelopmental pathways and synaptic connectivity. Our findings show similarities in cellular states across tumor subtypes with implications for post-operative treatment and provide an updated view of the spatial landscape of glioblastomas. Citation Format: Dylan Harwood, Vilde Pedersen, Nicolai S. Bager, Ane Y. Schmidt, Tobias O. Stannius, Ausrine Areskeviciute, Knud Josefsen, Dorte S. Nørøxe, David Scheie, Hannah E. Rostalski, Ulrik Lassen, Frederik O. Bagger, Joachim Weischenfeldt, Dieter H. Heiland, Kristoffer Vitting-Seerup, Signe R. Michaelsen, Bjarne W. Kristensen. Glioblastoma cells increase expression of neurodevelopmental programs and synaptic connectivity in the tumor periphery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1144.

Abstract 5905: Propentofylline enhances GBM sensitivity to temozolomide via targeting TROY signaling

Abstract Glioblastoma (GBM) is a high grade glioma that accounts for the majority of primary malignant brain tumors. The standard of care for GBM consists of maximal surgical resection, concurrent radiation and temozolomide (TMZ), and adjuvant TMZ. However, this has only led to a modest increase in median patient survival. TROY (TNFRSF19) is an orphan member of the TNF receptor superfamily that is differentially upregulated in GBM with low expression in normal brain tissue. Previously, we have reported that TROY is overexpressed in GBM and signals to mediate cell invasion and therapeutic resistance. Propentofylline (PPF) is a well-studied synthetic methylxanthine derivative that has strong BBB penetrance. We have shown that PPF decreases TROY expression in gliomas, inhibits invasion, and sensitizes GBM to TMZ in vitro. Here we examined the efficacy of PPF in combination with TMZ using in vivo studies of intracranial models of GBM patient-derived xenograft (PDX) models in murine. We tested 3 models of GBM PDX cells with various TROY expression levels (GBM8-high TROY; GBM43-moderate TROY; GBM22-low/no TROY). Our intracranial PDX experiments showed that PPF treatment alone did not increase survival in all PDX cells. The combination of PPF and TMZ treatment did provide a survival benefit (p &amp;lt; 0.039) relative to TMZ alone (only in GBM8-high TROY and GBM43-moderate TROY) that was partially lost when treatment was discontinued. However, continuous PPF administration following a concomitant PPF and TMZ treatment course led to extended survival (p &amp;lt; 0.0015) compared to TMZ alone resulting in increased DNA damage (γH2AX) and apoptotic markers (Cleaved Caspase-3). Immunohistochemical analyses showed that TROY expression was decreased in tumors treated with PPF. In addition, PPF-treated tumors showed a differential myeloid population with well circumscribed tumors as compared to control-treated or TMZ-treated tumors. Thus, our data demonstrates that PPF may provide a pharmacological approach to targeting TROY concomitant with standard-of-care to increase patient survival. Citation Format: Ryan Eghlimi, David Nascari, Angad Beniwal, Drake Alton, Dustin Grief, Joseph Loftus, Melanie Haluska, David Coleman, Nhan Tran. Propentofylline enhances GBM sensitivity to temozolomide via targeting TROY signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5905.

Abstract B010: PITAR, a p53 inactivating TRIM28 associated RNA, executes an alternate way of p53 inactivation

Abstract B010: PITAR, a <i>p</i>53 inactivating TRIM28 associated RNA, executes an alternate way of p53 inactivation

Cerebral venous sinus thrombosis detected using diffusion-weighted magnetic resonance imaging during maintenance temozolomide chemotherapy in a patient with glioblastoma: illustrative case.

Cerebral venous sinus thrombosis (CVST) sometimes occurs in the background of hypercoagulopathic disorders, including malignancy, chemotherapy, etc. Glioblastoma (GBM) is a malignancy found in the central nervous system, and reports on cases of GBM complicated by CVST are sparse. The authors herein report a case of GBM complicated by CVST during maintenance temozolomide (TMZ) chemotherapy and describe the utility of diffusion-weighted magnetic resonance imaging (MRI) for the detection of CVST. A 65-year-old male was treated for left temporal GBM. After surgical removal of the lesion, the patient was treated with chemoradiation therapy, which included 60 Gy local radiation with concomitant TMZ chemotherapy. He was subsequently received TMZ maintenance therapy. Routine MRI performed 7 months after surgery revealed no evidence of tumor recurrence. However, diffusion-weighted imaging (DWI) revealed a high-intensity signal at the posterior portion of the superior sagittal sinus, indicating the presence of a thrombus. In addition to the preexisting symptoms, the patient experienced some disorientation. Angiography revealed an obstruction in the superior sagittal sinus, right transverse sinus, right sigmoid sinus, and straight sinus. His symptoms improved with endovascular and anticoagulant therapy. Performing DWI during routine follow-up can help in the early diagnosis of CVST in patients with malignant gliomas.

An improved F98 glioblastoma rat model to evaluate novel treatment strategies incorporating the standard of care.

Glioblastoma (GB) is the most common and malignant primary brain tumor in adults with a median survival of 12-15 months. The F98 Fischer rat model is one of the most frequently used animal models for GB studies. However, suboptimal inoculation leads to extra-axial and extracranial tumor formations, affecting its translational value. We aim to improve the F98 rat model by incorporating MRI-guided (hypo)fractionated radiotherapy (3 x 9 Gy) and concomitant temozolomide chemotherapy, mimicking the current standard of care. To minimize undesired tumor growth, we reduced the number of inoculated cells (starting from 20 000 to 500 F98 cells), slowed the withdrawal of the syringe post-inoculation, and irradiated the inoculation track separately. Our results reveal that reducing the number of F98 GB cells correlates with a diminished risk of extra-axial and extracranial tumor growth. However, this introduces higher variability in days until GB confirmation and uniformity in GB growth. To strike a balance, the model inoculated with 5000 F98 cells displayed the best results and was chosen as the most favorable. In conclusion, our improved model offers enhanced translational potential, paving the way for more accurate and reliable assessments of novel adjuvant therapeutic approaches for GB.

Metabolism and signaling crosstalk in glioblastoma progression and therapy resistance.

Glioblastoma is the most common form of primary malignant brain tumor in adults and one of the most lethal human cancers, with high recurrence and therapy resistance. Glioblastoma cells display extensive genetic and cellular heterogeneity, which precludes a unique and common therapeutic approach. The standard of care in glioblastoma patients includes surgery followed by radiotherapy plus concomitant temozolomide. As in many other cancers, cell signaling is deeply affected due to mutations or alterations in the so-called molecular drivers. Moreover, glioblastoma cells undergo metabolic adaptations to meet the new demands in terms of energy and building blocks, with an increasing amount of evidence connecting metabolic transformation and cell signaling deregulation in this type of aggressive brain tumor. In this review, we summarize some of the most common alterations both in cell signaling and metabolism in glioblastoma, presenting an integrative discussion about how they contribute to therapy resistance. Furthermore, this review aims at providing a comprehensive overview of the state-of-the-art of therapeutic approaches and clinical trials exploiting signaling and metabolism in glioblastoma.