Newly-diagnosed Glioblastoma Research Articles

The Impact of Timing of Temozolomide Chemoradiotherapy for Newly Diagnosed Glioblastoma on Patient Overall Survival: A Multi-centre Retrospective Study

Abstract Background The optimal timing of initiating adjuvant temozolomide (TMZ) chemoradiotherapy after surgery in patients with glioblastoma is contentious. This study aimed to determine whether the timing of adjuvant treatment affects their overall survival (OS). Methods Consecutive adult patients with histologically-confirmed newly-diagnosed glioblastoma treated with adjuvant TMZ chemoradiotherapy across all neurosurgical centers in Hong Kong between 2006 and 2020 were analyzed. The surgery-to-chemoradiotherapy (S-CRT) interval was defined as the date of the first surgery to the date of initiation of adjuvant TMZ chemoradiotherapy. Results Four-hundred and seventy-two patients were reviewed. The median S-CRT interval was 41 days (IQR: 33-48) and the mOS was 16.7 months (95% CI: 15.9-18.2). The median age was 58 years (IQR: 50-63). Multivariable Cox regression with restricted cubic splines identified a non-linear relationship between the S-CRT interval and mOS. Post-hoc analysis-derived S-CRT intervals revealed that early CRT (< 5 weeks; adjusted hazard radio (aHR): 1.11; 95% CI 0.90-1.37) or late CRT (> 9 to 12 weeks; aHR 1.07; 95% CI 0.67-1.71) were not significantly associated with OS. Subgroup analyses for extent of resection (EOR) and pMGMT methylation status revealed no significant difference in treatment timing on OS. Conclusion The timing of adjuvant TMZ chemoradiotherapy if commenced within 12 weeks after glioblastoma diagnosis did not influence OS, regardless of EOR or pMGMT methylation status. Clinical judgement should be exercised in optimizing the timing of initiating adjuvant therapy.

CTNI-50. CLINICAL EFFICACY AND PK/PD RESPONSE IN A PHASE 0/2 STUDY OF NIRAPARIB PLUS RADIOTHERAPY FOR NEWLY-DIAGNOSED, MGMT-UNMETHYLATED GLIOBLASTOMA

Abstract BACKGROUND Poly (ADP-ribose) polymerase (PARP) mediates DNA damage response; niraparib is a PARP1/2-selective inhibitor. This Phase 0/2 study evaluates tumor pharmacokinetics (PK), pharmacodynamics (PD), and clinical efficacy of niraparib plus fractionated radiotherapy in newly diagnosed, O6-methylguanine methyltransferase (MGMT)-unmethylated glioblastoma (GBM). METHODS Newly-diagnosed GBM patients received 4 days of niraparib (300/200 mg QD) prior to planned resection 3-5 (cohort 1) or 8-10 hours (cohort 2) following the last dose. Tumor tissue (gadolinium-enhancing and non-enhancing regions), cerebrospinal fluid (CSF), and plasma were collected. Total and unbound drug concentrations were measured using validated LC-MS/MS methods. PARP inhibition was assessed by quantification of PAR induction after ex vivo irradiation vs non-irradiated control. A PK response was defined as unbound [niraparib] > 5-fold biochemical IC50 (19 nM) in non-enhancing tumor. Patients with MGMT-unmethylated tumors and a PK response were eligible for Phase 2 dosing of niraparib plus radiotherapy followed by niraparib monotherapy. RESULTS All Phase 0 patients (n=46) met the PK threshold. The mean unbound concentrations of niraparib in non-enhancing tumor regions were 335.1 nM (cohort 1; n=43) and 331.9 nM (cohort 2; n=3). Ex vivo PAR suppression was observed in 73% of the patients (24/33). 71.4% patients with unmethylated tumors were enrolled into Phase 2. Five patients in Phase 2 experienced Grade 4 thrombocytopenia related to niraparib and all adverse events resolved without sequelae. At a mean clinical follow-up of 13.4 months, median overall survival was 20.3 months. CONCLUSIONS Niraparib achieves pharmacologically relevant concentrations in non-enhancing, newly-diagnosed GBM tissue. Accompanying PD effects were observed in tumor tissue, no new safety signals were observed, and clinical outcomes were promising. A global Phase 3, open-label, randomized 2-arm study comparing niraparib versus temozolomide in adult patients with newly diagnosed, MGMT-unmethylated glioblastoma is underway.

RTID-04. A MULTICENTER, RANDOMIZED, CONTROLLED PHASE 2B TRIAL OF SURVIVIN VACCINE SURVAXM PLUS ADJUVANT TEMOZOLOMIDE FOR NEWLY-DIAGNOSED GLIOBLASTOMA (SURVIVE)

Abstract BACKGROUND Glioblastoma cells express high levels of survivin protein, whose presentation by MHC class I gets recognized by antibodies and cytotoxic T-lymphocytes (CTLs). A phase 2a trial (NCT02455557) demonstrated a median overall survival (OS) of 25.9 months in newly-diagnosed glioblastoma (nGBM) patients with 15-amino-acid-peptide-conjugate survivin vaccine (SurVaxM), which also stimulated production of survivin-directed antibodies and anti-tumor CTL. This phase 2b trial aims to further investigate efficacy and safety of SurVaxM plus adjuvant temozolomide (TMZ) for nGBM. METHODS SURVIVE is an ongoing, multicenter, randomized, placebo-controlled, investigator- and patient-blinded, phase 2b trial that randomizes nGBM patients receiving standard-of-care therapies to either SurVaxM (SurVaxM arm) or saline (control arm) in 3:2 ratio at 15 sites. Included patients have age ≥18 years, normal organ function, KPS≥70, and receive surgical resection with ≤1cm3 residual MRI contrast enhancement within 72 hours post-resection plus TMZ. Patients with recurrent, multicentric, brainstem- or cerebellar-origin GBM are excluded as well as patients on TTFields or other immunotherapies. All patients undergo 3 phases: (1) vaccine priming (VP) phase, starting ≤4 weeks after completing chemoradiation – 4 doses of SurVaxM or placebo administered q2weeks; (2) TMZ phase, started after ≥1 VP dose; and (3) vaccine maintenance phase, started 8 weeks after VP, with SurVaxM or placebo given q8weeks. TMZ phase overlaps with VP and VM phases. Primary endpoint is median OS. Assuming 1-year-OS of 75% in SurVaxM arm, based on prior trials, and 60% for control, the required sample size is N=228; 137 in SurVaxM and 91 in control arm. Accounting for dropouts, we aimed to enroll 239 patients. A log-rank test stratified by KPS (70-80 vs 90-100), MGMT methylation status, and IDH mutation status will be used for analysis. Secondary endpoints are OS and PFS at 15, 18, and 24 months, median PFS, and toxicity. A single sequential OS-driven interim analysis is planned when 50% of deaths occur. Trial is fully enrolled (NCT05163080).

DDDR-25. IBUDILAST AND ANTI-PD-L1 COMBINATION TREATMENT SIGNIFICANTLY IMPROVES SURVIVAL IN A SEX-DEPENDENT MANNER IN A MURINE MODEL OF GLIOBLASTOMA

Abstract INTRODUCTION Glioblastoma (GBM) is the most common primary malignant brain tumor, and there remains a significant need for new treatments. Previous trials studying immune checkpoint inhibitors (ICI) as single agents have been negative. Ibudilast is a brain penetrant inhibitor of the macrophage migration inhibitory factor (MIF)-CD74 interaction that sensitizes GBM to temozolomide in vitro and alters myeloid-derived suppressor cells in vitro and in vivo. The purpose of this study was to investigate whether ibudilast increases ICI efficacy in a murine model of GBM. METHODS 6-week-old male and female C57BL/6 mice were implanted with SB28 cells intracranially. One week after implantation, each group was randomized to receive intraperitoneal treatment with either: ibudilast (50 mg/kg), anti-PD-L1 (1mg/kg), combination, or vehicle control. Mice were euthanized at neurological endpoint. Survival was modeled with Cox proportional hazards regression. RESULTS Among females, there was a significant difference in survival among treatment groups (p=0.0002). Specifically, combination treatment led to significantly longer survival compared to ibudilast (p=0.004) and control (p=0.03), but not anti-PD-L1 (p=0.12). Among males, there was no significant difference in survival among groups (p=0.40). Males had significantly shorter median survival compared to females (overall: 18 versus 22 days, combination treatment: 20 days versus 32 days, anti-PD-L1: 14 versus 22 days, ibudilast: 17 versus 17 days, control: 18 versus 22 days, p=0.02). CONCLUSIONS Ibudilast with anti-PD-L1 is a promising combination treatment against GBM. Future research is needed to identify the mechanisms underlying this treatment regimen and its sex-dependent effect. These results may inform the development of a combination new clinical trial, as ibudilast is currently being evaluated in the newly-diagnosed and recurrent GBM setting with temozolomide.

CNSC-59. EPIGENETIC POTENTIATION OF ANTI-TUMOR IMMUNE RESPONSES USING VIRAL MIMICRY IN GLIOMAS

Abstract Clinical trials using immune checkpoint inhibition(ICI) have traditionally failed in glioblastoma (GBM). Viral mimicry, which augments anti-tumor immune responses and sensitizes response to immunotherapy in other cancers, involves the epigenetic activation of endogenous retroelements (REs). REs are silenced via the HUSH complex and H3K9me3. This process is mediated by ZNF638. We aimed to elucidate the role of viral mimicry in enhancing ICI through epigenetic reprogramming of the HUSH complex. We demonstrated that RE expression among 48 superfamilies inversely correlated with ZNF638 expression in gliomas, based on data from 71 newly-diagnosed GBMs. Using transcriptional deconvolution, we showed ZNF638 negatively correlates with innate antiviral immune response signatures(TLR3)(RTLR3=-0.300,pTLR3=0.00006). We validated these in-silico results in pure glioma cell lines, patient-derived GBM neurospheres, and syngeneic murine models. ZNF638 knockdown induced intracellular RE-mediated dsRNA signaling cascades via RIG-I and TLR3. This knockdown significantly increased PD-L1 expression(p<0.001), reduced H3K9 trimethylation, and enhanced cytoplasmic dsRNA accumulation in glioma cell lines. In patient-derived GBM neurospheres, ZNF638 knockdown upregulated immune and antiviral programs. Additionally, knockdown resulted in upregulation of several endogenous repeat elements (Alu, LTR). Single-cell RNA sequencing showed ZNF638 clustering in neural progenitor-like and oligodendrocyte-like cells, with increased retroelement expression in low ZNF638 cells. Tumors with lower ZNF638 expression showed increased CD8+ populations. Bulk RNA sequencing deconvolution revealed that ZNF638 is linked to reduced CD8 and DC infiltration in gliomas (RCD8=-0.202,RDC=-0.198;pCD8=8.79E-06,pDC=1.34E-05). In immunocompetent mice, ZNF638 KO and PD-L1 inhibition significantly improved survival (mOS >50 days, p<0.0001) and reduced tumor volume (p<0.001). Analysis of cohorts from multiple cancer types treated with anti-PD1 therapy demonstrated that ZNF638 expression predicts therapeutic response and overall survival. Our findings suggest that epigenetic reprogramming through HUSH inhibition may potentiate immunotherapy for GBM.

CTNI-25. TUMOR TREATING FIELDS (TTFIELDS) THERAPY WITH CHEMORADIATION, FOLLOWED BY MAINTENANCE TTFIELDS THERAPY/TEMOZOLOMIDE (TMZ), IN NEWLY DIAGNOSED GLIOBLASTOMA (NDGBM). RESULTS OF PHASE II CLINICAL STUDY

Abstract INTRODUCTION Tumor-Treating Fields (TTFields) are electric fields that exert physical forces to disrupt cancer cell function and tumor progression via a multimodal mechanism of action. Following the phase 3 pivotal EF-14 study, TTFields therapy concomitant with temozolomide (TMZ) maintenance therapy became approved for newly-diagnosed glioblastoma (ndGBM). Pre-clinical data and pilot clinical studies suggests synergistic effect of concomitant TTFields treatment with radiotherapy (RT). OBJECTIVE To assess the efficacy and safety of first line TTFields therapy concomitant with RT/TMZ vs RT/TMZ alone in adult patients with ndGBM. Design: 69 patients with ndGBM and KPS≥70 stratified by MGMT status, extent of resection, and age, were randomized 1:1. The experimental arm received TTFields therapy from the first day of chemoradiation, the control arm started 4 weeks after completion of chemoradiation. Patients continued TTFields therapy until second disease progression or 24months. The primary endpoint was 1-year PFS rate, and secondary endpoints included PFS, OS, and safety. Kaplan-Meier estimates were used to assess whether PFS and OS were improved with first line TTFields therapy/RT/TMZ vs RT/TMZ with delayed TTFields therapy. RESULTS Overall, 46 patients received maintenance chemotherapy and TTFields therapy. Mean age was 62 years (range:27–77). One-year PFS rate was 36% and 19% in the experimental and control arms, respectively (p-value=0.10). Median PFS was 9.9 and 5.6 months (HR 0.53, p-value 0.049). Median OS was 25.9 and 17 months (HR 0.85, p-value=0.6). Two-year OS rates were 52% and 31% (p-value 0.07). Among patients with high TTFields usage (≥75%) 2-year OS rates were 78% and 34% (p=0.01). CONCLUSIONS The addition of concomitant TTFields to standard treatment with temozolomide and RT for patients with ndGBM appears to be another step in improving the outcome of this patients population. This is further investigated in the large-scale TRIDENT study.

Prognostic significance of MRI contrast enhancement in newly diagnosed glioblastoma, IDH-wildtype according to WHO 2021 classification.

Contrast enhancement in glioblastoma, IDH-wildtype is common but not systematic. In the era of the WHO 2021 Classification of CNS Tumors, the prognostic impact of a contrast enhancement and the pattern of contrast enhancement is not clearly elucidated. We performed an observational, retrospective, single-centre cohort study at a tertiary neurosurgical oncology centre (January 2006 - December 2022). We screened adult patients with a newly-diagnosed glioblastoma, IDH-wildtype in order to assess the prognosis role of the contrast enhancement and the pattern of contrast enhancement. We included 1149 glioblastomas, IDH-wildtype: 26 (2.3%) had a no contrast enhancement, 45 (4.0%) had a faint and patchy contrast enhancement, 118 (10.5%) had a nodular contrast enhancement, and 960 (85.5%) had a ring-like contrast enhancement. Overall survival was longer in non-contrast enhanced glioblastomas (26.7 months) than in contrast enhanced glioblastomas (10.9 months) (p < 0.001). In contrast enhanced glioblastomas, a ring-like pattern was associated with shorter overall survival than in faint and patchy and nodular patterns (10.0 months versus 13.0 months, respectively) (p = 0.033). Whatever the presence of a contrast enhancement and the pattern of contrast enhancement, surgical resection was an independent predictor of longer overall survival, while age ≥ 70 years, preoperative KPS score < 70, tumour volume ≥ 30cm3, and postoperative residual contrast enhancement were independent predictors of shorter overall survival. A contrast enhancement is present in the majority (97.7%) of glioblastomas, IDH-wildtype and, regardless of the pattern, is associated with a shorter overall survival. The ring-like pattern of contrast enhancement is typical in glioblastomas, IDH-wildtype (85.5%) and remains an independent predictor of shorter overall survival compared to other patterns (faint and patchy and nodular).

Niraparib efficacy in patients with newly-diagnosed glioblastoma: Clinical readout of a phase 0/2 "trigger" trial.

2002 Background: Poly (ADP-ribose) polymerase (PARP) mediates DNA damage response; niraparib is an investigational PARP1/2-selective inhibitor. This Phase 0 study evaluates newly-diagnosed glioblastoma (GBM) tumor pharmacokinetics (PK) and pharmacodynamics (PD), graduating patients with O6-methylguanine methyltransferase (MGMT) unmethylated tumors into a therapeutic regimen of niraparib plus fractionated radiotherapy when PK threshold is met. Methods: Presumed newly-diagnosed GBM patients received 4 days of niraparib (300/200 mg QD) prior to planned resection 3-5 (cohort 1) or 8-10 hours (cohort2) following the last dose. Tumor tissue (Gadolinium enhancing and non-enhancing regions), cerebrospinal fluid (CSF), and plasma were collected. Total and unbound niraparib concentrations were measured using validated LC-MS/MS methods. PARP inhibition was assessed by quantification of PAR induction after ex vivo irradiation of surgical vs non-irradiated tissue. A PK ‘trigger’ determined eligibility for the Phase 2 component of the study and was defined as unbound [niraparib] &gt; 5-fold biochemical IC50 (i.e., 19 nM) in non-enhancing tumor. Patients with MGMT unmethylated tumors in excess of the PK threshold were eligible for Phase 2 dosing of niraparib plus radiotherapy followed by a maintenance phase of niraparib monotherapy. Results: All Phase 0 patients (n=46) met the PK threshold. In non-enhancing tumor regions, the mean unbound concentration of niraparib was 335.1 nM (n=43) for cohort 1 and 331.9 nM (n=3) for cohort 2. PAR suppression after ex vivo radiation was observed in 73% of the patients (24/33). Nineteen of 27 (70.3%) patients with unmethylated tumors were enrolled into Phase 2. Five patients in Phase 2 experienced Grade 4 thrombocytopenia related to niraparib. All adverse events resolved without sequelae. At time of data cutoff, median progression-free survival was 11.7 months. Mature overall survival (OS) data will be reported for the first time. Conclusions: Niraparib achieves pharmacologically relevant concentrations in non-enhancing, newly-diagnosed GBM tissue in excess of any other studied PARP inhibitor. Accompanying PD effects were observed in patient tumor tissue. For the first time, we report on the clinical efficacy of the study. A global Phase 3, open-label, randomized 2-arm study comparing niraparib versus temozolomide in adult patients with newly diagnosed, MGMT unmethylated glioblastoma is being planned. Clinical trial information: NCT05076513 .

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]

L-RNA aptamer-based CXCL12 inhibition combined with radiotherapy in newly-diagnosed glioblastoma: dose escalation of the phase I/II GLORIA trial

The chemokine CXCL12 promotes glioblastoma (GBM) recurrence after radiotherapy (RT) by facilitating vasculogenesis. Here we report outcomes of the dose-escalation part of GLORIA (NCT04121455), a phase I/II trial combining RT and the CXCL12-neutralizing aptamer olaptesed pegol (NOX-A12; 200/400/600 mg per week) in patients with incompletely resected, newly-diagnosed GBM lacking MGMT methylation. The primary endpoint was safety, secondary endpoints included maximum tolerable dose (MTD), recommended phase II dose (RP2D), NOX-A12 plasma levels, topography of recurrence, tumor vascularization, neurologic assessment in neuro-oncology (NANO), quality of life (QOL), median progression-free survival (PFS), 6-months PFS and overall survival (OS). Treatment was safe with no dose-limiting toxicities or treatment-related deaths. The MTD has not been reached and, thus, 600 mg per week of NOX-A12 was established as RP2D for the ongoing expansion part of the trial. With increasing NOX-A12 dose levels, a corresponding increase of NOX-A12 plasma levels was observed. Of ten patients enrolled, nine showed radiographic responses, four reached partial remission. All but one patient (90%) showed at best response reduced perfusion values in terms of relative cerebral blood volume (rCBV). The median PFS was 174 (range 58-260) days, 6-month PFS was 40.0% and the median OS 389 (144-562) days. In a post-hoc exploratory analysis of tumor tissue, higher frequency of CXCL12+ endothelial and glioma cells was significantly associated with longer PFS under NOX-A12. Our data imply safety of NOX-A12 and its efficacy signal warrants further investigation.

Abstract CT125: A phase 0/2 ‘trigger’ trial of pamiparib or olaparib plus radiotherapy in patients with newly-diagnosed or recurrent glioblastoma

Abstract Background: This Phase 0/2 clinical trial evaluates the pharmacokinetic (PK), pharmacodynamic (PD), and clinical response of newly-diagnosed and recurrent glioblastoma (GBM) patients to the PARP1/2 selective inhibitors, pamiparib and olaparib, in combination with radiotherapy. Materials/Methods: In this study, 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) prior to resection. In the Phase 0 component of the study total and unbound drug concentrations were measured using validated LC-MS/MS methods. A PK ‘trigger’, defined as unbound drug &amp;gt; 5-fold biochemical IC50 in Gd-nonenhancing tumor, determined eligibility for Phase 2. PARP inhibition was assessed via ex vivo tumor tissue radiation and quantification of PAR levels compared to non-irradiated control. When demonstrating a PK response, newly-diagnosed, MGMT-unmethylated GBM or recurrent GBM patients were eligible for Phase 2 dosing of pamiparib (Arms A and B) or olaparib (Arm C) with concurrent RT followed by maintenance pamiparib or olaparib. Results: A total of 41 patients (Arm A, n=16; Arm B, n=19; Arm C, n=6) were enrolled in the Phase 0 component of the study. In Arms A and B, mean unbound concentrations of pamiparib in Gd-nonenhancing tumor were 167.3 nM and 104.3 nM respectively, and in Arm C the mean unbound concentration of olaparib was 5.2 nM. All patients in the pamiparib arms (n=35) but only 1 of 6 patients in the olaparib Arm C exceeded the PK threshold. Radiation-induced PAR expression was 2.44-fold in untreated control vs 1.16 in Arm A (p&amp;lt;0.05), 0.82 in Arm B (p&amp;lt;0.01) and 1.11 in Arm C patients. In Arm A, 7 of 11 MGMT-unmethylated GBM patients advanced to Phase 2. Two patients were ineligible due to clinical status, 1 patient was ineligible per physician decision, and 1 patient declined to participate. In Arm B, 11 of 19 patients advanced to Phase 2. Eight patients were ineligible due to clinical status. At a mean follow-up of 5.8 months, median progression-free survival (PFS) was 5.8, 6.0, and 3.8 months for Arms A (n=7), B (n=11), and C (n=1), respectively. Grade 3+ toxicities related to pamiparib occurred in 4 patients, with 2 adverse events resulted in treatment discontinuation. No grade 3+ toxicities were documented in the olaparib arm. Conclusions: Pamiparib achieved pharmacologically-relevant concentrations in Gd-nonenhancing GBM tissue and suppressed induction of PAR levels ex vivo post-radiation. The majority of newly-diagnosed patients with MGMT-unmethylated GBM and recurrent GBM patients advanced to therapeutic dosing in this trial, and pamiparib was generally well-tolerated in these patients. Citation Format: Nader Sanai, Yu-Wei Chang, Jun Jiang, Jennifer Molloy, Chelsea Pennington-Krygier, Jocelyn Harmon, Amy Hong, John Wanebo, William Kennedy, Michael Garcia, Igor Barani, Wonsuk Yoo, Artak Tovmasyan, An-Chi Tien, Jing Li, Shwetal Mehta. A phase 0/2 ‘trigger’ trial of pamiparib or olaparib plus radiotherapy in patients with newly-diagnosed or recurrent glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT125.

A phase 2 Double-Blind, RandomizEd, Prospective, Placebo Controlled Study of NanO2 TM Combined With Radiation and Temozolomide in Patients with Newly-Diagnosed Glioblastoma MultiformE: RESTORE

A phase 2 Double-Blind, RandomizEd, Prospective, Placebo Controlled Study of NanO2 TM Combined With Radiation and Temozolomide in Patients with Newly-Diagnosed Glioblastoma MultiformE: RESTORE

Assessment of the clinical effectiveness and safety of immune checkpoint inhibitors for glioblastoma: A systematic review

Glioblastoma (GBM) is a malignant primary brain tumor which is commonly found in humans. Conventional therapeutic approaches for GBM offer only a short median overall survival (MOS), thereby accentuating its poor clinical outcome. Despite the promising potential shown by use of immune checkpoint inhibitor (ICI) in animal models to treat GBM, human trials result remains inconclusive. This systematic review evaluated the safety and clinical efficacy of ICIs in GBM patients. A literature search from Embase and MEDLINE (Ovid) was completed in October 2023. A total of 10 suitable articles, which encompass 168 patients (164 recurrent and 4 newly-diagnosed GBM), are taken into account. 3 studies assessed the OS, 7 studies assessed the PFS and/or response assessment in neuro-oncology (RANO) criteria and 8 studies assessed the safety, tolerability and/or adverse events. These studies show that the range of MOS of ICI treatments was between 2.6-10.4 months (MOS using current standard treatment for recurrent GBM = 3.5-12.5 months). The median PFS and the median period until patients reach partial response score based on RANO criteria are ranging from 1.5 months to 4.6 months (PFS using current standard treatment is 5.5 months). In conclusion, ICIs are safe in patients with GBM. Reported adverse effects only include mild fatigue, headache, hyperglycemia, and diarrhea. However, ICIs display suboptimal clinical efficacy compared to conventional GBM treatments. Therefore, further research is needed in order to improve the clinical efficacy of ICIs.

CTNI-22. A PHASE 0/2 ‘TRIGGER’ TRIAL OF NIRAPARIB IN PATIENTS WITH NEWLY-DIAGNOSED GLIOBLASTOMA

Abstract BACKGROUND Poly (ADP-ribose) polymerase (PARP) mediates DNA damage response; niraparib is an investigational PARP1/2-selective inhibitor. This Phase 0 study evaluates newly-diagnosed glioblastoma (GBM) tumor pharmacokinetics (PK) and pharmacodynamics (PD), graduating patients with O6-methylguanine methyltransferase (MGMT) unmethylated tumors into a therapeutic regimen of niraparib plus fractionated radiotherapy when PK threshold is met. METHODS Presumed newly-diagnosed GBM patients received 4 days of niraparib (300/200 mg QD) prior to planned resection 3-5 or 8-12 hours following the last dose. Tumor tissue (enhancing and non-enhancing regions), cerebrospinal fluid (CSF), and plasma were collected. Total and unbound niraparib concentrations were measured using validated LC-MS/MS methods. PARP inhibition was assessed by quantification of PAR induction after ex vivo irradiation of surgical vs non-irradiated tissue. A PK ‘trigger’ determined eligibility for the therapeutic expansion phase and was defined as unbound [niraparib] &amp;gt; 5-fold biochemical IC50 (i.e., 19 nM) in non-enhancing tumor. Patients with MGMT unmethylated tumors and positive PK were eligible for phase 2 dosing of niraparib plus radiotherapy followed by a maintenance phase of niraparib. RESULTS All phase 0 patients (n = 44) met the PK threshold. In non-enhancing tumor regions, the mean unbound concentration of niraparib was 226.7 nM (n = 38). PAR suppression after ex vivo radiation was observed in 71% of the patients (20/28). Eighteen out of 26 patients with unmethylated tumors enrolled in phase 2. Five of the 18 initial patients in phase 2 experienced grade 4 thrombocytopenia related to niraparib. All adverse events were resolved without sequelae. For patients who completed at least 6 months of follow-up, PFS6 was 64% (n = 11) with 9.2-month median follow-up. Median follow-up for all patients (n = 18) was 4.2 months with 8 patients remaining on treatment and 2 patients ongoing PFS6 follow-up. CONCLUSIONS Niraparib achieves pharmacologically-relevant concentrations in non-enhancing, newly-diagnosed GBM tissue in excess of any other studied PARP inhibitor.

CTNI-19. RESECTION AND CESIUM-131 RADIATION SOURCES IMBEDDED IN BIO-RESORBABLE COLLAGEN TILES (GAMMATILE™) FOLLOWED BY THE STUPP PROTOCOL IN NEWLY-DIAGNOSED GLIOBLASTOMA: GESTALT TRIAL-IN-PROGRESS UPDATE

Abstract OBJECTIVE To evaluate the safety and feasibility of combining resection with immediate initiation of radiation and subsequent Stupp protocol in newly-diagnosed glioblastoma (GBM). BACKGROUND Rapid early local progression (REP) after resection, prior to the initiation of EBRT+/-chemotherapy, occurs in 25-50%. This high-rate of REP supports initiation of an effective postoperative treatment as early as safely possible. Bio-resorbable collagen tiles with imbedded cesium-131 radiation sources (Gammatiles™) are FDA cleared for this use. Intraoperatively, tiles are placed within the resection bed, thus achieving an immediate initiation of surgically targeted radiation therapy (STaRT). DESIGN/ METHODS GESTALT is a single-arm 61 patient multi-center trial. Consented adults with suspected or confirmed GBM undergo a maximum safe resection with Gammatile™ (STaRT). Patients with molecular GBM (WHO 2021 criteria) start concurrent EBRT/Temozolomide beginning 25±4 days post-surgery. Subsequent EBRT (20 fractions, 4 weeks) to low and high-risk PTV takes Gammatile™ dose into account to a combined biologically equivalent dose of 46 and 60 Gy delivered in 2Gy/fraction, respectively. Adjuvant TMZ (6 cycles) begins 28±7 days after EBRT/Temozolomide. TTF is allowed. IDH-mutated gliomas are followed for safety. Outcomes include feasibility of incorporating Gammatile™ without delay of Stupp protocol, consent/attrition rates, safety, performance status trajectory (ECOG, KPS), immune competence (absolute lymphocyte counts), local control, PFS, and OS. RESULTS The trial opened in Fall 2022 at 4 sites. 12 additional sites are onboarding (NCT05342883). 16 patients are on trial as of abstract submission. Currently, this trial appears feasible and without any unexpected intolerances/toxicities. CONCLUSIONS This is the first trial in newly diagnosed GBM patients to combine resection, Gammatile™, and the Stupp protocol, in an attempt to reduce REP, as well as possibly, improve other outcomes. RESULTS will inform the routine and investigational use of Gammatile™, and if suggestive, will form the basis for a subsequent randomized trial.

IMMU-14. SINGLE CELL RNASEQ OF PBMCS FROM NEWLY-DIAGNOSED GLIOBLASTOMA PATIENTS

Abstract INTRODUCTION A multitude of recently published papers have found immunosuppression caused by glioblastoma (GBM) is not limited to the tumor microenvironment and impacts the peripheral immune system. Our group has recently reported an expansion of granulocyte macrophage precursors, a subset of hematopoietic stem and progenitor populations (HSPCs), in glioma-bearing mice relative to healthy, age-matched controls. Thus we sought to determine if GBM causes cell fate dysfunction in CD34+ HSPCs in patients. METHODS CD34+ cells were magnetically isolated from peripheral blood of newly-diagnosed GBM patients and healthy age-matched donors and processed for single-cell RNA sequencing. CD34+ cells were magnetically isolated from peripheral blood of newly-diagnosed GBM patients and healthy age-matched donors and processed for single-cell RNA sequencing using the 10X Genomics platform. CellRanger was used for primary analysis with default parameters. After quality control removal of doublets, dead, and low quality cells automated cell type annotation was performed using the Azimuth Hubmap Consortium human bone marrow reference. The annotated single cell object was then read into R and Seurat was used for differential expression analysis and visualization. RESULTS AND CONCLUSIONS There we no significant expansions of stem and progenitor populations. GBM patient CD34+ samples had upregulation of VWF, a marker of myeloid-bias cell subset. Within the mature immune cell compartments, we observed a significant expansion of NK cells in GBM patients including 1,997 genes differentially expressed in the NK cell cluster between cohorts. This includes downregulation of SLAMF6, which triggers cytolytic activity in NK cells, in GBM patients. Upregulation of early NK cell activation markers CD69 and JUN were seen in GBM patient samples. These results strongly suggest NK are likely activated in the context of GBM, but may not be functional.

BIOM-06. LONGITUDINAL CEREBROSPINAL FLUID LIQUID BIOPSY IN PHASE 0/2 TRIAL OF NIRAPARIB FOR NEWLY-DIAGNOSED GLIOBLASTOMA

Abstract INTRODUCTION Effective drug development in glioblastoma (GBM) requires visualization of tumor evolution in response to experimental therapy. Today, genetic and epigenetic mechanisms of tumor resistance are undetected in clinical trials. Here, we establish the feasibility of a liquid biopsy paradigm in tracking tumor evolution in response to a novel therapeutic using an intra-cavitary reservoir for serial cerebrospinal fluid (CSF) collection. METHODS We conducted a Phase 0/2 clinical trial of niraparib, a potent PARP1/2 inhibitor, in newly-diagnosed GBM patients (NCT05076513). Intra-cavitary reservoirs were placed in select patients following tumor resection. Monthly outpatient CSF samples were collected to longitudinally examine cell-free tumor DNA (cfDNA) using a 293-gene amplicon-based next-generation sequencing (NGS) panel and circulating tumor cells using single cell RNA-sequencing (scRNA-seq). Concordance analysis was performed using paired tumor tissue samples against multiple liquid biopsies. RESULTS Tumor-derived cfDNA and circulating tumor cells were successfully isolated from intra-cavitary reservoirs at regular intervals for the duration of the clinical trial. Twelve patients so far have been implanted with the reservoirs for CSF collection. Among 55 CSF samples, 53 (94%) has detectable cfDNA. Radiographic tumor burden is associated with concentration of cfDNA (ng/ml, p&amp;lt; 0.01). No adverse events were observed during liquid biopsy acquisition. CSF sequencing data was highly concordant with NGS analyses of tumor tissue. cfDNA and single-cell analyses from serial CSF samples reflected the disparate evolution of GBM patient tumors in the face of PARP1/2 inhibition. CONCLUSION This is the first reported experience of serial CSF liquid biopsy to monitor DNA- and RNA-based tumor evolution in the context of an experimental therapy. Our data demonstrate the feasibility of cfDNA NGS and scRNA-seq using longitudinal CSF sampling of clinical trial patients. This new strategy for serial tumor profiling will be an important component of future drug development efforts targeting the moving biology of glioblastoma.

CTNI-21. PHASE I STUDY OF BTK INHIBITOR IBRUTINIB WITH TEMOZOLOMIDE AND RADIATION IN NEWLY-DIAGNOSED GLIOBLASTOMA (EQUILIBRIUM): FINAL TRIAL REPORT

Abstract BACKGROUND Glioblastoma carries dismal prognosis for which novel therapeutics are urgently needed. Ibrutinib, an oral small molecule inhibitor of BTK, has been shown in preclinical models to inhibit cancer stem cells in glioblastoma. We sought to investigate safety and tolerability of ibrutinib for newly-diagnosed glioblastoma (nGBM). METHODS EQUILIBRIUM was a prospective, phase I trial conducted in nGBM patients with KPS ≥ 70% and normal organ function. Patients received standard of care chemoradiation plus ibrutinib in a 3 + 3 dose-escalation design (level 1: 420 mg daily, level 2: 560 mg daily, level -1: 280 mg daily). Primary study objective was to determine maximum tolerated dose (MTD) of ibrutinib in combination with radiotherapy (RT) of 60Gy over 6 weeks with/without 75 mg/m2 of temozolomide (TMZ) in MGMT methylated and unmethylated cohorts respectively. Secondary objective was to determine safety, overall survival (OS), and progression-free survival. RESULTS 26 patients were enrolled, with 12 (46%) females. Median age was 61.5 years (range 76-22). 15 (58%) patients were MGMT methylated and 11 (42%) were unmethylated. Dose-limiting toxicities (DLTs) were observed at all dose levels of ibrutinib+RT arm. MTD of ibrutinib was noted to be 420 mg daily with RT+TMZ in methylated arm. In Ibrutinib+RT+TMZ arm, median cycles of TMZ were 4 (range 0-6) and of ibrutinib were 3 (range 0-26). Median OS for MGMT methylated arm was 26.0 (22.0-NA) months and for MGMT unmethylated cohort was 14.0 (8.54-NA) months. Median OS for EGFR-amplified was 29.5 (21.9-NA) months and for EGFR-non-amplified was 21.8 (16.6-NA) months. 2-year OS for MGMT methylated arm was 56% (34-95%) and for MGMT unmethylated arm was 2% (6-70%). CONCLUSIONS 420 mg of Ibrutinib daily is safe and feasible with TMZ and RT for nGBM. Ibrutinib appears promising compared to historical outcomes in MGMT methylated patients. EGFR-amplified patients potentially derive significant benefit. Trial information: NCT03535350.

CNSC-17. WHOLE-BRAIN SPECTRAL CHANGE IN GLIOBLASTOMA PATIENTS: ASSOCIATIONS WITH CLINICAL COMORBIDITIES AND OVERALL SURVIVAL

Abstract Glioblastoma, a highly aggressive form of brain tumor, is a brain-wide disease. We evaluated the impact of tumor burden on whole brain resting-state functional magnetic resonance imaging (rs-fMRI) activity. Specifically, we analyzed rs-fMRI signals in the temporal frequency domain in terms of the power-law exponent and fractional amplitude of low-frequency fluctuations (fALFF). We contrasted 189 patients with newly-diagnosed glioblastoma versus 189 age-matched reference participants. The patient and reference datasets were matched for age and head motion. The principal finding was markedly flatter spectra and reduced grey matter fALFF in the patients as compared to the reference dataset. We posit that the whole-brain spectral change is attributable to global dysregulation of excitatory and inhibitory balance and metabolic demand in the tumor-bearing brain. Additionally, we observed that clinical comorbidities, in particular, seizures, and MGMT promoter methylation, were associated with flatter spectra. Notably, the degree of change in spectra was predictive of overall survival. Our findings suggest that frequency domain analysis of rs-fMRI activity provides prognostic information in glioblastoma patients and offers a means of noninvasively studying the effects of glioblastoma on the whole brain.

CTNI-61. MYCOPHENOLATE MOFETIL INHIBITS GLIOBLASTOMA PURINE METABOLISM IN HUMANS: AN INTERIM RESULT OF PHASE 0/1 CLINICAL TRIAL TO OVERCOME TREATMENT RESISTANCE IN NEWLY DIAGNOSED AND RECURRENT GLIOBLASTOMA

Abstract BACKGROUND Mycophenolate mofetil (MMF), a purine synthesis inhibitor, improves radiation and temozolomide efficacy in preclinical glioblastoma models. This phase 0/1 trial (NCT04477200) is the first-in-human study to assess the tolerability of MMF with chemoradiation in glioblastoma, MPA accumulation, and purine synthesis inhibition in tumor. METHODS Adult patients meeting eligibility are given MMF 500-2000 PO BID using TITE-CRM dose assignment. Thirty recurrent glioblastoma patients receive MMF one-week prior to and concurrently with re-irradiation (40.5 Gy), with 28 days of dose-limiting toxicity (DLT) period. Thirty newly-diagnosed glioblastoma patients receive MMF one-week prior to and concurrently with chemoradiation and followed for 28 days for DLT1-period. During the adjuvant temozolomide (days 1-5/28-day cycle) period, MMF is given days 0-5 on a separate dose-escalation (DLT2 period = cycles 1-2). Tissues from phase-0 recurrent glioblastoma patients (N = 8) receiving MMF 500-2000mg BID one-week pre-operatively are analyzed using mass spectrometry. RESULTS Enhancing and non-enhancing tumor from phase 0 subjects yielded above 1 µM active drug metabolite, and the GTP/IMP ratio was decreased by 75% in enhancing tumor in MMF-treated patients compared to untreated controls (p = 0.009), indicating effective target engagement and inhibition of purine synthesis. No DLT has been observed with adjuvant cyclic temozolomide in phase 1 newly-diagnosed group (N = 26), nor in the recurrent-disease group (N = 18) with re-irradiation. In newly diagnosed arm, 3 subjects experienced DLT1 at 2000mg BID; grade-3 hemiparesis and cognitive disturbance, and grade-4 thrombocytopenia. Other main toxicities are mild nausea and fatigue. Interim median overall survival in recurrent phase 1 is 15.6 months, and not reached yet in newly diagnosed phase 1. CONCLUSION MMF combined with chemoradiation has been reasonably well tolerated in glioblastoma patients with preliminary promising 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.