Groot, John de

PURPOSE GBM AGILE (ClinicalTrials.gov identifier: NCT03970447 ) is a phase II/III Bayesian adaptive platform registration trial testing multiple arms against a common control; the primary end point is overall survival (OS). Regorafenib, a multikinase inhibitor, showed OS benefit in recurrent (RD) glioblastoma in the phase II REGOMA trial and entered GBM AGILE as the first investigational arm. METHODS Patient subtypes included in the regorafenib arm of GBM AGILE were newly diagnosed unmethylated (NDU) and RD glioblastoma. Prospective defined sets of subtypes, or arm signatures, were NDU, RD, and all (NDU + RD). As the first investigational arm in GBM AGILE, regorafenib was equally randomized to the control arm. Treatment in the control arm is temozolomide + radiotherapy (in newly diagnosed) or lomustine (in RD). Efficacy was assessed by OS hazard ratio (HR), arm/control, and demonstrated when the Bayesian probability of benefit (HR <1.00) was ≥98%. Analysis was performed monthly for limited efficacy, which occurs when the Bayesian predictive power is <25% for all signatures, and determines stopping enrollment. Follow-up continued for 12 months after accrual stopped. RESULTS When the predictive power was <25% in all predefined signatures for regorafenib, accrual stopped for limited efficacy. The final analysis did not demonstrate OS improvement in the regorafenib arm in RD nor NDU glioblastoma. Median HRs were 1.05 (NDU), 1.07 (RD), and 1.07 (all) with final probabilities of benefit (HR <1.00) of 0.421 (NDU), 0.312 (RD), and 0.296 (all). Regorafenib was associated with increased toxicity relative to control. CONCLUSION GBM AGILE did not show superiority of regorafenib over control in RD (lomustine) or NDU (temozolomide + radiotherapy) glioblastoma, yet caused increased toxicities. Regorafenib has been removed from National Comprehensive Cancer Network guidelines as a treatment option for RD.

Abstract IDH-wildtype diffuse astrocytic gliomas with lower-grade histological features alongside specific genomic alterations (e.g., TERT promoter mutation, EGFR amplification, gain Chr7/loss Chr10) are presently diagnosed as glioblastoma, IDH-wildtype (GBM) under WHO 2021 criteria. Previous analyses categorized these into “early/evolving” or “surgically undersampled” GBMs. However, it remains unclear whether these tumors share identical clinical and prognostic features with histologic GBM. Data from IDH-wt molecular GBMs across six institutions were aggregated. Astrocytic IDH-wt tumors of any grade that lacked necrosis or microvascular proliferation on initial histopathology yet exhibited molecular alterations consistent with WHO 2021 GBM diagnosis, were included. Recursive partitioning analysis (RPA) was used to categorize patients into risk groups based on overall survival (OS). Among the 264 patients included, the median age was 60 years (IQR: 51-67), with 162 (61%) being male. Additionally, 210 (80%) were diagnosed since 2016, and 216 (82%) received chemoradiation plus adjuvant temozolomide (GBM-SOC). The median follow-up period was 3.9 years (95% CI: 3.4, 4.6). Identified univariate risk factors for worse survival included older age, biopsy-only status, EGFR amplification, absence of initial adjuvant treatment, low post-operative KPS, and tumor histologic grade of 3. RPA divided patients into four distinct survival groups (p&lt;0.0001). The “best” risk group comprised lower grade (&lt;=2) tumors (n=58, median OS (mOS): 40 months (95% CI: 33, NA)). The “second best” group included Grade 3 patients receiving GBM-SOC without steroids during initial RT (n=139, mOS: 25 months (95% CI: 22, 28)). The “second worst” group encompassed Grade 3 patients who were on steroids during initial RT while receiving GBM-SOC (n=38, mOS: 15 months (95% CI: 13, 20)). The “worst” group contained Grade 3 tumors that had not undergone SOC (n=29, mOS: 9 months (95% CI: 4, 26)). These data show that histologic features and treatment are strong indicators of patient outcomes.

Abstract While immunotherapy has transformed treatment in multiple solid tumors, its efficacy in high-grade glioma (HGG) remains limited. Understanding the molecular and clinical factors that influence HGG’s response to immunotherapy is essential to improving outcomes. We identified patients with grade 4 gliomas who had been treated with checkpoint inhibitor (CPI), virus therapy, or CMV-specific T- cell therapy and determined the association between their molecular, clinical, and demographic characteristics and survival outcomes. We identified 66 patients, 57 glioblastoma and 9 astrocytoma, IDH-mutant grade 4; 38 were treated with CPI, 22 with virus therapy, and 6 with CMV-specific T- cell therapy. PIK3CA mutation was associated with shorter PFS and OS (p=0.022, 0.073, respectively) among all patients and a shorter OS among CPI-treated patients (p=0.004). PIK3CA wild-type tumors had less PD-1 expression in CD3+/CD8+ T cells. In CPI-treated patients, IDH1/2 mutation was associated with a shorter OS (p=0.002), and mutations in RB1 and TERT promoter were associated with a shorter PFS (p-value=0.00056, 0.022, respectively). Length of CPI therapy of more than 6 months was associated with increased PFS and OS (p=0.048, 0.062, respectively), while steroid use at baseline was associated with a shorter OS (p=0.00023). Multifocal disease was associated with shorter PFS and OS durations (p=0.0017, 0.0013, respectively) among all patients. In HGG, PIK3CA, IDH1/2, RB1, and TERT promoter mutations may be associated with a poor response to immunotherapy. These results need to be validated in larger studies. Our results may provide the rationale for clinical trials combining PI3K and IDH inhibitors with CPI in HGG.

Abstract This review explores the pivotal role of preanalytical variables in bringing liquid biopsy approaches into the clinic for brain tumors. Preanalytical variables encompass a range of critical issues, from blood sample collection and handling to the impact of tumor heterogeneity and patient-specific factors. These variables introduce challenges such as false positives, false negatives, and variability in the analysis of tumor signals, which can hinder the diagnostic and prognostic utility of liquid biopsies. Understanding the nuances of preanalytical variables is essential for the successful implementation of liquid biopsy in clinical settings. This paper delves into strategies aimed at mitigating the influence of preanalytical variables by emphasizing the importance of standardized sample collection protocols, optimized sample processing and storage, quality control measures, and the integration of multiple liquid biopsy modalities.

Abstract Purpose While immunotherapy has transformed treatment in multiple solid tumors, its efficacy in high-grade glioma remains limited. Understanding the molecular and clinical factors that influence glioma’s response to immunotherapy is essential to improving outcomes. Methods We identified patients with recurrent glioblastoma or astrocytoma, IDH-mutant grade 4, who had been treated with checkpoint inhibitor (CPI), virus therapy, or cell therapy and determined the association between their molecular, clinical, and demographic characteristics and survival outcomes. Results We identified 66 patients, 57 glioblastoma and 9 astrocytoma, IDH-mutant grade 4; 38 were treated with CPI, 22 with virus therapy, and 6 with cell therapy. PIK3CA mutation was associated with shorter PFS and OS (p = 0.022, 0.073, respectively) among all patients and a shorter OS among CPI-treated patients (p = 0.004). Tumor tissue without the mutation had less PD-1 expression in CD3+/CD8 + T cells. In CPI-treated patients, IDH1/2 mutation was associated with a shorter OS (p = 0.002), and mutations in RB1 and TERT promoter were associated with a shorter PFS (p-value = 0.00056, 0.022, respectively). Length of CPI therapy of more than 6 months was associated with increased PFS and OS (p = 0.048, 0.062, respectively), while steroid use at baseline was associated with a shorter OS (p = 0.00023). Multifocal disease was associated with shorter PFS and OS durations (p = 0.0017, 0.0013, respectively) among all patients. Conclusions In high-grade glioma, PIK3CA, IDH1/2, RB1, and TERT promoter mutations may be associated with a poor response to immunotherapy. Our results may provide the rationale for clinical trials combining PI3K and IDH inhibitors with CPI in high-grade glioma.

Abstract Oligodendrogliomas are initially slow-growing brain tumors that are prone to malignant transformation despite surgery and cytotoxic therapy. Understanding of oligodendroglioma evolution and new treatments for patients have been encumbered by a paucity of patient-matched newly diagnosed and recurrent tumor samples for multiplatform analyses, and by a lack of preclinical models for interrogation of therapeutic vulnerabilities that drive oligodendroglioma growth. Here we integrate spatial and functional analyses of tumor samples and patient-derived organoid co-cultures to show that synaptic connectivity is a hallmark of oligodendroglioma evolution and recurrence. We find that patient-matched recurrent oligodendrogliomas are enriched in synaptic gene expression programs irrespective of previous therapy or histologic grade. Analyses of spatial, single-cell, and clinical data reveal epigenetic misactivation of synaptic genes that are concentrated in regions of cortical infiltration and can be used to predict eventual oligodendroglioma recurrence. To translate these findings to patients, we show that local field potentials from tumor-infiltrated cortex at the time of resection and neuronal hyperexcitability and synchrony in patient-derived organoid co-cultures are associated with oligodendroglioma proliferation and recurrence. In preclinical models, we find that neurophysiologic drugs block oligodendroglioma growth and pathologic electrophysiology. These results elucidate mechanisms underlying oligodendroglioma evolution from an indolent tumor to a fatal disease and shed light on new biomarkers and new treatments for patients.

Abstract GBM AGILE(NCT03970447) is a phase 2/3 Bayesian adaptive registration platform trial testing multiple therapies against a common control. Paxalisib, a PI3K/mTOR inhibitor, is the 3rd arm in the trial to conclude evaluation. METHODS Paxalisib was open to patients with newly diagnosed unmethylated (NDU) and recurrent (RD) glioblastoma, with three possible signatures: NDU, RD, and All(NDU+RD). Arm enrollment occurred Dec2020 through May2022. Control patients were enrolled from study initiation (July2019) and were treated with temozolomide(NDU) or lomustine(RD). GBM AGILE investigational arms have 1 or 2 stages, with adaptive randomization in stage 1 and fixed randomization if arms continue to stage 2. Efficacy is based on OS hazard ratio(HR) of Arm/Control. Efficacy goal is final Bayesian probability ≥ 98% for HR&lt;1.00 in combined Stages. An Arm continues to Stage 2 if Bayesian predictive power (PP) ≥ 0.8. An Arm stops accruing in Stage 1 if it reaches maximal sample size(N) or does not meet a minimum efficacy threshold (PP&lt;0.25 for all signatures when N&gt;50). Clinical cut-off is 12 months after accrual stops. The maximum N for paxalisib was approximately 150(Stage 1) and 50(Stage 2). RESULTS After paxalisib reached &gt;150 patients in Stage 1, accrual stopped [Paxalisib/control N 54/75(NDU), 100/188(RD)]. Neither PP thresholds for moving to Stage 2 nor stopping for minimum efficacy were met. Following an unplanned public disclosure that the arm did not continue to stage 2, clinical cut-off for final analysis (planned May2023) was updated to public disclosure date (August2022). At final analysis mean HRs were 0.89(NDU), 1.25(RD), 1.05(All), probabilities of HR&lt;1.00 of 0.72(NDU), 0.076(RD), 0.398(All). Model estimated median OS paxalisib/control (months) were 14.77/13.84(NDU) and 8.58/10.06(RD). CONCLUSION Paxalisib did not show survival benefit over cumulative control in final primary analysis; additional secondary analyses are being considered. GBM AGILE continues to rapidly and efficiently assess therapies in ND and RD glioblastoma.

Abstract Current standard of care for IDH-wildtype glioblastoma (GBM) includes maximal safe resection, adjuvant radiation, and chemotherapy with the alkylating agent temozolomide. A subset of gliomas treated with temozolomide develop somatic hypermutation with a predominance of C&gt;T transitions due to the alkylation effects on DNA. However, the frequency of occurrence, clinical ramifications, and predictive biomarkers for developing temozolomide-induced hypermutation (TMZ-HM) in GBM are unknown. Here we performed comprehensive histopathologic, genomic, and epigenomic evaluation of paired initial and recurrent GBM from 106 patients. Seven patients (7%) developed hypermutation at time of first recurrence, while an additional five patients (5%) developed hypermutation at a subsequent recurrence. Patients who developed TMZ-HM had a significantly longer interval between initial surgery and first recurrence (27.8 vs. 9.9 months, p&lt;0.001). In contrast to IDH-mutant gliomas where TMZ-HM is associated with poor prognosis, those patients with IDH-wildtype GBM who developed TMZ-HM had significantly longer overall survival from both initial surgery (67.9 vs. 20.3 months, p&lt;0.001) and from time of recurrence after development of hypermutation (30.9 vs. 9.5 months, p=0.001). There was no difference in oncogenic alteration frequency in initial GBM that subsequently developed TMZ-HM. However, 4 specific CpG sites out of 12 total interrogated sites in the promoter region of MGMT (a DNA repair enzyme) and 5 specific CpG sites in the promoter region of KCNQ1DN (a negative regulator of c-Myc) were significantly more hypermethylated in those GBM that developed TMZ-HM. We then generated a weighted risk score across these CpG sites that can be used to prospectively identify GBM likely to develop TMZ-HM associated with favorable survival. In summary, patients with GBM that develop TMZ-HM follow a more favorable clinical course, and specific MGMT and KCNQ1DN promoter hypermethylation patterns could serve as a biomarker to identify these patients who may potentially benefit from extended alkylating chemotherapy treatment.

Abstract DNA damage response (DDR) mechanisms are critical to maintenance of overall genomic stability, and their dysfunction can contribute to oncogenesis. Significant advances in our understanding of DDR pathways have raised the possibility of developing therapies that exploit these processes. In this expert-driven consensus review, we examine mechanisms of response to DNA damage, progress in development of DDR inhibitors in IDH-wild-type glioblastoma and IDH-mutant gliomas, and other important considerations such as biomarker development, preclinical models, combination therapies, mechanisms of resistance and clinical trial design considerations.

Abstract BACKGROUND Liquid biopsy in glioblastoma (GBM) is hindered by a lack of requisite circulating-free DNA (cfDNA) blood levels in due to the blood-brain barrier (BBB). Real-time image-guided low-intensity focused ultrasound (LIFU) with intravenously administered microbubble oscillators non-invasively causes BBB disruption (BBBD). This clinical trial aimed to evaluate the utility of LIFU for increasing cfDNA in blood for liquid biopsy in GBM. METHODS LIBERATE is an ongoing, prospective, multi-center, self-controlled, ongoing, pivotal trial evaluating the safety and technical efficacy of LIFU for BBBD to increase cfDNA in blood for GBM. Patients aged 18-80 years with suspected GBM planned for tumor biopsy or resection at ten centers in the US are being included. Patients are administered intravenous oscillating microbubbles for enhancing sonication, after which MR-guided BBBD using 220 kHz LIFU device is performed, with real-time acoustic feedback for effective sonication. Pre- and post-procedure, phlebotomies, and MRI brain are performed. The primary study endpoint is defined, per subject, as the ratio between cfDNA levels in blood 1-hour post-LIFU procedure compared to cfDNA level in blood pre-procedure. The primary study hypothesis is that BBBD with LIFU leads to ≥2-fold increase in cfDNA in blood. The secondary hypothesis is that there exists ≥75% concordance between biomarker patterns in the cfDNA sample from 1-hour post-LIFU sample and tumor tissue obtained later. Exploratory endpoints include (1) sensitivity of detection of known somatic mutations in cfDNA from blood samples collected before and after LIFU, (2) estimation of cfDNA levels in samples collected at 30 minutes, 1 hour, 2 hours, and 3 hours post-LIFU to determine the time of greatest yield, (3) correlation of MRI parameters related to BBBD grading and biomarkers in cfDNA from post-LIFU samples. Patient enrollment commenced in 2022, and 13 patients have been recruited by 06/09/2023. Clinical trial information: NCT05383872.