Galanis, Evanthia

Abstract Despite intensive research over the past two decades, all glioblastoma (GBM) Phase 3 drug trials have been negative. The utility of the preclinical studies used to inform development for 10 Phase 3 trials was evaluated by four criteria: 1) drug distribution to the brain, 2) tumor location (flank vs. intracranial), 3) GBM xenograft source (patient-derived (PD) vs. cell line-derived (CD)), and 4) magnitude of survival extension. For the trials evaluated, no preclinical brain:plasma (B/P) data were reported for enzastaurin, cilengitide, nimotuzumab, Depatux-M, or bevacizumab, although IgG typically has a B/P ≈1%. B/P for imatinib was 1-3% and the other four drugs ranged from 25% to 51%. Except for enzastaurin, all drugs were studied in orthotopic tumor survival studies. The best response for each drug compared to relevant control (relative increase in median survival) was 22% (nimotuzumab), 31% (marizomib), 36% (sunitinib CD) / 5% (sunitinib PD), 63% (bevacizumab/temozolomide), 140% (imatinib), 157% (Depatux-M), 220% (veliparib/temozolomide), 300% (cediranib); median survival was not reached for cilengitide. However, only veliparib and sunitinib were studied in orthotopic PD models, and a single CD model (U87 or D54) was used exclusively for four drugs (enzastaurin, nimotuzumab, sunitinib, marizomib). In summary, 6 of 10 drugs had unknown or very poor brain distribution, 8 of 10 drugs were tested exclusively in CD models, which have questionable translational value, and 3 of 10 drugs had nominal activity (<50% survival prolongation) in preclinical survival studies. The stunning lack of clinical progress in GBM is deeply discouraging, but is consistent with underwhelming preclinical testing and the contextual interpretation of those results. Acknowledging multifaceted reasons for failed clinical trials, a more rigorous and critical approach should be used in preclinical studies, coupled with follow-up surgical window of opportunity studies, to identify and promote only the most promising therapies into advanced clinical testing.

Abstract WSD0922-Fu is an oral, CNS-penetrant, small molecule EGFR inhibitor which potently inhibits EGFR aberrations specific to non-small cell lung cancer (NSCLC) and glioblastoma (GBM). MC1914 (NCT04197934) is a first-in-human phase 1 trial in patients with EGFR aberrant recurrent GBM and NSCLC. After determining the maximum tolerated dose, adults with recurrent GBM were treated in two expansion cohorts: (a) non-surgical cohort (6/12 patients thus far): EGFRvIII mutation, first recurrence; food-effect study included (b) surgical cohort (6/6 patients), any EGFR mutation, any recurrence; window-of-opportunity study (WOO) included. Among these 12 patients, median age = 60 years; 50% female; 58% ECOG 0). All patients received prior radiation and temozolomide. After the WOO or food-effect study, patients were dosed at 120 mg BID (5 days on, 2 days off), and escalated to 160 mg BID (5 days on, 2 days off) based on tolerability. Common adverse events (>40%) are comparable to other EGFR inhibitors (acneiform rash, diarrhea, fatigue, xerosis, pruritis). Treatment-related grade 3+ adverse events were limited to lymphopenia (n = 1). WSD0922-Fu exposure in the fed state exceeded the fasted state (median plasma Cmax and AUC0-24h are 1.6x and 1.3x, respectively) with a delayed Tmax (6.0 vs 1.8 hours). For the WOO, time between last dose administered to tumor collection ranged between 4 - 13.5 hours. Median tumor WSD0922-Fu concentration was 0.76 µg/g; estimated median unbound tumor concentration was 24.9 ng/g and within expectations for pharmacodynamic effect. Median brain/plasma ratio = 0.59; median unbound brain/unbound plasma = 0.88. Enrollment to the non-surgical cohort is ongoing, so formal efficacy data remain immature. However, examples of clinical efficacy will be shown along with data on recurrence patterns. Phase 2 clinical trial development is in progress.

Abstract BACKGROUND Craniopharyngiomas are a rare tumor along the pituitary-hypothalamic axis. Genetic analysis revealed that 95% of papillary craniopharyngiomas (PCP) have BRAF V600E mutations (Brastianos et al. Nature Genetics 2014). We previously reported that BRAF/MEK inhibition was associated with significant anti-tumor activity in newly-diagnosed PCP patients (Brastianos et al. NEJM 2023). We have now evaluated the efficacy of vemurafenib/cobimetinib in a separate cohort of patients with recurrent PCP whose tumors progressed after prior radiation. METHODS In this multicenter, NCI-sponsored cooperative group trial, patients with histologically confirmed BRAF-positive PCP who progressed after radiation were treated with vemurafenib/cobimetinib. The primary endpoint of response rate (RR) based on centrally determined imaging data was to be evaluated in 16 patients, where a partial response was defined as ≥20% decrease in volume. This single arm, Simon two-stage phase 2 trial had 89% power to detect a true RR ≥ 30% (vs. null 5%; α=0.04). In this design, 3 or more observed responses in 16 evaluable patients would be considered evidence of promising activity. RESULTS Of the planned 16 patients, a total of 5 patients enrolled before the study was closed due to slow accrual. Median follow-up was 50 months (95% CI: 32 to not yet reached). Based on volumetric response criteria, all 5 patients had a response to treatment (100%; 95% CI: 47.8% to 100%). To date, 2 patients progressed, one of whom died 22 months after study entry. This cohort met the criteria for efficacy under the original design with >3 responders. No grade 4 or 5 toxicities were observed. CONCLUSIONS Vemurafenib/cobimetinib resulted in an objective response in all patients with previously treated PCP. The study met primary endpoint, similar to that reported for previously untreated PCP. Thus, BRAF/MEK inhibitors could be an effective tool for previously treated PCP and warrants further evaluation. SUPPORT U10CA180821; U10CA180882; Genentech, https://acknowledgments.alliancefound.org;ClinicalTrials.gov: NCT03224767

Abstract BACKGROUND Pembrolizumab is FDA approved for solid tumors with high tumor mutation burden (TMB) and may thus have efficacy in hypermutant glioma. This study aimed to identify factors influencing efficacy of pembrolizumab in recurrent glioma. METHODS This retrospective study at Mayo Clinic included patients with adult-type diffuse gliomas who received pembrolizumab (≥2 cycles) for recurrent disease (01/01/2014–05/01/2025). The Mayo Clinic Solid Tumor Panel (MCSTP), which uses the Illumina TruSight Oncology 500 High-Throughput next-generation sequencing (NGS) assay, was also used to assess the molecular characteristics of the recurrent tumors. Responders to pembrolizumab were defined as patients who did not meet RANO 2.0 criteria for progressive disease on first radiographic response assessment. Progression-free survival (PFS) was analyzed using Kaplan-Meier and Cox-Regression analyses. RESULTS Sixty-two patients were identified (median age: 46 years; 65% male; 94% white). All patients received pembrolizumab and had prior alkylating chemotherapy. The median PFS from pembrolizumab initiation was 2.3 months. Twenty-five (40%) patients were responders. Patients with IDH-mutant, 1p/19q co-deleted gliomas (OLIGO, n=13) had a longer PFS (4.3 months) than IDH wildtype gliomas (IDH-WT, n=33, 2.2 months, p=0.012) and IDH-mutant, 1p/19q non-co-deleted (IDH-MUT, n=16, 1.7 months, p=0.0006). The proportion of responders was significantly greater in OLIGO patients (IDH-WT, 33%; IDH-MUT, 19%; OLIGO, 85%, p=0.0008). Overall PFS was not impacted by patient age, sex, or extent of initial resection. Twenty-nine percent of patient tumors tested thus far (6/21) had a high TMB (≥10 mut/Mb). Two-thirds (4/6) of high TMB patients were responders, while only one-third (5/15) of low TMB patients were responders. CONCLUSIONS Patients with recurrent OLIGO may have a longer PFS with pembrolizumab therapy than IDH-WT and IDH-MUT. Furthermore, high TMB may be associated with longer PFS with pembrolizumab therapy in glioma. Additional patients are being assessed using MCSTP (total expected n=43); complete data will be presented.

Abstract BACKGROUND High-grade and recurrent meningiomas frequently demonstrate aggressive behavior and therapeutic resistance, with limited treatment options. Dysregulation of the MAPK and FAK pathways drive meningioma progression, but compensatory activation between these pathways could limit single agent efficacy. Recently, a clinical trial (Alliance A071401) showed encouraging efficacy of single-agent FAK inhibition in recurrent/progressive meningioma (Brastianos et al, JCO 2023). This preclinical study aimed to evaluate the therapeutic potential of dual RAF/MEK (avutometinib) and FAK (VS-4718) inhibition in suppressing tumor growth and improving survival in intracranial meningioma models. METHODS Orthotopic intracranial models were established by injecting IOMM-Lee (Fluc-mCherry) or CH157-MN (eGFP-LUC2) cells into nu/nu mice. Mice were randomized into four groups: vehicle, VS-4718 (murine formulation of defactinib, 50 mg/kg, BID), avutometinib (0.3 mg/kg, QD), or combination therapy. Treatments were administered for a 4-week period. Tumor growth was monitored via bioluminescent imaging (BLI) at baseline, midpoint, and study endpoint. Pharmacokinetic (PK) and pharmacodynamic (PD) effects were assessed by intratumoral drug concentrations and Western blotting for p-ERK and p-AKT, respectively. RESULTS In the NF2-mutant CH157-MN model, avutometinib increased median survival from 12.5 to 20.5 days (p=0.001), while combination therapy extended survival further to 22 days (p<0.0001 vs vehicle). Similarly, in the NF2-wildtype IOMM-Lee model, avutometinib raised survival from 27.5 to 33 days (p=0.0237), with combination therapy reaching 34.5 days (p=0.0057 vs vehicle). VS-4718 monotherapy did not extend survival in both models. BLI demonstrated significant inhibition of tumor growth in both avutometinib and combination groups in both tumor models. PK analysis revealed Kp values of 0.26–0.37 for avutometinib and 0.46–0.50 for VS-4718 in orthotopic tumor tissue. Furthermore, combination therapy lowered p-ERK in tumors (p=0.001) compared to vehicle. CONCLUSION Dual RAF/MEK and FAK inhibitor therapy blocks MAPK activation and enhances survival in orthotopic meningioma models, supporting further clinical evaluation for aggressive meningiomas.

Abstract BACKGROUND Pembrolizumab elicits durable responses in many solid tumors, yet activity in gliomas has been limited. Lymphopenia has been reported in association with reduced survival and a shorter time to progression on checkpoint inhibition in other solid tumors. We evaluated whether low absolute lymphocyte count (ALC) is related to worse outcomes in pembrolizumab-treated patients with gliomas. METHODS In this single-center retrospective study, we identified adults with gliomas who received ≥1 dose of pembrolizumab and had available lymphocyte counts at our center between 05/01/2018 and 1/31/2025. Patients’ demographics, dexamethasone use, baseline ALC (before initiation of pembrolizumab), and clinical outcomes were collected. Overall Survival (OS) was estimated using Kaplan–Meier analysis from the date of starting pembrolizumab to the date of death. RESULTS Ninety patients met eligibility criteria (glioblastoma [GBM] n = 44, astrocytoma n = 20, oligodendroglioma n = 13, meningioma n = 8, other n = 5); 62% were male and 31% (n = 28) harbored IDH-mutant tumors. Across all histological subtypes, baseline ALC<750 cells/mm³ was associated with significantly shorter OS compared to baseline ALC≥750 cells/mm³ (3.7 vs 7.7 months, P = 0.0063) with similar dexamethasone exposure (63% vs 52%). In the recurrent GBM subgroup (n = 43; MGMT-methylated 26%), ALC≥750 cells/mm³ correlated with longer OS (8.5 vs 3.4 months, P = 0.0065) with a slightly lower proportion of patients on dexamethasone in high ALC group (52% vs 75%). Conversely, among patients with IDH-mutant gliomas (n = 28), no significant difference in OS was observed based on ALC levels (7.8 vs. 7.3 months, P = 0.58) with similar dexamethasone use (57% and 43% in high and low ALC groups, respectively). CONCLUSION Baseline lymphopenia preceding pembrolizumab treatment is associated with shorter OS in patients with GBM, but not in IDH-mutant gliomas. These associations require further validation in additional patient cohorts.

Abstract Background Disruption of the blood–brain barrier (BBB) in high-grade brain tumors is characterized by contrast accumulation on diagnostic imaging. This window of opportunity study correlates contrast imaging features with the tumor distribution of BBB-permeable (levetiracetam) and -impermeable (cefazolin) drugs. Methods Patients with a clinical diagnosis of a high-grade brain tumor underwent MRI for surgical planning. Cefazolin and levetiracetam were administered prior to skin incision, and serial plasma and image-registered tumor samples were collected during the operation. Drug levels were measured by LC-MS/MS, tissue drug levels were corrected for residual blood, and tumor-to-plasma concentration ratios were calculated. Intraoperative microdialysis was performed in a subset of patients to measure the same two drugs. Results Tumor (n = 125) and plasma (n = 261) samples were available for analysis from 42 operative cases. Across all samples, the tumor-to-plasma ratio was significantly lower for cefazolin (marginal mean [MM]: 0.15, 95% CI: 0.11–0.19) as compared to levetiracetam (MM: 0.70, 95% CI: 0.64–0.75; P < .001). When compared between contrast-enhancing and non-enhancing regions, tumor-to-plasma ratios for cefazolin varied by 4.4-fold (0.27, 95% CI: 0.20–0.35 vs. 0.06, 95% CI: 0.04–0.08, respectively; P < .001), and varied for levetiracetam by 1.4-fold (0.88, 95% CI: 0.78–0.97 vs. 0.61, 95% CI: 0.55–0.66, respectively; P < .001). These results were confirmed with the intra-operative microdialysis and a population pharmacokinetic analysis. Conclusions This study demonstrates significant inter- and intra-tumoral heterogeneity in drug delivery for both levetiracetam and cefazolin within high-grade brain tumors that is not necessarily predicted by clinical MR imaging and may reflect tumor-induced changes in both perfusion and BBB integrity.

Abstract Glioblastoma is the most common type of malignant primary brain tumor and a major cause of morbidity and mortality. In 2021, the World Health Organization updated the classification of Central Nervous System (CNS) tumors to restrict glioblastomas to isocitrate dehydrogenase-wildtype (IDHwt) tumors, improving understanding of the prognosis and optimal therapy for these tumors. This revision also enables more homogeneous populations of patients to be enrolled in clinical trials, facilitating the evaluation of novel therapies. In this updated consensus review from the Society for Neuro-Oncology (SNO) and the European Association of Neuro-Oncology (EANO), the current management of patients with glioblastoma is discussed. In addition, novel therapies such as immunotherapies, viral therapies, targeted molecular therapies, theranostics, and antibody–drug conjugates will be reviewed, as well as the current challenges and future directions for research.

Abstract Background Dasatinib is an oral inhibitor of the Src kinase family, with preclinical data indicating impact on gliomagenesis, tumor invasion, and radiosensitivity. Methods North Central Cancer Treatment Group N0877 is a phase 1 dose escalation and phase II randomized study evaluating the maximum tolerated dose (MTD), safety, and efficacy of dasatinib with radiation and temozolomide (TMZ) for glioblastoma. Following identification of the MTD, adult patients with a histologic diagnosis of glioblastoma were randomized 2:1 between dasatinib given with standard concurrent and adjuvant TMZ, versus placebo with standard concurrent and adjuvant TMZ. Radiation dose was 60 Gy in 30 fractions. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), toxicity, and quality of life. Results Thirteen patients were enrolled in the phase I component and established the MTD and phase II dose of 150 mg given daily. A total of 204 patients were enrolled in the phase II component. OS was not different between arms (median OS 15.6 months for dasatinib compared to 19.3 months for placebo, hazard ratio:1.21 favoring placebo, 95% CI: 0.88–1.65, log-rank P-value: .238). Similarly, PFS was not significantly different between the dasatinib and placebo arms. There was a significant increase in anemia, nausea, and creatinine elevation with dasatinib, but significantly more grade 3 lymphopenia with placebo. Conclusions The addition of dasatinib to standard chemoradiation did not improve outcomes for patients with glioblastoma. Clinical Trial Identifier NCT00869401.

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.