Citations

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 INTRODUCTION Leptomeningeal disease (LMD) represents a serious neurological complication of systemic malignancies. Once diagnosed, LMD has been associated with limited life-expectancy. Herein, we report a patient with non-small cell lung cancer (NSCLC) with LMD who achieved almost 7-year overall survival (OS) from her LMD diagnosis. CASE REPORT A 60-year-old female developed worsening dry cough at age of 52. A 3-cm FDG-avid right lower lobe lung mass was found. Biopsy revealed NSCLC with EGFR exon 19 deletion. Surveillance imaging was implemented given early-stage disease. Two years later, she was found to have focal LMD along with parenchymal brain metastases. She underwent surgical resection with concomitant placement of Ommaya Reservoir. She was initiated on Osimertinib. This resulted in improvement of her focal LMD, and control of extracranial disease for 33 months when neuroimaging revealed evidence of recurrent LMD over right lateral temporal lobe. Osimertinib dose was then increased from 80 mg to 160 mg daily. At 42 months, she developed LMD progression. Despite treatment with stereotactic radiosurgery, she had further LMD progression, and another surgical resection was performed at 55 months, yet LMD recurred at 62 months, and she was enrolled in phase-2 WSD0922 clinical trial utilizing an oral brain-penetrant non-competitive reversible EGFR inhibitor with complete radiological resolution of LMD. At 73 months, she had LMD relapse and was initiated on intrathecal pemetrexed and intravenous amivantamab, and has thus far received 11 doses of intrathecal pemetrexed and amivantamab every two weeks with complete radiological response. At last follow-up, the patient is alive 82 months from her LMD diagnosis with excellent functional status. DISCUSSION our case highlights that leveraging different mechanisms of action to target EGFR mutation in sequential fashion along with consideration of intrathecal chemotherapy in patients with LMD related to metastatic EGFR-mutated NSCLC can potentially help control LMD and prolong OS.

Abstract OBJECTIVE Despite advancements in therapy and improved survival rates for patients with primary central nervous system lymphoma (PCNSL), the optimal management strategy for recurrent or refractory PCNSL (r/r PCNSL) remains undefined. In such cases, repeat brain biopsy is often performed to confirm disease recurrence, though its diagnostic and therapeutic value is uncertain. This study evaluates whether repeat brain biopsy provides new, actionable diagnostic insights that influence treatment decisions. METHODS A retrospective analysis was conducted on patients with a confirmed diagnosis of PCNSL who underwent repeat brain biopsy for suspected recurrent or refractory disease between 2005 and 2023. Patients with a history of other CNS neoplasms, demyelinating disorders, or active systemic disease were excluded. RESULTS Twenty patients met inclusion criteria (55% female), with a mean age at biopsy of 56 years in the PCNSL group and 61 years in the r/r PCNSL group. While the overall distribution of presenting symptoms did not significantly differ (p = 0.2), gait instability, weakness, and cognitive decline were more common in r/r PCNSL. PCNSL more often presented with single lesions, while r/r PCNSL had predominantly multiple lesions (p < 0.05). Periventricular enhancement was significantly more frequent in r/r PCNSL (p < 0.05), though other radiologic features were comparable. Repeat biopsy confirmed DLBCL in 90% of cases; no infections or alternate malignancies were identified. Diagnostic clarification was the primary indication for repeat biopsy. Chemotherapy regimens were altered in 50% of post-biopsy cases, without a corresponding difference in overall survival (p = 0.79). Procedure-related morbidity was observed in three patients (15%). CONCLUSIONS The second biopsy in most cases reaffirmed the original diagnosis of diffuse large B cell lymphoma. Although biopsy results led to treatment adjustments; these changes did not affect overall survival.

Abstract Berubicin is a unique anthracycline engineered to have the ability to cross the blood-brain barrier (BBB). Herein we present the primary results from a large global trial of Berubicin vs. Lomustine randomizing patients with progressive disease after only one prior therapy, all being IDH WT and stratified for MGMT methylation. The primary endpoint was overall survival (OS), secondary endpoints included progression-free survival (PFS), overall response rates (ORR) of complete (CR) and partial (PR) responses. Eligibility was determined radiologically by central reads based on progression of disease, and in 2.5 years 252 patients were enrolled with 168 randomized to Berubicin and 84 to Lomustine. Safety assessment showed that Berubicin was well tolerated and myelosuppressive side effects were manageable with growth factors. Importantly, although anthracyclines are known to cause cardiotoxicity, evaluation with frequent troponin measurements, ECG and ECHO testing revealed no evidence of impact on cardiac function. The primary endpoint, OS, showed Berubicin and Lomustine had similar outcomes. Median overall survival for Berubicin was 8.7 months (6.7, 9.9) and for Lomustine was 9.3 months (6.7, 10.7) with a Hazard Ratio of 1.13 (p = 0.5351). PFS of Berubicin and Lomustine were also similar (1.5 vs, 1.6 months). There were no responses in the Lomustine arm and stable disease in 35.2% of patients while Berubicin had a response rate of 5.8% (PR) and stable disease of 33.6% with a combined disease control rate (DCR) of 39.4%. Additional data will be presented and discussed. Anthracyclines are characteristically used in combination for systemic therapy (e.g. leukemia, lymphoma, certain breast cancers), so there is promise that combination therapy will be the next pertinent approach to treatment of GBM. Evaluation of activity against a range of pediatric brain tumors is being pursued and preliminary results will be presented at the time of the conference.

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 Bevacizumab is an anti-angiogenic monoclonal antibody that inhibits vascular endothelial growth factor (VEGF) used in the treatment of various cancers including recurrent glioblastoma (rGBM) and is particularly useful in mitigating cerebral edema and radiation necrosis. Complications associated with bevacizumab that are of concern for patients requiring urgent surgical procedures include: impaired wound healing, increased bleeding risk and infection. Recent bevacizumab use (e.g. <28 days) is considered a contraindication to surgical procedures. Therapeutic plasma exchange (TPE) is a procedure that nonspecifically removes substances from plasma such as immunoglobulins. We reviewed our institutional experience with the use of TPE to remove bevacizumab for patients who required urgent neurosurgical intervention. METHODS Single center retrospective study from: 01/01/2022 to 12/31/2024 (first patient treated for this indication was in 2022). Inclusion criteria: patients who underwent perioperatively TPE to remove bevacizumab. Data collected from electronic medical record included age, gender, pertinent medical history, indication for bevacizumab and TPE for its removal, TPE procedure parameters, and clinical outcomes. RESULTS Four patients met study inclusion criteria, all were male. Three patients had a diagnosis of rGBM, one patient had a diagnosis of metastatic melanoma. All patients had received bevacizumab within 21 days of TPE (range 8-21). All subjects underwent 3 daily, 1 plasma volume TPE. Eleven of 12 procedures used the Fenwal Amicus® Separator. Neurosurgical outcomes were favorable. In one patient, bevacizumab levels measured by ELISA decreased from 1087.63 ng/mL to 145.35 ng/mL after the third procedure. No post-surgical wound complications (e.g., wound dehiscence, bleeding, infection) were observed in four patients requiring urgent neurosurgery despite recent administration of bevacizumab. CONCLUSIONS TPE was successful and well-tolerated by subjects in this study. Perioperative bevacizumab removal by TPE may be considered to reduce the risk of wound healing complications associated with bevacizumab.

Abstract BACKGROUND Mirdametinib is the first FDA-approved MEK1/2 inhibitor for both adults and children (≥2y) with symptomatic NF1-PN. In ReNeu, symptomatic improvement and PN volume reductions were observed at the earliest assessments (~91 and ~152 days, respectively) and were sustained. This analysis evaluated time to first onset and resolution of commonly reported TRAEs in the ReNeu trial. METHODS Data cutoff (DCO) was September 20, 2023. Median time to first onset and resolution (days) for common TRAEs (≥15%) were evaluated for prepubescents (≥2 to <12y, n=32), postpubescents (≥12 to <18y, n=24), younger adults (≥18 to ≤50y, n=48), and older adults (>50y, n=10). RESULTS Common TRAEs were mostly grades 1 to 2 (83%). In prepubescents, median day (range) of onset was 32 (14, 263) for vomiting, 71 (19, 386) for dermatitis acneiform, 123 (1, 663) for diarrhea, 124 (52, 775) for paronychia, and 127 (2, 663) for nausea. For postpubescents, median day (range) of onset was 8 (1, 438) for diarrhea, 8 (2, 574) for nausea, 12 (1, 252) for dermatitis acneiform, 28 (2, 354) for vomiting, and 110 (43, 245) for paronychia. In younger adults, median day (range) of onset was 5 (1, 352) for nausea, 8 (2, 15) for dermatitis acneiform, 9 (2, 73) for diarrhea, and 29 (1, 264) for vomiting. For older adults, median day (range) of onset was 4 (1, 286) for diarrhea, 9 (2, 15) for nausea, and 13 (2, 38) for dermatitis acneiform. Time to resolution was variable between TRAEs and among patients in all age groups; 90% resolved completely by DCO. Among all patients, 18 had a TRAE of asymptomatic ejection fraction decrease, with all but one resolving by DCO. CONCLUSIONS Overall, common TRAEs arose before treatment benefits and were generally resoluble by DCO. Proactively managing TRAEs may improve treatment experience and adherence.

Abstract BACKGROUND Most meningiomas are considered benign tumors, however, a subset of meningiomas are characterized by a more aggressive clinical course and require multimodal treatment. Beyond surgery and radiation, there are no effective medical treatments available. Somatostatin receptor 2 (SSTR2) is expressed by the majority of meningiomas. [177Lu]Lu-DOTA-TATE (177Lu-Dotatate) is a SSTR2-targeting radioligand therapeutic agent that has been successful in other oncological entities, including neuroendocrine tumors. Here we report the results of a phase 2 clinical trial (NCT03971461) evaluating 177Lu-Dotatate in patients with advanced and treatment-refractory intracranial meningiomas. METHODS In this multicenter, open-label, phase 2 study, adults with advanced intracranial meningiomas received 177Lu-Dotatate at 7.4 GBq (200 mCi) every eight weeks for four doses. [68Ga]Ga-DOTA-TATE (68Ga-Dotatate) PET was performed before and at the end of treatment. The primary endpoint was progression-free survival at 6 months (PFS-6). Correlative studies evaluated the association of PFS-6, objective response rate, progression-free survival, overall survival with radiographic tumor measurements, and 68Ga-Dotatate uptake on PET. RESULTS Thirty-two patients (F=21, M=11) with progressive meningiomas (WHO 1=7, WHO 2=24, WHO 3=1) were enrolled. Median age was 65.5 (range 41-78) years. All patients previously underwent tumor resection and at least one course of radiation. Three patients (9%) had received medical therapy. Treatment with 177Lu-Dotatate was well tolerated, no treatment-limiting toxicities were observed. Of 29 evaluable patients at the data cutoff, 19 patients (66%) had achieved PFS-6 (WHO 1=4, WHO 2=15). Radiographically, the best response was partial response (PR) in 2 patients (6%) and stable disease (SD) in 20 patients (63%). CONCLUSIONS Treatment with SSTR2-targeting 177Lu-Dotatate is well tolerated and 66% of patients achieved PFS-6, comparing favorably to historical benchmarks, 177Lu-Dotatate therefore may be a useful new therapeutic modality for patients with advanced meningiomas and will be further explored in MOMENTUM-1 (NCT#06955169), an open-label, randomized, phase 2 trial.

Abstract BACKGROUND CNS germinoma is typically treated with combination of chemotherapy and radiotherapy, with steroids used temporarily for symptom management. METHODS We report a case of CNS germinoma initially treated with steroid monotherapy with reduction in radiographic enhancement. RESULTS A 25 year old male initially presented with polydipsia and polyurea that improved with desmopressin, consistent with central diabetes insipidus. Brain imaging was unremarkable and he was lost to follow up. 3 years later, he developed progressively worsening bitemporal scotomas, intermittent binocular horizontal diplopia, reduced visual acuity, headaches, weight gain, and sexual dysfunction. MRI brain revealed enhancement of the pituitary stalk, optic chiasm and optic nerves, floor of the third ventricle, lateral ventricles, periventricular white matter, and anterior corpus callosum and fornix with associated T2 hyperintensity within the optic chiasm and adjacent brain parenchyma. Biopsy was consistent with germinoma. He was started on a dexamethasone taper beginning at 4 mg every 6 hours and plateauing at 4 mg twice daily. 3 weeks after steroid initiation, the areas of enhancement surrounding the frontal horns of the lateral ventricles showed reduction in size. DISCUSSION Reduced tumoral enhancement with steroid monotherapy is a well-known phenomenon in CNS lymphoma and has been reported in gliomas, attributed to direct induction of apoptosis in CNS lymphoma and alterations in the blood brain barrier via suppression of vascular permeability factors in both. This case adds to the scant literature regarding change in enhancement patterns with steroid monotherapy in CNS germinomas, which is likely related to a reduction in tumoral diffuse lymphocyte infiltration with steroid administration. The reduction in enhancement seen in multiple CNS mass-like pathologies emphasizes the importance of a tissue diagnosis for germinomas, as this steroid response is transient and not indicative of true tumor regression. Definitive treatment of germinomas is combination chemotherapy and radiation.

Abstract BACKGROUND Glioblastoma (GBM) is highly aggressive with poor prognosis, especially in recurrent cases where treatments are limited. Intra-arterial (IA) Yttrium-90 (Y90) microsphere therapy, FDA-approved for hepatocellular carcinoma, offers the potential for targeted radiotherapy in recurrent GBM (rGBM). The FRONTIER trial evaluated the safety and feasibility of IA Y90-glass microsphere treatment for rGBM under an FDA Investigational Device Exemption. Materials and METHODS This prospective, single-arm, multi-center study included patients with rGBM in non-dominant, non-eloquent regions. The primary endpoint was 30-day incidence of treatment-related limiting toxicities (primarily ≥grade 3 non-hematologic, with exclusions). Secondary endpoints included adverse event (AE) rate, neurological changes, technical success (PET absorbed dose within ±20% of target), and efficacy. Treatment regions, defined via cerebral angiography-MRI fusion to cover the recurrent lesion, were targeted with 40±4Gy. Post-treatment evaluations included MRI, Y90-PET, and neurological assessments. RESULTS The procedure was well-tolerated by all twelve subjects and discharge occurred the following day with no decline in neurologic status. No limiting toxicities or device-related AEs were reported. Five patients experienced 8 procedure-related AEs (6 Grade 1, 2 Grade 3). Technical success was 100%, with post-treatment Y90-PET derived median absorbed dose of 41.5 Gy to the treatment region (median volume 80.3 cc). The median tumor absorbed dose was considerably higher at 124.2 Gy (median tumor volume 5.8 cc), indicating preferential tumor perfusion. At 2 months, 67% had stable disease, and 33% showed reduced T1-contrast enhancing volume within the treated area. Median progression-free survival was 3.1 (95% CI 0.92-NE) and overall survival (OS) was 9.3 months (95% CI 5.0-NE) from Y90 treatment. Exploratory analysis revealed a significant OS benefit for patients receiving a tumor absorbed dose above the median (11.9 vs 5.7 months, p=0.0073). CONCLUSION Results from this initial cohort suggest IA Y90-microsphere therapy is technically feasible and well-tolerated in rGBM. Further investigation is warranted.