Mrugała, Maciej M.

Abstract Background DNA methylation profiling can be used to robustly predict postsurgical outcomes and response to radiotherapy (RT) for meningioma patients. To allow for seamless integration of these complementary models into clinical practice, a practical framework is needed. Methods We leveraged a cohort of nearly 2000 surgically-treated meningiomas with DNA methylation profiling and clinical outcomes data. Existing methylation-based prediction models were dichotomized to yield four risk groups: low and high recurrent risk, each with RT sensitive and resistant subgroups. Risk groups were correlated with progression-free survival in the context of existing biomarkers including extent of resection and WHO grade. Results We first demonstrated that all risk groups benefit from gross total resection. All “high-risk, RT sensitive” tumors (n = 306, 15.7%) also benefited from adjuvant RT: after GTR, median PFS increased from 4.68 (4.13-9.48) years to not reached (P = .003); after subtotal resection (STR), from 2.12 (1.59-3.02) to 4.09 (3.41-not reached) years (P = .004). “Low-risk, RT sensitive cases” (n = 1207, 61.8%) also benefited from RT after STR (median PFS 7.39 (6.66-12.8) vs. 16.53 (10.35-not reached) years, P = .03), suggesting that RT be considered in these patients. Neither “low-risk RT resistant” (n = 84, 4.3%) nor “high-risk RT resistant” (n = 356, 18.2%) cases benefited from RT, and the latter group was associated with universally poor outcomes. Conclusions We identify methylation-defined risk groups of meningioma for which additional benefit is gained from adjuvant RT, leading to a clinical decision-making framework for straightforward integration of molecular models into clinical practice.

Abstract BACKGROUND The IDH inhibitor vorasidenib was FDA-approved for treatment of IDH-mutant grade 2 gliomas in August 2024. We evaluated vorasidenib in patients with grade 3 and 4 IDH-mutant gliomas who would not have been eligible for the INDIGO trial. METHODS Retrospective review of patients with grade 3 or 4 IDH-mutant gliomas treated with vorasidenib between 9/1/24 and 5/31/25. Prior treatments, radiographic response, adverse events and seizure control were collected for each patient. RESULTS Thirty-two patients (median age 39.5, 46.9% female) met inclusion criteria. Tumor types included grade 3 oligodendroglioma (11, 34.4%), grade 3 astrocytoma (13, 40.6%) and grade 4 astrocytoma (8, 25%). Thirty patients had contrast-enhancement; 2 patients had non-enhancing tumor. Prior treatments included surgical resection (30, 93.8%), radiation (27, 84.4%), cytotoxic chemotherapy (25, 78.1%), bevacizumab (5, 15.6%), pembrolizumab (3, 9.4%), and ivosidenib (8, 25%). Four patients (12.5%) were naïve to systemic treatment at the time of vorasidenib initiation. Median duration of vorasidenib was 101.5 days (range 18-255) with 19 patients still on vorasidenib at the time of last follow-up. Seventeen patients (53.1%) had stable disease, 11 (34.4%) had progressive disease, 2 (6.3%) did not yet have response assessment, and 2 (6.3%) died. Grade 1 transaminitis occurred in 12 patients with no high grade transaminitis. Two patients developed lymphopenia; both were heavily pre-treated with multiple alkylating agents; no other hematologic toxicity was noted. One patient developed myalgias leading to vorasidenib discontinuation. Nine patients had fatigue, 4 headaches, 2 nausea, 2 decreased appetite. In patients with a history of epilepsy, there were no reported seizures. CONCLUSIONS Vorasidenib was well-tolerated in this heavily pre-treated cohort of grade 3–4 IDH-mutant gliomas, with low-grade transaminitis and fatigue being the most common toxicities. Preliminary results show disease stability in 53.1% of patients after a median of 3.5 months. Conclusions are limited by short-interval follow-up.

Abstract BACKGROUND The Response Assessment in Neuro-Oncology (RANO) was recently updated to RANO 2.0, which no longer requires follow-up imaging to confirm progression in recurrent glioma patients recieving immunotherapy, as previously recommended by iRANO. This study evaluates the utility of RANO 2.0 to determine whether radiographic progression on initial post-treatment MRI is sufficient to guide timely discontinuation of ineffective therapy. METHODS This retrospective study, conducted at Mayo Clinic, included patients ≥18 years receiving ≥2 cycles of off-label pembrolizumab for recurrent glioma between 1/1/2014 – 5/1/2025. Radiographic response was assessed using the first MRI performed ≥30 days after pembrolizumab initiation. Progression was defined as a ≥25% increase in the product of perpendicular diameters of the lesion, clear progression of non-measurable disease, new lesion appearance, clinical deterioration, or death. For suspected pseudo-progression, sequential MRIs were reviewed; if progression was confirmed, the original date was used. RESULTS Sixty-two patients were included (mean age: 46.1 years; 64.5% male), receiving pembrolizumab for a median duration of 2.8 (1.4 – 19.4) months. Median time to initial radiographic response assessment was 1.6 (1.1 – 3.5) months, and progression-free survival was 2.3 (0.7 – 15.2) months. Thirty-seven (59.7%) patients were identified with progression at initial evaluation. Among them, 11 were initially suspected of pseudo-progression, and continued pembrolizumab: 3 received additional radiation, 2 initiated bevacizumab, while 6 remained on their prior regimens [pembrolizumab only (3); pembrolizumab with bevacizumab (3)]. However, all were subsequently confirmed to have true progression, with a median delay of 1.4 (0.7 – 7.1) months until pembrolizumab discontinuation. No true pseudo-progression cases were observed. CONCLUSIONS Our findings support the clinical applicability of RANO 2.0 in recurrent glioma patients receiving pembrolizumab. Initial radiographic progression reliably predicted true progression, suggesting limited value in confirmatory follow-up imaging. Early recognition of treatment failure may reduce delays in initiating salvage therapies, along with associated toxicity and cost.

Abstract We describe a 46-year-old male with Neurofibromatosis type 1 (NF1) and a previously known parenchymal medullary mass identified in 2022, initially managed with surveillance. In late 2023, he developed a progressive brainstem syndrome prompting presentation to our center. MRI showed a T2/FLAIR hyperintense, heterogeneously enhancing ventral medullary mass with leptomeningeal involvement, a non-enhancing right pontine lesion, right optic nerve glioma, and nodular leptomeningeal foci at T4 and L4–L5. He received IMRT to the brainstem prior to tissue diagnosis with good local response. Due to progression at T4, biopsy revealed a hypercellular, mitotically active glioma without necrosis or microvascular proliferation. Molecular profiling demonstrated IDH1/2-wildtype, H3K27M-negative, retained ATRX, intact 1p/19q, and CDKN2A/B homozygous deletion. DNA methylation profiling classified the tumor as high-grade astrocytoma with piloid features (HGAP). Spinal lesions responded to proton therapy, but new metastatic foci emerged in the subependymal lateral ventricles, leptomeninges, and cervical spinal cord. He underwent whole-brain radiation, oral temozolomide, and intrathecal cytarabine/etoposide. In June 2024, cell-free DNA analysis showed a similar molecular profile with newly identified 1p/19q codeletion, diverging from tissue findings. The patient remains alive >3 years from initial presentation. HGAP is a novel molecular class of IDH-wildtype gliomas defined by DNA methylation profiling and MAPK pathway alterations (commonly NF1, BRAF, FGFR1), CDKN2A/B codeletion, and ATRX alterations. These tumors often resemble glioblastoma or diffuse midline gliomas on imaging and are typically infratentorial or spinal, complicating biopsy. Prognostic data are limited, with <50% 5-year overall survival and no clear prognostic value of MGMT promoter methylation. This case illustrates multifocal HGAP in a patient with NF1 with favorable survival. The acquired 1p/19q codeletion raises questions about tumor mosaicism, subclonal evolution, and prognostic implications.

Abstract Zanubrutinib is a second-generation Bruton Tyrosine Kinase (BTK) inhibitor, FDA-approved for Mantle Cell Lymphoma (MCL), designed to be more selective and potentially better tolerated than first-generation agents like Ibrutinib. Progressive multifocal leukoencephalopathy (PML), a rare but severe complication, has not previously been reported with Zanubrutinib. We report a 74-year-old woman with a germline CHEK2 mutation and asymptomatic MCL (CD5+, cyclin D1+, Ki67 10–20%) diagnosed in 2016, managed with surveillance. In 2023, she was also diagnosed with localized breast cancer treated with lumpectomy and exemestane. Later that year, she developed new headaches. Brain MRI revealed diffuse bilateral pachymeningeal enhancement, suspicious for lymphomatous spread, without parenchymal involvement. By early 2024, follow-up imaging showed stable pachymeningeal enhancement with new scattered punctate right frontal subcortical lesions, coinciding with systemic MCL progression. Spinal imaging revealed epidural and bone marrow involvement; CSF was negative for malignancy. Zanubrutinib was initiated in March 2024. By August 2024, new bilateral frontal and parietal fuzzy hyperintense and faintly enhancing white matter lesions emerged, while prior punctate lesions regressed. Biopsy confirmed PML with JC virus DNA by in situ hybridization and absence of B-cell clonality. Zanubrutinib was discontinued. Follow-up imaging showed regression of lesions without new enhancement, consistent with immune reconstitution. The initial subcortical punctate lesions remained stable. In 2025, she was diagnosed with localized pancreatic adenocarcinoma, precluding cytotoxic therapy initially due to concern for PML reactivation. However, as of May 2025, neuroimaging remains stable, and patient was started on palliative gemcitabine/paclitaxel. This is the first reported case of PML associated with Zanubrutinib. It underscores the importance of vigilance for PML even in patients without overt immunosuppression, especially those with overlapping malignancies and treatment exposures in the correct clinical context.

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 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 Von Hippel-Lindau (VHL) disease is a hereditary cancer syndrome characterized by development of multiple neoplasms, including central nervous system (CNS) hemangioblastomas, renal cell carcinoma (RCC), pancreatic neuroendocrine tumors (pNETs), and retinal hemangioblastomas. Belzutifan, a hypoxia-inducible factor 2-alpha (HIF-2α) inhibitor, has demonstrated efficacy in treating VHL-associated tumors. This study evaluates our institutional experience with belzutifan in patients with VHL-related tumors. MATERIAL AND METHODS We conducted a retrospective cohort study across three Mayo Clinic sites, including patients aged ≥18 years with genetically confirmed VHL disease who received belzutifan between October 2021 and March 2025. Clinical/radiological data, and adverse events (AEs) were extracted from electronic health records. Tumor responses were assessed using RECIST v1.1 criteria for RCC, pNET, CNS hemangioblastoma. Retinal hemangioblastoma responses were evaluated through ophthalmologic assessments. RESULTS Forty-five patients were included (median age 44 58% female). Sixty-seven percent had RCC, 91% had CNS hemangioblastomas, 53% had pNETs, and 62% had retinal hemangioblastomas. The median duration of belzutifan therapy was 22.6 months (range 1.0-41.4 months). Among patients with RCC (n=26), overall response rate (ORR) was 19% and median time to best response (MTBR) was 7.4 months. Five patients had partial response (PR), 15 had stable disease (SD), and 1 had progressive disease (PD). For CNS hemangioblastomas (n=41), ORR was 12%, MTBR was 6.2 months. 5 patients had PR, 30 had SD, and none had PD. For pNET (n=17), ORR was 41%, MTBR was 8.2 months. One patient had CR, 6 patients had PR, 6 had SD, none had PD. For retinal hemangioblastomas (n=28), 6 (21%) showed improvement, 9 (32%) remained stable, and 3 (11%) showed progression. MTBR was 6.7 months. Treatment-related AEs occurred in 98% of patients. Common AEs included anemia (89%), fatigue (80%), hypoxia (18%), and headache (13%). Grade 3 AEs were observed in 20% of patients, including anemia (7%), hypoxia (9%), fatigue (4%), pneumonitis (2%), loss of consciousness (2%). One patient experienced a grade 4 event (status epilepticus). Anemia management involved iron supplementation (n=11), RBC transfusion (n=3), dose reduction (n=2), treatment holiday (n=8), permanent discontinuation (n=1). Hypoxia management included dose reduction (n=1), treatment holiday (n=3), discontinuation (n=1). CONCLUSION Belzutifan shows clinical activity across various VHL-associated neoplasms in real-world practice, with a manageable safety profile. The lower ORR compared to the phase III trial may reflect differences in baseline disease, including lower tumor burden in our cohort. These findings support its continued use in VHL disease, with attention to monitoring and managing treatment-related AEs.

2053 Background: Recurrent gliomas are highly aggressive brain tumors, often resistant to conventional treatments. Immune checkpoint inhibitors (ICI) have emerged as promising therapeutic agents by targeting tumor cells through immune modulation. However, clinical trials have demonstrated limited efficacy in recurrent gliomas. This study aimed to identify potential factors influencing treatment efficacy of ICIs in recurrent gliomas. Methods: This retrospective study, conducted across the Mayo Clinic following IRB approval, included patients ≥ 18 years diagnosed with adult-type diffuse gliomas. Eligible patients received treatment with at least 2 cycles of ICI for recurrent glioma between 2014 – 2024. Patients treated with ICIs as initial therapy were excluded. Clinical, radiographic, histological, and molecular data were analyzed, with missing information excluded. Responders to ICI were defined as patients who did not meet iRANO criteria for progressive disease based on first radiographic response assessment (and confirmatory follow up imaging as needed for possible pseudo-progression). Survival outcomes [Progression-Free Survival (PFS) and Overall Survival (OS)] and potential predictive variables were analyzed using the Kaplan-Meier method and Cox-Regression Analyses. Results: 67 patients met eligibility criteria (mean age: 45.1 ± 15.0 years; 64.2% male; 94% white). 64 (95.5%) patients received Pembrolizumab, 2 (3%) Nivolumab, and 1(1.5%) combined Ipilimumab/Nivolumab, with a median treatment duration of 2.77 (1.39 – 19.4) months. All had prior alkylating chemotherapy. The OS (from diagnosis) for IDH wildtype (IDH-WT, n = 36), IDH mutant, 1p/19q non-co-deleted (IDH-MUT, n = 17) and IDH mutant, 1p/19q co-deleted (OLIGO, n = 14) gliomas were 3.1, 9.2, and 18.6 years, respectively. The median PFS from time of ICI was 2.23 (0.69 – 27.3) months. 24 (36.9%) patients were identified as Responders. PFS was not significantly different between patients with IDH-MUT and IDH-WT gliomas (2.30 vs 2.07 months, p = 0.593). However, patients with OLIGO gliomas had a significantly higher PFS compared to IDH-WT gliomas (5.16 vs 2.07 months, p = 0.021). The proportion of responders was greatest in OLIGO gliomas, however, did not reach statistical significance (IDH-WT, 31.4%; IDH-MUT, 29.4%; OLIGO, 61.5%, p = 0.120). Overall PFS was not impacted by patient age, sex, and extent of initial resection. When analyses were limited to Responders, the PFS for IDH-WT, IDH-MUT and OLIGO gliomas were 5.75, 7.01 and 10.8 months, respectively ( p = 0.434). Conclusions: Patients with recurrent OLIGO gliomas may have a longer PFS with ICI therapy compared with recurrent IDH-WT and IDH-MUT gliomas. However, there is significant variability in ICI treatment efficacy between patients. Further molecular profiling is in progress to evaluate additional predictive biomarkers of response.