Neth, Byran J.

BACKGROUND Laser interstitial thermal therapy is a minimally invasive surgical technique commonly used for treating epileptogenic foci in patients with drug-resistant epilepsy. Densely calcified lesions pose a challenge because they prevent the placement of a laser cannula within them and act as a heat shield. A 22-year-old male presented with intractable epilepsy with imaging demonstrating a densely calcified lesion in the right medial occipitotemporal gyrus radiographically consistent with a polymorphous low-grade neuroepithelial tumor of the young. OBSERVATIONS Two laser cannulas were stereotactically positioned to flank the centrally calcified portion of the lesion at its anterior and posterior aspects. Intraoperative MR thermography during each ablation showed that the dense calcification shielded ablative heating from spreading to the other side of the lesion. The sum of the thermal ablation zones covered the entirety of the lesion. Postprocedure MRI demonstrated overlapping peripherally enhancing ablation zones, which subsumed the entirety of the calcified mass. The patient tolerated the procedure well and remained seizure free at the 14-month follow-up. LESSONS Using multiple stereotactically placed laser filaments to flank epileptogenic lesions that are densely calcified is a strategy to effectively encompass the entirety of the lesion within the combined ablation zones. https://thejns.org/doi/10.3171/CASE26184

Abstract Background Vorasidenib is Food and Drug Administration‐approved for treatment of grade 2 isocitrate dehydrogenase (IDH)–mutant gliomas and has demonstrated a benefit in progression‐free survival compared to a placebo. This study assessed the cost‐effectiveness of this treatment strategy compared to standard treatment: observation or chemoradiation (CRT). Methods The authors used an integrated Markov model to compare quality‐adjusted life‐years (QALY) gained and cost‐effectiveness of patients with IDH‐mutated low‐grade glioma (LGG) treated with vorasidenib, observation, or CRT. Outcomes were expressed as incremental cost‐effectiveness ratios (ICERs) per QALY gained. Treatment is considered cost‐effective if it meets the commonly accepted willingness‐to‐pay threshold of $100,000 per QALY gained. Results Based on model parameters, vorasidenib demonstrated an ICER of $356,756 per QALY when compared to CRT. When compared to observation, vorasidenib demonstrated an improved ICER of $215,191 per QALY. On one‐way sensitivity analysis compared to observation, median cost of vorasidenib and median overall survival were most likely to affect ICER with only marginal changes on analysis of other model factors. For ICER to become ≤$100,000 compared to observation, the cost of vorasidenib would need to drop to below $14,072 monthly or have a median survival gain of at least 11.9 years. The probabilistic sensitivity analysis demonstrated that vorasidenib was favored in none of 5000 Monte Carlo iterations. Conclusion Using the best available data, the current price of vorasidenib does not meet commonly accepted cost‐effectiveness thresholds in treatment of IDH‐mutated LGGs.

Alzheimer’s disease (AD) is characterized by profound metabolic dysfunction and disturbances in gut–brain axis signaling. Ketogenic diet (KD) has demonstrated metabolic and cognitive benefits in both preclinical and clinical studies. However, factors that determine individual responsiveness or non-responsiveness to KD interventions remain poorly understood. Emerging evidence suggests that gut microbiome composition plays a critical role in modulating these factors. This study examined how KD responsiveness, determined by fecal microbiota transplantation (FMT) derived from human KD responders (RES) or non-responders (nRES)- influences cognition, gut barrier function, neuroinflammation, and microbial structure in 3xTg-AD mice. We further evaluated whether supplementing KD with a novel Synbiotic Yogurt (SY) formulated by our team could augment or restore responsiveness. We hypothesized that RES microbiota would confer superior KD-driven benefits and that KD-SY would synergistically improve metabolic and neurobiological outcomes, particularly among nRES recipients. Adult 3xTg-AD mice were antibiotic-cleansed and randomized to receive Control-, RES-, or nRES – FMT, while maintained on KD for four weeks. A second cohort received KD supplemented with SY or non-fat milk along with RES- or nRES-FMT. Behavioral tests, gut permeability assay, serum inflammatory markers, brain amyloid beta (Aβ), intestinal morphology, gene expression, and 16S rRNA microbial profiling were measured. RES-FMT recipients showed early improvements in spatial memory (Y-maze and novel object recognition) and consistently lower Aβ accumulation in cortex and hippocampus. They also showed higher synaptophysin and IL-10 expression. In contrast, nRES-FMT mice exhibited distinct microbiome clustering, lower microbial diversity, enrichment of Proteobacteria, and impaired gut barrier function relative to RES-FMT recipients. Functionally, specific taxa like Enterococcus, Enterobacter, and Paenibacillus were associated with greater vulnerability to AD-related pathology, while Akkermansia, Bifidobacterium, and Muribaculum were linked with lower vulnerability. SY supplementation improved metabolic and gut barrier indices across groups characterized by increased circulating ketone levels, lowered fasting glucose and glucose-ketone index, and decreased gut permeability. nRES-SY mice showed the strongest gains in recognition memory and reductions in brain Aβ1–42 burden. SY increased expression of barrier- and inflammation-modulating genes, including occludin, APLP2, and IL-10. Microbiome analysis demonstrated higher microbial diversity and enrichment of beneficial genera such as Paralactobacillus, Eubacterium, and Muribaculum. These findings show that KD responsiveness is strongly determined by gut microbiota composition and that SY supplementation can enhance or rescue metabolic, cognitive, and microbial outcomes, particularly in nonresponders. This supports a precision-microbiome strategy combining metabolic and Synbiotic interventions to improve gut–brain axis function in AD. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Abstract Background Isocitrate dehydrogenase (IDH)-mutant gliomas are infiltrative tumors with limited treatment options at recurrence. Early studies suggest IDH inhibition has therapeutic activity. We evaluated clinical outcomes associated with IDH-1 inhibitor ivosidenib in recurrent IDH-1-mutant gliomas and molecular predictors of response. Methods We retrospectively analyzed adults treated with ivosidenib from January 2021 to August 2025 with predominantly recurrent, pretreated CNS WHO grade 2-4 astrocytoma IDH-mutant or grade 2-3 oligodendroglioma, IDH-mutant and 1p/19q codeleted. Prior anticancer treatments, toxicities, enhancement status at ivosidenib initiation, and genomic alterations were collected. The primary endpoint was progression-free survival (PFS); secondary analyses evaluated associations between PFS, genomic complexity, and CDKN2A/B homozygous deletion. Results Ninety-two adults, median age 43, were included: 61 astrocytomas and 31 oligodendrogliomas, mostly grade 2. Before ivosidenib, 69 had surgery, 64 chemotherapy, and 64 radiation. Median time from diagnosis to ivosidenib was 4.8 years, with median of two prior progressions. Median treatment duration was 5.8 months. Median PFS was 15.2, 4.6, and 2.1 months for astrocytoma grades 2-4, 14.0 and 6.9 months for oligodendroglioma grades 2-3. Increasing genomic complexity was associated with shorter PFS in univariate analysis. Patients without CDKN2A/B homozygous deletion had median PFS of 19.2 months. Two patients with homozygous deletion had median PFS of 0.6 months. Conclusions In this retrospective analysis of predominantly recurrent IDH-1-mutant glioma, ivosidenib was associated with longer PFS in lower-grade, non-enhancing tumors that received little or no prior anticancer treatment and less complex genomic profiles. These findings support a context-dependent benefit of IDH inhibition in recurrent disease.

Abstract Background: Pembrolizumab has been increasingly used off label for recurrent gliomas, yet biomarkers predicting response are poorly defined. Gliomas exhibit substantial molecular heterogeneity across Glioblastoma, IDH-wildtype (GBM), Astrocytoma, IDH-Mutant (A-IDHm), and Oligodendroglioma, 1p/19q co-deleted (OLIGO), which may influence immunotherapy efficacy. This study aimed to identify molecular predictors of progression-free survival (PFS) in recurrent glioma patients treated with pembrolizumab. Methods: Adults ≥18 years with recurrent glioma receiving ≥2 cycles of pembrolizumab between 2014 - 2024 were retrospectively identified across Mayo Clinic. Next-generation sequencing (NGS) reports were reviewed and archival tumor tissue resected prior to pembrolizumab initiation was analyzed when available. Comprehensive molecular profiling was performed using the Mayo Clinic Solid Tumor Panel which employs the Illumina Tru-Sight Oncology 500 High-Throughput NGS assay. Progression was assessed using RANO 2.0 criteria. Genomic alterations (clinically relevant sequences and/or copy-number variants) were evaluated using the Kaplan-Meier method, with differences in PFS compared using the log-rank test. Results: Thirty-three patients were included [median (range) age: 44.0 (21-76) years; 63.6% male]. The interval between tumor tissue sampling and pembrolizumab initiation was 9.9 (0.9-176.1) months, and median treatment duration was 2.8 (1.4-10.4) months. Median PFS for the overall cohort was 2.4 (0.8-15.2) months, and median overall survival from pembrolizumab initiation was 6.9 (0.9-48.2) months. Patients with OLIGO (n=8) had a longer PFS [4.6 (1.9-15.2) months] than either A-IDHm [n=11; PFS 2.1 (1.1-4.4) months] or GBM [n=14; PFS 2.3 (0.8-9.2) months]. Within OLIGO, CDKN2A/B heterozygous deletion (n=3) predicted a shorter PFS (3.9 vs 10.9 months; p=0.0462), while in A-IDHm, FANC mutation (n=2) was associated with a longer PFS (4.17 vs 1.61 months; p=0.0224). No significant associations with PFS were observed for other altered genes or pathways evaluated, including but not limited to Tumor Mutational Burden, EGFR, RB1, TP53, FUBP1, NF 1 or 2, PTEN, PDGFRA, PIK3CA, PIK3R1, CDK4, KRAS, MLH1, MLH2, MSH6 genomic alterations or CDKN2A/B homozygous deletion (all p>0.05). Conclusions: Pembrolizumab shows limited overall efficacy in recurrent gliomas, however, exploratory analyses identified several subtype-specific genomic alterations that may correlate with PFS. These hypothesis-generating findings highlight the potential influence of underlying tumor biology on immunotherapy response and warrant further validation in larger, prospective cohorts. Citation Format: Shameel Shafqat, Muhammad Asad Maqbool, Hussam Al Kateb, Terry C. Burns, Jian L. Campian, Shannon P. Fortin Ensign, Evanthia Galanis, Julie E. Hammack, Cristaine M. Ida, Mitch L. Klebig, Timothy J. Kaufmann, Autumn C. Moon, Maciej M. Mrugala, Bryan J. Neth, Alyx B. aPorter, Michael W. Ruff, Ugur T. Sener, Wendy J. Sherman, Joon H. Uhm, Rachael A. Vaubel, Sani H. Kizilbash. Molecular correlates of progression-free survival in recurrent gliomas treated with pembrolizumab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5253.

Abstract There is a growing number of cancer survivors given improvement in early cancer diagnosis, therapeutics, and supportive care strategies. Cognitive impairment is among the most common and clinically significant symptoms managed by cancer survivors, which negatively impacts quality of life, functional and occupational status for patients and their care partners. Cancer-related cognitive impairment is often multifactorial—impacted by patient and cancer-specific factors. For systemic (non-CNS) malignancies, cognitive impairment has been identified in up to 75%, depending on cohort, which persists in up to 35% of patients in the years following initial treatment. The most common areas of impairment include memory and processing speed, and executive function. These adverse effects of cancer treatment have been reported after chemotherapy, hormone therapy, targeted therapy, and immunotherapy. This review will summarize existing knowledge regarding the nature and pattern of cognitive changes, mechanisms and risk factors underlying these changes, and biomarkers to support identification of this adverse consequence of cancer therapies.

Abstract Background Immunohistochemically detected phosphorylated α‐synuclein (p‐α‐syn) in cutaneous nerves has been found in >95% of patients meeting consensus criteria for dementia with Lewy bodies (DLB); however, its performance in prodromal stages (mild cognitive impairment‐Lewy body [MCI‐LB]) and clinical practice is unknown. Objective We evaluated skin biopsy for p‐α‐syn in a convenience cohort of patients with suspected MCI‐LB or DLB in a tertiary care setting. Methods 53 patients underwent commercially available skin biopsy for skin nerve p‐α‐syn as part of a clinical evaluation for suspected MCI‐LB/DLB. Consensus MCI‐LB/DLB criteria blinded to skin biopsy result were applied through retrospective chart review; those not definitively meeting criteria were considered questionable synucleinopathy (QS). Results Median age at skin biopsy was 70 years (range, 43–87 years) with 81% men. 36 patients (68%) had positive skin biopsies. 32/43 (74%) patients meeting clinical consensus criteria for DLB/MCI‐LB had a positive skin biopsy, with higher frequency in MCI‐LB (87%) compared with DLB (60%). 4/10 (40%) QS had positive biopsies. One patient with a positive skin biopsy had no evidence of central nervous system (CNS) α‐syn on autopsy. Conclusions Positive skin biopsy for p‐α‐syn occurs across the spectrum of cognitive presentations of Lewy body disease including prodromal DLB, albeit at a lower frequency in this retrospective review of atypical cases compared with typical clinical presentations. A positive skin biopsy may not reflect CNS synucleinopathy as the etiology for a patient's symptoms in some cases. Longitudinal studies of skin biopsies for p‐α‐syn in suspected MCI‐LB/DLB with autopsy confirmation are needed. © 2025 International Parkinson and Movement Disorder Society.

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.