Kizilbash, Sani H

Background: Post-treatment prognosis and monitoring are critical for determining the timing of salvage treatment in glioblastoma patients but has been challenging due to difficulties differentiating progression from treatment effects in conventional images. This exploratory study aimed to establish the correlation of radiomics image features from time series of amino acid tracer 18F-DOPA PET images, with outcomes, using machine learning and dimension reduction analysis. Methods: 18F-DOPA PET images were collected for a patient cohort with wild-type IDH and unmethylated MGMT who underwent dose-escalated radiation therapy. Quantitative features were derived from the high uptake region (T/N > 2.0) in pre- and post-radiation therapy follow-up 18F-DOPA PET images. A customized workflow was utilized for pre-selecting predictive features, followed by manifold learning. Machine learning algorithms were employed to establish associations between imaging features and remaining survival (RS), defined as the time between a follow-up scan and date of death. Results: The ML models exhibited 81–83% ROC_AUC in predicting RS evaluated on an independent test dataset. A RS map is proposed for monitoring tumor alterations through serial 18F-DOPA PET scans, demonstrating superior sensitivity and better correlation with survival compared to the RANO criteria. Conclusions: Our study demonstrates that ML models utilizing FU 18F-DOPA PET images have the potential to effectively predict future survival outcomes in patients with glioblastoma treated with dose-escalated radiation therapy. The capability to assess changes in tumor over time through imaging can potentially assist in patient stratification and the selection of salvage treatments, while also aiding in distinguishing treatment effects from genuine tumor progression.

Abstract Purpose: Isocitrate dehydrogenase (IDH) 1/2–isoform inhibitors have clinical efficacy in IDH1/IDH2-mutated neoplasms. However, primary resistance and secondary resistance limit their therapeutic potential. LY3410738, an oral, brain-penetrant, dual IDH1/IDH2-mutated isoform-selective inhibitor, was designed to overcome resistance. Patients and Methods: This global, multicenter, open-label, phase I study of patients with IDH-mutant solid tumors evaluated LY3410738 as monotherapy (dose escalation) for advanced solid tumors in combination with cisplatin–gemcitabine (CISGEM) for newly diagnosed cholangiocarcinoma or with durvalumab for relapsed/refractory cholangiocarcinoma (dose expansion; NCT04521686). Primary objectives were the maximum tolerated dose, recommended phase II dose, and preliminary antitumor activity. Safety, pharmacokinetics, inhibition of D-2-hydroxyglutarate, and ctDNA were assessed. Results: Overall, 119 patients received LY3410738 alone (N = 94) or in combination with CISGEM (N = 19) or durvalumab (N = 6). No dose-limiting toxicities were observed; the maximum tolerated dose was not determined. Common adverse events included nausea, vomiting, and decreased appetite. Overall response rates of 5.2% and 11.1% and disease control rates of 56.9% and 63.0% were observed for patients with relapsed/refractory IDH1- or IDH2-mutant cholangiocarcinoma or IDH1-mutant glioma, respectively. D-2-hydroxyglutarate normalization was rapid and durable. In dose-expansion cohorts, combination treatments were tolerable, with one dose-limiting toxicity in the durvalumab cohort. LY3410738 plus CISGEM demonstrated a response rate of 42.1%, a median duration of response of 8.1 months, and a median progression-free survival of 10.2 months for patients with newly diagnosed IDH-mutant cholangiocarcinoma. Conclusions: LY3410738 demonstrated largely cytostatic antitumor activity in IDH1- or IDH2-mutated cholangiocarcinoma and IDH1-mutated gliomas. LY3410738 plus CISGEM exhibited favorable antitumor activity in patients with treatment-naïve IDH-mutated cholangiocarcinoma, warranting further exploration as a treatment strategy.

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 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.

e13893 Background: For individuals with CNS tumors who have experience difficulties with in-person (IP) evaluations due to disease-related neurologic disability or the costs associated with travel, telehealth (TH) offers a convenient and timely alternative for accessing specialized neuro-oncology care. We report our institution’s experience with telehealth utilization in neuro-oncology. Methods: We conducted a retrospective review of patients who had at least one neuro-oncology telehealth visit between August 2021 and May 2024 at Mayo Clinic in Rochester, Minnesota. Reasons for visits, outcomes of appointments, acute care utilization following visits was reviewed. Results: A total of 660 patients who had at least one TH visit between August 2021 and May 2024 were included in the analysis. Median age was 56 (range 20-98), 49% were female, and 92% were white. Most patients resided in the US Midwest (84%), followed by the South (8%), West (5%), Northeast (1%), and US Territories (< 1%). Less than two percent were international patients. The most common primary visit diagnosis was glioblastoma (GBM, 26%), followed by astrocytoma, IDH-mutant (17%), meningioma (17%), oligodendroglioma, IDH-mutant, 1p/19q codeleted (7%). Of 6657 visits reviewed, 2745 (41%) were conducted via TH. Telehealth visits served various purposes, including consultation for newly diagnosed tumors or abnormal MRIs (n = 26), second opinion for an established tumor diagnosis (n = 119), discussion about clinical trial participation (n = 108), tumor-related treatment discussions (n = 719), chemotherapy education (n = 161), new symptom assessment (n = 117), symptom management (n = 366), and tumor surveillance (n = 1694). Outcomes from telehealth visits included enrollment in clinical trials (n = 28), proceeding with tumor-directed surgery (n = 46), initiation of radiation therapy (n = 88), starting or changing systemic therapy (n = 377), continuing existing systemic therapy (n = 932), transition to supportive care (n = 45), tumor diagnostic workup (n = 28), continuation of tumor surveillance (n = 1254). Acute care utilization, defined as an emergency department visit or hospitalization within one month of an appointment, was the same following telehealth visits compared to in-person visits (6.9% for IP vs 5% for TH, p = 0.507). Conclusions: Our findings demonstrate that telehealth can effectively support all aspects of neuro-oncology care, ranging from initial diagnosis discussions to systemic therapy management and transitions to supportive care. Telehealth offers a convenient and accessible method of care delivery option for patients faced with neurologic illness. Additionally, THs do not lead to increased acute care utilization compared to IP evaluations.

e13891 Background: Most patients with central nervous system (CNS) malignancy develop cognitive impairment, fatigue, and mood-related symptoms that are impacted by cancer and treatment, including radiation therapy. We currently have limited therapies to mitigate neurocognitive toxicity. It is important to accurately assess neurocognitive function and symptom burden when working to establish therapeutics. The objective of this trial is to assess the effectiveness of therapies aimed at improving neurocognitive function and quality of life by leveraging a decentralized approach incorporating an established digital neurocognitive assessment tool and development of a remote symptom collection/medication log to improve capture of longitudinal neurocognitive data. Methods: This is an open-label decentralized clinical trial (NCT06377696) that randomizes patients who have received intracranial radiation for primary and secondary brain tumors in a 1:1 allocation to health promotion with a wearable device +/- metformin (targeting radiation-related toxicity). Remote symptom collection is reported through digital patient surveys. Medication adherence is being monitored through a digital medication log developed for the study. Remote neurologic examination is performed by clinical neuro-oncologists at telehealth visits. Participants perform serial remote cognitive assessments with an established digital neurocognitive testing platform – Mayo Test Drive (MTD). Cognitive assessments and symptom surveys were designed to be completed on a smartphone, tablet, or computer device. Results: The study started enrollment on May 31, 2024. As of January 27, 2025, 54 of 100 planned participants have enrolled (27 on each arm). 51 participants remain active on trial; 3 withdrew from trial participation (2 prior to treatment, 1 after treatment). The overall completion rate for a quality-of-life questionnaire (EORTC QLQ-C30) is 85.0%, and each dose of metformin logged is 78.5%. The overall completion rate for virtual neurologic examination and short test of mental status is 94.7%. For MTD, the overall completion rate is 97.9%. The average MTD session duration was 16 minutes. Most participants completed MTD testing using a smartphone (90.5%) at home (89.1%). Conclusions: These results provide preliminary support that a decentralized trial assessing neurocognitive outcomes is feasible in patients with CNS malignancy. The completion rates of questionnaires and objective cognitive evaluation are comparable or higher than expected with historic norms. Final study results will provide real-world cognitive and quality-of-life data for patients with CNS tumors while providing preliminary data on the effectiveness of device-based health promotion +/- metformin for treatment related cognitive decline. Clinical trial information: NCT06377696 .

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.

TPS2099 Background: Gliomas are the most common primary central nervous system (CNS) malignancy in adults, accounting for 26.3% of all brain tumors. Care at high volume centers is associated with an overall survival benefit, but access to in-person evaluations can be challenging due to disease-related neurological disability and loss of income. Telehealth represents a convenient and efficient alternative to in-person evaluations, but acceptability and comparative safety of this care delivery modality has not been prospectively evaluated among glioma patients undergoing chemotherapy. Methods: This single-arm non-randomized pragmatic clinical trial evaluates patient satisfaction with, and safety of video-enabled telehealth assessments compared to in-person evaluations for patients with glioma undergoing temozolomide chemotherapy. The study includes adult patients with a diagnosis of glioma requiring adjuvant temozolomide chemotherapy. Participants act as their own controls, alternating between in-person and telehealth assessments while undergoing chemotherapy dosed per standard of care. Monitoring labs are completed locally and transmitted electronically. For participants without access to Wi-Fi or a device (e.g. mobile phone or computer), cellular-enabled tablet devices are provided to facilitate appointments and completion of electronic study components. All participants who travel to in-person appointments are reimbursed for travel expenses. The primary outcome measure is patient satisfaction with care delivered, as measured by institutional Press-Ganey survey scores obtained following telehealth and in-person assessments. A key secondary outcome measure is completion rate of planned oral chemotherapy, tracked using a digital pill diary incorporated into our institutional electronic health record. The digital diary allows real-time tracking of chemotherapy adherence and adverse events experienced by participants. Other secondary outcomes include acute care utilization days following telehealth and in-person visits (defined as emergency department evaluations and days of inpatient stay), neurologic disability as measured by the Neurologic Assessment in Neuro-Oncology (NANO) scale, and disease related quality of life measured by the EORTC QLQ-C30. All participant surveys are self-reported and completed electronically. This decentralized pragmatic clinical trial provides unprecedented, prospective real-world data on utilization of telehealth services compared to in-person visits for patients undergoing chemotherapy for glioma. We expect the data generated to inform the design and conduct of future decentralized interventional neuro-oncology trials. NCT06625047 opened for enrollment in October 2024, 16 of 30 intended participants were accrued as of January 2025. Clinical trial information: NCT06625047 .

TPS2092 Background: Glioblastoma (GBM) is the most common primary brain malignancy in adults. GBM is universally recurrent and associated with dismal outcomes. Re-irradiation (reRT) is ideal for evaluating combination therapy for recurrent GBM (rGBM) due to its multifactorial mechanism of action, including downstream immunomodulatory activity. RT (especially multi-fraction) increases immunogenicity in preclinical models by promoting immune activation, immune migration, and antigen uptake. Additionally, a recent study demonstrated enhanced PD-L1 expression in the glioma tumor microenvironment (TME) following RT, and combining stereotactic RT with a PD-1 inhibitor improved survival in murine models. Retifanlimab is a humanized monoclonal anti-PD1 IgG4 antibody that received FDA approval for adults with metastatic or recurrent locally advanced Merkel cell carcinoma. Bevacizumab, an anti-VEGF antibody, is a treatment for radiation necrosis/cerebral edema with less immune suppression than corticosteroids. In a previous Phase 2 study, hypofractionated RT (HFRT), retifanlimab, and bevacizumab was associated with a 9-month overall survival (OS) rate of 71.4%. To demonstrate the efficacy of this regimen compared to HFRT and bevacizumab, we have designed a new randomized controlled Phase 2 trial. We hypothesize that combination reRT with retifanlimab will produce a more robust anti-tumor immune response and improve OS compared to reRT without retifanlimab. Methods: This is a multicenter, open-label, randomized, controlled Phase 2 study of retifanlimab, bevacizumab, and HFRT for adult patients with rGBM. Patients are randomized 1:1 to the experimental (bevacizumab + retifanlimab + HFRT) or control cohort (bevacizumab + HFRT). Key eligibility criteria include age ≥ 18 years, Karnofsky performance status ≥ 60, ≥ 4 months since administration of any prior bevacizumab, and dexamethasone dose ≤ 4 mg at the time of randomization. The primary endpoint is 9-month OS. Secondary endpoints include OS, progression-free survival, objective response rate, neurologic assessment by NANO criteria, and adverse events profile. Protocol treatment will continue up to two years, or until progression or intolerable toxicity. Survival follow up will continue every two months, up to four years. Seven of the planned 94 patients have been enrolled as of submission on 1/28/25. Clinical trial #: NCT06160206. Funding provided by Incyte. Clinical trial information: NCT06160206 .

Abstract Oncogenic translocations involving the MET gene have been reported in several cancer types, but detailed clinicogenomic characterization of these cancers is not well defined. In addition, prospective clinical trials evaluating the antitumor activity of MET inhibitors in MET rearrangement–positive cancers are limited. In this study, in a pan-cancer analysis of &gt;46,000 solid tumors with comprehensive genomic profiling, we identified oncogenic MET rearrangements in ∼0.04% of cancers. Preliminary analysis from a phase II clinical trial of the type I MET tyrosine kinase inhibitor (TKI) vebreltinib in MET fusion–positive solid tumors demonstrated an objective response rate of 50% and disease control rate of 79%, with antitumor activity seen in diverse cancer types, including lung adenocarcinoma and intrahepatic cholangiocarcinoma, among others. Similar to MET exon 14–altered lung cancer, secondary mutations in the kinase domain can confer resistance to MET TKIs in MET fusion–positive cancers. Overall, these data categorize MET rearrangements as actionable targets in solid tumors. Significance: MET rearrangement–positive cancers are not well-characterized, and optimal treatment strategies are yet to be defined. Through comprehensive genomic analysis, preclinical modeling, and preliminary results of a phase II clinical trial, we demonstrate that MET fusions are a unique molecular subtype of cancers targetable with vebreltinib, a TKI in development.