scholarly journals P14.60 FET PET response upon radiochemotherapy followed by Tumor Treating Fields (TTFields) in a patient with progressive high-grade glioma

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii81-iii81
Author(s):  
A F Keßler ◽  
J Weiland ◽  
T Linsenmann ◽  
R Ernestus ◽  
C Hagemann ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Treatment Response ◽  
High Grade Glioma ◽  
High Grade ◽  
Who Grade ◽  
Fet Pet ◽  
Tumor Treating Fields ◽  
Grade Ii ◽  
The Right ◽  
Pet Scans

Abstract BACKGROUND The addition of Tumor Treating Fields (TTFields) to the first-line therapy in glioblastoma (GBM) demonstrated significantly improved progression free survival, overall survival and longterm survival rates in the EF-14 phase 3 trial. However, responder analysis of patients with recurrent GBM (rGBM) treated with TTFields monotherapy (in the EF-11 trial) revealed delayed response monitored by MRI analysis. More recent data suggests that O-(2-18F-fluoroethyl)-L-tyrosine (FET) PET may add valuable information for monitoring therapy response of glioblastoma patients treated with TTFields. Here, we report on FET PET response in a patient with progressive anaplastic astrocytoma WHO grade III (AA) treated with TTFields in combination with temozolomide (TMZ) chemotherapy. METHODS We present a 38-year old patient with an initial diagnosis of a diffuse astrocytoma WHO grade II in 2011, and malignisation to an AA on progression. The treatment regimen included initially radio-chemotherapy (RCT) with TMZ. On further progression of the AA in 2017, TTFields were added to another 6 cycles of TMZ. Several FET PET scans for differentiation of tumor progression from treatment-related changes were performed over time. The definitive diagnosis (tumor progression and grading) was confirmed by histopathology after stereotactic biopsy (SB). RESULTS In 2012, the patient was first diagnosed with a low grade astrocytoma WHO grade II of the right frontal, temporal and parietal lobe including infiltration of thalamus and corpus was confirmed by SB, followed by irradiation. On progression in 2015, a FET PET Scan showed FET avidity in all tumor affected regions of the brain. SB confirmed an AA, while FET PET scans showed only a mild response in the temporoparietal region after 6 cycles of TMZ. In 2017, the next progression without further malignisation was confirmed by SB and treated RCT with 41.4 Gy and TMZ chemotherapy, followed by application of TTFields with an average usage rate of 85.7 % over 6 months. Thus, the TTFields adherence was well above the independent prognostic threshold of 75 %. No additional adverse events due to the combined therapy of TTFields and TMZ were observed. Due to a new contrast enhancing lesion in the right frontal lobe (10x7mm), another FET PET scan was performed 1.5 years later. In this scan, obtained after combined TTFields and RCT therapy a strong response regarding FET avidity was observed. CONCLUSION In summary, FET PET is able to add important additional information for evaluation of treatment response in high grade glioma patients, in particular for TTFields treated patients, while adding TTFields to radiochemotherapy might even enhance treatment response of high grade glioma. Further studies might elucidate the role of FET PET imaging for therapy monitoring in high grade glioma patients treated with TTFields.

scholarly journals The Value of 5-Aminolevulinic Acid in Low-grade Gliomas and High-grade Gliomas Lacking Glioblastoma Imaging Features: An Analysis Based on Fluorescence, Magnetic Resonance Imaging, 18F-Fluoroethyl Tyrosine Positron Emission Tomography, and Tumor Molecular Factors

Neurosurgery ◽  
2015 ◽  
Vol 78 (3) ◽  
pp. 401-411 ◽  
Author(s):  
Mohammed Jaber ◽  
Johannes Wölfer ◽  
Christian Ewelt ◽  
Markus Holling ◽  
Martin Hasselblatt ◽  
...  
Keyword(s):  
Aminolevulinic Acid ◽  
Methylation Status ◽  
Imaging Features ◽  
High Grade ◽  
Ki 67 ◽  
Who Grade ◽  
Fet Pet ◽  
Grade Ii ◽  
Grade Iii ◽  
Mib 1

Abstract BACKGROUND: Approximately 20% of grade II and most grade III gliomas fluoresce after 5-aminolevulinic acid (5-ALA) application. Conversely, approximately 30% of nonenhancing gliomas are actually high grade. OBJECTIVE: The aim of this study was to identify preoperative factors (ie, age, enhancement, 18F-fluoroethyl tyrosine positron emission tomography [18F-FET PET] uptake ratios) for predicting fluorescence in gliomas without typical glioblastomas imaging features and to determine whether fluorescence will allow prediction of tumor grade or molecular characteristics. METHODS: Patients harboring gliomas without typical glioblastoma imaging features were given 5-ALA. Fluorescence was recorded intraoperatively, and biopsy specimens collected from fluorescing tissue. World Health Organization (WHO) grade, Ki-67/MIB-1 index, IDH1 (R132H) mutation status, O6-methylguanine DNA methyltransferase (MGMT) promoter methylation status, and 1p/19q co-deletion status were assessed. Predictive factors for fluorescence were derived from preoperative magnetic resonance imaging and 18F-FET PET. Classification and regression tree analysis and receiver-operating-characteristic curves were generated for defining predictors. RESULTS: Of 166 tumors, 82 were diagnosed as WHO grade II, 76 as grade III, and 8 as glioblastomas grade IV. Contrast enhancement, tumor volume, and 18F-FET PET uptake ratio >1.85 predicted fluorescence. Fluorescence correlated with WHO grade (P < .001) and Ki-67/MIB-1 index (P < .001), but not with MGMT promoter methylation status, IDH1 mutation status, or 1p19q co-deletion status. The Ki-67/MIB-1 index in fluorescing grade III gliomas was higher than in nonfluorescing tumors, whereas in fluorescing and nonfluorescing grade II tumors, no differences were noted. CONCLUSION: Age, tumor volume, and 18F-FET PET uptake are factors predicting 5-ALA-induced fluorescence in gliomas without typical glioblastoma imaging features. Fluorescence was associated with an increased Ki-67/MIB-1 index and high-grade pathology. Whether fluorescence in grade II gliomas identifies a subtype with worse prognosis remains to be determined.

P14.79 Differentiation of treatment-related changes from tumor progression following brachytherapy in patients with WHO II and III gliomas using FET PET

2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii53-ii53
Author(s):  
E K Bauer ◽  
J Werner ◽  
A Brunn ◽  
M Deckert ◽  
D Ruess ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Characteristic Curve ◽  
Diagnostic Value ◽  
Mri Findings ◽  
Who Grade ◽  
Fet Pet ◽  
Diagnostic Uncertainty ◽  
Radiation Induced ◽  
Grade Ii ◽  
Induced Changes

Abstract BACKGROUND Following brachytherapy, the differentiation of radiation-induced changes (e.g., radiation necrosis) from actual tumor progression using MRI is challenging. To overcome this diagnostic uncertainty, we evaluated the diagnostic value of O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in glioma patients treated with brachytherapy. MATERIAL AND METHODS From 2006–2019, we retrospectively identified WHO grade II or III glioma patients (i) treated with brachytherapy using Iodine-125 seeds, (ii) equivocal or progressive MRI findings inside the radiation field, and (iii) additional FET PET imaging for diagnostic evaluation. Static FET PET parameters such as maximum and mean tumor-to-brain ratios (TBR) and dynamic FET PET parameters (i.e., time-to-peak, slope) were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses and Fisher’s exact test. Diagnoses were confirmed histologically or clinicoradiologically. RESULTS Following brachytherapy, suspect MRI findings occurred after a median time of 33 months (range, 5–111 months). In 10 of 21 patients (WHO grade II, n=5; WHO grade III, n=16), treatment-related changes were diagnosed. The best diagnostic performance for identification of treatment-related changes was obtained using maximum TBRs (threshold <3.20; accuracy, 86%; sensitivity, 100%; specificity, 73%; P=0.007). Mean TBRs reached an accuracy of 76% (threshold <2.05; sensitivity, 89%; specificity, 64%; P=0.010). Dynamic PET parameters did not reach statistically significant results. CONCLUSION Our data suggest that static FET PET parameters add valuable diagnostic information to diagnose radiation-induced changes in glioma patients treated with brachytherapy.

INNV-10. TUMOR TREATING FIELDS (TTF) AS MAINTENANCE THERAPY FOR AN OLIGODENDROGLIOMA CASE AND LONG-TERM FOLLOW-UP

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi107-vi107
Author(s):  
Uvin Ko ◽  
Steven Du ◽  
Matthew Moldenhauer ◽  
Xiao-Tang Kong
Keyword(s):  
Maintenance Therapy ◽  
Tumor Progression ◽  
Brain Mri ◽  
High Grade Glioma ◽  
Residual Tumor ◽  
Potential Effect ◽  
Distribution Area ◽  
High Grade ◽  
Initial Image ◽  
Tumor Treating Fields

Abstract INTRODUCTION Recurrence of low- and high-grade gliomas is observed often after radiation and chemotherapy. Despite continued research on glioma management, there is limited knowledge regarding maintenance treatment after standard care. Tumor Treating Fields as maintenance therapy after radiation and chemotherapy may potentially help prevent recurrence. CASE REPORT In 2011, a 35-year-old male reported headaches to a local ED. A non-enhancing mass was detected on his brain MRI. Observation was advised by his local surgeon. The patient presented with seizures in early 2014, and his brain MRI found the mass developed new enhancement. In late 2014, the patient had multiple seizures, and significant progression of the tumor was discovered. The patient underwent craniotomy and biopsy in the middle cerebral artery distribution area in early 2015. Pathology reported grade II oligodendroglioma; however, the patient only underwent a biopsy, which might have missed the high-grade glioma region. His brain MRI showed a significant enhancing lesion with rapid growth, which was clinically more consistent with grade III oligodendroglioma. Radiation therapy was conducted followed by 6 cycles of PCV chemotherapy throughout 11 months. Post-radiation-chemotherapy brain MRI was stable with a moderate size residual tumor at the right insula region. Following patient wishes, NovoTTF-100A, or Optune, was administered 6 weeks after completion of chemotherapy as maintenance therapy for 2 years to prevent tumor progression. Now, after 3 years being off Optune, the patient is stable without new neurological symptoms or tumor progression. DISCUSSION: Our case highlights the potential effect of Tumor Treating Fields as maintenance therapy after initial radiation and chemotherapy for low- and high-grade oligodendrogliomas. The patient had rapid tumor progression prior to diagnosis and only underwent a biopsy without resection, yet uncommonly, has survived since initial image diagnosis 10 years ago and tissue diagnosis 6 years ago and is fully functional currently.

NIMG-20. DIFFERENTIATION OF TREATMENT-RELATED CHANGES FROM TUMOR PROGRESSION FOLLOWING BRACHYTHERAPY IN PATIENTS WITH WHO II AND III GLIOMAS USING FET PET

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi132-vi132
Author(s):  
Elena Bauer ◽  
Jan Werner ◽  
Anna Brunn ◽  
Martina Deckert ◽  
Daniel Ruess ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Characteristic Curve ◽  
Diagnostic Value ◽  
Mri Findings ◽  
Who Grade ◽  
Fet Pet ◽  
Diagnostic Uncertainty ◽  
Radiation Induced ◽  
Grade Ii ◽  
Induced Changes

Abstract BACKGROUND Following brachytherapy, the differentiation of radiation-induced changes (e.g., radiation necrosis) from actual tumor progression using MRI is challenging. To overcome this diagnostic uncertainty, we evaluated the diagnostic value of O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in glioma patients treated with brachytherapy. MATERIAL AND METHODS From 2006-2019, we retrospectively identified WHO grade II or III glioma patients (i) treated with brachytherapy using Iodine-125 seeds, (ii) equivocal or progressive MRI findings inside the radiation field, and (iii) additional FET PET imaging for diagnostic evaluation. Static FET PET parameters such as maximum and mean tumor-to-brain ratios (TBR) and dynamic FET PET parameters (i.e., time-to-peak, slope) were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses and Fisher’s exact test. Diagnoses were confirmed histologically or clinicoradiologically. RESULTS Following brachytherapy, suspect MRI findings occurred after a median time of 33 months (range, 5-111 months). In 10 of 21 patients (WHO grade II, n=5; WHO grade III, n=16), treatment-related changes were diagnosed. The best diagnostic performance for identification of treatment-related changes was obtained using maximum TBRs (threshold < 3.20;accuracy, 86%; sensitivity, 100%; specificity, 73%; P=0.007). Mean TBRs reached an accuracy of 76% (threshold < 2.05; sensitivity, 89%; specificity, 64%; P=0.010). Dynamic PET parameters did not reach statistically significant results. CONCLUSION Our data suggest that static FET PET parameters add valuable diagnostic information to diagnose radiation-induced changes in glioma patients treated with brachytherapy.

scholarly journals Prediction of TERTp-mutation status in IDH-wildtype high-grade gliomas using pre-treatment dynamic [18F]FET PET radiomics

2021 ◽  
Author(s):  
Zhicong Li ◽  
Lena Kaiser ◽  
Adrien Holzgreve ◽  
Viktoria C. Ruf ◽  
Bogdana Suchorska ◽  
...  
Keyword(s):  
High Grade Glioma ◽  
Recursive Feature Elimination ◽  
High Grade ◽  
Who Grade ◽  
Mutation Status ◽  
Fet Pet ◽  
Logistic Regression Models ◽  
Time To Peak ◽  
High Grade Gliomas ◽  
Pre Treatment

Abstract Purpose To evaluate radiomic features extracted from standard static images (20–40 min p.i.), early summation images (5–15 min p.i.), and dynamic [18F]FET PET images for the prediction of TERTp-mutation status in patients with IDH-wildtype high-grade glioma. Methods A total of 159 patients (median age 60.2 years, range 19–82 years) with newly diagnosed IDH-wildtype diffuse astrocytic glioma (WHO grade III or IV) and dynamic [18F]FET PET prior to surgical intervention were enrolled and divided into a training (n = 112) and a testing cohort (n = 47) randomly. First-order, shape, and texture radiomic features were extracted from standard static (20–40 min summation images; TBR20–40), early static (5–15 min summation images; TBR5–15), and dynamic (time-to-peak; TTP) images, respectively. Recursive feature elimination was used for feature selection by 10-fold cross-validation in the training cohort after normalization, and logistic regression models were generated using the radiomic features extracted from each image to differentiate TERTp-mutation status. The areas under the ROC curve (AUC), accuracy, sensitivity, specificity, and positive and negative predictive value were calculated to illustrate diagnostic power in both the training and testing cohort. Results The TTP model comprised nine selected features and achieved highest predictability of TERTp-mutation with an AUC of 0.82 (95% confidence interval 0.71–0.92) and sensitivity of 92.1% in the independent testing cohort. Weak predictive capability was obtained in the TBR5–15 model, with an AUC of 0.61 (95% CI 0.42–0.80) in the testing cohort, while no predictive power was observed in the TBR20–40 model. Conclusions Radiomics based on TTP images extracted from dynamic [18F]FET PET can predict the TERTp-mutation status of IDH-wildtype diffuse astrocytic high-grade gliomas with high accuracy preoperatively.

Comparison Between 18F-Dopa and 18F-Fet PET/CT in Patients with Suspicious Recurrent High Grade Glioma: A Literature Review and Our Experience

2019 ◽  
Vol 12 (3) ◽  
pp. 220-228 ◽  
Author(s):  
Laura Evangelista ◽  
Lea Cuppari ◽  
Luisa Bellu ◽  
Daniele Bertin ◽  
Mario Caccese ◽  
...  
Keyword(s):  
Case Series ◽  
High Grade Glioma ◽  
High Grade ◽  
True Negative ◽  
Fet Pet ◽  
Positron Emission ◽  
Pet Ct ◽  
Magnetic Resonance Imaging Mri ◽  
Definition Of ◽  
Sensitivity Specificity

Purpose: The aims of the present study were to: 1- critically assess the utility of L-3,4- dihydroxy-6-18Ffluoro-phenyl-alanine (18F-DOPA) and O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) Positron Emission Tomography (PET)/Computed Tomography (CT) in patients with high grade glioma (HGG) and 2- describe the results of 18F-DOPA and 18F-FET PET/CT in a case series of patients with recurrent HGG. Methods: We searched for studies using the following databases: PubMed, Web of Science and Scopus. The search terms were: glioma OR brain neoplasm and DOPA OR DOPA PET OR DOPA PET/CT and FET OR FET PET OR FET PET/CT. From a mono-institutional database, we retrospectively analyzed the 18F-DOPA and 18F-FET PET/CT of 29 patients (age: 56 ± 12 years) with suspicious for recurrent HGG. All patients underwent 18F-DOPA or 18F-FET PET/CT for a multidisciplinary decision. The final definition of recurrence was made by magnetic resonance imaging (MRI) and/or multidisciplinary decision, mainly based on the clinical data. Results: Fifty-one articles were found, of which 49 were discarded, therefore 2 studies were finally selected. In both the studies, 18F-DOPA and 18F-FET as exchangeable in clinical practice particularly for HGG patients. From our institutional experience, in 29 patients, we found that sensitivity, specificity and accuracy of 18F-DOPA PET/CT in HGG were 100% (95% confidence interval- 95%CI - 81-100%), 63% (95%CI: 39-82%) and 62% (95%CI: 39-81%), respectively. 18F-FET PET/CT was true positive in 4 and true negative in 4 patients. Sensitivity, specificity and accuracy for 18F-FET PET/CT in HGG were 100%. Conclusion: 18F-DOPA and 18F-FET PET/CT have a similar diagnostic accuracy in patients with recurrent HGG. However, 18F-DOPA PET/CT could be affected by inflammation conditions (false positive) that can alter the final results. Large comparative trials are warranted in order to better understand the utility of 18F-DOPA or 18F-FET PET/CT in patients with HGG.

scholarly journals CTIM-06. DENDRITIC CELL VACCINE STUDY FOR RECURRENT, HIGH-GRADE GLIOMA: TISSUE-BASED RNA SEQUENCING AND SERUM CYTOKINE LEVELS AS POTENTIAL BIOMARKERS

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii33-ii34
Author(s):  
Macarena De La Fuente ◽  
Tulay Koru-Sengul ◽  
Deborah Heros ◽  
Feng Miao ◽  
Alain Fernandez Marrero ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Rna Sequencing ◽  
Tumor Antigens ◽  
High Grade Glioma ◽  
Treatment Discontinuation ◽  
Sequencing Analysis ◽  
High Grade ◽  
Who Grade ◽  
Cytokine Levels ◽  
Grade 3

Abstract BACKGROUND Glioblastoma is the most common primary malignant brain tumor. Despite multimodality treatment approach, median progression-free survival (PFS) is only 8 months, median overall-survival (OS) 14 months and 5-year survival rate of under 10%. Dendritic cells (DCs) are the professional antigen presenting cells of the immune system. The rationale for sensitizing dendritic cells to a pool of non-selected tumor antigens is based on the marked heterogeneity present within glioblastoma tumor cells. METHODS Phase 1/feasibility study of DC vaccine for recurrent high-grade glioma was conducted. Pooled, non-selected tumor antigens collected via tumor cell lysate were used for DC sensitization. RNA sequencing analysis was performed on all tumor samples. Cytokine levels in serum were detected using a Luminex cytokine panel. RESULTS A total of 20 patients were enrolled onto this study (median age 58yrs, range: 39–74, 65% male). Pathology showed WHO grade IV glioblastoma in 14 (70%) and grade III anaplastic astrocytoma in 6 (30%) patients. IDH wild type in 19 (95%) patients. Treatment emergent adverse events (all grades, regardless of attribution) occurred in more than 15% of the patients (20% fatigue, 15% dizziness, 15% headache, none leading to treatment discontinuation). There were five grade 3–4 and none grade 5 events. One grade 4 event (seizure) probable related to investigational treatment leading to treatment discontinuation. Four grade 3 events (dysphasia, possible related; intracranial hemorrhage unrelated; muscle weakness, unlikely related and hematoma, unrelated). Median PFS was 3.8 months. Median OS was 11 months. RNA sequencing in tumor samples and correlation with cytokine levels in serum is currently been analyzed. CONCLUSION Tumor lysate pulsed DC vaccination demonstrates acceptable safety and tolerability in high-grade glioma patients. Evaluations of integrating molecular profiling RNA sequencing information and cytokine levels to identify potential subset of patients with significant clinical benefit will be provided.

scholarly journals HGG-12. A CASE OF PEDIATRIC SPINAL HIGH-GRADE GLIOMA WITH NTRK1 GENE FUSION

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii346-iii346
Author(s):  
Tamaki Morisako ◽  
Daisuke Umebayashi ◽  
Kazuaki Kamata ◽  
Hiroyuki Yamamoto ◽  
Takumi Yamanaka ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Mr Imaging ◽  
Tumor Progression ◽  
Gene Fusion ◽  
High Grade Glioma ◽  
Gene Panel ◽  
Partial Resection ◽  
Low Grade ◽  
High Grade ◽  
Surgical Specimen

Abstract INTRODUCTION Tumors arising from the spinal cord are uncommon, especially high-grade tumors in pediatric patients. We report a case of high-grade glioma in the spinal cord harboring NTRK1 gene fusion, who received effective entrectinib therapy. CASE REPORT: A 5-year-old boy presented right hemiparesis and MR imaging revealed an intramedullary enhancing mass at the vertebral body level between C3 and Th1. He underwent microsurgical partial resection and the histological diagnosis was low-grade astrocytoma. After the first-line chemotherapy with vincristine and carboplatin, his right hemiparesis deteriorated and recurrent MR imaging showed growth of the tumor. He underwent microsurgical partial resection again and the histological examination was high-grade glioma with endothelial proliferation and necrosis. The chemoradiotherapy with temozolomide and focal irradiation of 50.4 Gy were given, and his neurological symptom slightly improved. One month later, he presented respiratory disturbance and required assisted ventilation with tracheostomy. MR imaging showed tumor progression invading upward to medulla oblongata. NTRK1 gene fusion was detected in the previous surgical specimen by a gene panel testing, and he received entrectinib, a potent inhibitor of tropomyosin receptor kinase (TRK). Since then, no tumor progression has been demonstrated for several months by MRI and he has been stable neurologically. CONCLUSION High-grade spinal cord tumors are rare and effective treatment strategies have not been addressed. Although the frequency of the gene fusion is very low in pediatric gliomas, identification of the driver gene aberration like in this case by a gene panel can provide potential targeted therapies for selected patients.

CTNI-22. A PHASE 0/1 ‘TRIGGER’ TRIAL OF RIBOCICLIB PLUS EVEROLIMUS IN RECURRENT HIGH-GRADE GLIOMA

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi64-vi64
Author(s):  
Nader Sanai ◽  
An-Chi Tien ◽  
Jun Jiang ◽  
Yu-Wei Chang ◽  
Chelsea Pennington-Krygier ◽  
...  
Keyword(s):  
High Grade Glioma ◽  
High Grade ◽  
Mtor Inhibition ◽  
Who Grade ◽  
Expansion Phase ◽  
Pik3ca Mutations ◽  
Pten Loss ◽  
Drug Concentrations ◽  
Phase 0 ◽  
Unbound Concentration

Abstract BACKGROUND mTOR activation is a mechanism of resistance in CDK4/6 targeting. We evaluated tumor pharmacokinetics (PK) and tumor pharmacodynamics (PD) of combined CDK4/6 and mTOR inhibition in recurrent high-grade glioma (HGG) patients. METHODS Recurrent HGG patients with (1) intact RB, (2) CDKN2A/B deletion or CDK4/6 amplification, and (3) PTEN loss or PIK3CA mutations receive five days of presurgical ribociclib plus everolimus prior to resection at 2, 8 or 24 hours after the final dose. Beginning at 400mg QD ribociclib plus 2.5mg QD everolimus, six dose-escalations summit at 600mg QD plus 60mg QW. Gadolinium [Gd]-enhancing and nonenhancing tumor regions, CSF, and plasma are collected. Total and unbound drug concentrations are determined using validated LC-MS/MS methods. RB and S6 phosphorylation are compared to matched archival tissue. To select patients for a therapeutic expansion phase of combined drug therapy, the protocol includes a PK ‘trigger’ (i.e., for each drug, unbound concentration in Gd-nonenhancing tumor > 5-fold biochemical IC50) and a PD ‘trigger’ (i.e., for each tumor, > 30% decrease in pRB and pS6). RESULTS 21 patients with WHO Grade III (n=2) and IV (n=19) gliomas were enrolled into the Phase 0 component of the study. No dose-limiting toxicities were observed. In Gd-nonenhancing tumor regions, the median unbound concentration of ribociclib was 719 nM, whereas unbound everolimus tumor concentrations were undetectable. Across all dose-levels, 62% (13/21) and 22% (5/21) of tumors demonstrated decreased tumor RB and S6 phosphorylation, respectively. Tumor proliferation (MIB-1) was decreased in 67% (14/21) of all patients. No patients qualified for the therapeutic expansion phase. CONCLUSION In adult HGG, ribociclib achieves pharmacologically-relevant concentrations in Gd-nonenhancing tumor whereas everolimus exhibits no meaningful tumor penetration. These findings support further clinical development of ribociclib, but not everolimus, for the treatment of high-grade glioma patients.

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