ACTR-82. LASER INTERSTITIAL THERMAL THERAPY (LITT) OF RECURRENT GLIOBLASTOMA (GBM) INDUCES TEMPORARY DISRUPTION OF THE PERITUMORAL BLOOD BRAIN BARRIER (BBB) AND MAY IMPROVE EFFICACY OF CHEMOTHERAPY WITH POOR CNS PENETRATION

Abstract INTRODUCTION A central challenge in glioblastoma treatment is the presence of the blood-brain barrier (BBB) and blood-tumor barrier (BTB), which prevent access of drugs to the brain and tumor respectively. Recent evidence in patients suggests laser interstitial thermal therapy (LITT), used clinically for tumor ablation, locally disrupts BBB integrity, potentially creating a therapeutic window to deliver otherwise brain-impermeant agents. METHODS A mouse model for LITT, established using a Nd-YAG laser coupled to a 600 mm fiber optic and thermocouple probe, was inserted via burrhole to target the somatosensory cortex. Syngeneic GL261 tumor cells were stereotactically implanted prior to LITT. BBB and BTB permeability were assessed through measurement of fluorescein and doxorubicin after IV injection. Permeability of IV dextran (10 and 70 kDa) and human IgG was monitored by immunohistochemistry (IHC) analysis. Mechanisms of BBB breakdown in vivo were explored utilizing electron microscopy and IHC. RESULTS By fluorescein assay, LITT-induced BBB and BTB permeability began one day post-treatment and was sustained for at least 2 weeks. Additionally, both normal brain and brain tumors demonstrated an increase in Dextran 10 kDa, Dextran 70 kDa, and human IgG extravasation after IV injection in vivo. Mechanistically, we provide evidence that LITT triggers both a decrease in tight junction integrity and an increase in brain endothelial cell transcytosis. As proof-of-concept that LITT can enhance tumor delivery of systemic drugs, LITT increased IV doxorubicin permeability in brain in vivo. Moreover, LITT plus doxorubicin significantly increased survival in brain tumor-bearing mice compared to doxorubicin or LITT alone. CONCLUSIONS Our data suggest that LITT increases BBB and BTB permeability over a defined time window to large molecular weight agents, including antibodies, through multiple cellular mechanisms. Our preclinical results with LITT plus doxorubicin, which mirror a current clinical trial, indicate LITT can enhance the efficacy of systemically delivered drugs.

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SCIDOT-50. A RAT MODEL FOR LASER INTERSTITIAL THERMAL THERAPY FOR GLIOBLASTOMA: EFFECTS ON PERI-ABLATION BLOOD-BRAIN BARRIER AND IMPLICATIONS FOR POST-ABLATION CHEMOTHERAPY

Neuro-Oncology ◽

10.1093/neuonc/noz175.1185 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi282-vi282

Author(s):

Tavarekere Nagaraja ◽

James Ewing ◽

Katelynn Farmer ◽

Grahm Valadie ◽

Stephen Brown ◽

...

Keyword(s):

Tumor Cells ◽

Blood Brain Barrier ◽

Thermal Therapy ◽

Female Rats ◽

Brain Barrier ◽

Laser Interstitial Thermal Therapy ◽

Lethal Temperatures ◽

Blood Brain ◽

U251 Cells ◽

Bbb Opening

Abstract Laser interstitial thermal therapy (LITT) is a minimally invasive tumor cytoreductive treatment for recurrent gliomas, brain tumors in eloquent regions or otherwise inaccessible to traditional open surgery. LITT offers quicker recovery and shorter hospital stays as additional advantages. A laser fiberoptic catheter is positioned in the body of the tumor under magnetic resonance imaging (MRI) guidance via a twist drill hole in the skull. Using MR thermometry, the tumor is ablated by laser heating to lethal temperatures. The peri-ablation zones get heated to sub-lethal temperatures and subsequently recover. It has been reported in humans that opening of the blood-brain barrier (BBB) occurs, lasting several weeks after ablation. We have adapted Visualase®, a clinically available LITT system, for use in a rat glioblastoma model. Athymic female rats (n=7) were implanted with U251 tumor cells in one brain hemisphere. Tumor growth was monitored using MRI. When tumors reached about 4 mm in diameter, they were ablated under supervision of MR diffusion-weighted MRI, sparing the surrounding normal brain tissue. Contrast-enhanced MRI data were obtained before LITT, immediately after and at post-LITT 24 h. The brains were processed for histopathology and stained with hematoxylin and eosin (H&E) for visualizing the extent of the tumor and for major histocompatibility complex (MHC) to identify the human-derived U251 cells. All rats survived the LITT procedure. A ring of contrast enhancement around ablation perimeter was observed immediately after, and also at 24 h. H&E data showed near-complete ablation of the tumors. However, MHC staining showed U251 cells still remaining in the ablation vicinity. These data suggest this model is useful for examining the temporal and spatial development of peri-ablation BBB opening following LITT. Concurrent timing of post-ablation chemotherapy to the development and presence of post-LITT BBB opening may aid in efficient targeting of remaining tumor cells.

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Marizomib alone or in combination with bevacizumab in patients with recurrent glioblastoma: phase I/II clinical trial data

Neuro-Oncology Advances ◽

10.1093/noajnl/vdab142 ◽

2021 ◽

Author(s):

Daniela A Bota ◽

Warren Mason ◽

Santosh Kesari ◽

Rajiv Magge ◽

Benjamin Winograd ◽

...

Keyword(s):

Phase I ◽

Blood Brain Barrier ◽

Dose Escalation ◽

Safety Profile ◽

Clinical Trial Data ◽

Progression Free Survival ◽

Recurrent Glioblastoma ◽

Brain Barrier ◽

Part C ◽

Blood Brain

Abstract Background This phase I/II trial in patients with recurrent glioblastoma (GBM) evaluates the safety and preliminary efficacy of marizomib, an irreversible pan-proteasome inhibitor that crosses the blood–brain barrier. Patients and Methods Part A assessed the safety and efficacy of marizomib monotherapy. In Part B, escalating doses of marizomib (0.5–0.8 mg/m2) in combination with bevacizumab were evaluated. Part C explored intra-patient dose escalation of marizomib (0.8–1.0 mg/m2) for the combination. Results In Part A, 30 patients received marizomib monotherapy. The most common AEs were fatigue (66.7%), headache (46.7%), hallucination (43.3%), and insomnia (43.3%). One patient (3.3%) achieved a partial response. In Part B, the recommended phase II dose of marizomib was 0.8 mg/m2 when combined with bevacizumab 10 mg/kg. In Part C, dose escalation to 1.0 mg/m2 was not tolerated. Pooled analysis of 67 patients treated with marizomib ≤0.8 mg/m2 and bevacizumab showed a non-overlapping safety profile consistent with the known safety profile of each agent: the most common grade ≥3 AEs were hypertension (16.4%), confusion (13.4%), headache (10.4%), and fatigue (10.4%). The overall response rate was 34.3%, including 2 patients with complete response. Six-month progression-free survival was 29.8%; median overall survival was 9.1 months. Conclusions The safety profile of marizomib as monotherapy and in combination with bevacizumab was consistent with previous observations that marizomib crosses the blood–brain barrier. Preliminary efficacy did not demonstrate a meaningful benefit of the addition of marizomib to bevacizumab for the treatment of recurrent GBM.

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EXTH-07. TEMPORAL ASSESSMENT OF ALTERED PERI-ABLATION BLOOD-BRAIN BARRIER PERMEABILITY FOLLOWING TUMOR CYTOREDUCTION BY THERMAL THERAPY IN A RAT ORTHOTOPIC GLIOBLASTOMA MODEL

Neuro-Oncology ◽

10.1093/neuonc/noab196.646 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi164-vi164

Author(s):

Tavarekere Nagaraja ◽

Seamus Bartlett ◽

Glauber Cabral ◽

Katelynn Farmer ◽

Robert Knight ◽

...

Keyword(s):

Blood Brain Barrier ◽

Evans Blue ◽

Thermal Therapy ◽

Female Rats ◽

Brain Barrier ◽

Gadolinium Contrast ◽

Dce Mri ◽

Blood Brain ◽

Bbb Permeability ◽

Bbb Opening

Abstract Laser interstitial thermal therapy (LITT) is a minimally invasive tumor cytoreductive treatment for recurrent gliomas, brain tumors in eloquent regions and/or otherwise inaccessible. Following reports of persistent peri-ablation blood-brain barrier (BBB) opening in humans, we examined this phenomenon using a rat glioblastoma model. Athymic female rats were implanted with U251 tumor cells in one brain hemisphere. Tumor growth was monitored using magnetic resonance imaging (MRI) and dynamic contrast enhanced (DCE)-MRI. When tumors reached about 4 mm in diameter, they were ablated under supervision of diffusion-weighted MRI using Visualase®, a clinical LITT system. Four rats were used as controls. Longitudinal MRI data were obtained before LITT, and at post-LITT 2 (n=9), 3 (n=3) and 4 (n=9) weeks. After the terminal MRI at each time point, rats were injected intravenously with fluorescent isothiocyanate dextran (FITC-dextran; 2000 kDa) and Evans Blue (68 kDa after binding to plasma albumin) and the brains immersion fixed in 10% paraformaldehyde. The brains were cut into 100 μM thick slices in a vibratome and examined for the distribution of the two fluorophores. All rats survived the LITT procedure. The sham controls showed increased tumor burden by 2 weeks and were sacrificed. DCE-MRI data and fluorescent data showed elevated BBB permeability in peri-ablation regions, with leakage of a gadolinium contrast on DCE-MRI and of Evans Blue, but not of FITC-dextran. Histology showed little tumor tissue at 2 weeks, but evidence of recurrence at ablation margins at later times. These data demonstrate that LITT is adaptable to rat glioma models and can be performed under MRI monitoring. Peri-ablation regions showed selective increase in BBB permeability acutely due to sublethal heating, but later increases in permeability may be due to tumor recurrence. We suggest this model is useful for examining the temporal and spatial development of peri-ablation BBB opening following LITT.

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A phase I/IIa study to evaluate the safety and efficacy of blood-brain barrier (BBB) opening with the SonoCloud-9 implantable ultrasound device in recurrent glioblastoma patients receiving IV carboplatin.

Journal of Clinical Oncology ◽

10.1200/jco.2021.39.15_suppl.2049 ◽

2021 ◽

Vol 39 (15_suppl) ◽

pp. 2049-2049

Author(s):

Ahmed Idbaih ◽

Francois Ducray ◽

Roger Stupp ◽

Nathalie Baize ◽

Olivier L. Chinot ◽

...

Keyword(s):

Phase I ◽

Blood Brain Barrier ◽

Tissue Concentration ◽

Primary Objective ◽

Recurrent Glioblastoma ◽

Mass Spectrometry Data ◽

Brain Barrier ◽

Pulsed Ultrasound ◽

Blurred Vision ◽

Blood Brain

2049 Background: Low intensity pulsed ultrasound (LIPU) in conjunction with intravenous microbubbles can transiently and reversibly disrupt the blood-brain barrier (BBB), allowing for an increase in the tissue concentration of chemotherapy agents in the brain. Mass spectrometry data from preclinical models (mouse, swine) showed a > 5x enhancement in carboplatin brain concentrations, which correlated well with the spatial distribution of a Gadolinium (Gd) contrast agent used for magnetic resonance imaging (MRI). Methods: The primary objective of this phase I/IIa study (NCT03744026) was to demonstrate the safety of BBB disruption using LIPU in patients with recurrent glioblastoma. This study was a 3+3 design using escalating numbers (3, 6, 9) of activated 1 MHz ultrasound emitters. Nine patients were treated in the escalation phase and another 12 patients were treated with 9 emitters in the expansion phase. Eligibility included recurrent GBM (any recurrence) with a maximum tumor size of < 70 mm. The SonoCloud-9 device (CarThera, Paris, France) was implanted during tumor debulking/resection surgery and replaced the bone flap, with the device targeting the tumor and surrounding peritumoral brain. The device was activated every four weeks for a duration of 270 seconds, concomitantly with IV DEFINITY microbubbles (10 ml/kg), to disrupt the BBB prior to administration of carboplatin (AUC 4-6). MRI was performed to verify safety and evaluate efficacy of BBB disruption with Gd enhancement. Results: No DLTs were observed. The overall tolerance of the SonoCloud-9 implant was good, with two transient, manageable grade 3 wound infections and one grade 1 acquired meningocele event considered as probably related to the overall procedure. The most frequent neurologic adverse events were grade 1 blurred vision (5%) and dizziness (5%). Conclusions: Significant Gd enhancement was observed after more than 90% of sonication sessions, suggesting effective BBB disruption and carboplatin enhancement. Clinical trial information: NCT03744026.

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TRLS-08. CNS PENETRATION AND PRELIMINARY EFFICACY OF SACUTIZUMAB GOVITECAN IN BREAST BRAIN METASTASIS AND GLIOBLASTOMA: A SURGICAL STUDY

Neuro-Oncology Advances ◽

10.1093/noajnl/vdz014.041 ◽

2019 ◽

Vol 1 (Supplement_1) ◽

pp. i10-i10 ◽

Cited By ~ 1

Author(s):

Andrew Brenner ◽

John Floyd ◽

Prathiba Surapaneni ◽

Vinu Madhusudanan-Kunnuparampil ◽

Stefano Tiziani

Keyword(s):

Blood Brain Barrier ◽

Standard Dose ◽

Total Concentration ◽

Therapeutic Benefit ◽

Brain Barrier ◽

Priority Review ◽

Antibody Drug Conjugate ◽

Blood Brain ◽

Cns Penetration ◽

Breast Cancer Brain Metastases

Abstract Sacituzumab govitecan (SG) is an antibody drug conjugate (ADC) that targets Trop-2 for the selective delivery of SN-38 to tumors. SG carries SN-38, a topoisomerase inhibitor active in the nanomolar range for most cells (including TNBC and GBM) and freely cross the blood brain barrier. SN-38 is conjugated to SG by a linker designated CL2A which is sensitive to acidic conditions. SG has since been granted priority review designation by the FDA, with approval anticipated for triple negative breast cancer. Brain metastases is a significant concern in this patient population, but whether this agent is able to target the CNS through the blood brain barrier is unknown. Based upon the characteristics of this specific ADC, including the use of a pH labile linker and a payload with good CNS penetration, it is our specific hypothesis that the SG can achieve intratumoral concentrations of SN-38 sufficient to achieve therapeutic benefit in patients with neoplastic involvement of the brain. We further hypothesize that while total concentration of SN-38 will correlate with expression of trop2, free SN-38 will correlate more strongly with intratumoral hypoxia. To address this, we are performing a non-randomized, prospective study of SG in subjects with CNS involvement and planned surgical resection. SG is given as single dose at 10mg/kg pre-operatively on Day-1. Surgery will be followed by post-operative treatment with sacituzumab govitecan given intravenously with standard dose of 10 mg/kg on day1 and day 8 of 21-day cycle, until disease progression. Approximately 20 patients, 2 cohorts of 10 patients each with GBM and breast brain tumors, will be enrolled. Tumors will be analyzed for total antibody, free SN-38, and total SN-38 (free SN-38 + Antibody-SN38) concentrations in tumor tissue. Correlations will be made to Trop2 expression and hypoxia. Interim results will be presented.

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