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ImmunoPET-informed sequence for focused ultrasound-targeted mCD47 blockade controls glioma.

Authors: Sheybani ND, Breza VR, Paul S, McCauley KS, Berr SS, Miller GW, Neumann KD, Price RJ

Phagocytic immunotherapies such as CD47 blockade have emerged as promising strategies for glioblastoma (GB) therapy, but the blood brain/tumor barriers (BBB/BTB) pose a persistent challenge for mCD47 delivery that can be overcome by focused ultrasound (FUS)-mediated BBB/BTB disruption. We here leverage immuno-PET imaging to determine how timing of [<sup>89</sup>Zr]-mCD47 injection relative to FUS impacts antibody penetrance into orthotopic murine gliomas. We then design and implement a rational paradigm for combining FUS and mCD47 for glioma therapy. We demonstrate that timing of antibody injection relative to FUS BBB/BTB disruption is a critical determinant of mCD47 access, with post-FUS injection conferring superlative antibody delivery to gliomas. We also show that mCD47 delivery across the BBB/BTB with repeat sessions of FUS can significantly constrain tumor outgrowth and extend survival in glioma-bearing mice. This study generates provocative insights for ongoing pre-clinical and clinical evaluations of FUS-mediated antibody delivery to brain tumors. Moreover, our results confirm that mCD47 delivery with FUS is a promising therapeutic strategy for GB therapy.

Introduction

Purpose Drug delivery with BBB opening
Study Objective To determine how the timing of mCD47 antibody administration relative to focused ultrasound-mediated BBB/BTB disruption affects antibody penetration into orthotopic murine gliomas and therapeutic efficacy.
Animal model / Human subject Mice (C57BL/6, sex: female, age: 6-10 weeks, implanted with GL261 cells)
Disease model glioblastoma (glioma)
MRI or image guidance method 1.5T MRI (Avanto, Siemens), 3T MRI (Prisma, Siemens)
Targeted brain region(s) Striatum
Cargo name and characteristics mCD47: murine monoclonal anti‑CD47 antibody (protein)
Route of administration intravenous

Outcomes and Safety

Summary of Outcomes Injecting mCD47 after FUS-mediated BBB/BTB disruption produced superior antibody delivery into orthotopic gliomas. Repeated sessions of FUS-mediated mCD47 delivery significantly constrained tumor outgrowth and extended survival in glioma-bearing mice; the successful FUS-related parameters were post-FUS antibody injection timing and repeat FUS sessions.
Duration of biological effect 48 hours
Safety-related matter No adverse effects are reported.

Brain Region

Ultrasound Parameters

Ultrasound instrument spherical single-element transducer and FUS system (RK-100, FUS Instruments)
FUS Frequency 1.1 MHz
FUS Pressure 0.4 MPa
FUS Mode pulsed
Duration of a single FUS session 2 min
Treatment frequency single, multiple

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