ImmunoPET Evaluation of Focused Ultrasound-mediated Delivery and Immunomodulation by anti-CD47 Immunotherapy in the Setting of Current Standard-of-Care Treatment for Glioblastoma

Project Summary: A long-standing problem in the treatment of glioblastoma (GBM), the most common and deadly primary brain

tumor, is the efficient delivery of therapeutics to the highly invasive tumor cells that pervasively infiltrate the brain and are sheltered from many therapeutics behind an intact, functional blood-brain barrier (BBB). This problem is compounded by the fact that pre-clinical models of GBM often do not recapitulate the highly invasive nature of

clinical disease and do not incorporate the multi-modal standard-of-care (SOC) treatments that the majority of patients receive. SOC interventions are important to include in our pre-clinical modeling because they

significantly alter the clinically relevant disease state, and new investigational therapies will likely be first tested in the setting of the SOC. Focused ultrasound in combination with intravenously administered microbubbles (MB- FUS) is an emerging technology that has been shown to induce transient BBB opening without permanent

damage. In the field of neuro-oncology, MB-FUS has been reported to increase delivery of a variety of agents and improve survival in preclinical brain tumor studies and is currently undergoing early-stage testing in humans. A critical next step in the development of this novel treatment paradigm is characterizing the pharmacokinetics

(PK) of therapeutic classes that have historically been excluded from treatment considerations in GBM due to the BBB, such as therapeutic monoclonal antibodies (mAbs). This proposed F30 project will study the delivery and effects of a new immunotherapeutic mAb, anti-CD47 (mCD47). To address the aforementioned gaps and

needs, Dr. Graeme Woodworth (primary sponsor), Dr. Miroslaw Janowski (co-sponsor), Dr, Gavin Dunn (co- sponsor), and Mr. Malla (PD/PI) propose to leverage PET-CT for evaluating MB-FUS-mediated delivery of mAbs in a clinically representative animal model of invasive, post-surgical GBM. The central hypothesis of this proposal

is that MB-FUS will augment the delivery and immunomodulatory effects of mCD47 co-localized within targeted regions of the post-surgical, non-contrast enhancing resection cavity margins. In Aim 1 we will radiolabel and define the MB-FUS-mediated biodistribution and pharmacokinetics of mCD47 in the peri-resectional non-CE

regions of post-surgical GBM. In Aim 2, we will assess the impact of MB-FUS-mediated mCD47 treatment in the setting of current standard resective surgery and chemotherapy (TMZ). Successful completion of the proposed studies will generate critical data for rationally designing clinical trials using this interventional MB-FUS-immuno-

PET workflow, which we are exceptionally well positioned to translate given our i) ongoing clinical trial evaluating adjuvant MB-FUS prior to each standard monthly dose of TMZ in GBM patients and ii) our established infrastructure for applying MB-FUS and immunoPET in both animals and patients.