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Abstract #0759

Multimodal Imaging of a Dual PI3K/mTOR Inhibitor Demonstrates Strong Effects on Vascular Function

Shelby Katherine Wyatt1, Kai H. Barck1, Jason R. Oeh2, Hani Bou-Reslan1, Tim C. Cao1, Hartmut Koeppen3, Lori S. Friedman2, Deepak Sampath2, Richard A. D. Carano1

1Biomedical Imaging, Genentech, Inc, South San Francisco, CA, USA; 2Translational Oncology, Genentech, Inc, South San Francisco, CA, USA; 3Pathology, Genentech, Inc, South San Francisco, CA, USA

Multispectral (MS)-DCE-MRI and DCE-ultrasound studies were performed to assess the PI3K/mTORi effects on vascular function. MS-DCE-MRI demonstrated tumor growth suppression, Ktrans reduction, and suggests potential vp changes, while DCE-US demonstrated a decrease in blood flow and enhancement factor following PI3K/mTORi. These responses are consistent with vasoconstriction as well as vessel density reduction. These results help elucidate PI3K/mTORi effects on tumor vasculature function and advocate the use of MS-DCE-MRI and DCE-US as biomarkers for similar therapies.