WE‐D‐210A‐04: Novel PET Probes to Image the Immune System and Cancer — From Discovery to Clinical Applications

Monitoring immune function using molecular imaging could significantly impact the diagnosis and treatment evaluation of immunological disorders and therapeutic immune responses. Positron Emission Tomography (PET) is a molecular imaging modality with applications in cancer and other diseases. PET studies of immune function have been limited by a lack of specialized probes. We identified [18F]FAC (1‐(2′‐deoxy‐2′‐[18F]fluoroarabinofuranosyl) cytosine) by differential screening as a new PET probe for the deoxyribonucleotide salvage pathway. [18F]FAC PET enabled visualization of lymphoid organs and was sensitive to localized immune activation in a mouse model of anti‐tumor immunity. [18F]FAC microPET also detected early changes in lymphoid mass in systemic autoimmunity and allowed evaluation of immunosuppressive therapy. We have also developed a series of [18F]FAC analogs with improved pharmacokinetic properties. Data in animal models and preliminary studies in humans support the use of [18F]FAC and its analogs for immune monitoring by PET and suggest a wide range of clinical applications in immune disorders and in certain types of cancer. Research sponsored in part by Sofie Biosciences through a UC Discovery grant.