[11C]AS2471907

[11C]AS2471907 is a **radiolabeled small molecule positron emission tomography (PET) tracer** developed to image **11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1)** in the human brain. 11β-HSD1 catalyzes the conversion of cortisone to cortisol, a key process in stress response, and has been implicated in metabolic and neuropsychiatric disorders including diabetes, obesity, depression, and Alzheimer's disease. [11C]AS2471907 was utilized in early-phase clinical imaging to quantify brain enzyme availability and evaluate target engagement, particularly to support the development of 11β-HSD1 inhibitors. The tracer demonstrates highly specific binding to 11β-HSD1 and desirable imaging properties, including regional brain uptake and reliable test-retest reproducibility. It was developed by Astellas Pharma and first evaluated in human and nonhuman primate PET studies, though 11C synthetic challenges prompted parallel development of [18F]AS2471907 as a more practical alternative[1][2][3][4][8].