RT Journal Article SR Electronic T1 AMG580: a Novel Small Molecule Phosphodiesterase 10A (PDE10A) PET Tracer JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP jpet.114.220517 DO 10.1124/jpet.114.220517 A1 Hang Chen A1 Dianna Lester-Zeiner A1 Jianxia Shi A1 Silke Miller A1 Charlies Glaus A1 Essa Hu A1 Ning Chen A1 Jessica Able A1 Christopher Biorn A1 Jamie Wong A1 Ji Ma A1 Klaus Michelsen A1 Geraldine Hill Della Puppa A1 Tim Kazules A1 Hui Hannah Dou A1 Santosh Talreja A1 Xiaoning Zhao A1 Ada Chen A1 Shannon Rumfelt A1 Roxanne Kunz A1 Hu Ye A1 Oliver R Thiel A1 Toni Williamson A1 Carl Davis A1 Amy Poter A1 David Immke A1 Jennifer R Allen A1 James Treanor YR 2014 UL http://jpet.aspetjournals.org/content/early/2014/12/11/jpet.114.220517.abstract AB Phosphodiesterase 10A (PDE10A) inhibitors have therapeutic potential for the treatment of psychiatric and neurological disorders, such as schizophrenia and Huntington's disease. One of the key requirements for successful CNS drug development is to demonstrate target coverage of therapeutic candidates in brain for lead optimization in the drug discovery phase and for assisting dose selection in clinical development. Therefore, we identified AMG 580, a novel, selective small molecule antagonist with sub-nanomolar affinity for rat, primate, and human PDE10A. We showed that AMG 580 is suitable as a tracer for lead optimization to determine target coverage by novel PDE10A inhibitors using LC-MS/MS technology. [3H]-AMG 580 bound with high affinity in a specific and saturable manner to both striatal homogenates and brain slices from rats, baboons, and human in vitro. Moreover, [18F]-AMG 580 demonstrated prominent uptake by positron emission tomography (PET) in rats suggesting that radiolabelled AMG 580 may be suitable for further development as a non-invasive radiotracer for target coverage measurements in clinical studies. These results indicate that AMG 580 is a potential imaging biomarker for mapping PDE10A distribution and ensuring target coverage by therapeutic PDE10A inhibitors in clinical studies.