The pre-clinical characterization of the aryl piperazinyl urea inhibitor of fatty acid amide hydrolase (FAAH) JNJ-42165279 is described. JNJ-42165279 covalently inactivates the FAAH enzyme, but is highly selective with regard to other enzymes, ion channels, transporters, and receptors. JNJ-42165279 exhibited excellent ADME and pharmacodynamic properties as evidenced by its ability to block FAAH in the brain and periphery of rats and thereby cause an elevation of the concentrations of anandamide (AEA), oleoyl ethanolamide (OEA), and palmitoyl ethanolamide (PEA). The compound was also efficacious in the spinal nerve ligation (SNL) model of neuropathic pain. The combination of good physical, ADME, and PD properties of JNJ-42165279 supported it entering the clinical portfolio. KEYWORDS: FAAH, covalent, ethanolamides, enzyme, anandamide T he fatty acid amide hydrolases 1,2 interrupt the actions, through degradation, of a variety of endogenous lipid signaling molecules.3 FAAH rapidly degrades several fatty acid ethanolamides, including FAAH's primary substrate, AEA (N-arachidonyl ethanolamide or anandamide), 4 PEA (N-palmitoyl ethanolamide), 5,6 and OEA (N-oleoyl ethanolamide).7 In contrast, FAAH-2 catabolizes ethanolamides less efficiently, but will hydrolyze long-chain primary amides. The likely source of AEA's analgesic pharmacology is its ability to agonize the cannabinoid receptor CB 1 .8−10 However, AEA is synthesized on demand and then rapidly broken down locally, which mitigates the side-effects observed as a result of systemic CB 1 agonism (e.g., Δ 9 THC pharmacology). As AEA is synthesized in a localized manner, one might hypothesize that inhibiting FAAH could lead to elevated concentrations of AEA in relevant tissues. Indeed, prior reports have described an increase in AEA levels in the plasma and brains 11−14 of rats and in the plasma of humans upon inhibition of FAAH.Small molecule interruption of FAAH activity has been examined in numerous laboratories (Figure 1)

Implementing screening assays that identify functional and structural cardiotoxicity earlier in the drug development pipeline has the potential to improve safety and decrease the cost and time required to bring new drugs to market. In this study, a metabolic biomarker-based assay was developed that predicts the cardiotoxicity potential of a drug based on changes in the metabolism and viability of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). Assay development and testing was conducted in 2 phases: (1) biomarker identification and (2) targeted assay development. In the first phase, metabolomic data from hiPSC-CM spent media following exposure to 66 drugs were used to identify biomarkers that identified both functional and structural cardiotoxicants. Four metabolites that represent different metabolic pathways (arachidonic acid, lactic acid, 2′-deoxycytidine, and thymidine) were identified as indicators of cardiotoxicity. In phase 2, a targeted, exposure-based biomarker assay was developed that measured these metabolites and hiPSC-CM viability across an 8-point concentration curve. Metabolite-specific predictive thresholds for identifying the cardiotoxicity potential of a drug were established and optimized for balanced accuracy or sensitivity. When predictive thresholds were optimized for balanced accuracy, the assay predicted the cardiotoxicity potential of 81 drugs with 86% balanced accuracy, 83% sensitivity, and 90% specificity. Alternatively, optimizing the thresholds for sensitivity yields a balanced accuracy of 85%, 90% sensitivity, and 79% specificity. This new hiPSC-CM-based assay provides a paradigm that can identify structural and functional cardiotoxic drugs that could be used in conjunction with other endpoints to provide a more comprehensive evaluation of a drug’s cardiotoxicity potential.