Because of its excellent GPR potency good hERG selectivity a

Because of its excellent GPR119 potency, good hERG selectivity and favorable rat t, Tubastatin A sale was scaled-up and further profiled. The synthetic protocols described in , were both suitable for a multi-gram scale synthesis of compound . An off-target screen was performed against an extensive panel of 168 receptors, ion channels, and enzymes, and no off-target activities were found with ICs<10μM. Compound was also selective over CYP3A4 (IC>50μM) and hPXR (EC>30μM). In equilibration solubility studies, crystalline had FaSSIF solubility 0.051mg/mL (vs 0.009mg/mL of compound ), which confirmed the improvements observed in the kinetic FaSSIF solubility data (139μM vs 21μM) and verified that compound indeed exhibited improved FaSSIF solubility compared to compound . In liver microsomal stability studies, the intrinsic clearance (Cl) of compound was determined to be 189, 39, 44, and 39mL/min/kg in rat, dog, rhesus and human liver microsomes, respectively. Compared with the previous benzyloxy compound (Cl was 1104, 60, 319, 42mL/min/kg in rat, dog, rhesus and human liver microsomes), compound was significantly more stable in rat and rhesus liver microsomes. As a result, compound had improved pharmacokinetic profiles in rat and rhesus monkey, which are shown in . In rat PK studies, compound possessed lower unbound clearance than compound (430 vs 1000mL/min/kg). Previously, compound had low bioavailability in rat and rhesus (27% and 5%), likely due to first-pass metabolism. In contrast, the bioavailability of compound was improved to 80% (rat) and 44% (rhesus). In mouse oral glucose tolerance test (oGTT) dose titration PK/PD studies, the MED (minimal efficacious dose for maximal efficacy) for was determined to be 0.1mpk compared to the MED of compound at 3mpk. The mouse oGTT efficacy was ablated in GPR119 mice at a suprapharmacological dose of 3mpk, which confirmed that the efficacy was GPR119-mediated. Compound also had low rat oGTT MED that was 0.3mpk. Based on mouse oGTT MED which was 0.1mpk, and the blood concentration of at 90min post-dosing at 0.1mpk was 10nM in mice, the target plasma trough in humans for acute efficacy was estimated to be ∼6nM. The predicted human half-life of compound was ∼12h, suitable for QD. The projected human dose (QD) was <10mg, which is much lower than ∼300mg of compound . The predicted PK of and are very similar, with the decreased dose resulting from the significantly increased potency and thus reduced plasma trough target of . One major issue for the development of GPR119 agonists for the treatment of type 2 diabetes is the poor translation from rodent efficacy models to human clinical trials., Species differences in pharmacology between mouse and human has been reported. Consequently, we were also interested in identification of a suitable tool compound for NHP (non-human primate) studies to further support PD translation of GPR119 pharmacology to humans. Compound possesses excellent rhesus GPR119 potency (rhesus GPR119 EC=0.1nM) and an excellent rhesus PK profile, and was therefore selected for further profiling in rhesus glycemic efficacy studies that will be reported elsewhere in due course. In summary, starting from our previous preclinical candidate , left-hand side SAR/SPR studies led to the discovery of a phenyl acetamide lead with improved physical properties such as FaSSIF solubility (). Incorporation of 2,6 di-F substitution and an azetidine amide were found to be optimal LHS modifications, which further improved GPR119 potency. The RHS piperidine capping group optimization which focused on solubility, hERG selectivity, and rat t subsequently, led to the discovery of compound . Compared with compound , compound had reduced Vd (from 1725 to 72L/kg), which contributed to its reduced rat t. The predicted human half-life of compound was suitable for QD dosing. Because of high GPR119 potency, its projected human dose was much lower than that of compound . Compound was a candidate for NHP (Non-Human Primate) efficacy studies. Results of those pharmacodynamic studies in rhesus will be reported in due course.