Pexacerfont (BMS-562086) is a selective antagonist of the corticotropin-releasing factor receptor (IC50: 6.1±0.6 nM for the human CRF1 receptor).

Pexacerfont shows an effective and specific inhibitory effect (IC50=6.1 ± 0.6 nM) toward the human CRF1 receptor. It also has greater than 1000-fold lower affinity (IC50>1000 nM) for the CRF-binding protein and biogenic amine receptors[1].

Pexacerfont is active in rats (1-10 mg/kg, orally) in the defensive withdrawal and elevated plus-maze models of anxiety. The CLp of Pexacerfont was higher in rats (17.9 mL/kg per min) and dogs (11.6 mL/kg per min) than in chimpanzees (2.0 mL/kg per min). The plasma Pexacerfont concentrations exhibited a multiexponential decline in rats, dogs, and chimpanzees after the intravenous bolus dose. Assuming the value of CLp of Pexacerfont approximates the value of CLb in these three species, Pexacerfont has an estimated hepatic extraction ratio of 0.32, 0.38, and 0.08 in rats, dogs, and chimpanzees, respectively (calculated by dividing CLp by respective hepatic blood flow, 55.2, 30.9, and 25.5 mL/kg per min for rats, dogs, and chimpanzees). The assumption that CLb is equal to CLp is reasonable at least in rats, where the blood to the plasma concentration ratio of BMS-562086-equivalent radioactivity was 0.95 at 1 h postdose[1].