Novel Vanilloid Receptor-1 Antagonists: 3. The Identification of a Second-Generation Clinical Candidate with Improved Physicochemical and Pharmacokinetic Properties
作者:Hui-Ling Wang、Jodie Katon、Chenera Balan、Anthony W. Bannon、Charles Bernard、Elizabeth M. Doherty、Celia Dominguez、Narender R. Gavva、Vijay Gore、Vu Ma、Nobuko Nishimura、Sekhar Surapaneni、Phi Tang、Rami Tamir、Oliver Thiel、James J. S. Treanor、Mark H. Norman
DOI:10.1021/jm070191h
日期:2007.7.1
Based on the previously reported clinical candidate, AMG 517 (compound 1), a series of related piperazinylpyrimidine analogues were synthesized and evaluated as antagonists of the vanilloid 1 receptor (VR1 or TRPV1). Optimization of in vitro potency and physicochemical and pharmacokinetic properties led to the discovery of (R)-N-(4-(6-(4-(1-(4-fluorophenyl)ethyl)piperazin-1-yl)pyrimidin-4-yloxy)benzo[d]thiazol-2-yl)acetamide (16p), a potent TRPV1 antagonist [rTRPV1(CAP) IC50 = 3.7 nM] with excellent aqueous solubility (>= 200 mu g/mL in 0.01 N HCl) and a reduced half-life (rat t(1/2) = 3.8 h, dog t(1/2) = 2.7 h, monkey t(1/2) = 3.2 h) as compared to AMG 517. In addition, compound 16p was shown to be efficacious at blocking a TRPV1-mediated physiological response in vivo (ED50 = 1.9 mg/kg, p.o. in the capsaicin-induced flinch model in rats) and was also effective at reducing thermal hyperalgesia induced by complete Freund's adjuvant in rats (MED = 1 mg/kg, p.o). Based on its improved overall profile, compound 16p (AMG 628) was selected as a second-generation candidate for further evaluation in human clinical trials as a potential new treatment for chronic pain.