PF-514273

PF-514273 is a small molecule antagonist developed by Pfizer that acts as an extremely selective antagonist for the cannabinoid CB1 receptor, demonstrating roughly 10,000-fold selectivity over the closely related CB2 receptor. It is a bicyclic lactam-based compound with central nervous system activity. PF-514273 was investigated in early phase clinical studies as a potential treatment for obesity due to its high selectivity and potency for the CB1 receptor (Ki ≈ 1 nM). Its selectivity profile made it a useful tool for scientific research on cannabinoid receptor function. Clinical development for obesity was discontinued following phase 1 studies[1][3][7][9].