Pfizer was developing UK-396,082, an imidazole-propionic acid, as an oral treatment for thrombosis and pulmonary fibrosis. UK-396,082 is a potent and selective inhibitor of activated thrombin-activatable fibrinolysis inhibitor (activated TAFI; TAFIa) with Ki of 10 nM. UK-396,082 displays excellent selectivity over plasma carboxypeptidase N (>1,000-fold); exhibits antithrombotic efficacy in a rabbit model of venous thrombosis, yet has no effect on surgical bleeding in the rabbit; possesses excellent preclinical and clinical pharmacokinetic profile. UK-396,082 showed potential for the treatment of thrombosis and other fibrin-dependent diseases in humans, however its development was discontinued.