Characterization of the novel P-selectin inhibitor PSI-697 [2-(4-chlorobenzyl)-3-hydroxy-7,8,9,10-tetrahydrobenzo[h] quinoline-4-carboxylic acid] in vitro and in rodent models of vascular inflammation and thrombosis.

P-selectin plays a significant and well documented role in vascular disease by mediating leukocyte and platelet rolling and adhesion. This study characterizes the in vitro activity, pharmacokinetic properties, and the anti-inflammatory and antithrombotic efficacy of the orally active P-selectin small-molecule antagonist PSI-697 [2-(4-chlorobenzyl)-3-hydroxy-7,8,9,10-tetrahydrobenzo[h] quinoline-4-carboxylic acid; molecular mass, 367.83]. Biacore and cell-based assays were used to demonstrate the ability of PSI-697 to dose dependently inhibit the binding of human P-selectin to human P-selectin glycoprotein ligand-1, inhibiting 50% of binding at 50 to 125 microM. The pharmacokinetics of PSI-697 in rats were characterized by low clearance, short half-life, low volume of distribution, and moderate apparent oral bioavailability. A surgical inflammation model, using exteriorized rat cremaster venules, demonstrated that PSI-697 (50 mg/kg p.o.) significantly reduced the number of rolling leukocytes by 39% (P < 0.05) versus vehicle control. In a rat venous thrombosis model, PSI-697 (100 mg/kg p.o.) reduced thrombus weight by 18% (P < 0.05) relative to vehicle, without prolonging bleeding time. Finally, in a rat carotid injury model, PSI-697 (30 or 15 mg/kg p.o.) administered 1 h before arterial injury and once daily thereafter for 13 days resulted in dose-dependent decreases in intima/media ratios of 40.2% (P = 0.025) and 25.7% (P = 0.002) compared with vehicle controls. These data demonstrate the activity of PSI-697 in vitro and after oral administration in animal models of both arterial and venous injury and support the clinical evaluation of this novel antagonist of P-selectin in atherothrombotic and venous thrombotic indications.

Synthesis and biological evaluation of quinoline salicylic acids as P-selectin antagonists.

Leukocyte recruitment of sites of inflammation and tissue injury involves leukocyte rolling along the endothelial wall, followed by firm adherence of the leukocyte, and finally transmigration of the leukocyte across cell junctions into the underlying tissue. The initial rolling step is mediated by the interaction of leukocyte glycoproteins containing active moieties such as sialyl Lewisx (sLex) with P-selectin expressed on endothelial cells. Consequently, inhibition of this interaction by means of a small molecule P-selectin antagonist is an attractive strategy for the treatment of inflammatory diseases such as arthritis. High-throughput screening of the Wyeth chemical library identified the quinoline salicylic acid class of compounds (1) as antagonists of P-selectin, with potency in in vitro and cell-based assays far superior to that of sLex. Through iterative medicinal chemistry, we identified analogues with improved P-selectin activity, decreased inhibition of dihydrooratate dehydrogenase, and acceptable CYP profiles. Lead compound 36 was efficacious in the rat AIA model of rheumatoid arthritis.

2-(4-Chlorobenzyl)-3-hydroxy-7,8,9,10-tetrahydrobenzo[H]quinoline-4-carboxylic acid (PSI-697): identification of a clinical candidate from the quinoline salicylic acid series of P-selectin antagonists.

P-selectin-PSGL-1 interaction causes rolling of leukocytes on the endothelial cell surface, which subsequently leads to firm adherence and leukocyte transmigration through the vessel wall into the surrounding tissues. P-selectin is upregulated on the surface of both platelets and endothelium in a variety of atherosclerosis-associated conditions. Consequently, inhibition of this interaction by means of a small molecule P-selectin antagonist is an attractive strategy for the treatment of atherosclerosis. High-throughput screening and subsequent analoging had led to the identification of compound 1 as the lead candidate. Herein, we report the continuation of this work and the discovery of a second-generation series, the tetrahydrobenzoquinoline salicylic acids. These compounds have improved pharmacokinetic properties, and a number of them have shown oral efficacy in mouse and rat models of atherogenesis and vascular injury. The lead 31 (PSI-697), is currently in clinical development for the treatment of atherothrombotic vascular events.

Quinic acid derivatives as sialyl Lewis(x)-mimicking selectin inhibitors: design, synthesis, and crystal structure in complex with E-selectin.

A search for noncarbohydrate sLe(x) mimics led to the development of quinic acid derivatives as selectin inhibitors. At Wyeth we solved the first cocrystal structure of a small molecule, quinic acid, with E-selectin. In the cocomplex two hydroxyls of quinic acid mimic the calcium-bound fucose of the tetrasaccharide sLe(x). The X-ray structure, together with structure based computational methods, was used to design quinic acid based libraries that were synthesized and evaluated for their ability to block the interaction of sLex with P-selectin. A large number of analogues were prepared using solution-phase parallel synthesis. Selected compounds showed decrease in leukocyte rolling in the IVM mouse model. Compound 2 inhibited neutrophil influx in the murine TIP model and demonstrated good plasma exposure.