Berlex Biosciences is investigating several series of Factor Xa inhibitors aimed at the prevention and treatment of thrombotic disorders [297584]. Some compounds are based on the structure of ZK-805412, a Z,Z-2,7-bis(dibenzylidene)cycloheptanone, which showed nanomolar Factor Xa inhibitor potency [301618]. Specific inhibitors identified in the program include ZK-806350 and ZK- 807191. Other series include condensed diphenoxypyridines, indoles, benzimidazoles and carbazoles [279707,279714,297584, 279710,279716,279718]. The inhibitory activity of 2,6-diphenoxypyridines on Factor Xa has been demonstrated in vitro [328787]. Berlex and Warner-Lambert are collaborating on Factor Xa inhibitors [347062].