molecules of the month

The Servier thrombin activatable fibrinolysis inhibitor (TAFIa) inhibitor (S62798) is a fibrinolytic (clot degrading) agent which entered Ph. II in the EU for pulmonary embolism, but development appears to have been cancelled. TAFIa inhibitors are suggested to reduce clotting risk without  the risk of major hemorrhage since they don’t interfere with platelet activation and blood coagulation. The phosphinic acid acts as a zinc binding motif, and was cyclized in order to reduce conformational flexibility and increase selectivity against other carboxypeptidases. This phosphorus-containing molecule has interesting drug properties as it is a highly polar, renally excreted compound possessing two acidic sites and multiple potentially basic atoms. The binding mode is also interesting with numerous highly polar interactions including zinc metal-binding within a short…