Vega Therapeutics Inc. has reported promising preclinical data on VGA-039, a first-in-class monoclonal antibody directed against human protein S (ProS) that inhibits ProS cofactor activity for tissue factor pathway inhibitor α (TFPIα) and activated protein C (aPC), thus enhancing thrombin generation by acting on both the initiation (TFPIα) and propagation (aPC) phases of coagulation for potential activity against various bleeding disorders.