Warfarin-GPRP: Development and Evaluation of a Novel Warfarin-Based Peptide Conjugate for Enhanced Anticoagulant Activity

Warfarin, as a widely used vitamin K antagonist oral anticoagulant in clinical practice, has large differences in efficacy between individuals and severe bleeding risk. In this study, we synthesized and evaluated Warfarin-GPRP, a warfarin-based peptide conjugate incorporating the Gly-Pro-Arg-Pro (GPRP) sequence to enhance anticoagulant efficacy while mitigating bleeding risks of anticoagulant therapy. In <i>in vivo</i> model, Warfarin-GPRP effectively inhibited venous thrombosis at a dose of 0.82 μmol/kg, with a 100% survival rate, in contrast to warfarin sodium, which resulted in significant haemorrhagic side effects and high mortality. Notably, International normalized ratio (INR) values in the Warfarin-GPRP group (0.90 ± 0.06) remained within the normal range, while warfarin-treated rats exhibited a higher INR value (4.68 ± 1.54). In addition, Warfarin-GPRP also inhibited thrombin activation (FIIa) and suppressed the TF/FVIIa complex, which suggests its action through a unique pathway from warfarin. Mass spectrometry further revealed that Warfarin-GPRP localized to thrombotic sites, supporting targeted anticoagulation without significant systemic accumulation. These findings demonstrate Warfarin-GPRP as potentially safer and more precise alternative for traditional anticoagulation therapy, showing significant advantages over warfarin, warranting further clinical investigation.