Discovery of BT-114143, a Novel and Potent Small-Molecule Plasminogen Inhibitor for Hyperfibrinolysis

Blood coagulation and fibrinolysis are essential physiological functions, whose dysregulation is a life-threatening emergent situation requiring immediate medical intervention. In particular, hyperfibrinolysis-triggered bleeding occurs in certain medical conditions such as postpartum hemorrhage (PPH) or during perioperative procedures, natural disasters, traumatic accidents as well as battlefield situations, and is one of the major causes of mortalities worldwide during peacetime and war. Tranexamic acid (TXA) has been widely used as an antifibrinolytic drug since 1960s, however, the low potency of TXA has limited its clinical applications. Here, we have developed BT-114143, a novel and potent small-molecule plasminogen inhibitor. BT-114143 exhibited over four-fold higher affinity for recombinant human plasminogen than TXA in surface plasmon resonance (SPR) analysis. Similarly, affinity of BT-114143 was at least one magnitude higher than that of either epsilon-aminocaproic acid (EACA) or p-aminomethylbenzoic acid (PAMBA) (Table 1). In vivo efficacy studies were conducted in recombinant tissue plasminogen activator (rt-PA)-triggered rat tail bleeding model and rabbit liver bleeding model by hepatectomy. BT-114143 reduced bleeding time dose-dependently in both animal models, but also exhibited similar potency as compared to TXA. Similar potency between BT-114143 and TXA was further confirmed by rt-PA triggered fibrinolysis in either rat or rabbit whole blood in thromboelastography (TEG) assay, suggesting interspecies difference in response to bleeding. However, ex vivo studies on human plasma clot lysis assay and human whole blood TEG assay (Figure 1) demonstrated nearly ten-fold antifibrinolytic potency as compared to TXA, suggesting superior efficacy for treatment of hyperfibrinolysis-related bleedings. In addition, a panel of GLP toxicology studies has confirmed the preclinical safety of BT-114143. Moreover, electrophysiological analysis has demonstrated comparable inhibitory effect of BT-114143 and TXA on GABA_A receptor and Glycine receptor. At present, BT-114143 is undergoing phase I clinical study in China (CTR20222910) and is expected to apply for FDA approval for clinical trial in 2024. Furthermore, BT-114143 is being developed for intramuscular (i.m.) injection, making it more suitable for emergency situations including PPH, traumatic injuries, natural disasters, and combat injuries.