Rapid clearing CT-001 restored hemostasis in mice with coagulopathy induced by activated protein C.

BACKGROUND: Activated protein C (APC) is one of the mechanisms contributing to coagulopathy, which is associated with high mortality. The counteraction of the APC pathway could help ameliorate bleeding. However, patients also transform frequently from a hemorrhagic state to a prothrombotic state at a later time. Therefore, a prohemostatic therapeutic intervention should take this thrombotic risk into consideration. OBJECTIVES: CT-001 is a novel factor VIIa (FVIIa) with enhanced activity and desialylated N-glycans for rapid clearance. We assessed CT-001 clearance in multiple species and its ability to reverse APC-mediated coagulopathic blood loss. METHODS: The N-glycans on CT-001 were characterized by liquid chromatography-mass spectrometry. Three species were used to evaluate the pharmacokinetics of the molecule. The potency and efficacy of CT-001 under APC pathway-induced coagulopathic conditions were assessed by coagulation assays and bleeding models. RESULTS: The N-glycosylation sites of CT-001 had high occupancy of desialylated N-glycans. CT-001 exhibited 5 to 16 times higher plasma clearance in human tissue factor knockin mice, rats, and cynomolgus monkeys than wildtype FVIIa. CT-001 corrected the activated partial thromboplastin time and thrombin generation of coagulopathic plasma to normal in in vitro studies. In an APC-mediated saphenous vein bleeding model, 3 mg/kg of CT-001 reduced bleeding time in comparison with wildtype FVIIa. The correction of bleeding by CT-001 was also observed in a coagulopathic tail amputation severe hemorrhage mouse model. The efficacy of CT-001 is independent of the presence of tranexamic acid, and the combination of CT-001 and tranexamic acid does not lead to increased thrombogenicity. CONCLUSION: CT-001 corrected APC pathway-mediated coagulopathic conditions in preclinical studies and could be a potentially safe and effective procoagulant agent for addressing APC-mediated bleeding.

CT-001, a novel fast-clearing factor VIIa, enhanced the hemostatic activity in postpartum samples.

ABSTRACT: The hemostatic system is upregulated to protect pregnant mothers from hemorrhage during childbirth. Studies of the details just before and after delivery, however, are lacking. Recombinant factor VIIa (rFVIIa) has recently been granted approval by the European Medicines Agency for the treatment of postpartum hemorrhage (PPH). A next-generation molecule, CT-001, is being developed as a potentially safer and more efficacious rFVIIa-based therapy. We sought to evaluate the peripartum hemostatic status of pregnant women and assess the ex vivo hemostatic activity of rFVIIa and CT-001 in peripartum blood samples. Pregnant women from 2 study sites were enrolled in this prospective observational study. Baseline blood samples were collected up to 3 days before delivery. Postdelivery samples were collected 45 (±15) minutes after delivery. Between the 2 time points, soluble fibrin monomer and D-dimer increased whereas tissue factor, FVIII, FV, and fibrinogen decreased. Interestingly, the postdelivery lag time and time to peak in the thrombin generation assay were shortened, and the peak thrombin generation capacity was maintained despite the reduced levels of coagulation proteins after delivery. Furthermore, both rFVIIa and CT-001 were effective in enhancing clotting activity of postdelivery samples in activated partial thromboplastin time, prothrombin time, thrombin generation, and viscoelastic hemostatic assays, with CT-001 demonstrating greater activity. In conclusion, despite apparent ongoing consumption of coagulation factors at the time of delivery, thrombin output was maintained. Both rFVIIa and CT-001 enhanced the upregulated hemostatic activity in postdelivery samples, and consistent with previous studies comparing CT-001 and rFVIIa in vitro and in in vivo, CT-001 demonstrated greater activity than rFVIIa.

Selective modulation of activated protein C activities by a nonactive site-targeting nanobody library.

Activated protein C (APC) is a pleiotropic coagulation protease with anticoagulant, anti-inflammatory, and cytoprotective activities. Selective modulation of these APC activities contributes to our understanding of the regulation of these physiological mechanisms and permits the development of therapeutics for the pathologies associated with these pathways. An antibody library targeting the nonactive site of APC was generated using llama antibodies (nanobodies). Twenty-one nanobodies were identified that selectively recognize APC compared with the protein C zymogen. Overall, 3 clusters of nanobodies were identified based on the competition for APC in biolayer interferometry studies. APC functional assays for anticoagulant activity, histone H3 cleavage, and protease-activated receptor 1 (PAR1) cleavage were used to understand their diversity. These functional assays revealed 13 novel nanobody-induced APC activity profiles via the selective modulation of APC pleiotropic activities, with the potential to regulate specific mechanisms for therapeutic purposes. Within these, 3 nanobodies (LP2, LP8, and LP17) inhibited all 3 APC functions. Four nanobodies (LP1, LP5, LP16, and LP20) inhibited only 2 of the 3 functions. Monofunction inhibition specific to APC anticoagulation activity was observed only by 2 nanobodies (LP9 and LP11). LP11 was also found to shift the ratio of APC cleavage of PAR1 at R46 relative to R41, which results in APC-mediated biased PAR1 signaling and APC cytoprotective effects. Thus, LP11 has an activity profile that could potentially promote hemostasis and cytoprotection in bleedings associated with hemophilia or coagulopathy by selectively modulating APC anticoagulation and PAR1 cleavage profile.

CT-001 is a rapid clearing factor VIIa with enhanced clearance and hemostatic activity for the treatment of acute bleeding in non-hemophilia settings.

INTRODUCTION: Acute bleeding leads to significant morbidity and mortality. Recombinant wildtype Factor VIIa (WT FVIIa) had been reported to have some therapeutic effects in some clinical trials, however, its use was associated with thromboembolic events. We sought to develop a novel FVIIa molecule (CT-001) with enhanced activity and lowered thrombogenicity risk. METHODS AND METHODS: CT-001 has 4 N-glycans (T106N/N145/V253N/N322) with terminal sialic acid residues removed to promote active clearance via the asialoglycoprotein receptor, and P10Q/K32E substitutions introduced to its gamma-carboxyglutamic acid (Gla) domain for enhanced phospholipid affinity and activity. RESULTS: In mice, CT-001 had a half-life of 5 min and a clearance of 467 mL/h/kg at 3 mg/kg, significantly faster than WT FVIIa (t1/2 = 1.8 h, Cl = 39 mL/h/kg). Interestingly, CT-001 was efficacious in reducing blood loss even with its rapid clearance. In a severe hemorrhage mouse model with tail amputated 5 cm from the tip, 1 mg/kg CT-001 provided efficacy comparable to 3 mg/kg WT FVIIa. The fast clearance of CT-001 resulted in significantly reduced thrombogenicity in comparison to WT FVIIa in a FeCl3-induced carotid artery thrombosis mouse model, and further confirmed in a soluble tissue factor-induced thrombosis model. CONCLUSIONS: The data on CT-001 demonstrate that a short duration of highly active FVIIa procoagulant activity has the potential to be an optimal paradigm for the treatment of acute bleeds.

In vitro characterization of CT-001-a short-acting factor VIIa with enhanced prohemostatic activity.

BACKGROUND: Traumatic injury and the associated acute bleeding are leading causes of death in people aged 1 to 44 years. Acute bleeding in pathological and surgical settings also represents a significant burden to the society. Yet there are no approved hemostatic drugs currently available. While clinically proven as an effective pro-coagulant, activated factor VII (FVIIa) use in acute bleeding has been hampered by unwanted thromboembolic events. Enhancing the ability of FVIIa to quickly stop a bleed and clear rapidly from circulation may yield an ideal molecule suitable for use in patients with acute bleeding. OBJECTIVES: To address this need and the current liability of FVIIa, we produced a novel FVIIa molecule (CT-001) with enhanced potency and shortened plasma residence time by cell line engineering and FVIIa protein engineering for superior efficacy for acute bleeding and safety. METHODS: To address safety, CT-001, a FVIIa protein with 4 desialylated N-glycans was generated to promote active recognition and clearance via the asialoglycoprotein receptor. To enhance potency, the gamma-carboxylated domain was modified with P10Q and K32E, which enhanced membrane binding. RESULTS: Together, these changes significantly enhanced potency and clearance while retaining the ability to interact with the key hemostatic checkpoint proteins antithrombin and tissue factor pathway inhibitor. CONCLUSIONS: These results demonstrate that a FVIIa molecule engineered to combine supra-physiological activity and shorter duration of action has the potential to overcome the current limitations of recombinant FVIIa to be a safe and effective approach to the treatment of acute bleeding.