[New anticoagulants in 2024: Development of factor XI and XIa inhibitors]. / Les nouveaux anticoagulants en 2024 : développement des inhibiteurs du facteur XI et du XIa.

Thrombosis remains one of the leading causes of death in the world. The history of anticoagulation has evolved considerably from non-specific drugs (i.e., heparins and vitamin K antagonists, VKA) to agents that directly target specific coagulation factors (i.e., argatroban, fondaparinux and direct oral anticoagulants, DOAC). Since the last decade, DOAC are widely used in clinical practice because of their ease to use, their favorable pharmacological profile and the fact that they do not require monitoring. However, despite having a better safety profile than vitamin K antagonist, their bleeding risk is not negligible. New anticoagulants targeting the contact phase of coagulation are currently being developed and could make it possible to prevent the risk of thrombosis without impairing hemostasis. Epidemiological and preclinical data on FXI deficiency make FXI a promising therapeutic target. The aim of this review is to summarize the results of the various clinical trials available that focus on FXI/FXIa inhibition, and to highlight the challenges that this new therapeutic class of anticoagulants will face.

Pharmacokinetics, pharmacodynamics, and safety of fesomersen, a novel antisense inhibitor of factor XI, in healthy Chinese, Japanese, and Caucasian volunteers.

The inhibition of coagulation factor XI (FXI) presents an attractive approach for anticoagulation as it is not expected to increase the risk of clinically relevant bleeding and is anticipated to be at least as effective as currently available anticoagulants. Fesomersen is a conjugated antisense oligonucleotide that selectively inhibits the expression of FXI. The article describes three clinical studies that investigated the safety, pharmacokinetic (PK), and pharmacodynamic (PD) profiles of fesomersen after subcutaneous (s.c.) injection to healthy participants. The studies included participants from diverse ethnic backgrounds (Caucasian, Japanese, and Chinese). Fesomersen demonstrated good safety and tolerability in all three studies. No major bleeding events were observed. After single-dose s.c. injection, fesomersen was rapidly absorbed into the systemic circulation, with maximum fesomersen-equivalent (fesomersen-eq) concentrations (Cmax) in plasma observed within a few hours. After reaching Cmax, plasma fesomersen-eq concentrations declined in a biphasic fashion. The PD analyses showed that the injection of fesomersen led to dose-dependent reductions in FXI activity and increases in activated partial thromboplastin time (aPTT). The maximum observed PD effects were reached between Day 15 and 30, and FXI activity and aPTT returned to near-baseline levels by Day 90 after a single dose. The PK/PD profiles after a single injection were similar among the various ethnic groups. Collectively, the study results suggest that fesomersen has a favorable safety profile and predictable and similar PK and PD profiles across Chinese, Japanese, and Caucasian participants.

Revisión sistemática de los ensayos clínicos sobre terapia antitrombótica con inhibidores del factor XI / Systematic review of clinical trials on the antithrombotic therapy with factor XI inhibitors

Antecedentes y objetivo La información proveniente de los ensayos clínicos fase 2 sugiere que los inhibidores del factor XI podrían mostrar un perfil de eficacia/seguridad más favorable que las terapias antitrombóticas actuales. El objetivo de esta revisión sistemática es analizar la evidencia disponible derivada de esos estudios. Métodos Se realizó una búsqueda bibliográfica en las bases de datos PubMed, Cochrane Library, Scopus y EMBASE, y en las plataformas de registro de ensayos clínicos Clinical Trials y Cochrane Central Register of Controlled Trials. Los resultados se publicaron según la declaración PRISMA. Resultados Se identificaron un total de 18 ensayos clínicos concluidos o en curso abordando múltiples escenarios, incluyendo fibrilación auricular, ictus, infarto de miocardio y tromboembolismo venoso. Se analizó la evidencia procedente de 8 estudios con resultados disponibles. En general, los estudios fase 2 con inhibidores del factor XI mostraron un perfil adecuado de eficacia y seguridad. El balance beneficio/riesgo fue más favorable en términos de reducción de tromboembolismo venoso en pacientes sometidos a artroplastia total de rodilla. Para esta indicación, los inhibidores del factor XI mostraron una reducción global del 50% en la tasa de complicaciones trombóticas y del 60% en la tasa de hemorragias comparado con enoxaparina. En los estudios de pacientes con fibrilación auricular, ictus e infarto de miocardio se observaron resultados más modestos. Conclusión Los inhibidores del Factor XI abren nuevas perspectivas en el tratamiento y la profilaxis antitrombótica. Los estudios fase 3 en curso permitirán definir los fármacos e indicaciones más idóneas. (AU)

Background and objective Data from phase 2 clinical trials suggest that factor XI inhibitors may exhibit a more favourable efficacy/safety profile than current antithrombotic therapies. This systematic review aims to analyze the available evidence derived from these studies. Methods A literature search in the PubMed, Cochrane Library, Scopus, EMBASE databases, and clinical trial registration platforms Clinical Trials and Cochrane Central Register of Controlled was conducted. The results were reported in accordance with the PRISMA statement. Results A total of 18 completed or ongoing clinical trials addressing multiple scenarios, including atrial fibrillation, stroke, myocardial infarction, and venous thromboembolism, were identified. Evidence from 8 studies with available results was analyzed. Overall, phase 2 studies with factor XI inhibitors demonstrated an acceptable efficacy and safety profile. The benefit-risk balance, in terms of reducing venous thromboembolism in patients undergoing total knee arthroplasty, was more favourable. For this scenario, factor XI inhibitors showed a 50% reduction in the overall rate of thrombotic complications and a 60% reduction in bleeding compared to enoxaparin. Modest results in studies involving patients with atrial fibrillation, stroke, and myocardial infarction were observed. Conclusions Factor XI inhibitors offer new prospects in antithrombotic treatment and prevention. Ongoing phase 3 studies will help define the most suitable drugs and indications. (AU)

[New perspective of anticoagulation in intensive care unit: basic and clinical advances in coagulation factor XII and XI inhibitors].

Anticoagulation therapy stands as a key treatment for thrombotic diseases. The consequential bleeding risk tied to existing anticoagulation methods significantly impacts patient prognosis. In the intensive care unit (ICU), patients often necessitate organ support, leading to the inevitable placement of artificial devices in blood vessels, thereby requiring anticoagulation treatment to avert clot formation that might impede organ support. Nevertheless, these patients commonly encounter a heightened risk of bleeding. Hemophilia B, identified in 1953, manifests as a deficiency in coagulation factor XI (FXI), which focused people's perspective on the endogenous coagulation pathway, that is, the contact pathway. Upon interaction between the surface of artificial devices and FXII, FXII activates, subsequently triggering FXI and initiating the "coagulation cascade" within the contact pathway. Inhibitors targeting the contact pathway encompass two primary categories: FXII inhibitors and FXI inhibitors, capable of impeding this process. This article reviews the role of FXII and FXI in activating the contact pathway, seeking to illuminate their contributions to thrombus formation. By listing the relatively mature drugs and their indications, clinicians are familiar with this new anticoagulant.

One case of surgical treatment of coagulation factor XI deficiency complicated with esophageal cancer: a case report.

BACKGROUND: Coagulation factor XI deficiency is an autosomal recessive hereditary disease with a low incidence. It usually occurs after surgery or trauma; Esophageal cancer is a common malignant tumor of the digestive tract in China. But so far, surgery-based comprehensive treatment of esophageal cancer still dominates. CASE PRESENTATION: We report a case of an Asian patient with XI factor deficiency and lower esophageal squamous cell carcinoma who was admitted to our hospital recently. After active preoperative preparation, the operation was successfully performed, and there was no obvious abnormal bleeding during and after the operation. CONCLUSIONS: Coagulation factor XI deficiency is a relatively rare disease, and patients with the disease will face a greater risk of bleeding during the perioperative period. The encouraging perioperative outcome enables us to have a deeper understanding of surgical treatment strategies for patients with Coagulation factor XI deficiency.

Systematic review of clinical trials on antithrombotic therapy with factor XI inhibitors.

INTRODUCTION AND OBJECTIVE: Data from phase 2 clinical trials suggest that factor XI inhibitors may exhibit a more favorable efficacy/safety profile compared to current antithrombotic therapies. The aim of this systematic review is to analyze the available evidence derived from these studies. METHODS: A literature search in the PubMed, Cochrane Library, Scopus, EMBASE databases, and clinical trial registration platforms Clinical Trials and Cochrane Central Register of Controlled was conducted. In accordance with the PRISMA statement, results were reported. RESULTS: A total of 18 completed or ongoing clinical trials addressing multiple scenarios, including atrial fibrillation, stroke, myocardial infarction, and venous thromboembolism, were identified. Evidence from 8 studies with available results was analyzed. Phase 2 studies with factor XI inhibitors, overall, demonstrated an acceptable efficacy and safety profile. The benefit-risk balance, in terms of reducing venous thromboembolism in patients undergoing total knee arthroplasty, was more favorable. For this scenario, factor XI inhibitors showed a 50% reduction in the overall rate of thrombotic complications and a 60% reduction in the rate of bleeding compared to enoxaparin. Modest results in studies involving patients with atrial fibrillation, stroke, and myocardial infarction were observed. CONCLUSIONS: Factor XI inhibitors offer new prospects in antithrombotic treatment and prophylaxis. Ongoing phase 3 studies will help define the most suitable drugs and indications.

Factor XI deficiency: phenotypic age-related considerations and clinical approach towards bleeding risk assessment.

ABSTRACT: Factor XI (FXI) deficiency is a rare bleeding disorder that presents complex challenges in patient assessment and bleeding risk management. Despite generally causing mild to moderate bleeding symptoms, clinical manifestations can vary, and bleeding tendency does not always correlate with FXI plasma levels or genotype. Our manuscript delves into the age-related nuances of FXI deficiency across an individual's lifespan. We emphasize issues faced by specific groups, including neonates and females of reproductive age experiencing abnormal uterine bleeding and postpartum hemorrhage. Older patients present unique challenges and concerns related to the management of bleeding as well as thrombotic complications. The current assortment of diagnostic laboratory assays shows limited success in predicting bleeding risk in the perisurgical setting of patients with FXI deficiency. This review explores the intricate interplay between individual bleeding profiles, surgical sites, and FXI activity levels. We also evaluate the accuracy of existing laboratory assays in predicting bleeding and discuss the potential role of investigational global assays in perioperative assessment. Furthermore, we outline our suggested diagnostic approach to refine treatment strategies and decision making. Available treatment options are presented, including antifibrinolytics, replacement products, and recombinant activated FVII. Finally, we discuss promising nonreplacement therapies for the treatment of rare bleeding disorders that can potentially address the challenges faced when managing FXI deficiency-related bleeding complications.

Maturity-onset Diabetes of the Young Type 7 (MODY7) and the Krüppellike Factor 11 Mutation (KLF11). A Review.

INTRODUCTION: Maturity-onset diabetes of the young (MODY) is a rare disease due to a single gene mutation that affects several family members in most cases. The Krüppel-like factor 11 (KLF11) gene mutation is associated with decreased insulin sensitivity to high glucose levels. KLF 11 has been implicated in the pathogenesis of MODY type 7 but given its low prevalence, prolonged subclinical period, and the emergence of new information, doubts are raised about its association. METHODS: A literature search of the PubMed, Scopus, and EBSCO databases was performed. The terms "Diabetes Mellitus, Type 2/genetics", "Mason-Type Diabetes" , "Maturity-Onset diabetes of the young", "KLF11 protein, human", and "Maturity-Onset Diabetes of the Young, Type 7" were used"., "Diagnosis" The search selection was not standardized. RESULTS: The KLF1 mutation is rare and represents <1% of the mutations associated with monogenic diabetes. Its isolation in European family lines in the first studies and the emergence of new variants pose new diagnostic challenges. This article reviews the definition, epidemiology, pathophysiology, diagnosis, and treatment of MODY type 7. CONCLUSION: MODY type 7 diabetes represents a rare form of monogenic diabetes with incomplete penetrance. Given its rarity, its association with impaired glucose metabolism has been questioned. Strict evaluation of glycemic control and the appearance of microvascular complications are key areas in the follow-up of patients diagnosed with MODY 7. More studies will be required to characterize the population with KLF11 mutation and clarify its correlation with MODY.

Hereditary coagulation factor XI deficiency: a rare or neglected disease? Results from a retrospective, single-centre cohort in northern Italy.

To examine real-life clinical data regarding hereditary factor XI (FXI) deficiency from a secondary care centre. Retrospective review of clinical records for every FXI:C 0.7 IU/ml or less reported from 2012 to 2020. Seventy-nine patients were included. Six (7.6%) had a severe deficiency (FXI:C <0.2 IU/ml). Only 55 (69.6%) patients were referred to the Haemostasis Centre. Among them, six (15%) were subsequently not identified at increased haemorrhagic risk before a surgical/obstetrical procedure. Thirty-three (41.8%) experienced at least one bleeding event, minor (25 patients) and/or major (16 patients). Minor bleedings were predominantly spontaneous and more frequent in women, major events were mainly provoked. No correlation was found between FXI:C and risk of bleeding ( P  = 0.9153). Lower FXI:C, but not a positive bleeding history, was related with higher likelihood of being referred to the Haemostasis Centre ( P  = 0.0333). Hereditary FXI deficiency prevalence is likely underestimated, real-life clinical practices outside reference centres could be suboptimal.

Factor XI Inhibition for the Prevention of Catheter-Associated Thrombosis in Patients With Cancer Undergoing Central Line Placement: A Phase 2 Clinical Trial.

BACKGROUND: Despite the ubiquitous utilization of central venous catheters in clinical practice, their use commonly provokes thromboembolism. No prophylactic strategy has shown sufficient efficacy to justify routine use. Coagulation factors FXI (factor XI) and FXII (factor XII) represent novel targets for device-associated thrombosis, which may mitigate bleeding risk. Our objective was to evaluate the safety and efficacy of an anti-FXI mAb (monoclonal antibody), gruticibart (AB023), in a prospective, single-arm study of patients with cancer receiving central line placement. METHODS: We enrolled ambulatory cancer patients undergoing central line placement to receive a single dose of gruticibart (2 mg/kg) administered through the venous catheter within 24 hours of placement and a follow-up surveillance ultrasound at day 14 for evaluation of catheter thrombosis. A parallel, noninterventional study was used as a comparator. RESULTS: In total, 22 subjects (n=11 per study) were enrolled. The overall incidence of catheter-associated thrombosis was 12.5% in the interventional study and 40.0% in the control study. The anti-FXI mAb, gruticibart, significantly prolonged the activated partial thromboplastin time in all subjects on day 14 compared with baseline (P<0.001). Gruticibart was well tolerated and without infusion reactions, drug-related adverse events, or clinically relevant bleeding. Platelet flow cytometry demonstrated no difference in platelet activation following administration of gruticibart. T (thrombin)-AT (antithrombin) and activated FXI-AT complexes increased following central line placement in the control study, which was not demonstrated in our intervention study. CRP (C-reactive protein) did not significantly increase on day 14 in those who received gruticibart, but it did significantly increase in the noninterventional study. CONCLUSIONS: FXI inhibition with gruticibart was well tolerated without any significant adverse or bleeding-related events and resulted in a lower incidence of catheter-associated thrombosis on surveillance ultrasound compared with the published literature and our internal control study. These findings suggest that targeting FXI could represent a safe intervention to prevent catheter thrombosis. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04465760.

Factor XI/XIa inhibitors for the prevention and treatment of venous and arterial thromboembolism: A narrative review.

During the past decade, direct oral anticoagulants (DOACs) have advanced and simplified the prevention and treatment of venous thromboembolism (VTE). However, there remains a high incidence of bleeds, which calls for agents that have a reduced risk of bleeding. Factor XI (FXI) deficiency is associated with lower rates of venous thrombosis and stroke compared to the general population with a lower risk of bleeding. In conjunction with this, phase 2 studies have demonstrated safety and the potential for reduced thrombotic events with FXI inhibitors as compared to currently available medications. The aim of this review is to summarize key data on the clinical pharmacology of FXI, the latest developments in clinical trials of FXI inhibitors, and to describe the efficacy and safety profiles of FXI inhibitors for the prevention of venous and arterial thromboembolism.

Effect of factor XI inhibition on tumor cell-induced coagulation activation.

BACKGROUND: Cancer-associated thrombosis is a frequent complication in patients with malignancies. While factor XI (FXI)/FXIa inhibition is efficacious in preventing postoperative venous thromboembolism, its role in tumor cell-induced coagulation is less defined. OBJECTIVES: We thus aimed to provide mechanistic insights into FXI/FXIa inhibition in tumor cell-induced coagulation activation. METHODS: Procoagulant activity (PCA) of 4 different tissue factor (TF) expressing tumor cell lines was analyzed by single-stage clotting and thrombin generation assay in the presence of a FXIa inhibitor, BMS-262084 (BMS), an inhibitory FXI antibody (anti-FXI), or peak and trough concentrations of rivaroxaban or tinzaparin. Further, tumor cell-induced platelet aggregation was recorded. Recombinant human TF served as positive control. RESULTS: Although BMS and anti-FXI potently inhibited FXIa amidolytic activity, both inhibitors efficiently mitigated recombinant human TF- and tumor cell-induced fibrin clot formation and platelet aggregation only in the presence of low TF PCA. The anticoagulant effects showed an inverse correlation with the magnitude of cellular TF PCA expression. Similarly, BMS markedly interfered with tumor cell-induced thrombin generation, with the most prominent effects on peak and total thrombin. In addition, anticoagulant effects of FXIa inhibition by 10 µM BMS were in a similar range to those obtained by 600 nM rivaroxaban and 1.6 µM tinzaparin at low TF PCA levels. However, rivaroxaban and tinzaparin also exerted marked anticoagulant activity at high TF PCA levels. CONCLUSION: Our findings indicate that FXI/FXIa inhibition interferes with tumor cell-induced coagulation activation only at low TF PCA expression levels, a finding with potential implications for future in vivo studies.

High molecular weight kininogen interactions with the homologs prekallikrein and factor XI: importance to surface-induced coagulation.

BACKGROUND: In plasma, high molecular weight kininogen (HK) is either free or bound to prekallikrein (PK) or factor (F) XI (FXI). During contact activation, HK is thought to anchor PK and FXI to surfaces, facilitating their conversion to the proteases plasma kallikrein and FXIa. Mice lacking HK have normal hemostasis but are resistant to injury-induced arterial thrombosis. OBJECTIVES: To identify amino acids on the HK-D6 domain involved in PK and FXI binding and study the importance of the HK-PK and HK-FXI interactions to coagulation. METHODS: Twenty-four HK variants with alanine replacements spanning residues 542-613 were tested in PK/FXI binding and activated partial thromboplastin time clotting assays. Surface-induced FXI and PK activation in plasma were studied in the presence or absence of HK. Kng1-/- mice lacking HK were supplemented with human or murine HK and tested in an arterial thrombosis model. RESULTS: Overlapping binding sites for PK and FXI were identified in the HK-D6 domain. HK variants with defects only in FXI binding corrected the activated partial thromboplastin time of HK-deficient plasma poorly compared to a variant defective only in PK-binding. In plasma, HK deficiency appeared to have a greater deleterious effect on FXI activation than PK activation. Human HK corrected the defect in arterial thrombus formation in HK-deficient mice poorly due to a specific defect in binding to mouse FXI. CONCLUSION: Clinical observations indicate FXI is required for hemostasis, while HK is not. Yet, the HK-FXI interaction is required for contact activation-induced clotting in vitro and in vivo suggesting an important role in thrombosis and perhaps other FXI-related activities.