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Published on: September 9, 2012
Factor XI inhibition in patients with acute coronary syndrome
Carmelo Raffo1, Davide Capodanno1
1Cardiovascular Department, A.O.U. Polyclinic 'G. Rodolico-San Marco', University of Catania, Catania.
Insights
Factor XI (FXI) inhibitors show potential for reducing ischemic events after heart attacks without increasing bleeding risk. Early trials like PACIFIC-AMI suggest FXI inhibition is safe, though efficacy requires further study in larger trials.
Area of Science:
- Cardiology
- Pharmacology
- Hematology
Background:
- Acute coronary syndrome (ACS) patients have hypercoagulable states, increasing recurrent ischemic events.
- Current antiplatelet and anticoagulant therapies reduce ischemic risk but carry significant bleeding risks.
- Factor XI (FXI) deficiency is linked to reduced thrombosis with minimal bleeding, suggesting FXI inhibition as a therapeutic target.
Purpose of the Study:
- To evaluate the safety and efficacy of FXI inhibitors in secondary prevention after myocardial infarction (MI).
- To explore the potential of FXI inhibitors to decouple thrombosis from hemostasis, reducing ischemic risk without increasing bleeding.
Main Methods:
- The PACIFIC-AMI trial assessed the safety of an oral FXIa inhibitor, asundexian, in patients post-MI.
- Primary endpoint was BARC Types 2, 3, or 5 bleeding, comparing asundexian doses to placebo.
- Efficacy was a secondary outcome, with the study lacking statistical power for definitive conclusions.
Main Results:
- No significant difference in major bleeding events was observed between asundexian doses and placebo.
- Efficacy data were neutral, consistent with the trial's limited statistical power to detect such differences.
Conclusions:
- FXI inhibition is a promising strategy for secondary prevention in acute MI patients.
- Further investigation in larger Phase 3 trials, like LIBREXIA-ACS, is crucial to confirm the efficacy of FXI inhibitors.
Abstract:
A hypercoagulable condition is typical of patients with acute coronary syndrome and is a determining factor in the genesis of recurrent ischaemic events. Modern pharmacological therapies consisting of antiplatelets and anticoagulants derive their rationale for use on the pathophysiological mechanisms most commonly associated with myocardial infarction (MI); they have contributed to reducing the ischaemic risk of these patients, but left ample room for improvement. In particular, trials that have studied the association of an anticoagulant with antiplatelet drugs have provided promising results in terms of efficacy, but highlighted a significant bleeding risk. Evidence derived from experimental animal and epidemiological studies has shown how factor XI (FXI) deficiency is associated with a reduction in thrombotic events but with modest bleeding. These data added to the role that FXI plays in the coagulation cascade constituted an incipit for the pharmacological attempt to decouple thrombosis from haemostasis by means of the inhibition of this factor. The theoretical assumption that FXI inhibitor drugs may be able to reduce the ischaemic risk without significantly increasing the haemorrhagic risk makes these compounds a potential therapeutic aid for patients in secondary prevention after acute MI. To date, on these patients, we only have data from a Phase 2 trial, PACIFIC-AMI (Study to Gather Information About the Proper Dosing and Safety of the Oral FXIa Inhibitor BAY 2 433 334 in Patients Following an Acute Heart Attack). In this study, the primary endpoint-represented by the Bleeding Academic Research Consortium (BARC) composite of Type 2, 3, or 5 bleeding-showed no significant differences between the various doses of asundexian tested (10, 20, and 50 mg quoque die), and between these and placebo (asundexian all doses vs. placebo: hazard ratio, 0.98; 90% confidence interval, 0.71-1.35). The data on efficacy, however, showed neutral results, but it should be noted that the study did not have the adequate statistical power to evaluate this outcome. Valuable information could, therefore, derive in the future from the ongoing Phase 3 trial with milvexian, LIBREXIA-ACS (A Study of Milvexian in Participants After a Recent Acute Coronary Syndrome) and from any future studies that could be started by testing different molecules.
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