Assessing the Effect of Asundexian on Thrombotic Status, in Particular Endogenous Fibrinolysis, in Patients With Atrial Fibrillation

The risk of a clot forming in a blood vessel, which can cause a heart attack or stroke, is determined partly by how "sticky" the blood is and partly by the effectiveness of the natural defences in the blood in dissolving any clots that start forming (clot lysis, or "fibrinolysis"). There are available tests that can assess how "sticky" the blood is, and we can overcome that with specific blood-thinning medications (such as anticoagulants [such as warfarin, apixaban, rivaroxaban] and antiplatelet agents [such as aspirin and clopidogrel]). However, we have not been able to assess the effectiveness of natural clot dissolving mechanisms, until recently.

In the last few years, using new blood testing techniques, we and other groups, have shown that individuals who have less effective natural clot lysis, have a much higher risk of heart attack, stroke and death. Therefore, we would like to find medications that can make clot lysis more effective, in such individuals, to reduce their risk of stroke and heart attack. Unfortunately, most blood thinning tablets for long term use do not improve clot lysis.

Earlier, our group has shown that the anticoagulant apixaban, mildly improved clot lysis.

We would now like to assess clot lysis in patients taking apixaban and compare it to patients taking a very new type of anticoagulant called asundexian, to see if asundexian can improve clot lysis more than apixaban.

The easiest way to do this, is to test additional blood samples from patients who are already taking part in a clinical trial comparing apixaban and asundexian (OCEANIC-AF). OCEANIC-AF is a phase 3, multicentre, randomised clinical trial, comparing asundexian, a new type of blood thinner (factor XI inhibitor) with a commonly used blood thinner (apixaban, a factor X inhibitor), to see if it carries a lower risk of bleeding.