DURHAM, N.C-A new type of anti-clotting drug Asundexian, caused fewer bleeding incidents among patients with atrial fibrillation than the commonly prescribed apixaban, according to results from a head-to-head comparison of the two.
The study, led by cardiologist at Duke Clinical Research Institute, was reported April 3 at the American College of Cardiology annual scientific sessions meeting and simultaneously published in the journal The Lancet.

"Anti-clotting therapy is a lifesaver for people who develop atrial fibrillation, which can increase the risk of stroke by five-fold," said presenter and senior author Manesh Patel, M.D., chief of the Division of Cardiology at Duke University School of Medicine and member of the Duke Clinical Research Institute. "But a serious complication associated with anti-clotting therapies is bleeding, leading many patients to reduce or stop taking their medications. As a result, there is great interest in alternatives that reduce this risk."
Asundexian is a new class of anti-clotting drug that is under investigation. It works by inhibiting a blood protein called Factor XI, which contributes to the development of blood clots but is not involved in the process of healing blood vessels.
In the PACIFIC-AF trial-a phase 2 study funded by Bayer AG, which manufactures the investigative therapy-the researchers focused on bleeding outcomes arising from two different doses among patients with atrial fibrillation.
Both doses of asundexian taken once daily, 20 mg and 50 mg, were tested in comparison to similar dosages of apixaban, which is one of several commonly prescribed anti-clotting therapies that affect a different blood clotting protein.
The trial included 755 patients with an average age of about 74 years old. At both doses, patients who took asundexian had a 67-percent lower risk of bleeding compared to patients taking apixaban.
"Reducing bleeding risks for atrial fibrillation patients is encouraging," said lead author Jonathan Piccini, M.D., clinical cardiac electrophysiologist at Duke University School of Medicine. "One in four people will develop atrial fibrillation-it's the leading cause of heart arrhythmia and is a risk factor for stroke-so it's important that we have safe and effective therapies. We're eager to see the research move into phase 3 studies.