The novel blood thinner rivaroxaban is more effective at preventing recurrence of life-threatening blood clots in the legs and lungs, and as safe as aspirin, an international research team has found. The results came from the EINSTEIN CHOICE trial - Reduced-dosed Rivaroxaban in the Long-term Prevention of Recurrent Symptomatic VTE (Venous Thromboembolism).

The large international study of 3,396 patients with venous thromboembolism in 31 countries shows that Bayer and Johnson & Johnson’s rivaroxaban, trade name Xarelto, is more effective than aspirin. The study was funded by Bayer AG.

Venous thromboembolism is a chronic disease, with risks of additional blood clots over a patient’s lifetime. Many physicians and patients are now opting out of long-term treatment with blood thinners because of concern about the risk of bleeding. Some are choosing aspirin instead because they consider it to be safer.

Extended Rivaroxaban Treatment

Principal investigator Dr. Jeffrey Weitz, professor of medicine and biochemistry and biomedical sciences at the Michael G. DeGroote School of Medicine at McMaster University, said:

“In testing two doses of rivaroxaban, we found that we have the option of lowering the daily dose for extended treatment. This will ease the long-term concerns of both patients and their doctors."

Over a 351-day period the study found that patients taking aspirin had the highest rate of recurrent blood clots, at 4.4 percent. Rates of recurrent clots for patients taking 20mg and 10mg of rivaroxaban were significantly lower, at 1.5 and 1.2 percent respectively.

There were no statistically significant differences between the treatments in terms of bleeding side-effects. The rates of major bleeding were 0.3 percent in the group taking aspirin, and 0.5 percent and a 0.4 percent in the groups taking 20 mg and 10mg of rivaroxaban, respectively.

Rivaroxaban is associated with lower rates of serious and fatal bleeding events than warfarin but is associated with higher rates of bleeding in the gastrointestinal tract.

Rivaroxaban works by inhibiting both free Factor Xa and Factor Xa bound in the prothrombinase complex. It is a highly selective direct Factor Xa inhibitor with oral bioavailability and rapid onset of action. Inhibition of Factor Xa interrupts the intrinsic and extrinsic pathway of the blood coagulation cascade, inhibiting both thrombin formation and development of thrombi.

Venous thromboembolism affects more than 900,000 Americans each year and are the third most common vascular diagnosis after heart attack and stroke, according to the American Heart Association.

Jeffrey I. Weitz, Anthonie W.A. Lensing, Martin H. Prins, Rupert Bauersachs, Jan Beyer-Westendorf, Henri Bounameaux, Timothy A. Brighton, Alexander T. Cohen, Bruce L. Davidson, Hervé Decousus, Maria C.S. Freitas, Gerlind Holberg, Ajay K. Kakkar, Lloyd Haskell, Bonno van Bellen, Akos F. Pap, Scott D. Berkowitz, Peter Verhamme, Philip S. Wells, Paolo Prandoni Rivaroxaban or Aspirin for Extended Treatment of Venous Thromboembolism New England Journal of Medicine, 2017; DOI: 10.1056/NEJMoa1700518

Image: David Gregory & Debbie Marshall, Wellcome Images

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