Study: New Anticlotting Drug Beats Warfarin

Aug. 29, 2011 (Paris) -- The experimental anticlotting pill Eliquis beat out the standard drug, warfarin, at preventing strokes in people with a heart condition that puts them at high risk of blood clots and stroke, researchers report.

The new drug, also known as apixaban, cut the risk of stroke by 21% compared with warfarin in people with atrial fibrillation (AF). It lowered the risk of dying by 11%.

The side effect of serious internal bleeding, the key safety concern of anticlotting medication, was reduced by 31% with Eliquis compared to warfarin.

Two other anticlotting pills in the race to find warfarin alternatives, Pradaxa and Xarelto, have also shown benefits over the older treatment in major studies. But Eliquis is the first to reduce all three measures of stroke, deaths, and bleeds.

"This is a real home run ... another dagger in the heart of warfarin for stroke prevention," says Ralph Brindis, MD, a cardiologist at Kaiser Permanente in Oakland, Calif. Brindis is immediate past president of the American College of Cardiology. He was not involved with the work.

Results of the two-year study pitting Eliquis against warfarin in 18,201 people with AF and at least one other risk factor for stroke were presented here at the European Society of Cardiology Congress 2011. The study was also published online in TheNew England Journal of Medicine.

Atrial Fibrillation and Stroke Risk

Atrial fibrillation, a condition characterized by irregular heart rhythms, affects 2.6 million Americans, with risk increasing with age. People with AF are more likely to suffer a stroke than people without AF because their erratic heartbeats allow blood to pool and form clots in an upper chamber of the heart. The clots can travel to the brain and block blood flow, causing a stroke.

Warfarin, which is also sold under the brand names Coumadin and Jantoven, has been the standard treatment for AF for decades. It can cut stroke risk by up to 70%. But frequent blood tests are needed to make sure the patient is getting a correct dose. If too much is given, you can suffer a side effect of a dangerous bleed. Take too little, and the risk of a potentially deadly blood clot increases further.

Because it works by blocking vitamin K, eating foods that are high in the nutrient, like dark leafy greens, can make warfarin less effective. Many drugs, including some antibiotics and painkillers, can interact with the drug, blocking or enhancing its effect.

As a result, only about half of patients who can benefit from the drug actually take it.

Overall, 1.3% of patients per year in the Eliquis group suffered a stroke or major blood clot vs. 1.6% per year in the warfarin group. The rate of serious internal  bleeding was 2.1% per year in the Eliquis group vs. 3.1% per year in the warfarin group. And 3.5% of patients per year in the Eliquis group died vs. 3.9% per year in the warfarin group.