By Sarah Sloat
Bayer AG (>> Bayer) said late Thursday it halted a phase 3 study for the use of blood-thinning drug Xarelto because it didn't show improved efficacy compared with another treatment using aspirin.
The Navigate Esus study was testing Xarelto for the secondary prevention of strokes and systemic embolism in patients who recently had an embolic stroke of undetermined source.
Researchers stopped the trial early because the Xarelto and aspirin arms of the study showed comparable efficacy, and there was little chance of an overall benefit if it were completed, the German pharmaceutical and chemicals company said.
"While bleeding rates were low overall, an increase in bleeding was observed in the [Xarelto] arm compared to the low-dose aspirin arm," Bayer said.
Xarelto, also known as rivaroxaban, is a prescription anticoagulant which been approved for seven indications. The drug contributed just over 2.9 billion euros ($3.4 billion) in sales to Bayer's pharmaceutical division last year.
The drug was developed jointly by Bayer and Janssen Pharmaceuticals, a unit of Johnson & Johnson (>> Johnson & Johnson). It is marketed outside the U.S. by Bayer and within the U.S. by Janssen.
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