Johnson & Johnson and Bayer’s Xarelto has been feeling the heat in the next-gen anticoagulant market from high-flying rival Eliquis. Over the weekend, though, the medication got a big boost that could expand its potential treatment population by more than half.

Sunday at the European Society of Cardiology annual meeting, the two drugmakers rolled out data showing Xarelto, when paired with aspirin, could top solo aspirin—the current standard of care—in reducing the likelihood of a cardiovascular event in patients with coronary artery disease (CAD) and/or peripheral artery disease (PAD). Adding Xarelto to the aspirin regimen slashed the combined risk of death, stroke and heart attack by 24%.

"Any benefit, when it is something that deals with death or heart attack or stroke, is important. I think we would have been satisfied seeing a 15% benefit, but seeing a 24% benefit in the primary endpoint is particularly exciting and gratifying. These are important events, they’re irreversible events ... It’s a big deal and we’re pretty excited about it," Peter DiBattiste, the global development head of the cardiovascular and metabolism unit at J&J's Janssen, said in an interview.

Results were impressive when broken down, too, Credit Suisse’s Vamil Divan noted. Xarelto pared down the stroke rate by 42%, the CV death rate by 22% and the rate of death from any cause by 18%, he wrote in a note to clients. And researchers recorded a significant jump in major bleeding events, a factor that could limit initial uptake, they found no significant increase in either fatal or intracranial bleeds.

"We expect these results to help drive a re-acceleration of growth for Xarelto," Divan said. Earlier this month, he predicted positive results could drive an additional $1.5 billion or so in annual sales in the U.S. alone.

It won’t happen overnight, though. While Divan does expect the Xarelto-aspirin tandem to become the standard of care in CAD and PAD patients, it likely won’t be able to claim that title until the second half of 2018 or the first half of 2019—after the data is added to Xarelto’s product label and treatment guidelines, he said.

Still, it’s a lift the drugmakers can use. While their product shot out to the front of the field after launch, eclipsing Boehringer Ingelheim’s Pradaxa, third-to-market Eliquis—from Pfizer and Bristol-Myers Squibb—has ramped things up over the past few years. And in May, Bristol’s execs announced that their contender had unseated Xarelto as the class leader based on total prescriptions.