Eliquis bleeding antidote aces PhIII study, threatening to beat rivals to market

In a three-horse race for the new-age anticoagulant throne, safety is key--hence the importance of an antidote to reverse the drugs' effects if necessary. On Wednesday, Pfizer ($PFE) and Bristol-Myers Squibb ($BMY) got some positive data on an undo med for their market trailer, Eliquis. And that antidote could be on the way in the not-too-distant future.

In a Phase III study, Portola Pharma's ($PTLA) FDA-designated breakthrough candidate met both its primary and secondary endpoints with high statistical significance, immediately reversing Eliquis' effects, it said. The prospect, andexanet alfa, was well tolerated in trial participants, with no serious adverse events reported.

"These highly statistically significant Phase III ANNEXA-A data demonstrate that andexanet alfa has the potential to be the first agent approved as a universal Factor Xa inhibitor antidote," John Curnutte, EVP of R&D for Portola, said in a statement. The company anticipates filing a BLA with the FDA for accelerated approval at the end of 2015, he added.

That's not to say Eliquis' rivals--Johnson & Johnson ($JNJ) and Bayer's Xarelto and Boehringer Ingelheim's Pradaxa--don't have their own antidote prospects. Portola is currently testing andexanet alfa with Xarelto and expects to report data later this year, it said. And Boehringer is testing its own investigational antidote--also an FDA-tabbed breakthrough--in a Phase III study of Pradaxa patients who have uncontrolled bleeding or require emergency surgery or procedures.

Whichever drug can boast an antidote first may gain a marketing edge, with safety concerns already taking their toll on Pradaxa's market share. Though the German pharma's drug hit the warfarin-replacement scene ahead of its competitors, thousands of reports of severe or fatal bleeding have helped Xarelto manage to take a commanding lead.

On the other hand, an analysis of FDA adverse events reports suggesting that Eliquis tops its brethren in the safety category hasn't gotten it all that far--yet. So far, the treatment has fallen far short of analysts' expectations. Thanks to stepped-up marketing efforts from Pfizer and BMS, however, it showed some signs of life in Q2, pulling in 13 times its second-quarter sales haul from the same period last year.

- read Portola's release
- see more on Boehringer's candidate

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