Fight for anticoagulant market heats up with antidote deals

Xarelto does not have a quick-acting antidote to heavy bleeding.--Courtesy of Bayer

What would top Xarelto for Bayer and Johnson & Johnson? Xarelto with an easy antidote. The anticoagulant, one of a handful of new alternatives to the difficult-to-administer warfarin, comes with a risk of bleeding. So does warfarin. But warfarin has a quick-acting antidote. Xarelto and its new peers do not.

Yet, that is. Bayer and J&J ($JNJ) have teamed up with Portola Pharmaceuticals to test PRT4445, an agent that may be able to counteract heavy bleeding. If it proves itself, then doctors wary of the warfarin alternatives would be more likely to choose Xarelto over warfarin.

They might also select Xarelto over Pradaxa, the first warfarin alternative to market. Sold by Boehringer Ingelheim, and now used by millions of patients globally, Pradaxa has been blamed for more than 1,000 deaths. Some high-profile cases have scared off doctors who might dislike the cumbersome warfarin, but prefer a ready-to-hand antidote in case of emergency. Boehringer is working to identify its own antidote for Pradaxa, a thrombin inhibitor, and points out that instances of severe bleeding in Pradaxa patients are still less common than in warfarin patients.

The battle for share in the warfarin-alternative market is important for all 5 companies. Each is expecting big sales from their respective products; Bayer, for one, has pegged Xarelto as a $2.5 billion-a-year product.

Unfortunately for Bayer and J&J, an antidote to Xa factor inhibitors would also work in bleeding emergencies triggered by Eliquis, a competing Xa drug from Pfizer ($PFE) and Bristol-Myers Squibb ($BMY). And those companies have their own deal with Portola.

Already sold in the U.S. and E.U. for certain types of blood clots, Eliquis only recently won approval to prevent stroke in patients with atrial fibrillation. Its supporting data on the efficacy side is considered stronger than Xarelto's. So, while an antidote may give Xarelto an edge over warfarin or even Pradaxa, it still may lose out in the balance against Eliquis.

- see the release from J&J
- read the MedPage Today story