Bayer, J&J Sign Partner Deal With Portola for Xarelto Antidote

Bayer AG and Johnson & Johnson will work together with Portola Pharmaceuticals Inc. to quell doctors’ concerns about the lack of an antidote to their new blood-thinner Xarelto.

The companies will collaborate on PRT4445, Portola’s experimental antidote for Factor Xa inhibitors like Xarelto, Leverkusen, Germany-based Bayer and New Brunswick, New Jersey-based J&J said in an e-mailed press release today. A proof-of-concept study in healthy volunteers should be done by the second half of this year, the partners said.

Xarelto and competitor Eliquis, a Factor Xa inhibitor developed by Bristol-Myers Squibb Co. and Pfizer Inc. were hailed as a benefit for patients who may have otherwise relied on the older, more difficult to administer drug warfarin to help prevent blood clots and strokes. Still, doctors were concerned that without an antidote it might be difficult to undo blood thinning in cases of an emergency, like sudden bleeding or the need for an immediate operation.

“Although when normalization of blood clotting is necessary, stopping the intake of Xarelto is usually effective, we understand the desire of doctors to have a specific antidote to reverse the anticoagulation effects,” Kemal Malik, Bayer’s head of global development, said in today’s statement.

The partners will pay Portola an undisclosed amount for the collaboration. The South San Francisco-based company will keep global development and commercialization rights for the compound.

Portola signed a similar deal in November with Pfizer and its partner Bristol-Myers. That agreement also allowed Portola to keep the rights on the compound.

Xarelto won approval in November 2011 for U.S. patients with atrial fibrillation, an irregular heartbeat that increases the risk of blood clots and strokes and that afflicts about 2.66 million people in the U.S. Eliquis was approved in December 2012 for the same patients.

Bayer has said Xarelto will probably have peak annual sales of more than 2 billion euros ($2.71 billion).

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