Alexion Pharmaceuticals has signed a definitive agreement to acquire Portola Pharmaceuticals for a total consideration of $1.41bn, or $18 per share.

Portola Pharmaceuticals is a commercial-stage biopharmaceutical company focused on developing therapeutics for life-threatening blood disorders.

The company’s commercialised medicine, Andexxa marketed as Ondexxya in Europe is indicated as a blood-thinning antidote.

Andexxa is a Factor Xa inhibitor reversal agent, which reverses the anticoagulant effects of Factor Xa inhibitors rivaroxaban and apixaban in case of severe and uncontrolled bleeding.

Portola Pharmaceuticals president and CEO Scott Garland said: “In developing and launching Andexxa, Portola has established a strong foundation for changing the standard of care for patients receiving Factor Xa inhibitors that experience a major, life-threatening bleed.

“Andexxa rapidly reverses the pharmacologic effect of rivaroxaban and apixaban within two minutes, reducing anti-Factor Xa activity by 92%.”

Alexion expects the deal to add near-term diversification to its commercial portfolio. The company will also leverage its commercial expertise to expand access to the drug.

Alexion Pharmaceuticals CEO Ludwig Hantson said: “We believe Andexxa has the potential to become the global standard of care for patients who experience life-threatening bleeds while taking Factor Xa inhibitors apixaban and rivaroxaban.

“By leveraging Alexion’s strong operational and sales infrastructure and deep relationships in hospital channels, we are well-positioned to expand the number of patients helped by Andexxa, while also driving value for shareholders.”

Approved by the boards of both companies, the merger agreement is subject to customary conditions and expected for completion in the third quarter of this year.

Last October, Alexion agreed to acquire Achillion Pharmaceuticals for an upfront payment of around $930m, or $6.30 per share.

Achillion Pharmaceuticals develops Factor D inhibitor therapies for complement alternative pathway-mediated rare disease.