Horizon Pharma has acquired Raptor Pharmaceutical for $800 million. The transaction is expected to close in the fourth quarter of 2016.

“The proposed acquisition of Raptor furthers our commitment to helping people with rare diseases and is a significant step in advancing our strategy to expand our rare disease business,” said Timothy Walbert, chairman, president and chief executive officer, Horizon Pharma. “Along with the potential for accelerated revenue growth, the addition of Raptor strengthens our U.S. orphan business and provides a platform to expand our orphan business in Europe and other key international markets.”

The deal strengthens Horizon’s focus on rare diseases and provides expansion into Europe and other international markets. It also adds Procysbi delayed-release capsules and Quinsair (aerosolized form of levofloxacin) global rights, with Procysbi having strong patent protection through 2034. In addition, it diversifies Horizon’s revenue with 11 medicines across three business units—orphan, rheumatology and primary care—while bolstering rare disease revenue, which in the first half of 2016 was 45% of total Horizon revenue.

“This transaction will deliver significant and immediate value to our shareholders through a compelling all-cash premium and provide ongoing value to our patients, their families and the physicians who treat them,” said Julie Anne Smith, president and chief executive officer, Raptor Pharmaceutical.