Horizon will buy Hyperion and add new drugs to its rare disease portfolio

Horizon Pharma has agreed to buy US-based Hyperion Therapeutics for $1.1 billion (£742 million).

Horizon will gain two rare disease drugs: Ravicti (glycerol phenylbutyrate) and Buphenyl (sodium phenylbutyrate), which are used to treat urea cycle disorders (UCDs), genetic conditions where deficiencies in several metabolic enzymes cause nitrogen waste to accumulate in the blood. Both drugs provide alternative pathways for the excretion of excess nitrogen. UCDs affect around 2100 people in the US, and the two drugs made over $100 million in net sales in 2014.

Horizon hopes the acquisition will help to boost sales after some of its osteoarthritis drugs were dropped by US healthcare retailers Express Scripts and CVS Health last year. In early 2014, the company took over Vidara Therapeutics and moved its headquarters from the US to Ireland.