Horizon Pharma buying Hyperion for about $1.1 billion

Horizon Pharma is buying Hyperion Therapeutics for about $1.1 billion, gaining two treatments for genetic disorders.

Dublin-based Horizon Pharma will pay $46 per share for Brisbane, California-based Hyperion, marking a 5.6 percent premium to that stock's closing price on Friday.

The move adds the drugs Raviciti and Buphenyl to Horizon's offerings. Both drugs are aimed at treating inherited disorders called urea cycle disorders which affect about 2,100 people in the U.S. The genetic condition affects how the body removes nitrogen from the blood. Nitrogen buildup can be toxic.

Combined, the drugs had sales of $113.6 million in 2014.

Horizon has five products, of which Actimmune is focused on treating the genetic condition chronic granulomatous disease, which is a group of immune system conditions. It had sales of $25.3 million in 2014. The biotechnology company's biggest revenue comes from the rheumatoid arthritis and osteoarthritis treatment Vimovo, at $163 million in 2014.

Overall, Horizon had $297 million in nets sales from in 2014.

The companies expect the deal to close during the second quarter.

Shares of shares of Hyperion rose $2.76, or 6.5 percent to $45.50 in premarket trading while Horizon Pharma PLC rose $2.39, or 11 percent, to $24.20.