Dublin-based pharmaceutical company Vidara Therapeutics has been acquired by US drug giant Horizon Pharma in a deal worth $660 million (€474 million).

The privately-owned firm, which employs 24 staff at its Irish base on Dublin’s North Wall Quay, produces several commonly prescribed anti-inflammatory drugs, most notably Actimmune which is used in the treatment of severe osteopetrosis.

It recorded net sales of Actimmune of $58.9 million last year.

Horizon Pharma, which specialises in treatments for arthritis, pain and inflammatory diseases, said today that it will acquire Vidara through a reverse merger for stock and cash valued at approximately $660 million.

Horizon Pharma will be the name of the new company, and it will be based in the Republic with a portfolio of four products marketed primarily in the US.

The deal, which is subject to shareholder approval, will give Horizon Pharma a “tax efficient corporate structure” to support its organic growth and acquisition strategy, it added

The new company’s tax rate is expected to be about 20 per cent or less, compared with a rate in the high 30s for Horizon as a stand-alone entity, according to a US regulatory filing.

Under the deal, the shareholders of Vidara will retain approximately 26 per cent of Horizon Pharma and receive $200 million in cash, subject to certain adjustments.

The new company will list on Nasdaq.

Vidara Therapeutics was formed in 2012 when Dublin-based AGI Therapeutics was acquired by Aravis Limited, a member of the Vidara Therapeutics group of companies.

Following the acquisition, AGI de-listed from the Alternative Investment Market of the London Stock Exchange (AIM) and the Enterprise Securities Market of the Irish Stock Market (ESM).

Several senior executives with AGI moved to Vidara, including John Devane, now chief scientific officer with Vidara and Mary Martin, vice president of regulatory affairs.

“The addition of Actimmune complements our commercial business model focused on targeted promotion to primary care physicians and specialists,” chairman, president and chief executive of Horizon Pharma Timothy Walbert said.

The acquisition is expected to be concluded in middle of this year.

Last year Irish pharma company Elan was sold to US group Perrigo, with the US firm citing Ireland’s low tax environment as a factor in the deal.