Pharmaceutical and healthcare giant MSD is to close one of its Irish factories with the loss of 280 jobs.
The company is to pull out of its base in Rathdrum, Co Wicklow, by the end of 2015 after a review of its worldwide manufacturing capabilities.
MSD Ireland will continue to employ about 2,000 people.
Enterprise agency IDA Ireland said it will work intensively with MSD on finding a buyer for the facility and creating alternative employment in the area.
MSD Ireland has sites in Dublin, Carlow, Cork, Tipperary and Wicklow. MSD, created out of a merger involving Merck, Sharpe & Dohme and Schering-Plough, said it notified employees in Rathdrum at a meeting earlier.
The company said manufacturing will start to be phased out in 2014 but no staff reductions are anticipated until the end of 2014.
John Smith, site director, said: "Rathdrum has been a significant manufacturing site since 1961 and has a long history of operational excellence.
"The proposal to cease operations is not a reflection of the site's performance or the highly skilled people working there. The proposed action is the result of MSD's ongoing review of the global manufacturing capacities needed to support its growth, business goals, product portfolio and pipeline."
The closure will see the company relocate products manufactured in Rathdrum to MSD sites in Ballydine, Co Tipperary, and Singapore, and some third-party manufacturers.
MSD makes prescription medicines, vaccines, biologic therapies, and consumer care and animal health products, sold in more than 140 countries.