Drugmaker Shire, Plc, said Monday it will pay $4.2 billion for Exton-based ViroPharma.
Shire is registered, headquartered and based in the Channel Islands, Ireland and the United Kingdom, but one of its main U.S. facilities is in Chesterbrook.
Shire's best-selling drug is the Vyvanse, a medicine for attention deficit hyperactivity disorder.
The $4.2 billion translates to $50 per share price, which is a 27% premium to ViroPharma's closing share price on Friday.
Some of Shire's drugs are used to treat rare diseases, the prices of which can bring higher profits for pharmaceutical companies.
The acquisition of ViroPharma is meant to add to the rare-drug portfolio. ViroPharma makes Cinryze, which is used for the prophylactic treatment of Hereditary Angioedema (HAE).
“The acquisition of ViroPharma will immediately benefit Shire and is entirely consistent with our clear strategic objective of strengthening our rare disease portfolio," Shire Chief Executive Officer Flemming Ornskov said in a statement. "It brings us a new growth driving product which augments our already strong growth prospects."
Ornskov joined Shire in 2013 and has been working to re-organize the company. One move was to cancel a planned move to a new building in Malvern.
Vincent J. Milano, ViroPharma’s chief executive officer, said in the statement, “We are pleased to announce our merger with Shire, which like ViroPharma, is focused on developing products for patients suffering from rare diseases. After thoroughly evaluating our strategic options we determined that this transaction is in the best interests of ViroPharma, our shareholders and our patients."