Shire extends expiration date for offer to buy ViroPharma

DUBLIN — Drug maker Shire is extending the deadline for its offer to buy Exton, Pa.-based ViroPharma for $4.2 billion, Shire said Friday.

The company said it had extended the expiration date of its tender offer for ViroPharma until Jan. 9. The offer had previously been planned to expire on Thursday. Shire announced the $50-per-share offer last month.

As of 6 p.m. Thursday, about 50.2 million of ViroPharma's shares, or 76% of the total shares of the company, had been put up for sale in connection with the offer, Shire said. ViroPharma develops treatments for rare diseases, including Cinryze (C1 esterase inhibitor [human]) for hereditary angioedema.