Sept 26 (Reuters) - Italy's Alfasigma S.p.A said on Tuesday it had agreed to buy U.S. drugmaker Intercept Pharmaceuticals for $794 million to expand its presence in the United States.

Alfasigma will pay $19 per Intercept share, which represents a premium of 82% to its last closing price. (Reporting by Manas Mishra in Bengaluru; Editing by Shilpi Majumdar)