Pharmasset, Inc. (Nasdaq:VRUS) and Gilead Sciences, Inc. (Nasdaq:GILD) announced today that the companies have signed a definitive agreement under which Gilead will acquire Pharmasset for $137 per share in cash. Pharmasset is a clinical-stage pharmaceutical whose primary focus is the development of oral therapeutics for the treatment of hepatitis C virus (HCV) infection. The transaction, which values Pharmasset at approximately $11 billion, is expected to close in the first quarter of 2012.

Greenberg Traurig is representing Morgan Stanley & Co. LLC as financial advisor to Pharmasset in this transaction. Greenberg Traurig’s team for Morgan Stanley was led by Co-Chair of the firm’s M&A Steering Committee, David Schwartzbaum, and included corporate shareholder Michael Helsel and associate Joseph Gangitano, all of whom are in the firm’s New York office.