Gilead Sciences, Inc., agreed to pay $11 billion in cash for Pharmasset, Inc., on November 21, 2011 to acquire the target’s treatments for hepatitis C, also known as HCV . At $137 per Pharmasset share, the deal came at an 89 percent premium to Pharmasset’s closing price on November 18, 2011, the last trading day before the deal’s announcement, and a 59 percent premium to the target’s previous all-time high.
The acquisition would be the largest ever by Gilead, which has done a string of smaller deals, including the $1.4 billion purchase of CV Therapeutics, Inc., in 2009 and the $2.5 billion acquisition of Myogen Inc. in 2006. Pharmasset’s most valuable drug, a treatment known as PSI-7977, is still in trials and may not receive regulatory approvals until 2014. Gilead’s strength is in treatments for HIV.
