Gilead, Pharmasset deal

Gilead will acquire HCV company Pharmasset for $137 per share in cash. The price is an 89% premium to Pharmasset's close of $72.67 on Nov. 18, before the deal was announced, and values Pharmasset at about $11 billion.

Pharmasset's PSI-7977 is in Phase III testing in combination with ribavirin to treat HCV genotype 2 and 3 infection. Data from the trial, which is the first all-oral regimen in Phase III testing, is expected in 2013. PSI-7977 is a single isomer form of PSI-7851, a nucleotide analog HCV NS5B polymerase inhibitor. Gilead also will gain two compounds in Phase IIb testing: PSI-938; and mericitabine, which is licensed to Roche (SIX:ROG; OTCQX:RHHBY, Basel, Switzerland). PSI-938 is a third-generation guanosine nucleoside analog polymerase inhibitor of HCV, and mericitabine is a prodrug of PSI-6130, a cytidine nucleoside analog non-structural protein 5B (NS5B) polymerase inhibitor. Gilead's HCV portfolio includes an oral, interferon-free regimen in Phase II trials. ...