Gilead Sciences, the world’s largest HIV drug manufacturer, has announced that it will acquire Pharmasset for $11bn.

The value of the transaction is equal to $137 per share in cash and will be financed on hand, by bank debt and by senior unsecured notes.

Gilead hopes the acquisition will accelerate its work in developing all-oral regimens for the treatment of hepatitis C, regardless of viral genotype.

Pharmasset has three clinical-stage product candidates for the treatment of the virus advancing in trials in various populations.

The company’s lead product candidate, PSI-7977, has recently been advanced into two PhaseIII studies in genotype 2 and 3 patients.

Gilead chairman and CEO John Martin explained, "The compound, together with Pharmasset’s other pipeline candidates, represents a strong strategic fit with Gilead’s vision, pipeline and capabilities. This transaction will serve to drive the long-term growth of our business."

The California-based company expects the transaction to reduce its earnings through to 2014 and add to profit in 2015 and beyond.

Steven Wymer’s Fidelity Growth Company Fund held 7.44 million shares in Pharmasset as of 30 September and is expected to make $478.4m in the sale, reports Bloomberg.