NEW YORK (AP) -- Drugmaker InterMune said Wednesday it expects to raise $79.6 million from a stock offering. The Brisbane, Calif., company said it is selling 6.5 million shares for $13 each.

Shares of InterMune closed at $13.73 Tuesday and the offering is priced at a 5.3% discount.

InterMune said it will use the proceeds to fund the marketing and a U.S. clinical trial of its lung disease drug Esbriet. Esbriet is used to treat a terminal lung disease called idiopathic pulmonary fibrosis, or IPF, which causes inflammation and scarring of the lung. InterMune began the drug in Europe in September 2011. It is available in a number of European countries but has not been approved in the U.S.

The proceeds will also fund work on new formulations of Esbriet and studies of the drug in new indications

The underwriters of the offering will have the option to buy another 975,000 shares to cover any over-allotments, potentially raising InterMune's proceeds.