Swiss pharmaceuticals group Roche revealed this week that it has agreed to acquire California-based biotechnology company InterMune Inc. in a deal worth $8.3 billion.

Roche will pay a 38 percent premium over InterMune's closing price on Friday last week, or $74.00 per share, in an all-cash deal, the Swiss drugmaker said in a statement.

The acquisition of InterMune, a developer of treatments for lung diseases, will allow Roche to broaden and strengthen its respiratory portfolio globally and the company expects that the deal will positively contribute to earnings from 2016.

InterMune is aiming to launch its pirfenidone drug in the U.S. by the end of this year. The drug was developed to treat a terminal lung disease, called idiopathic pulmonary fibrosis, which causes breathing problems due to inflammation and scarring of lung tissue.

The drug has been available in Europe since 2011, marketed under the name Esbriet, and it is also available in Canada. Industry analysts, polled by Thomson Reuters Pharma, expect the drug to have sales of $1.04 billion in 2019.

Roche is planning to diversify away from cancer drugs, where it is the world leader, by migrating into other treatment areas, such as respiratory medicine, according to a Reuters report.

The company already sells drugs for cystic fibrosis and severe asthma in the U.S. and has other experimental respiratory products in clinical development, including an asthma drug called lebrikizumab.