Johnson & Johnson is buying the biopharmaceutical company Alios BioPharma Inc. for about $1.75 billion.

Alios is a privately held company that focuses on developing therapies for viral diseases.

The deal includes Alios’ portfolio of potential therapeutics for viral infections including compound AL-8176, an orally administered antiviral therapy currently in Phase 2 studies for the treatment of infants with respiratory syncytial virus. RSV typically causes only mild, cold-like symptoms in most children. But it is also the most common cause of pneumonia in U.S. infants.

“AL-8176 complements our existing early stage portfolio for RSV which aims to prevent and treat this disease, the leading cause of acute lower respiratory infection in children under the age of five,” William N. Hait, Global Head of Research Development at Janssen Pharmaceutical Cos. of Johnson & Johnson, said in a statement.

The acquisition is targeted to close in the fourth quarter.

Johnson & Johnson is based in New Brunswick, New Jersey. Its stock rose 3 cents to $106.57 in premarket trading Tuesday shortly before the market opening.