GlaxoSmithKline (NYSE: GSK) and partner Theravance, Inc. (Nasdaq: THRX) on Friday formally submitted applications for approval of a new respiratory drug in the U.S. and in Europe.

Glaxo and Theravance began a collaboration a decade ago to develop respiratory drugs to help succeed Advair, Glaxo’s aging best-seller.

The application for fluticasone furoate/vilanterol is for treatment of chronic obstructive pulmonary disease (COPD) in the U.S. and Europe.

GSK also seeks to use it for asthma treatment in the EU.

An application for asthma treatment in the U.S. remains under review, the companies said.

In the U.S. the drug would be called Breo and administered by an inhaler called Ellipta.

In Europe, the drug would be called Relvar and administered by a dry-power inhaler called Ellipta.

GSK operates its North American headquarters in Research Triangle Park.

If successful, the drug could replace more than half of Advair’s $7.8 billion in annual sales, according to analysts at UBS AG.

(Bloomberg news contributed to this report.)