GSK sees little prospect of U.S. generic Advair in 2016

LONDON, May 6 (Reuters) - After relying for years on its top-selling lung drug Advair, GlaxoSmithKline (Other OTC: GLAXF - news) is now braced for the worst in the form of cheap generics - but not just yet.

Chief Executive Andrew Witty said on Wednesday that the chances of cheap copies of its highly profitable inhaled medicine reaching the world's biggest market in 2016 were "vanishingly small".

For the first time, the drugmaker has factored in the introduction of a generic alternative to Advair in the United (Shenzhen: 000925.SZ - news) States in making assumptions about its sales prospects over the next five years.

Witty said this could in theory mean annual U.S. sales of Advair falling to less than 300 million pounds ($457 million) by 2020, down from 392 million pounds in the first quarter of 2015 or 1.57 billion on an annualised basis.

However, Witty stressed at an analyst meeting that it was still unclear if or when generics would arrive in the United States, adding there had been "no change" in the company's view of the likelihood of copycat versions being launched.

"Clearly, if there was no generic Advair in the U.S. that would be an upside to the guidance we've given you for the pharmaceuticals business," he said.

GSK expects pharmaceuticals sales to grow at a low single digit annual rate between 2016 and 2020, with the possible introduction of generic Advair in the U.S. factored in.

($1 = 0.6560 pounds) (Reporting by Ben Hirschler; Editing by Elaine Hardcastle)