Glaxo chief says several uncertainties still in 2008

LONDON (Reuters) - GlaxoSmithKline (GSK.L) has decided not to increase its earnings outlook for 2008, despite beating expectations in the second quarter, because of several uncertainties still facing the business this year.

"As we've always made clear, 2008 was going to be a year with a number of swing factors associated with it and some of those are still to come," Chief Executive Andrew Witty told reporters in a post-results call on Wednesday.

"Although we now see Avandia, for example, beginning to plateau after its decline, we are right now just beginning to see generics for Lamictal and we'll see other impacts during the year."

He added Glaxo had decided to delay completion of the company's 12 billion pounds share buyback programme because of the need to exploit opportunities for fresh investment. The company would still buy back another 1 billion pounds of shares this year.

(Reporting by Ben Hirschler)