* Q3 earnings of 28.5p/shr, just under 28.7p consensus
* Sales 6.76 bln pounds vs 6.81 bln consensus
* Glaxo set for big H1N1 vaccine boost in Q4 * Shares down 1 percent in London market down 1.8 percent
(Adds CEO comments, analyst reaction, latest shares, details)
By Ben Hirschler
LONDON, Oct 28 (Reuters) - Sharply higher sales of flu drug Relenza buoyed GlaxoSmithKline's quarterly sales, and the British group said it was in line for a booster from its swine flu vaccine in the last three months of the year.
Third-quarter earnings per share growth of 13 percent, flattered by a weak pound, was just shy of expectations, while group revenue rose 15 percent, helped by recent diversification, the world's second-biggest drugmaker said on Wednesday.
Glaxo has lost plenty of business this year to cheap generics, as patents on its older medicines expire, resulting in a 12 percent fall in U.S. sales in the period.
But windfall sales of drugs and vaccines due to H1N1 are softening the blow.
As with many of its rivals, 2009 is turning out better than initially feared, and Chief Executive Andrew Witty said he expected further growth in the fourth quarter of the year, "including significant sales of influenza products".
Glaxo said previously it had taken orders for 440 million doses of its H1N1 vaccine Pandemrix, and analysts say it could book around 1 billion pounds ($1.64 billion) of this business in the fourth quarter as immunisation campaigns get underway.
Witty told reporters that market expectations for sales of the vaccine were "pretty close to being right", adding Glaxo had booked further orders and still had capacity for more.
European drugmakers Glaxo, Sanofi-Aventis, Novartis and AstraZeneca are set to win the bulk of the business for mass swine flu vaccination programmes launched by governments around the world.
Glaxo also gains from having the inhaled flu drug Relenza, which registered sales of 182 million pounds in the third quarter, against just 12 million pounds a year earlier.
Roche has seen a similar sharp jump in sales of its rival flu drug Tamiflu.
Glaxo's pretax profit totalled 2.07 billion pounds in the third quarter, equivalent to earnings per share before major restructuring of 28.5 pence, on sales of 6.76 billion.
The mean consensus forecast had been for earnings of 28.7p and sales of 6.81 billion pounds, according to Thomson Reuters I/B/E/S.
Sanford Bernstein analyst Tim Anderson said the results were broadly in line, helped substantially by currencies.
"GSK has a decent revenue and EPS profile through 2015, but its valuation seems to reflect this already," he added, as shares in the group traded 1 percent lower in a London market down 1.8 percent at 1400 GMT.
MOVING ON FROM "WHITE PILLS"
While H1N1 may be a one-off, Witty said his strategy of diversifying away from reliance on "white pills in Western markets" would mean more predictable long-term growth, as emerging market and consumer products sales increase.
Less than 30 percent of third-quarter sales were generated from traditional pharmaceuticals and markets, compared with 38 percent last year.
"What we've begun to show very clearly in these results is the change in dynamics in our business and particularly the good progress we are making towards diversifying our portfolio," he said.
Witty added he would continue to look actively for bolt-on acquisitions, but only if the price was right. He has eschewed large-scale acquisitions of the kind pursued this year by Pfizer and Merck & Co.
Progress on the research front included encouraging results with experimental heart drug darapladib, which Witty said was now six months ahead of schedule in late-stage clinical trials.
Glaxo trades at about 10.4 times forecast 2010 earnings, a premium to AstraZeneca and Sanofi, which report on Thursday and Friday respectively, but a discount to Swiss rivals Roche and Novartis. (Additional reporting by Kate Kelland, editing by Will Waterman) ($1=.6107 Pound)