PREVIEW-New drug data may shape Actelion's future

* Data due on top seller Tracleer and sleep drug almorexant

* Use of Tracleer in fatal lung disease could double sales * Almorexant potential billion-dollar per annum drug

* Actelion seen as takeover target for larger drugmaker

By Sam Cage

ZURICH, Dec 1 (Reuters) - Europe's biggest biotech company Actelion (ATLN.VX) faces a nail-biting few weeks, waiting on clinical data that could go a long way to deciding the Swiss group's future.

Analysts say Actelion is overly dependent on its billion-dollar a year sales of heart and lung drug Tracleer and needs to establish its use for other diseases whilst bringing through more new products to diversify its revenue base.

Key clinical data on both these goals are due in the next few weeks. Analysts think if the data is positive on Tracleer it could double its sales and they are also keenly awaiting first late-stage trials on sleep drug almorexant.

Actelion's potential comes at a price for investors, its shares are trading at 16 times forecast 2010 earnings, significantly more than companies like GlaxoSmithKline (GSK.L), Novartis (NOVN.VX) and Roche (ROG.VX).

The company has the kind of business -- with strong cashflow, a big-selling medicine and promising new drugs -- that interests Big Pharma and analysts reckon a larger rival like Glaxo, which already has a partnership deal on almorexant, could snap it up.

Any acquisition could cost upwards of $10 billion once a premium is taken into account, said Andrew Weiss, analyst at bank Vontobel. "They're an interesting prospect for a pharmaceutical company," he said.

"For Glaxo it would be a nice fit because they already owe Actelion a lot of money in the case of almorexant working," he added.

DOUBLING SALES?

Tracleer has fought off competition in pulmonary arterial hypertension (PAH) from Gilead Sciences' (GILD.O) Letairis and Pfizer's (PFE.N) Thelin, but Actelion still relies almost exclusively on that disease. Positive results on Tracleer's use against fatal lung disease idiopathic pulmonary fibrosis (IPF) could significantly boost Actelion stock, as the company believes it could more than double current sales.

Tracleer revenue hit $1.2 billion last year and Thomson Pharma consensus forecasts point to sales of $1.8 billion in 2013, though analysts caution it loses patent protection in 2015.

The IPF data is due early next year and, if positive, could have an swift impact on Actelion's top- and bottom-lines as the drug is already approved against PAH and off-label use could start almost immediately.

"It has a much more important impact short-term on the development of total revenues and the profitability of the company," said Olav Zilian, analyst at Swiss brokerage Helvea.

Data on sleep medicine almorexant is expected before the end of this year. Thomson Pharma indicates sales hitting $580 million in 2013 and many analysts tip it as another billion-dollar per annum earner.

But the clinical read-out will only be for short-term use and other trials will be necessary before any approval, so it is unlikely to be a major driver of the share price near term.

"It's the first Phase III study so it's a positive step along the road," said Andy Smith, biotech fund manager at Axa Framlington. Actelion makes up less than 0.5 percent of Smith's 45 million pound ($74 million) fund and he has cut exposure due to caution on the IPF trial.

"It's going to be volatile in Actelion in the next few months," he said. "There will be disappointment if nothing works."

(Editing by Ben Hirschler and Elaine Hardcastle) ($1=.6070 Pound) ((zurich.newsroom@reuters.com; +41 (0)58 306 7457; Reuters Messaging: sam.cage.reuters.com@reuters.net))