Hopes for a key new heart and lung drug overshadowed nine-month results from Actelion, which showed a modest 4% slide in sales of the Swiss group's current mainstay Tracleer.

Europe's largest biotechnology company said on Thursday net income rose a higher-than-expected 16%, helped by cost cutting, prompting it to reiterate its 2012 outlook.

Detailed results to be presented at a conference next week will shed more light on whether new drug macitentan, a follow-on to pulmonary arterial hypertension (PAH) blockbuster Tracleer, can supplant the older product.

Actelion said in April the new drug succeeded in slowing the often deadly disease and the data next week will reveal details about how much macitentan improved patients' capacity to exercise and its impact on survival.

The company repeated that macitentan, which it has now branded as Opsumit, was on track for regulatory filing in Europe and the United States in the fourth quarter of 2012.

Tracleer currently makes up just under 90% of Actelion's total sales, but is facing growing competition from Gilead Sciences's Letairis which has eroded its market share.

Sales of the drug fell 4% to 1.13 billion francs ($1.2 billion) in the first nine months of 2012.

But total third-quarter sales rose 9% to 438.5 million francs, beating the average analyst forecast of 429 million in a Reuters poll.

Cost savings

"Actelion delivered a nice beat for the third quarter 2012 mainly due to a stronger than expected impact of the cost savings program," Sarasin analyst David Kaegi said in a note.

"In terms of share price performance, financial results are clearly taking a back seat currently as the market will focus on the detailed results for the follow-on product of Tracleer."

Actelion booked a restructuring charge of 5.1 million francs linked to a cost-cutting programme announced in July, which aims to refocus research and development spending and secure future growth beyond Tracleer.

It said there would be some additional charges in coming quarters, making the total restructuring charge between about 8 million francs and 9 million.

Actelion stuck to its guidance for product sales to fall by low single-digits and mid-single digit core earnings growth in 2012.

Net income in the third quarter rose 15% to 94.577 million francs, also beating forecasts, while core earnings excluding doubtful debt rose 7% in the first nine months of the year to 443.6 million francs.

The company, founded in 1997 by former Roche Holding veteran Jean-Paul Clozel, said it would accelerate its share buyback programme and would conclude the 800 million franc program within the next 12 months.