Swiss biotechnology group Actelion said revenues in 2005 reached 664 million Swiss francs ($504m), up a massive 41% on the previous year, helped by rapid take-up of its pulmonary arterial hypertension drug Tracleer.

Tracleer (bosentan) brought in 633 million francs, up 41% for the year, although in the fourth quarter the rise was only 3%, which Actelion blamed on buying pattern variations, although it is now facing competition in the PAH sector from Pfizer, which won approval for rival drug Revatio (sildenafil) last year.

Nevertheless, Tracleer’s performance helped drive Actelion’s operating income up 78% to 152 million francs.

The firm's chief executive, Jean-Paul Clozel, said: "in 2005, our educational efforts resulted in a rapidly-expanding PAH market, with consequently outstanding Tracleer sales growth. We are well-prepared for future growth, with Tracleer being the best-documented oral PAH drug, supported by an experienced marketing and sales team as well as by many label-expansion studies."

Actelion's second commercial product - the type 1 Gaucher disease medication Zavesca (miglustat) - achieved sales of 14.4 million francs, rocketing 136% year-on-year.

Actelion now expects revenues in 2006 to be in the region of 810-840 million francs, keeping it on track to break the billion-franc barrier by 2009.