The corks will be popping at Actelion tonight as the Swiss firm is due to complete its acquisition of US firm CoTherix at the end of Tuesday, a deal that is worth in the region of $420 million.

The Allschwill-based firm noted that its “indirect wholly-owned subsidiary,” Curl Acquisition, has acquired over 97% of CoTherix shares in a public tender offer and the remaining stockholders will receive the same $13.50 cash price per share paid in the original offer.

The rationale behind the deal is pretty clear, as Actelion will be strengthening its already-dominant position in the pulmonary arterial hypertension franchise. It currently has Tracleer (bosentan) which had sales of over $500 million in the first nine months of 2006 and will now be getting hold of CoTherix’ Ventavis (iloprost) Inhalation Solution, the only approved inhaled therapy for the treatment of PAH in the USA.

Full-year 2006 sales of the latter are expected to top $100 million and Actelion has said that it had already explored the use of Tracleer in combination with Ventavis in clinical trials.