Actelion's management, and its philosophy of remaining independent, has received a boost with support coming from a major backer.

The backing of Swiss investor Rudolf Maag, who has a 4.2% stake in Actelion, comes at a time when dissident stockholder Elliott Advisors, which has a near-6% holding, is increasing its calls for the resignation of chief executive Jean-Paul Clozel and chairman Robert Cawthorn. The hedge fund has also repeatedly asked the Allschwil-based group to explore a future sale.

However Mr Maag has issued a statement saying the company "enjoys a strong, risk-balanced pipeline and invests the shareholder's money in the right projects". He added: "I am convinced that pursuing a stand-alone strategy where the benefits of these investments can be fully realised will maximise shareholder value over the medium to long-term."

Mr Maag went on to say: "I am concerned about the distraction some shareholders are causing at the company, at a critical time of the company's development, where everybody needs to stay very focused on the key task at hand, ie bringing the significant potential in the product pipeline to fruition in the coming years."

An Actelion spokesman told Reuters the company welcomed the support of Mr Maag and said the board had also received positive feedback from investors at its recent roadshows.

As for Elliott, it has set up a website ( for investors to register their shares and exercise their voting rights at the Actelion annual general meeting on May 5. Elliott representative Dominik Dolenec noted last week that 90% of Actelion’s revenue is generated by just one product, the pulmonary arterial hypertension blockbuster Tracleer (bosentan) which will lose patent protection around 2015. A couple of recent Phase III failures (the sleep disorder drug almorexant and the endothelin receptor antagonist clazosentan) mean the company "finally has left but one shot in the gun", he says, namely the Tracleer follow-up macitentan.

It is "unclear whether macitentan will be able to fulfill expectations", Mr Dolenec claimed, arguing that "Actelion cannot afford to solve its Tracleer problem by an acquisition". He added that "we are not so arrogant to say a sale would be the only right action for Actelion" and "if they can credibly argue that the stand-alone strategy could increase shareholders’ value higher than a potential bidder would be willing to pay...then the company should stay alone".

Elliott is expected to announce its own slate of prospective board members in the next few days.