Europe's largest biotech Actelion was dealt a blow when a jury in a Californian court said Japanese drugmaker Asahi Kasei should be awarded up to $547 million in a licensing dispute. The decision comes at a difficult time for Actelion, which is also under fire from largest shareholder Elliott Advisors and will have to square up to the New York-based hedge fund at its annual general meeting in Basel on Thursday.

Here are some key facts about the Actelion vs. Asahi case.

• Asahi Kasei Pharma filed a complaint in the State Court in California against Actelion Ltd and its subsidiaries Actelion Pharmaceuticals US Inc., Actelion Pharmaceuticals Ltd, Actelion US Holding Company, CoTherix as well as Actelion's chief executive Jean-Paul Clozel, Martine Clozel and Simon Buckingham in November 2008.

• A jury in the Superior Court of the State of California, County of San Mateo, has awarded Asahi up to $547 million in a dispute over a licensing and development agreement.

• An arbitration in California ruled at the end of 2009 that Actelion unit CoTherix should pay Asahi $91 million plus interest after the Japanese group disputed the basis for CoTherix's termination of a development agreement.

• Actelion bought CoTherix for $420 million in 2007.

• CoTherix and Asahi struck a licensing agreement in 2006 to develop Asahi's rho kinase inhibitor, fasudil.

• At the beginning of 2007, CoTherix said it would no longer continue to develop fasudil and returned it to the Japanese group.

• Fasudil was being developed as a drug for pulmonary arterial hypertension (PAH) as well as chest pains that often precede heart attacks.

• Asahi is arguing that Actelion stopped development of the product to make sure it would not face competition to PAH mainstay treatment Tracleer.

• Asahi is also arguing that Actelion breached an agreement after it did not carry out trials on fasudil in the U.S. and Europe. As a result of this, Asahi said it did not have the data it needed to file for approval in Japan.

• PAH is a serious disease of the arteries to the lungs. The main symptoms are breathlessness, chest tightness, limited exercise capacity and fatigue.