Biotechnology Switzerland-based Actelion (SIX: ATLN), Europe's biggest biotech company, says that it has decided not to exercise its option to acquire the privately held French company Trophos SA, following disappointing pivotal Phase III clinical trial results with the latter's lead investigational drug olesoxime in the treatment of amyotrophic lateral sclerosis (ALS), an orphan disease also known as Lou Gehrig's. 13 December 2011