There are certainly some roller coaster rides you can go on if you trade biotech or pharmaceutical stocks. In addition to the unknown and known events that every company has, there are constantly (at least it seems that way) news related to the company’s development of drugs and therapeutics that dramatically impact the stock. That was the case the other day for PTC Therapeutics, Inc. (PTCT) which closed down more than 19% after disappointing phase 3 trial results on nonsense mutation cystic fibrosis treatment candidate.