Just nine months ago, shares of NPS Pharmaceuticals Inc. jumped 32 percent on positive Phase III data for Gattex (teduglutide) in short bowel syndrome. But on Monday those gains were erased – and then some – in the wake of concerns about three cancer cases in the Phase III follow-on trial.NPS' stock (NASDAQ:NPSP) fell $2.59, or 33.4 percent, to close Monday at $5.17.The concerns stemmed from data presented at the American College of Gastroenterology annual meeting, particularly an interim analysis of the open-label, follow-on STEPS 2 trial.