Amylin Pharmaceuticals Inc. (AMLN) and Eli Lilly & Co. (LLY)’s Byetta medicine and Novo Nordisk A/S’s Victoza face scrutiny after some researchers warned that prolonged use of the insulin-raising treatments may make diabetics more vulnerable to cancers. A debate on the potential dangers of GLP-1 therapies, the class of drugs to which Byetta and Victoza belong, will be a highlight of the European Association for the Study of Diabetes conference in Lisbon this week. A review of a database of side effects showed patients taking Byetta and a Merck & Co. drug had a sixfold increased chance of pancreatitis, which in turn raises the risk of tumors, researchers led by Robert Elashoff of the University of California at Los Angeles said this year.