Eli Lilly (NYSE: LLY) just unveiled new data showing that one of its diabetes drugs -- Tradjenta -- doesn't increase the risk of cardiovascular events, including heart attack and stroke. The results could help Tradjenta capture a greater share of the multibillion dollar DPP-4 class of diabetes drugs, so let's learn more about it.In healthy people, the body's pancreas produces insulin that stores or converts glucose, a simple sugar found in carbohydrates and produced in the liver, into energy.