in october 1996, dr. john eng licensed his discovery, exendin-4 to amylin. dr. eng discovered exendin-4 in the venom of a gila monster. exendin-4 is similar to the human gut hormone glp-1, which is responsible for regulating insulin and glucagon release. unlike human glp-1, however, exendin-4 doesn’t degrade for hours, making it a much better candidate for a drug. amylin developed exenatide, a synthetic version of exendin-4. in 2002, eli lilly signed an agreement with amylin for $325 million to partner in development of exenatide. in may 2005, byetta (commercial name for exenatide) was approved in the united states.