After a third round through the US Food and Drug Administration, Amylin's Bydureon (exenatide) type 2 diabetes drug finally hit the US market in February. Bydureon was once anticipated to be a blockbuster drug but safety concerns delayed its approval (Nat. Biotechnol. 28, 1224, 2010) and gave rival Victoza a head start. Bydureon was developed by the San Diego–based Amylin and Eli Lilly of Indianapolis as a long-acting formulation of its own drug Byetta (exenatide), an analog of the insulin-boosting glucagon-like peptide 1 (GLP-1), a first-in-class synthetic gut hormone. Although both contain the same active compound, Bydureon requires once weekly injections compared with Byetta's twice daily. Competitor Victoza (liraglutide) from Novo Nordisk in Princeton, New Jersey, also a GLP-1 agonist, was approved in early 2010 as a once-a-day injection. Victoza took 16 months to gain 50% of the share of prescriptions in its class, says Steve Yoo, a biotech analyst at Leerink Swann in New York. “That's a phenomenal market launch.” Bydureon is unlikely to capture as much of the market as quickly, despite its less frequent dosing scheme, he adds. Acting against Amylin's new drug are the results of one trial, which showed Victoza was slightly better at controlling blood sugar than Byetta (Lancet, 374, 39–47, 2009). Victoza is also less cumbersome for individuals to prepare and the needle is smaller than that for Bydureon. Nevertheless, Bydureon could still capture a big chunk of the market. There is a niche for once-weekly GLP-1, Yoo says, and priced at about $4,200 a year, “it's competitive to Victoza. We think the class will simply grow.” As part of Bydureon's approval, Amylin agreed to several postmarketing requirements that include assessing thyroid cancer and pancreatitis risks, cardiovascular events and other health problems.