Nat. Biotechnol. 27, 682–685 (2009); published online 7 August 2009; corrected after print 8 October 2009

In the version of this article initially published, GLP-1 was incorrectly described as “glucose-lowering peptide-1”; the correct definition is “glucagon-like peptide-1.” The article also stated incorrectly that Amylin and Lilly “filed a new drug application for this drug in July...” referring to Exenatide Once Weekly. This should be corrected to “their new drug application was accepted for review by the FDA in July....” The error has been corrected in the HTML and PDF versions of the article.