Nat. Biotechnol. 32, 626–632 (2014); published online 8 July 2014; corrected after print 3 September 2014; 10.1038/nbt.2949

In the version of this article initially published, in Table 8, Enbrel (etanercept) was left off the table. It should have been in the number 2 spot in the table with 2013 revenue at $8,729 million. In addition, the units of the last column, which are in $ millions, were omitted in the title. The error has been corrected in the HTML and PDF versions of the article.