US FDA delays approval of Lilly/Amylin's once-weekly Byetta and MannKind's Afrezza

The US Food and Drug Administration has issued a complete response letter regarding the New Drug Application for Bydureon, an extended-release injectable suspension versions of drug major Eli Lilly and biotech firm Amylin's diabetes drug Byetta (exenatide), which currently generates sales around $700 million a year. Such a letter was also received by MannKind for its insulin-based product Afrezza.

In the complete response letter to Lilly and Amylin there are no requests for new preclinical or clinical trials. Requests raised in the letter primarily relate to the finalization of the product labeling with accompanying Risk Evaluation and Mitigation Strategy (REMS) and clarification of existing manufacturing processes. Moreover, the companies stated, the letter does not contain requests related to the December 2009 observations from the FDA's pre-approval inspection at the Ohio manufacturing facility. All of those observations have been addressed, the drugmakers contend.

"This is a significant step forward in our ability to bring this important therapy to patients," said Orville Kolterman, senior vice president of R&D at Amylin, adding: "We have a clear path forward and are working diligently to submit our response to the FDA in the next few weeks."