FDA Accuses Amylin of Withholding Byetta Safety Information

Washington, DCA recently posted memo from the US Food and Drug Administration (FDA) accuses Amylin Pharmaceuticals of withholding information about the safety of Byetta, a diabetes medication. The memo, written concerning an application for Bydureon, claims Amylin withheld information about Byetta side effects, information that was uncovered during a study conducted for Canadian regulatory authorities. Byetta has been linked to a number of serious side effects, including acute pancreatitis.

According to the FDA memo (found at the FDA website; www.fda.gov), dated January 27, 2012, the approval of Bydureon, which has the same active ingredient as Byetta, was long and complicated, "in part due to Amylin's withholding of information on Byetta that FDA deemed to be important to its evaluation of the safety and effectiveness of Bydureon."

When Amylin applied for approval of Bydureon it requested that FDA use the safety and efficacy findings from Byetta trials, which the FDA agreed to do. But the FDA says it was not made aware of a "thorough QT [tQT] study" conducted for Canadian authorities. That study, the FDA notes, raised concerns for Health Canada, which lead to approval of Bydureon being delayed. Health Canada notified the FDA of the study, which the FDA then confirmed with Amylin.

The tQT study measured the effect exenatide—the active ingredient in Byetta—had on the patient's heart rhythm. The results concerned Health Canada enough that the agency delayed approval of Bydureon until labeling agreements could be reached.

Mary Parks, the FDA division director who wrote the memo, further noted that despite the FDA requesting information from the tQT study be included in a resubmitted Bydureon application, Amylin did not comply, sending the info as an addendum to the Byetta file instead of as part of the Bydureon application.

Bydureon is a once-weekly version of Byetta. It was approved for use in January 2012, after a lengthy approvals process that included the drug being denied approval twice.

Byetta has been linked to serious side effects that resulted in the FDA issuing two safety alerts. The alerts, released in October 2007 and August 2008, warned about the risk of pancreatitis, including necrotizing or hemorrhagic pancreatitis.