FDA says Amylin withheld data on extended-release drug
Amylin won US Food and Drug Administration (FDA) approval for the drug, Bydureon (exenatide), in January after the Agency twice rejected the application. A FDA document detailing the review has now blamed the delays, at least in part, on the concealment of cardiac safety data by Amylin.
The reviewer wrote: “The review and this eventual recommendation for approval of Bydureon has been a long and complicated process, 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.”
In initial discussions about the application for Bydureon Amylin asked the FDA if it could use safety and efficacy data from its immediate-release equivalent, Byetta. As both drugs have the same active ingredient the FDA agreed to the request.
However, the FDA later learnt, after being alerted by Health Canada, that Amylin had excluded data from a thorough QT (tQT) of Byetta. Data from the study caused a disagreement about labelling that delayed Health Canada approval but the FDA was unaware of the trial when it reviewed Bydureon.
The FDA asked Amylin to include the study in its resubmission. Amylin added the result and datasets to the Byetta IND (investigational new drug) but, yet again, the data was absent from the submission for Bydureon. The FDA reviewed the data as part of the Bydureon new drug application regardless.
Review of the tQT study prompted the FDA to reject the Bydureon application for a second time. In its complete response letter the FDA cited two new clinical issues it discovered from the tQT study.
The FDA reviewer wrote: “To address this deficiency, the applicant was told to conduct a tQT study in which Byetta was administered at doses which would approximate exposures to Bydureon.” In July Amylin submitted data from the study and six months later the FDA approved the product.
