The chances of Eli Lilly, Amylin and Alkermes' once-weekly diabetes drug Bydureon finally getting approval in the USA have been boosted by positive safety data in terms of heart rate.

The partners announced results from "a thorough QT study" to look at the potential arrhythmia liability of Bydureon, an extended-release version of Lilly and Amylin's Byetta (exenatide), a twice-daily treatment. The trial was conducted to satisfy the US Food and Drug Administration which issued a complete response letter for the drug in October last year.

Using "multiple heart rate correction methodologies", the study met its primary endpoint, demonstrating that exenatide did not prolong the corrected QT (QTc) interval in healthy individuals and found no relationship between QTc interval and plasma exenatide concentrations. Amylin's head of R&D, Chrisitian Weyer, claimed that the findings of the study "are clear. Exenatide did not lead to QT prolongation, even at very high concentrations in the blood".

He added that "we are confident in these results and will continue to work toward making Bydureon available to patients in the USA as soon as possible." The companies plan to submit the data to the FDA in the third quarter as part of their reply to the agency's CRL.

Last month, the European Commission has granted marketing authorisation to Bydureon and analysts believe that the USA will follow. Credit Suisse's Catherine Arnold issued a research note saying that "after a string of regulatory delays, Bydureon's clean bill of health from its tQT study lays out a clear path to approval". She believes US approval is likely by early 2012.