In response to an application by U.S. drugmaker Eli Lilly for approval of a New Drug Application (NDA) for its type 2 diabetes treatment empagliflozin, the U.S. Food and Drug Administration (FDA) has initially put registration on ice, citing "previously observed" deficiencies at a Boehringer plant where the drug was to be manufactured.

The FDA said the deficiencies must be restored before the application is approved. However, it has not asked for any new clinical trials.

In quality control inspections in November 2012 and again May 2013, the U.S. authority said Boehringer, at its main production facility in Mainz, Germany, had failed to satisfactorily explain how foreign particles could find their way into the active ingredient's production.

Boehringer and Lilly established an alliance for diabetes in January 2011 that focuses on pipeline compounds representing several of the largest treatment classes.

The FDA regularly inspects production facilities of pharmaceutical producers supplying the U.S. market and in extreme cases can block their import.

Boehringer and Lilly said they are "committed to working with the FDA to make empagliflozin available to adults with type 2 diabetes" and plan to submit a response to the FDA as soon as possible.