Boehringer Ingelheim says it will act promptly to resolve a series of manufacturing complaints highlighted by regulators in the USA concerning violations at its German headquarters.

The US Food and Drug Administration has issued a warning letter concerning the firm's manufacturing practices following an agency inspection in Ingelheim in November 2012. The FDA has published the letter, dated May 6, on its website noting that investigators that identified significant violations of current good manufacturing practice for the manufacture of active pharmaceutical ingredient and for finished drugs.

Among the list of complaints in the letter, the FDA states that Boehringer did not conduct a thorough investigation to determine the source of foreign particles in its API in an unnamed drug, "nor did you implement timely and appropriate corrective and preventive actions". The company also stands accused of failing to reject drugs "that did not meet established standards or specifications and any other relevant quality control criteria".

The FDA also claims that Boehringer failed to thoroughly investigate "any unexplained discrepancy or failure of a batch or any of its components to meet any of its specifications, whether or not the batch has already been distributed".

Gerhard Koeller, head of corporate division quality at Boehringer Ingelheim, responded by saying the firm takes this matter very seriously "and is fully committed to working with the FDA on a comprehensive action plan" that addresses the agency's concerns. He added that "we will invest all our energy to remedy the situation in order to meet all FDA requests, building on the experience gained from all 22 inspections successfully passed at the Ingelheim site in the last five years by different authorities around the world, other than the latest FDA inspection in November".

News of the warning letter came days after Boehringer, which has been plagued by manufacturing problems at its Ben Venue Laboratories unit in the USA, announced that Wolfram Carius, its board member with responsibility for biopharmaceuticals and production, is stepping down at the end of June. He will be succeeded by Wolfgang Baiker, who has been head of development  worldwide since 2010.