FDA's 6/30/2006 warning letter to Sanofi Pasteur identifies several issues noted during a March 2005 inspection that were not corrected prior to the 2006 inspection. Why didn't FDA issue a Warning Letter for these issues in 2005?

Following the compliance issues surrounding Chiron's production of influenza vaccine in 2004, FDA instituted annual inspections of influenza vaccine manufacturers. The March 2005 inspection of Sanofi Pasteur was one of the first of these yearly inspections.

The FDA Form 483, such as the one issued at the conclusion of the March 2005 inspection, is a list of observations that is issued by FDA investigators at the conclusion of an FDA inspection of a firm. These observations do not represent a final agency determination of compliance. At the completion of an inspection, a firm has the opportunity to respond to the citations and correct deficiencies. Therefore, while there were issues raised in the FD-483 for the March 2005 inspection, further agency review concluded that the inspection be classified as "voluntary action indicated," meaning the firm had the opportunity to correct problems as outlined in its response.

During the April 2006 inspection of the firm, FDA determined that some of Sanofi Pasteur's corrective actions were not adequate and that additional problems existed such that a Warning Letter is appropriate at this time.