The FDA has warned Sanofi-Aventis’ U.S. unit for failing to submit reports of possible serious drug side effects in a timely manner. In a Jan. 28 letter made public last week, the FDA said an early response from the drugmaker and its "promised corrective actions are inadequate to address the deficiencies."

Sanofi spokesman Jack Cox said the company acknowledged the FDA's observations and is working with it to comply. The letter stems from agency inspections of Sanofi's Bridgewater, N.J., facility in April and May 2010, where it found Sanofi had inadequate procedures in place to monitor adverse events and failed to submit serious and unexpected adverse drug experiences by the FDA's deadline.

It also did not include information on postmarketing studies for several drugs—including diabetes drug Apidra, colon cancer drug Eloxatin and antibiotic Ketek—in its annual report to the FDA. Information on completed, unpublished clinical trials of Apidra, Eloxatin and sleep aid Ambien were also not submitted as required.

Sanofi responded to the agency in June, July and October 2010 with plans to correct the problem, but the FDA said its response was lacking. It told Sanofi to take prompt action and respond within 15 days.

Separately, the FDA warned Sanofi's German unit regarding manufacturing violations that led to contamination issues. That letter, dated Feb. 9, cited Sanofi for not having proper written or manufacturing procedures in place or staff properly trained to prevent contamination. Sanofi's Cox said it had moved quickly to address the problems and takes the matter seriously.