Despite receiving a prior wrist slap from the FDA in the shape of a Form 483, Sanofi is still working to right the ship at a U.S. drug ingredients plant tied to its longstanding subsidiary Genzyme.

The FDA has slapped a warning letter on Sanofi’s Genzyme facility in Framingham, Massachusetts, after an inspection last summer uncovered issues around subpar manufacturing error investigations, inconsistent active pharmaceutical ingredient (API) production, improper equipment and more.

The initial inspection in Framingham ran from June 12 to July 9, 2024, and yielded a Form 483, which the FDA says Sanofi responded to by late July. The letter itself, which marks an escalation from the Form 483, was posted by the FDA on Tuesday and issued to Sanofi last week.

“We take all inspections extremely seriously and we are fully committed to working with the FDA to resolve all findings holistically, robustly and promptly to meet the agency’s requirements and expectations,” a Sanofi spokesperson said of the situation over email.

He added that there has been “no interruption” to manufacturing or the supply of drugs from the Framingham site tied to the FDA’s production rebuke.

As for the write-up itself, the FDA scolded Sanofi for its failure to investigate critical deviations in its manufacturing process, noting that some 20% of bioreactor runs attempted at the plant between January 2022 and July 2024 were rejected for contamination or other quality failures.

Sanofi dropped the ball when it came to exploring the causes behind these issues, which included “multiple microbiological contamination events,” the FDA noted.

The French pharma also failed to show that its production process can reproducibly manufacture an API to certain quality standards, the regulator said.

Sanofi “repeatedly deviated” from the validated manufacturing process for an unnamed product, according to the agency's letter.

The FDA also chided Sanofi for using equipment “unsuitable for its intended use in microbiologically controlled manufacturing environments,” as well as lackluster quality control oversight and improper reporting and evaluation of production hiccups.

On the first criticism, the FDA noted that Sanofi operators were using mobile carts for certain processes that required the workers to “get down on the floor and manually lock and unlock the cart brakes.” The operators carried out these actions “despite previously determining equipment proximity to the floor as a contributing root cause in microbiological contamination events,” the FDA said.

Summarizing the manufacturing infractions, the FDA argued that Sanofi’s quality unit at the Framingham plant is unable to fully exercise its authority and responsibilities.

Sanofi acquired Genzyme for a little over $20 billion back in 2011. Genzyme has historically focused its efforts on rare inherited disorders, kidney diseases, cancer, transplant and immune disease, as well as areas like cardiovascular and neurodegenerative disease.

Back when Sanofi overhauled its branding in 2022, the French pharma absorbed the Genzyme unit—as well as its storied vaccines division Sanofi Pasteur—under the singular Sanofi corporate moniker.