Sanofi and Regeneron Pharmaceuticals, Inc. announced the US Food and Drug Administration (FDA) issued a Complete Response Letter (CRL) regarding the Biologics License Applications (BLA) for sarilumab, an investigational interleukin-6 receptor (IL-6R) antibody for the treatment of adult patients with moderately to severely active rheumatoid arthritis (RA).

The CRL refers to certain deficiencies identified during a routine good manufacturing practice inspection of the Sanofi Le Trait facility where sarilumab is filled and finished, one of the last steps in the manufacturing process. Satisfactory resolution of these deficiencies is required before the BLA can be approved. Sanofi submitted a comprehensive corrective action plan to the FDA and is implementing the corrective actions specified in that plan. Sanofi is working closely with the FDA towards a timely resolution that addresses these concerns. The CRL does not identify any concerns relating to the safety or efficacy of sarilumab.

Sanofi and Regeneron remain committed to the development of sarilumab and providing the therapy to RA patients in the US as quickly as possible. If approved by the FDA, sarilumab would be commercialized by Regeneron and Sanofi Genzyme, the specialty care global business unit of Sanofi.