Genzyme, the Cambridge unit of French drug maker a Sanofi SA, said it has received a “Refuse to File” letter from the Food and Drug Administration in response to its application for the approval of Lemtrada as a treatment for relapsing multiple sclerosis.

After consultations, the FDA has requested that Genzyme “modify the presentation of the data sets to enable the agency to better navigate the application,” Genzyme said in a press release.

Genzyme said it will work with the FDA over the coming weeks to resubmit the application as soon as possible.