Sanofi’s Lemtrada Drug May Be Too Risky, FDA Staff Says

Sanofi’s multiple sclerosis treatment Lemtrada may not offer enough benefit to patients to outweigh risks including cancer, U.S. regulators said. Securities linked to the drug’s success plummeted.

Lemtrada’s “serious and potentially fatal safety issues,” which include the risk of autoimmune and thyroid diseases, may make the medicine too dangerous to approve unless there is substantial clinical benefit shown, Food and Drug Administration staff said in a report today. Agency reviewers also questioned whether Sanofi conducted adequate trials to prove the annual infusion works.