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Jan 6, 2026 12:00 PM

FDA Flags Liver Injury Risk In Sanofi's Rejected Multiple Sclerosis Drug

In December 2025, the U.S. Food and Drug Administration (FDA) issued a complete response letter (CRL) for Sanofi SA's (NASDAQ:SNY) new drug application of tolebrutinib to treat non-relapsing secondary progressive multiple sclerosis (nrSPMS) in adult patients.

The press release was thin on information related to the rejection. The FDA publicly shared the complete response letter, citing both efficacy and safety concerns.

The regulatory agency wrote that, "a favorable benefit-risk profile could not be established for any patient subpopulation."

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Unraveling FDA's Rejection Reasons

The FDA determined a ...