Sanofi MS drug rejected in US gets an endorsement in Europe

An article from Sanofi MS drug rejected in US gets an endorsement in Europe Tolebrutinib, which the FDA recently turned back due to safety concerns, received a positive recommendation that positions the therapy for its first regulatory approval. Published April 24, 2026 Delilah Alvarado Reporter Share Copy link Email LinkedIn X/Twitter Facebook Print License Add us on Google European drug regulators have given a positive review to an experimental multiple sclerosis treatment from Sanofi that the Food and Drug Administration rejected earlier this year, positioning the therapy to receive its first marketing approval in the months ahead. The European Medicines Agency on Friday said its recommended clearance of the drug, tolebrutinib, in people who have "secondary progressive” multiple sclerosis and haven't relapsed in the last two years.

A final decision is expected in the coming months, according to Sanofi. An approval of the drug, which would be sold as Cenrifki, would enable Sanofi to recoup some returns on a multibillion-dollar buyout that hasn’t yet paid dividends. Sanofi acquired tolebrutinib drug through a $3.7 billion acquisition of Principia Biopharma in 2020.

The drug is part of a newer class of drugs that block an enzyme known as Bruton’s tyrosine kinase. These “BTK inhibitors” which were originally known as cancer therapies, but are now being positioned as autoimmune disease treatments. Unlike their predecessors, the newer group of BTK blockers are able to get into the brain, making them enticing to drugmakers for their potential to address conditions like MS.

However, safety concerns, such as the potential for livery injury, have cropped up in testing of multiple drugs including Sanofi’s. BTK blockers have also struggled to fulfill their potential in multiple sclerosis. One, from Merck KGaA, failed in clinical testing.

And Sanofi’s stumbled in two late-stage trials in people with relapsing disease as well as in another test in primary progressive MS. Sanofi found a path forward for tolebrutinib in non-relapsing secondary progressive MS, for which there are few treatment options. There, the drug helped meaningfully delay the onset of disability progression, leading to submissions in the U.S.

and elsewhere. Sanofi had expected a decision in late September but then revealed a delay from the Food and Drug Administration and, eventually, a rejection in January. In its rejection letter, the FDA questioned the drug’s benefits and cited the risk of severe, or potentially fatal, drug-induced liver injury.

Sanofi claimed it had been caught by surprise, arguing the agency’s decision represented a “significant and meaningful change in direction” from earlier feedback. In its recommendation, the European Medicines Agency acknowledged the potential for liver-related side effects, but noted the therapy’s benefits on disability progression. Addressing that progression is “one of the most significant unmet needs in MS care,” Sanofi said in a statement.

Regulatory reviews elsewhere are ongoing. Beyond tolebrutinib, two other BTK inhibitors have been approved for immune conditions, including a different one from Sanofi known as Wayrilz. Roche is also advancing a BTK blocker for relapsing MS, despite some lingering questions about to its approval chances.

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