Sanofi Tolebrutinib FDA Delay And PPMS Trial Failure
Sanofi tolebrutinib faces a U.S. FDA delay for nrSPMS and a failed Phase 3 PPMS trial, prompting expanded access and an impairment test before Q4 results.

KEY TAKEAWAYS
- Sanofi said the FDA review for tolebrutinib in nrSPMS will extend beyond Dec. 28, 2025.
- Sanofi submitted an expanded access protocol at the FDA's request to provide tolebrutinib to eligible nrSPMS patients.
- PERSEUS Phase 3 in PPMS failed its primary endpoint and Sanofi will not pursue regulatory registration in PPMS.
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Sanofi said on Dec. 15 that the U.S. Food and Drug Administration (FDA) review of tolebrutinib for non-relapsing secondary progressive multiple sclerosis (nrSPMS) will extend beyond the Dec. 28, 2025 target. The company also disclosed that a Phase 3 trial in primary progressive multiple sclerosis (PPMS) failed its primary endpoint, prompting an impairment test to be reported with its Q4 and full-year 2025 results in January 2026.
FDA Review Delay and Expanded Access for nrSPMS
In a Paris-dated press release, Sanofi said ongoing discussions with the FDA indicated the regulatory decision for tolebrutinib in nrSPMS will be delayed. The company expects further guidance from the agency by the end of the first quarter of 2026. Sanofi submitted an expanded access protocol at the FDA’s request to provide the investigational therapy to eligible nrSPMS patients outside clinical trials. The company had previously disclosed a three-month extension to the review timeline in September 2025.
Tolebrutinib is an investigational, oral, brain-penetrant Bruton’s tyrosine kinase (BTK) inhibitor designed to target “smoldering neuroinflammation,” which drives disability progression in multiple sclerosis. Sanofi said it “strongly believes in the risk-benefit profile of tolebrutinib for the treatment of nrSPMS.”
PERSEUS Trial Failure Ends PPMS Registration Path
The global, randomized, double-blind Phase 3 PERSEUS study compared daily oral tolebrutinib with placebo for up to about 60 months in patients with PPMS. The trial did not delay the time to six-month composite confirmed disability progression versus placebo, failing its primary endpoint. Following these results, Sanofi said it will not pursue regulatory registration for tolebrutinib in PPMS.
The safety profile observed in PERSEUS was consistent with previous trials. Sanofi reiterated that drug-induced liver injury remains an identified risk requiring strict monitoring. Patients with PPMS represent about 10% of the overall multiple sclerosis population, highlighting the limited commercial scope of this indication.
Impairment Test and Financial Outlook
Sanofi will conduct an impairment test on the intangible asset value of tolebrutinib, with results to be disclosed alongside its Q4 and full-year 2025 financial results in January 2026. The company said the test will not affect business net income or earnings per share and confirmed no change to its 2025 financial guidance.
Tolebrutinib received Breakthrough Therapy designation from the FDA in December 2024 and provisional approval in the United Arab Emirates in July 2025. It remains under regulatory review in the European Union and other jurisdictions worldwide.
Sanofi described multiple sclerosis as a progressive neurologic disorder characterized by accumulating disability, which continues to present a significant unmet medical need. Secondary progressive MS refers to patients who previously experienced relapses but now accumulate disability without relapses. The company continues to pursue regulatory approval for tolebrutinib in nrSPMS in the U.S., EU, and other markets.





