The FDA has extended its review of tolebrutinib, Sanofi’s investigational BTK inhibitor, with a new decision date of Dec. 28, 2025. Sanofi is seeking approval for tolebrutinib to treat non-relapsing secondary progressive MS (SPMS) and to slow disability accumulation in adults with MS, regardless of relapses.
The extension follows additional analyses submitted by Sanofi, which the FDA classified as a “major amendment.” Despite the delay, Sanofi remains confident in the therapy’s potential. Phase 3 data show tolebrutinib delayed disability progression by 31% in SPMS (HERCULES trial) and reduced disability worsening by 29% in relapsing MS compared with Aubagio (GEMINI studies). The therapy recently earned its first global approval in the UAE, and results from a trial in primary progressive MS are expected soon.
Many recent MS medications have also had similar three-month delays in final approval from the FDA, and this does not necessarily indicate any problem or issue with the drug itself.
For more information about tolebrutinib and BTK inhibitors, please see the following:
- BTK Inhibitors in MS Treatment: Recent Clinical Trial Results and Key Takeaways (InforMS Magazine, Winter 2024)
- BTK inhibitors Update: Tolebrutinib Phase 3 Clinical Trial Results (eMS News, September 2024)
- What are BTK Inhibitors and Why are They Different? (2023 Spring Education Summit presentation; Opens in YouTube)
- Update on the US regulatory review of tolebrutinib in non-relapsing, secondary progressive multiple sclerosis (Press Release from Sanofi, September 22, 2025)
