Press Release: The Chicago MS Alliance’s statement on the FDA’s decision on tolebrutinib
Chicago, December 29, 2025. The Chicago MS Alliance (CMSA) is issuing a statement regarding the US Food and Drug Administration’s (FDA) Complete Response Letter (CRL) for the new drug application regarding tolebrutinib in non-relapsing secondary progressive multiple sclerosis (nrSPMS).
The phase 3 HERCULES trial met its primary endpoint, with tolebrutinib demonstrating a 31% relative reduction in the risk of confirmed disability progression versus placebo (1).
While the FDA has not publicly provided detailed rationale for the CRL, the sponsor has described this action as a meaningful change in direction from prior FDA feedback (2). The CMSA believes additional clarity is needed regarding what specific information or analyses are required to support a path forward.
Progressive MS remains an area of substantial unmet need. Although therapies are approved for relapsing forms of MS, there is currently no FDA-approved therapy specifically indicated for nrSPMS. The CMSA urges timely transparency and collaboration among regulators, scientific experts, clinicians, and people living with MS to ensure decisions are clearly explained and next steps are well-defined.
About the Chicago MS Alliance
The Chicago MS Alliance, founded in 2024, is a patient advocacy organization focused on advancing care for MS and related disorders in the Chicagoland area. The Alliance is made up of neuroimmunology specialists throughout the region, uniting experts to improve care. Visit us at chicago-ms.org. (3)
1- Fox, R. J., Bar-Or, A., Traboulsee, A., Oreja-Guevara, C., Giovannoni, G., Vermersch, P., Syed, S., Li, Y., Vargas, W. S., Turner, T. J., Wallstroem, E., & Reich, D. S. (2025). Tolebrutinib in Nonrelapsing Secondary Progressive Multiple Sclerosis. New England Journal of Medicine. https://doi.org/10.1056/nejmoa2415988.
2- Sanofi press release, December 24, 2025. https://www.sanofi.com/en/media-room/press-releases/2025/2025-12-24-06-00-00-3210238.
3- For financial disclosures of the board members, please reference the Open Payments website.