Sanofi's Multiple Sclerosis Treatment Misses Primary End Point in Phase 3 Trial

02:01 AM EST, 12/15/2025 (MT Newswires) -- Sanofi's (SAN.PA) tolebrutinib did not meet the primary endpoint of delaying the six-month composite confirmed disability progression of primary progressive multiple sclerosis in its phase 3 trial. The phase 3 Perseus trial evaluated tolebrutinib's safety and effectiveness for patients with primary progressive multiple sclerosis, according to a Monday release. As such, the biopharma company will not seek regulatory registration for the use of tolebrutinib for primary progressive multiple sclerosis.