Sanofi's MS drug tolebrutinib failed its main trial for primary progressive MS and faces delayed U.S. review.

Sanofi announced that its oral multiple sclerosis drug tolebrutinib failed to meet its primary endpoint in a Phase 3 trial for primary progressive MS, showing no significant delay in disability progression versus placebo. The drug also faces a delay in U.S. regulatory review for non-relapsing secondary progressive MS, with a decision now expected by end of Q1 2026. Sanofi will not pursue approval for primary progressive MS, will conduct an impairment review, and has submitted an expanded access protocol in response to FDA requests. The company maintains confidence in the drug’s potential for other MS forms.