Sanofi Stock (SAN.PA, SNY) Slides After Tolebrutinib Double Setback: FDA Delay, Trial Miss, and Fresh Analyst Forecasts (Dec. 15, 2025)
Sanofi shares fell about 4% in Paris on December 15 after the company reported a U.S. regulatory delay for tolebrutinib in non-relapsing secondary progressive MS and a failed Phase 3 trial in primary progressive MS. Sanofi will not seek approval for the latter indication. The FDA decision for nrSPMS is now expected after December 28, with further guidance by end of Q1 2026.
