Why Sanofi Shares Are Falling Today

The FDA has placed Sanofi SA's SNY Phase 3 studies of tolebrutinib in multiple sclerosis and myasthenia gravis on partial clinical hold.
New enrollment in the U.S. is paused, and participants in the U.S. who have been in the trial for fewer than 60 days shall suspend the study drug.
The participants who have completed at least 60-days in the trial should continue treatment.
The FDA action was based on a limited number of drug-induced liver injury cases identified with tolebrutinib exposure in Phase 3 studies.
Most impacted patients were determined to have concurrent complications known historically to predispose to drug-induced liver injury.
The elevations of laboratory values used for monitoring liver injury were reversible after drug discontinuation for all cases. Following earlier dialog with FDA about these cases, study protocols were revised in May to update the monitoring frequency, and enrollment criteria were revised to exclude preexisting risk factors for hepatic dysfunction.
Enrollment in the clinical program continues with the revised study protocols and enhanced safety monitoring in countries outside the U.S.
The program in multiple sclerosis has been enrolling patients since 2019 and includes more than 2,000 patients currently on tolebrutinib therapy with durations of treatment as long as three years.
Price Action: SNY shares are down 4.42% at $50.34 during the premarket session on the last check Thursday.