Introduction Teriflunomide, approved for the treatment of relapsing-remitting multiple sclerosis, has a well-characterized safety profile based on individual clinical studies. We report pooled safety and tolerability data from four, double-blind, placebo-controlled trials of teriflunomide. Post-approval updates on hair thinning and pregnancy outcomes, sometimes concerns for patients initiating teriflunomide, are reported.

Methods Data were pooled from phase 2 (NCT01487096) and phase 3 TEMSO (NCT00134563), TOWER (NCT00751881), and TOPIC (NCT00622700) studies. Patients were randomized to receive teriflunomide 14 mg, 7 mg, or placebo. Safety analyses were performed for all patients exposed to teriflunomide.

Results The pooled dataset included 3044 patients. Commonly reported adverse events (AEs) were in accordance with individual clinical studies, most being transient and mild-to-moderate in intensity. Incidence of hepatic AEs was higher in teriflunomide groups; however, serious hepatic AEs were similar across groups (∼2–3%). Hair thinning was higher in teriflunomide than placebo groups, but typically resolved on treatment without intervention and led to discontinuation in <2% of patients. No structural or functional abnormalities were reported in 42 newborns from teriflunomide-exposed parents.

Conclusions These data from >6800 patient-years of teriflunomide exposure were consistent with individual studies and no new, unexpected safety signals were observed. (Study supported by Genzyme, a Sanofi company).