A Randomized, Multinational, Double-Blind, Placebo-Controlled, Parallel-Group Design Pilot Study to Estimate the Tolerability, Safety, Pharmacokinetics, and Pharmacodynamic Effects of Teriflunomide for 24 Weeks When Added to Treatment With Interferon-beta in Subjects With Multiple Sclerosis.

The primary objective was to estimate the tolerability and safety of 2 doses of teriflunomide administered once daily for 24 weeks, compared with placebo, in patients with multiple sclerosis \[MS\] with relapses who were on a stable dose of interferon-β \[IFN-β\].Secondary objectives were:* to estimate the effects of the 2 doses of teriflunomide, compared to placebo, in combination with a stable dose of IFN-β on Magnetic Resonance Imaging \[MRI\] parameters, relapse rate and patient-reported fatigue;* to perform pharmacokinetic analyses of the 2 doses of teriflunomide in combination with a stable dose of IFN-β.