Long-term Extension to Study AC-058B301 to Investigate Safety, Tolerability and Disease Control of Ponesimod 20 mg in Patients With Relapsing Multiple Sclerosis

The AC-058B303 study (extension study) is the long-term extension for the AC-058B301 study (core study). The core study has been designed to investigate the efficacy, safety and tolerability of ponesimod in subjects with RMS. The subjects are treated with either ponesimod or the active comparator, teriflunomide in the core study. The purpose of this long term extension of the core study is to characterize the long-term safety and control of disease of ponesimod in subjects with RMS. In particular, the study will allow to observe potential adverse events which may only occur after long term treatment with ponesimod. The study will also investigate the effect of re-initiation of ponesimod after a brief interruption in a relatively large population (all subjects treated with ponesimod in the core study and eligible for the extension study) on disease activity in terms of relapses and MS-related MRI lesions. There is currently limited guidance on when a new MS treatment should be started after discontinuation of teriflunomide and the study will contribute with data on safety and efficacy of switching from teriflunomide to ponesimod after an interruption as mandated by the protocol. The study will also allow confirmation of sustained efficacy of ponesimod in terms of relapses, MRI lesions and reduction of disability accumulation during long-term treatment. In addition, combined data from the core study together with the results of the current extension study will allow comparison of MS activity in subjects who were switched from teriflunomide to ponesimod versus those who were treated with ponesimod in both studies.