Genzyme is the company that is developing Alemtuzumab (formerly known as Campath-1h) for MS. Alemtuzumab is clearly the most effective of the emerging drugs in clinical development. Sanofi on the other hand are developing Teriflunomide, an oral disease-modifying therapy, that has been reported to reduce the attack rate in relapsing-remitting MS compared to placebo by about 30%. How will Sanofi integrate these two compounds into clinical practice? Will Alemtuzumab be used as induction therapy and Teriflunomide as maintenance therapy? What is clear is that Sanofi will become a major player in the MS arena.