New Tysabri data reaffirm substantial efficacy in treatment of people with MS and demonstrate stability of anti-JCV antibody status Biogen Idec, 18 Mar 2013 Accessed on 21 Mar 2013 from http://www.biogenidec.com/PRESS_RELEASE_DETAILS.aspx?ID=5981&ReqId=1797077. CommentRecommendBookmarkWatch