Elan (ELN) topped the gainer list this month as speculation over FDA approval of their multiple sclerosis drug, Tysabri continues to mount. Arena (ARNA), profiled in the October issue of Neurotech Insights, jumped after announcing positive news from its Phase II obesity trial. Cephalon (CEPH), our featured company for December, annouced settlement of several Provigil patent suits, advancement of Sparlon for ADHD to approvable status, and the acquisition of Zeneus to expand their oncology portfolio. Micrus Endovascular (MEND) was up after announcing approval of additions to their portfolio of microcoils for treatment of hemorrhagic stroke….