Isis Pharmaceuticals, Inc. (NASDAQ: ISIS) announced the initiation of a pivotal Phase 3 study evaluating ISIS-SMNRx in approximately 120 non-ambulatory children with spinal muscular atrophy (SMA). SMA is a severe and rare genetic neuromuscular disease characterized by muscle atrophy and weakness. The Phase 3 study, CHERISH, is the second Phase 3 study Isis has initiated in a global late-stage clinical development program for ISIS-SMNRx. Isis earned a $27 million milestone payment from its development partner, Biogen Idec, for the dosing of the first patient in this study. Isis is also evaluating ISIS-SMNRx in the Phase 3 study, ENDEAR, in infants with SMA. Isis is conducting both Phase 3 studies with agreement from the U.S. Food and Drug Administration (FDA) for special protocol assessments, or SPAs.