Isis ($ISIS) and partner Biogen Idec ($BIIB) have kicked off a Phase II study of a spinal muscular atrophy treatment, part of the pair's $300 million alliance to advance antisense treatments. Isis is due about $9.3 million in milestone payments tied to the first dosing in a study on children with SMA and the extension of another on infants. The initial deal, signed in 2012, gave Isis an upfront payment of $29 million with $45 million tied to development milestones and up to $225 million down the line. More