Biogen’s SPINRAZA (nusinersen) has been approved by the FDA for the treatment of spinal muscular atrophy (SMA) in pediatric and adult patients.   The drug was under Priority Review and is the first and only treatment approved in the U.S. for SMA, a leading genetic cause of death in infants and toddlers that is marked by progressive, debilitating muscle weakness.   The approval was based on positive results from multiple clinical studies in more than 170 patients.  In ENDEAR, a pivotal contro...