Ionis Pharmaceuticals (IONS) shares have surged today after the company announced that nusinersen, their investigational treatment for spinal muscular atrophy, met the primary endpoint pre-specified for the interim analysis of ENDEAR. The analysis concluded that infants receiving nusinersen experienced a statistically significant improvement in certain motor functions. As a result of these findings, Biogen (BIIB) has exercised its option to develop and commercialize nusinersen globally and paid Ionis a $75M license fee.