The first drug approved to treat patients with the potentially fatal genetic disease spinal muscular atrophy (SMA) has been approved for use in the United States, the Food and Drug Administration (FDA) announced on 23 December 2016.
The medicines regulator has given fast-track approval to nusinersen (Spinraza), which has been granted orphan drug status because of the rareness of the condition.
The decision follows the results of a clinical trial involving 121 patients diagnosed with infantile-onset SMA before the age of six months and who received their first dose of nusinersen before seven months. The babies either received an injection of nusinersen into their spinal fluid or underwent a mock skin prick procedure without the drug.
Of the 82 patients assessed as part of an interim analysis, 40% of those treated with nusinersen saw an improvement in motor milestones, such as head control, sitting, kicking, rolling, crawling, standing and walking. None of the babies in the control group saw an improvement in these parameters.
Additional open-label studies, which involved patients of various ages between eight days and 15 years, supported the findings of the controlled trial, even though the results were more difficult to interpret, according to the FDA.
The most common side effects found in trial participants were upper and lower respiratory infections and constipation.
Billy Dunn, director of the division of neurology products in the FDA’s Center for Drug Evaluation and Research, says: “There has been a long-standing need for a treatment for SMA, the most common genetic cause of death in infants, and a disease that can affect people at any stage of life.”
Nusinersen is marketed by Biogen of Cambridge Massachusetts and is developed by Ionis Pharmaceuticals, Carlsbad, California.