Majority of Children with Spinal Muscular Atrophy Treated with Spinraza Are Able to Walk Within Age-Appropriate Timelines

New results from the NURTURE (NCT02386553) clinical trial, published in Muscle & Nerve, indicate that treatment of children with genetically diagnosed but presymptomatic spinal muscular atrophy (SMA) using Spinraza (nusinersen; Biogen, Cambridge, MA) was effective and helped preserve motor function long term. Analysis of results also provides novel insights into early markers of SMA disease progression before the onset of symptoms.

NURTURE is an open-label study examining the efficacy of Spinraza for the treatment of children with genetically diagnosed but presymptomatic SMA. The study includes 25 participants no older than 6 weeks who have multiple copies of survival motor neuron 2 (SMN2). The primary endpoint is time to death or respiratory intervention, with secondary outcomes assessing growth, World Health Organization (WHO) motor milestones, adverse events, and laboratory parameters. After the initial 3-year analysis, participants showed improvements in secondary outcomes.

Data reported in Muscle & Nerve from an additional 2-year follow up period revealed that all 25 participants were still alive, and none discontinued treatment. Nine of the 10 participants with 3 SMN2 copies achieved WHO motor milestones within age-appropriate timelines, with 1 participant walking with assistance late, but then meeting the timeline for walking alone. All participants with 2 SMN2 copies sat without support, 14/15 achieved walking with assistance, and 13/15 walked alone. Overall, 23 of the 25 participants were able to walk after 5 years of treatment. Additionally, researchers identified that the subgroup of participants with 2 SMN2 copies, excluding those with a compound muscle action potential (CMAP) no less than 2 mV or with areflexia, showed better outcomes than the rest of the cohort.

“The NURTURE data show how small differences in baseline characteristics can greatly impact outcomes, including motor function, respiratory function, swallowing and feeding,” said Thomas Crawford, MD, Codirector of the Muscular Dystrophy Association Clinic.

SMA is a rare neuromuscular disorder characterized by progressive muscle weakness due to loss of motor neurons that affects approximately 1 out of every 10,000 people in the United States. It is the most common genetic cause of infant death.