Background: NURTURE (NCT02386553) is an ongoing open-label single-arm efficacy/safety study of intrathecal nusinersen in infants who initiate treatment in a presymptomatic stage of spinal muscular atrophy (SMA). Methods: Enrolled infants were age ≤6 weeks at first dose, clinically presymptomatic, had genetically diagnosed SMA, and 2 or 3 copies of SMN2. Primary endpoint is time to death or respiratory intervention (≥6 hours/day continuously for ≥7 days or tracheostomy). Results: As of July 5, 2017, 25 infants (2 copies SMN2, n=15;3 copies, n=10) were enrolled. All infants were alive. Two infants (both with 2 copies SMN2) required respiratory intervention (but not tracheostomy or permanent ventilation) during an acute, reversible viral infection and thus met the primary -endpoint. At last visit, 22/24 (92%) infants had achieved WHO motor milestones sitting without support and 8/16 (50%;2 SMN2, n=3/11;3 SMN2, n=5/5) on study >13 months achieved walking alone. AEs were reported in 24/25 (96%) infants; most 20/25 (80%) had AEs that were mild/moderate in severity; 9 had serious AEs. Four infants had an AE possibly related to study drug, which resolved despite continued treatment. No new safety concerns were identified. Conclusions: Nusinersen continued to benefit infants who initiated treatment in a presymptomatic stage of SMA.
Study Support: Biogen