Onasemnogene abeparvovec gene therapy for treatment of patients with spinal muscular atrophy: Updated real-world practical considerations

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease resulting from biallelic pathogenic variants of the survival motor neuron 1 ( SMN1 ) gene that leads to motor neuron degeneration, progressive muscle atrophy, and weakness. In its most severe form and without timely initiation of treatment, SMA can be fatal or lead to a requirement for permanent ventilation by 2 years of age. Approved treatments for SMA target an increase in SMN protein production. These include nusinersen and risdiplam, which modify splicing of the SMN2 pre-mRNA, and onasemnogene abeparvovec, a viral-mediated gene therapy. In 2020, an expert panel provided recommendations and practical considerations regarding onasemnogene abeparvovec administration. As more countries have approved onasemnogene abeparvovec and new data have emerged from clinical trials and real-world use, a similar expert panel provides updated recommendations along with additional guidance. Specific recommendations are centered around family preparation prior to and immediately following dosing to minimize risk of infectious illness, timing of anti–adeno-associated virus serotype 9 antibody titer testing for those patients with exclusionary titers, modifying immunization schedules, avoiding potential complications with long-term corticosteroid administration, safety monitoring, considerations for combination therapy, implementing newborn screening, and emphasizing the need for ongoing multidisciplinary care and adherence to standard-of-care guidelines.