Objective: To review the efficacy and safety of onasemnogene abeparvovec-xioi (Zolgensma) in the treatment of spinal muscular atrophy (SMA). Data Sources: An English-language literature search of PubMed, MEDLINE, and Ovid (1946 to December 2019) was completed using the terms onasemnogene, AVXS-101, and spinal muscular atrophy. Manufacturer prescribing information, article bibliographies, and data from ClinicalTrials.gov were incorporated in the reviewed data. Study Selection/Data Extraction: All studies registered on ClinicalTrials.gov were incorporated in the reviewed data. Data Synthesis: Onasemnogene is the first agent for SMA utilizing gene therapy to directly provide survival motor neuron 1 ( SMN1) gene to produce SMN protein. Four publications of 1 clinical trial, 1 comparison study of treatment effects, and 1 combination therapy case series have been published. Relevance to Patient Care and Clinical Practice: Onasemnogene is a one time dose approved by the Food and Drug Administration for SMA patients <2 years old who possess mutations in both copies of the SMN1 gene. Conclusion: Onasemnogene appears to be an efficacious therapy for younger pediatric patients with SMA type 1. Concerns include drug cost and potential liver toxicity. Long-term benefits and risks have not been determined.

Nusinersen is safe and effective in patients with SMA. It was well tolerated across all studied age groups.

The American Academy of Pediatrics recommends opioids as first-line agents in the treatment of NAS when pharmacological treatment is indicated. Limited data suggest that clonidine, in combination with other agents or as monotherapy, may be as effective, with minimal adverse effects and reduced treatment time. Prospective clinical trials are necessary to clarify the ultimate role of clonidine in NAS and establish long-term safety.