Onasemnogene Abeparvovec-xioi: Gene Therapy for Spinal Muscular Atrophy

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 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.