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 <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.