This document addresses gene therapy for spinal muscular atrophy (SMA), a rare and often fatal genetic disease affecting muscle strength and movement. One gene therapy product, Zolgensma^® (onasemnogene abeparvovec-xioi), has been approved by the Food and Drug Administration (FDA).

Note: Please refer to clinical pharmacy criteria for information regarding other disease-modifying treatments for SMA; for example: nusinersen (Spinraza) or risdiplam (Evyrsdi).

Position Statement

Medically Necessary:

A one-time infusion of onasemnogene abeparvovec-xioi is considered medically necessary in individuals with spinal muscular atrophy (SMA) when all of the following criteria are met:

1. Confirmed SMA diagnosis as documented by a bi-allelic SMN1 5q gene variant or deletions and either of the following:
   1. No more than 3 copies of SMN2; or
   2. Onset of SMA-associated signs and symptoms before 6 months of age; and
2. Two years of age or younger at the time of vector infusion; and
3. Anti-adeno-associated viral vector, serotype 9 (AAV9) antibody titer less than or equal to 1:50; and
4. No use of invasive ventilatory support (tracheotomy with positive pressure) or use of non-invasive ventilator support (BiPAP) for more than 16 hours per day as a result of advanced SMA disease; and
5. No serious concomitant illness (for example, severe liver or kidney disease, symptomatic cardiomyopathy, active viral infection).

Investigational and Not Medically Necessary:

Onasemnogene abeparvovec-xioi is considered investigational and not medically necessary when the criteria above are not met, including for repeat infusions, and for all other indications.