# FDA approval of ISEMBYLD for SMA

> Live situation record from CLSTR: https://clstr.news/situations/fda-approval-of-isembyld-for-sma
> Updated: 2026-09-18T12:01:46.000Z. Sources: 7. Developments: 2.

The U.S. Food and Drug Administration (FDA) has approved ISEMBYLD (apitegromab-mstn), developed by Scholar Rock, for the treatment of spinal muscular atrophy (SMA) in adults and children aged two years and older who are already receiving SMN2-targeted treatment.

As the first muscle-targeted therapy for SMA, the monoclonal antibody works by blocking myostatin to combat muscle loss. Clinical data indicated that a 10 mg/kg dose improved motor function compared to a placebo, though the treatment was associated with an increased risk of fractures. 

While approved for SMA, the drug is also being studied for its potential to preserve lean muscle mass in patients using weight-loss medications like tirzepatide, though this application has not yet received approval.

## Timeline

### 2026-09-18: FDA approves apitegromabe to combat muscle loss in SMA patients

The FDA has approved apitegromabe (Isembyld) for spinal muscular atrophy. The drug blocks myostatin to prevent muscle loss and is being studied to preserve muscle during weight loss.

3 sources. https://clstr.news/cluster/fda-approves-apitegromabe-to-combat-muscle-loss-in-sma-patients

### 2026-09-10: FDA approves ISEMBYLD for spinal muscular atrophy treatment

The FDA approved ISEMBYLD, a first-in-class muscle-targeted therapy by Scholar Rock, for adults and children with spinal muscular atrophy (SMA) receiving SMN2-targeted treatments.

4 sources. https://clstr.news/cluster/fda-approves-isembyld-for-spinal-muscular-atrophy-treatment

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Cite as: FDA approval of ISEMBYLD for SMA. CLSTR, https://clstr.news/situations/fda-approval-of-isembyld-for-sma