Business Wire·Sep 11, 2026, 6:25 PM ET

Scholar Rock Announces FDA Approval of ISEMBYLD™ (apitegromab-mstn), the First and Only Muscle-Targeted Treatment for Children and Adults with Spinal Muscular Atrophy (SMA)

FDA approved ISEMBYLD (apitegromab-mstn) for adults & children ≥2 years with spinal muscular atrophy (SMA) currently receiving SMN2-targeted treatment.
ISEMBYLD is the first muscle-targeted treatment to demonstrate motor function improvement in SMA patients on SMN2-targeted therapy.
Phase 3 SAPPHIRE study showed a 2.2-point improvement in HFMSE motor function scores for patients receiving 10 mg/kg ISEMBYLD versus placebo (p=0.0121).
34.2% of ISEMBYLD-treated patients achieved ≥3-point HFMSE improvement compared to 13.5% on placebo (odds ratio 3.8; p=0.0125).
U.S. commercial launch is underway with product availability for shipment in the coming days.
Scholar Rock Supports™ dedicated team is now available to assist patients & caregivers with insurance, financial aid, & infusion logistics.
Scholar Rock received a Rare Pediatric Disease Priority Review Voucher upon approval.
Most common adverse reactions include upper respiratory tract infections, vomiting, cough, viral infections, headache, gastroenteritis, pharyngitis, & hypersensitivity.
Bone fractures occurred in 9% of ISEMBYLD patients versus 2% in placebo patients.
Conference call & webcast scheduled for Monday, September 14, 2026, at 8:00 a.m. ET.