ISEMBYLD (apitegromab-mstn) injection
Spinal muscular atrophy · Adults and pediatric patients aged 2 years and older with spinal muscular atrophy who are currently receiving an SMN2-targeted treatment
SRRK · Scholar Rock
Regulatory designations
Full timeline
5 milestonesFDA approved ISEMBYLD for spinal muscular atrophy
FDA approved ISEMBYLD for adults and pediatric patients aged 2 years and older with spinal muscular atrophy who are currently receiving an SMN2-targeted treatment. It is the first FDA-approved SMA therapy that directly targets muscle loss. The approval also resulted in a Rare Pediatric Disease Priority Review Voucher for Scholar Rock.
FDA — Approval of ISEMBYLD for spinal muscular atrophy↗Scholar Rock confirmed FDA acceptance of the resubmission
The accepted application included Catalent Indiana and a second U.S.-based fill-finish facility.
Scholar Rock — BLA acceptance and manufacturing update↗Scholar Rock resubmitted the BLA
The resubmission added a second fill-finish facility and a standard safety update after alignment with FDA.
Scholar Rock — Apitegromab BLA resubmission↗FDA issued a Complete Response Letter in the first review cycle
The CRL was solely related to observations at the third-party Catalent Indiana fill-finish facility and did not cite other approvability concerns.
Scholar Rock — Apitegromab Complete Response Letter↗Related News
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)
Sep 2, 2026Scholar Rock Receives FDA Fast Track Designation for Apitegromab Facioscapulohumeral Muscular Dystrophy (FSHD) Program as Participant Dosing Commences in Phase 2 FORGE Trial
Aug 27, 2026Scholar Rock to Present at Upcoming Investor Conferences
Aug 21, 2026Scholar Rock Provides Update on Global Apitegromab Regulatory Progress Across U.S., Europe, and Japan
Aug 14, 2026Scholar Rock Reports New Employee Inducement Grants Under Nasdaq Listing Rule 5635(c)(4)