# ISEMBYLD (apitegromab-mstn) injection PDUFA Event: Spinal muscular atrophy

Canonical URL: https://biopharmsignal.com/pdufa-calendar/SRRK/apitegromab-spinal-muscular-atrophy-review-2

Ticker: SRRK

Company: Scholar Rock

Event date: 2026-09-11

Event type: FDA Decision

Stage: PDUFA

Result: Approved

Result date: 2026-09-11

Application type: BLA

Review cycle: 2

FDA approved ISEMBYLD for spinal muscular atrophy. FDA approved ISEMBYLD for adults and pediatric patients aged 2 years and older with spinal muscular atroph...

## Event Timeline

### September 11, 2026 — FDA 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](https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-first-therapy-target-muscle-loss-spinal-muscular-atrophy)

### May 7, 2026 — 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](https://investors.scholarrock.com/news-releases/news-release-details/scholar-rock-reports-first-quarter-2026-financial-results-and/)

### March 31, 2026 — 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](https://investors.scholarrock.com/news-releases/news-release-details/scholar-rock-resubmits-biologics-license-application-bla-fda/)

### September 23, 2025 — 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](https://investors.scholarrock.com/node/11491/pdf)

### October 7, 2024 — SAPPHIRE reported positive Phase 3 results

Apitegromab demonstrated a statistically significant and clinically meaningful improvement in motor function in the pivotal SAPPHIRE trial.

[Scholar Rock — SAPPHIRE topline results](https://investors.scholarrock.com/static-files/693dd276-5581-4b1a-9834-b24e16dbe17f)

## Regulatory Designations

- Priority Review FDA: [Scholar Rock — Apitegromab designations and BLA resubmission](https://investors.scholarrock.com/news-releases/news-release-details/scholar-rock-resubmits-biologics-license-application-bla-fda/)

- Fast Track FDA: [Scholar Rock — Apitegromab designations and BLA resubmission](https://investors.scholarrock.com/news-releases/news-release-details/scholar-rock-resubmits-biologics-license-application-bla-fda/)

- Orphan Drug FDA: [Scholar Rock — Apitegromab designations and BLA resubmission](https://investors.scholarrock.com/news-releases/news-release-details/scholar-rock-resubmits-biologics-license-application-bla-fda/)

- Rare Pediatric Disease FDA: [Scholar Rock — Apitegromab designations and BLA resubmission](https://investors.scholarrock.com/news-releases/news-release-details/scholar-rock-resubmits-biologics-license-application-bla-fda/)

- PRIME EMA: [Scholar Rock — Apitegromab designations and BLA resubmission](https://investors.scholarrock.com/news-releases/news-release-details/scholar-rock-resubmits-biologics-license-application-bla-fda/)

- Orphan Drug EMA: [Scholar Rock — Apitegromab designations and BLA resubmission](https://investors.scholarrock.com/news-releases/news-release-details/scholar-rock-resubmits-biologics-license-application-bla-fda/)

## Related Pages

- SRRK PDUFA calendar: https://biopharmsignal.com/pdufa-calendar/SRRK.md

- SRRK company profile: https://biopharmsignal.com/company/SRRK.md

- PDUFA calendar: https://biopharmsignal.com/pdufa-calendar.md

## Related News

- 2026-09-21 — Scholar Rock Reports New Employee Inducement Grants Under Nasdaq Listing Rule 5635(c)(4): https://biopharmsignal.com/news/SRRK/scholar-rock-reports-new-employee-inducement-grants-under-nasdaq-listing-rule-56-502ae038.md

- 2026-09-21 — Scholar Rock Reports New Employee Inducement Grants Under Nasdaq Listing Rule 5635(c)(4): https://biopharmsignal.com/news/SRRK/scholar-rock-reports-new-employee-inducement-grants-under-nasdaq-listing-rule-56-eeff1e5f.md

- 2026-09-11 — 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): https://biopharmsignal.com/news/SRRK/scholar-rock-announces-fda-approval-of-isembyld-apitegromab-mstn-the-first-and-o-82eb78c6.md

- 2026-09-11 — 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): https://biopharmsignal.com/news/SRRK/scholar-rock-announces-fda-approval-of-isembyld-apitegromab-mstn-the-first-and-o-99cb4df7.md

- 2026-09-02 — Scholar Rock Receives FDA Fast Track Designation for Apitegromab Facioscapulohumeral Muscular Dystrophy (FSHD) Program as Participant Dosing Commences in Phase 2 FORGE Trial: https://biopharmsignal.com/news/SRRK/scholar-rock-receives-fda-fast-track-designation-for-apitegromab-facioscapulohum-06a077f2.md