Apitegromab

Apitegromab remains on track to be the first and only muscle-targeted treatment for people living with Spinal Muscular Atrophy

Scholar Rock, a late-stage biopharmaceutical company focused on advancing innovative treatments for neuromuscular diseases, cardiometabolic disorders, and other serious diseases, today announced that the U.S. Food and Drug Administration (FDA) has accepted its Biologics License Application (BLA) for apitegromab (SRK-015), an investigational muscle-targeted treatment that is being developed to provide clinically meaningful improvement in motor function for people living with spinal muscular atrophy (SMA) who are receiving an SMN-targeted treatment.

The FDA will review the application under priority review and has assigned a Prescription Drug User Fee Act (PDUFA) target action date of September 22, 2025. The FDA priority review designation conveys that the FDA has determined that if apitegromab is approved, it could offer significant improvement in the safety or effectiveness of treatment of the serious condition of SMA.

The Company has also submitted and received validation for its Marketing Authorisation Application (MAA) to the European Medicines Agency (EMA) for apitegromab for the treatment of SMA. Validation confirms that the application is complete and the formal review process by EMA can begin.

Apitegromab’s regulatory submissions are based on positive efficacy and safety data from the pivotal Phase 3 SAPPHIRE trial (NCT05156320), for which the Company reported positive topline data in October 2024, as well as supportive data from the Phase 2 TOPAZ trial and long-term extension ONYX trial. The results from SAPPHIRE, including primary and secondary endpoint analyses, were featured in multiple clinical presentations at the 2025 Muscular Dystrophy Association (MDA) Clinical & Scientific Conference earlier this month.

SAPPHIRE achieved its primary endpoint, demonstrating a statistically significant and clinically meaningful motor function improvement in people with SMA receiving apitegromab and chronic dosing of SMN-targeted treatments (either nusinersen or risdiplam) versus placebo (nusinersen or risdiplam) as measured by the gold standard Hammersmith Functional Motor Scale Expanded (HFMSE).

In anticipation of potential regulatory approvals, Scholar Rock is planning for a U.S. commercial launch upon approval in 2025, with European launch anticipated in 2026.