Scholar Rock Eyes Sept. 30 FDA Decision for SMA Drug Apitegromab

Key Points

• Scholar Rock expects an FDA decision on September 30 for apitegromab, an investigational treatment for spinal muscular atrophy (SMA) that could become the first muscle-targeted therapy approved for the disease.
• The prior application received a complete response letter solely over manufacturing observations at Catalent Indiana—not clinical data. Scholar Rock resubmitted its application with an alternate fill-finish facility, which is now under FDA review after the Catalent site was classified as Official Action Indicated.
• The company is preparing for a potential U.S. launch and has begun a Phase II study testing apitegromab in facioscapulohumeral muscular dystrophy, expanding the drug’s potential beyond SMA.

Scholar Rock NASDAQ: SRRK CEO David Hallal said the company is preparing for a September 30 FDA decision date for apitegromab, its investigational treatment for spinal muscular atrophy, or SMA, following a resubmitted biologics license application supported by an alternate fill-finish manufacturing facility.

Speaking at a Canaccord Genuity conference, Hallal said apitegromab could become the first muscle-targeted therapy approved for children and adults with SMA. He described the drug as the first myostatin inhibitor to demonstrate success in a Phase III registration trial in any disease.

Selective Myostatin Approach

Hallal said myostatin, a protein discovered in 1997, acts as the body’s natural negative regulator of muscle growth. While multiple companies have previously pursued myostatin-inhibition strategies, he said those programs failed because targeting the mature protein or its receptor could lead to unwanted effects involving related proteins in the TGFβ superfamily.

Scholar Rock’s approach targets the latent, or inactive, form of myostatin, which Hallal described as a chemically protected form of the protein released from muscle. He said the company developed an antibody designed to selectively inhibit latent myostatin, seeking to avoid the off-target effects associated with other approaches.

According to Hallal, apitegromab entered healthy-volunteer clinical testing in 2018 and SMA development in 2019. He said the company selected SMA because muscle is the principal organ affected by the disease, while available treatments have largely focused on improving survival motor neuron, or SMN, protein production and motor neuron health.

Manufacturing Path to FDA Decision

The company’s prior application received a complete response letter tied solely to good manufacturing practice observations at Catalent Indiana’s fill-finish site, Hallal said. He emphasized that the issue was not related to apitegromab’s clinical data.

Scholar Rock subsequently worked with the FDA on a parallel plan involving an additional fill-finish facility. The company resubmitted its BLA on March 30, 2026, with two possible manufacturing paths to approval: a successful reinspection of the Catalent Indiana site or qualification of the alternate facility.

Hallal said FDA inspectors visited Catalent Indiana in April, but the facility was subsequently classified as Official Action Indicated, or OAI. While drug product can continue to be filled and released commercially from the site, Hallal said the classification prevents new drug approvals using that facility.

He said Scholar Rock had previously agreed with the FDA on the data required to support qualification of the second facility and the timeline for submission without triggering a major amendment to the application. The company submitted the agreed data package ahead of schedule, and Hallal said the agency is now reviewing it.

Hallal said the alternate facility has a recent positive FDA and European Medicines Agency inspection history and has received multiple product approvals in the past year where pre-license or pre-approval inspections were waived. The company does not expect an inspection of the second site to be required, though Hallal did not rule out the possibility.

He added that Scholar Rock has already filled more commercial vials at the alternate facility than it had at Catalent Indiana as of September 2025. Those vials are held by a third-party provider pending approval, labeling and packaging.

Commercial Preparation and European Review

Hallal said Scholar Rock has been building commercial capabilities ahead of a potential U.S. launch, including an experienced team led by executives Keith Woods and Rebecca McLeod, whom he said previously led the U.S. and global launch of VYVGART.

The company has established Scholar Rock Supports, a program intended to help SMA patients and families navigate access and reimbursement matters. Hallal said payer coverage processes could take time, including the development of medical policies and the eventual establishment of a drug-specific J-code for the treatment’s every-four-week infusion schedule.

He said a 2025 survey of more than 30 key opinion leaders managing over 500 patients found that about 23% would call all eligible patients to offer apitegromab at approval. A year later, that figure had risen to approximately 42%, according to Hallal.

Hallal also pointed to Scholar Rock’s 188-patient Phase III trial, saying patients assigned to placebo lost motor function while those receiving apitegromab gained motor function despite background SMN-targeted therapy.

In Europe, Hallal said Scholar Rock’s marketing authorization application initially listed only the Catalent Indiana facility. The company is now planning discussions with the EMA on the appropriate process for providing information on the alternate facility. He said potential options could include withdrawing and resubmitting the application, but no revised timeline was provided.

FSHD Program Advances

Beyond SMA, Hallal highlighted Scholar Rock’s newly initiated 60-patient Phase II FORGE study of apitegromab in facioscapulohumeral muscular dystrophy, or FSHD. The trial will evaluate the treatment as monotherapy in patients with a moderate FSHD phenotype.

He said preclinical testing in a FLExDUX4 mouse model showed improvements in muscle mass, force and exercise endurance. Hallal added that Scholar Rock sees potential for the platform across additional neuromuscular diseases, including muscular dystrophies and muscular atrophies.

About Scholar Rock (NASDAQ:SRRK)

Scholar Rock is a clinical-stage biotechnology company focused on the discovery and development of protein therapeutics that selectively target growth factors involved in disease processes. The company's research platform is designed to modulate endogenous growth factor activation and signaling with high specificity, aiming to restore normal biological function across a range of disorders. Scholar Rock's approach is distinguished by its emphasis on engineering antibodies and biologics that interact with growth factor precursors or latent complexes rather than the active form, potentially offering improved safety and efficacy profiles.

The company's lead program, SRK-015 (appercept), is an investigational monoclonal antibody targeting the activation of latent myostatin proproteins and is being evaluated for the treatment of spinal muscular atrophy (SMA).

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