Clinical Trials

Overview

Apitegromab – Scholar Rock

Apitegromab is an investigational muscle-targeted treatment that aims to improve motor function for people living with SMA.

In March 2025, the European Medicines Agency (EMA) accepted the Marketing Authorisation Application (MAA) for apitegromab, supported by positive efficacy and safety data from a pivotal Phase 3 trial and acknowledging the unmet need in SMA. This has initiated the review process for potential approval across the European Union. Similarly, the U.S. Food and Drug Administration (FDA) has granted Priority Review, with a Prescription Drug User Fee Act (PDUFA) date set for September 22nd, 2025

Method of action

Apitegromab is a fully human monoclonal antibody that very specifically targets the latent (or inactive) form of myostatin. 

Myostatin is a protein expressed primarily in skeletal muscle cells to inhibit muscle growth, working in concert with other growth factors and hormones to maintain appropriate muscle mass. When injected into the bloodstream, apitegromab selectively binds to latent myostatin which prevents the conversion of myostatin to its active form in muscle tissues, thereby allowing muscle growth and strength.

Trials of apitegromab (SRK-015)

Trial Name
TOPAZ
Age:
2 to 21 years old
Aim:
To assess the safety and efficacy of apitegromab in SMA (Type 2 and Type 3) in pediatric and adult patients.
Status:
Completed
Location:
Italy, Spain, the Netherlands, USA
Identifier:
NCT03921528 2018-004383-65
Trial Name
SAPPHIRE
Age:
2 to 21 years old
Aim:
To evaluate the efficacy and safety of apitegromab in patients with SMA (Type 2 and Type 3) receiving background nusinersen or risdiplam therapy.
Status:
Completed
Location:
Belgium, France, Germany, Italy, Netherlands, Poland, Spain, UK, USA
Identifier:
NCT03921528 2021-005314-34
Trial Name
ONYX
Age:
2 years old and older
Aim:
To evaluate the long-term safety and efficacy of apitegromab in patients with SMA (Type 2 and Type 3) who completed previous investigational trials of TOPAZ and SAPPHIRE.
Status:
Ongoing
Location:
Belgium, France, Germany, Italy, Netherlands, Poland, Spain, UK, USA
Identifier:
NCT05626855 2022-001771-14
Trial Name
OPAL
Age:
up to 2 years old
Aim:
To evaluate the pharmacokinetics, pharmacodynamics, efficacy, and safety of apitegromab in subjects <2 years old with SMA.
Status:
Enrolment starting in September 2025
Location:
TBC
Identifier:
NCT07047144

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