Phase 2 Study Evaluating Apitegromab for the Treatment of FSHD

A Phase 2, Randomized, Double-Blind, Placebo-Controlled, Multicenter, 52-Week Study Evaluating the Efficacy and Safety of Apitegromab in Participants With Facioscapulohumeral Muscular Dystrophy (FORGE)

A randomized Phase 2 study to evaluate the efficacy and safety of apitegromab as a monotherapy in participant with FSHD

Study Overview

• Status: Not yet recruiting
• Conditions: Facioscapulohumeral Muscular Dystrophy; FSHD
• Intervention / Treatment: Drug: Apitegromab; Drug: Placebo

Detailed Description

This Phase 2, randomized, double-blind, placebo-controlled, multicenter study is designed to evaluate the efficacy, safety, and tolerability of apitegromab in participants with facioscapulohumeral muscular dystrophy (FSHD)

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Scholar Rock, Inc. Clinical Trials Administration; Phone Number: 857-259-3860; Email: MedicalInformation@scholarrock.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Male or female participants, 18 to 60 years of age at the time of informed consent.
2. Genetic diagnosis of FSHD Type 1 or FSHD Type 2, confirmed with the appropriate documentation from an accredited laboratory
3. Clinical severity score of 1.5 to 3.0 (Ricci score; range 0 to 5), inclusive, at screening
4. Baseline 10-meter walk/run test time ≤5 seconds

Exclusion Criteria:

1. Prior history of a hypersensitivity reaction to a mAb or recombinant protein bearing an Fc domain (eg, a soluble receptor-Fc fusion protein), apitegromab, or excipients of apitegromab
2. Treatment with other investigational drugs in a clinical trial within 3 months or 5 half-lives, whichever is longer, before screening
3. Previous treatment with apitegromab, or with other anti-myostatin therapies, including activin receptor antagonists
4. Current or prior use of anabolic steroids, growth hormones, glucagon-like peptide-1 receptor agonist or other substances with known effects on muscle.
5. Use of therapies with potentially significant muscle effects (eg, androgens, insulin-like growth factor, growth hormone, systemic beta-agonist, botulinum toxin, or muscle relaxants or muscle-enhancing supplements) or potentially significant neuromuscular effects (eg, acetylcholinesterase inhibitors) within 60 days before screening
6. Use of systemic or corticosteroids within 60 days prior to screening. Inhaled or topical steroids are allowed.
7. Pregnant or breastfeeding.
8. Contraindications for MRI that may include, but are not limited to, certain implanted electronic devices, cochlear implants, metallic foreign bodies, vascular clips, and metallic implants; or claustrophobia, contrast agent allergies, inability to lie still, or external medical devices that may not be removed.

History of alcoholism, or illicit drug use (drugs that are illegal and have not been prescribed).

Taking medications that impede coagulation or platelet aggregation or has a history or active coagulopathy disorder.

Any acute or comorbid condition interfering with the well-being of the participant within 7 days prior to screening, including active systemic infection, the need for acute treatment, or inpatient observation due to any reason

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Apitegromab; 10 mg/kg IV	Drug: Apitegromab; Apitegromab (SRK-015) is a fully human anti-proMyostatin monoclonal antibody (mAb) that specifically binds to human pro/latent myostatin, inhibiting myostatin activation. Apitegromab will be administered every 4 weeks by intravenous (IV) infusion.; Other Names: SRK-015
Placebo Comparator: Placebo; Placebo IV	Drug: Placebo; Placebo is administered every 4 weeks by intravenous (IV) infusion and does not contain the active ingredient.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assess the efficacy of apitegromab compared with placebo in participants with FSHD	Percent change from baseline in total lean muscle volume (LMV) as measured by full body magnetic resonance imaging (MRI) at week 52	52 Weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Further assess the efficacy of apitegromab compared with placebo in participants with FSHD	Percent change from baseline in total LMV as measured by full body MRI at week 24	24 Weeks
Further assess the efficacy of apitegromab compared with placebo in participants with FSHD	Change from baseline in additional muscle parameters, such as muscle fat fraction at week 24 and week 52	24 Weeks and 52 Weeks
Further assess the efficacy of apitegromab compared with placebo in participants with FSHD	Change from baseline in additional muscle parameters, such as muscle fat infiltration, at week 24 and week 52	24 Weeks and 52 Weeks
Evaluate the pharmacokinetics of apitegromab in participants with FSHD	Serum concentrations of apitegromab	52 Weeks
Evaluate the pharmacodynamics of apitegromab in participants with FSHD	Serum concentrations of total latent myostatin	52 Weeks
Evaluate the safety and tolerability of apitegromab in participants with FSHD	Incidence of anti-drug antibodies against apitegromab in serum	52 Weeks
Evaluate the safety and tolerability of apitegromab in FSHD participants	Incidence of adverse events and serious adverse events	52 Weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluate improvement(s) over time in motor function in participants with FSHD receiving apitegromab	Change from baseline in quantitative muscle testing in kilogram-force. Higher score indicates greater function.	52 Weeks
Evaluate improvement(s) over time in motor function in participants with FSHD receiving apitegromab	Change from baseline in relative surface area as assessed by reachable workspace. Higher score indicates greater function.	52 Weeks
Evaluate improvement(s) over time in motor function in participants with FSHD receiving apitegromab	Change from baseline in FSHD composite outcome measure (FSHD-COM) total score (0 - 72 scale; Higher score indicates greater impairment)	52 Weeks

Collaborators and Investigators

• Sponsor: Scholar Rock, Inc.

Study record dates

Study Major Dates

• Study Start (Estimated): August 1, 2026
• Primary Completion (Estimated): June 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: February 10, 2026
• First Submitted That Met QC Criteria: February 24, 2026
• First Posted (Actual): February 27, 2026

Study Record Updates

• Last Update Posted (Actual): February 27, 2026
• Last Update Submitted That Met QC Criteria: February 24, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Nervous System Diseases; Muscular Diseases; Neuromuscular Diseases; Genetic Diseases, Inborn; Muscular Disorders, Atrophic; Muscular Dystrophies; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Muscular Dystrophy, Facioscapulohumeral; apitegromab
• Other Study ID Numbers: SRK-015-009

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No