Evaluate Safety and Biological Activity of ATYR1940 in Participants With Early Onset Facioscapulohumeral Muscular Dystrophy

An Open-Label, Intrapatient Dose-Escalation Study to Evaluate the Safety, Tolerability, Immunogenicity, and Biological Activity of ATYR1940 in Patients With Early Onset and Other Pediatric Onset Facioscapulohumeral Muscular Dystrophy

The purpose of this study is to assess the safety and biological activity of ATYR1940 in participants with early onset FSHD.

A Phase 1b/2 open-label, intraparticipant dose-escalation study aiming to evaluate the safety, tolerability, immunogenicity, biological and pharmacodynamic activity of intravenous ATYR1940, administered once weekly for 12 weeks, in early onset FSHD participants with signs or symptoms prior to 10 years of age.

Inclusion Criteria:

• Established, genetically confirmed diagnosis of FSHD.
• Onset of FSHD signs or symptoms prior to 10 years of age, as documented in the participant's medical record or based on participant or family report.
• Provide written informed consent or assent
• In the Investigator's opinion, participant is willing and able to complete all study procedures and comply with the weekly study visit schedule.

Exclusion Criteria:

• Currently receiving treatment with an immunomodulatory agent including targeted biological therapies within the 3 months before baseline; corticosteroids within 3 months before baseline; or high-dose non-steroidal anti-inflammatory agents within 2 weeks before baseline.
• Currently receiving curcumin or albuterol; use of a product that putatively enhances muscle growth or activity on a chronic basis within 4 weeks before baseline; statin treatment initiation or significant adjustment to statin regimen within 3 months before baseline (stable, chronic statin use is permissible).
• Use of an investigational product or device within 30 days before baseline.
• Evidence of an alternative diagnosis other than FSHD or a coexisting myopathy or dystrophy, based on prior muscle biopsy or other available investigations.
• History of severe restrictive or obstructive lung disease, or evidence for interstitial lung disease on screening chest radiograph.
• History of anti-synthetase syndrome, prior Jo-1 Ab-positivity, or a positive or equivocally positive Jo-1 Ab test result during screening.
• Chronic infection, such as hepatitis B, hepatitis C, or human immunodeficiency virus or a history of tuberculosis.
• Vaccination within 8 weeks before baseline or vaccination is planned during study participation.
• Symptomatic cardiomyopathy or severe cardiac arrhythmia, that may, in the Investigator's opinion, limit the participant's ability to complete the study protocol.
• Muscle biopsy within 30 days before baseline.