The Safety and Biological Activity of ATYR1940 in Patients With Limb Girdle or Facioscapulohumeral Muscular Dystrophies

ATYR1940-C-004 is a Phase1b/2 open-label intrapatient study dose escalation study aiming to
evaluate the safety, tolerability, immunogenicity, biological activity of intravenous
ATYR1940, administered once weekly for 8 weeks, then twice a weekly for 4 weeks in adult
patients with LGMD2B and FSHD. Approximately 8 LGMD2B and 8 FHSD patients will be enrolled.

Inclusion Criteria:

- Provided informed consent

- Investigator's opinion, patient is willing and able to complete all study procedures
and comply with the study visit schedule.

Patients with LGMD2B:

- Established, genetically confirmed diagnosis of LGMD2B.

- Either the presence of a STIR-positive muscle on lower extremity skeletal muscle MRI,
or, if no STIR-positive muscles, meets muscle biomarker criteria.

Patients with FSHD:

- Established, genetically confirmed diagnosis of FSHD.

- The presence of a STIR-positive muscle on lower extremity skeletal muscle MRI.

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 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 LGMD2B or 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 patient's ability to complete the study protocol.

- Muscle biopsy within 30 days before baseline.