Safety, Tolerability, PK, and Activity of ATYR1940 in Patients With Muscular Dystrophy - Study Extension

The purpose of this study is to assess the safety and tolerability profile of ATYR1940 in the
treatment of adult patients with molecularly defined genetic muscular dystrophies, and to
additionally explore the pharmacokinetics and biologic activity of ATYR1940 in adult patients
with molecularly defined genetic muscular dystrophies. Patients who successfully complete a
parent study (NCT02239224) are eligible for enrollment into this long-term extension study.

Inclusion Criteria:

- Patient has an established, genetically-confirmed, diagnosis of facioscapulohumeral
dystrophy with clinical findings meeting existing criteria

- Patient is a male or female aged 18 to 65 years, inclusive.

- Patients who previously participated in Study ATYR1940-C-002 and who meet the entry
criteria above for the current study will be eligible for enrollment.

Exclusion Criteria:

- Patient is currently receiving treatment with an immunomodulatory agent or has a
history of such treatment, including targeted biological therapies (e.g., etanercept,
omalizumab) within the 3 months before Baseline; corticosteroids within 4 weeks before
Baseline; or non-steroidal anti-inflammatory agents (NSAIDs) within 2 weeks before
Baseline.

- Patient has a severe retinopathy.

- Patient has a history of obstructive or restrictive lung disease (including
interstitial lung disease, pulmonary fibrosis, or asthma), or evidence for
interstitial lung disease on Screening chest radiograph.

- Patient has evidence of clinically significant cardiovascular, pulmonary, hepatic,
renal, hematological, metabolic, dermatological, or gastrointestinal disease, or has a
condition that requires immediate surgical intervention or other treatment or may not
allow safe participation.

- Patient has used any investigational product or device (other than a mobility
assistance device) within 30 days before Baseline.

- If female and of childbearing potential (premenopausal and not surgically sterile),
patient has a positive pregnancy test at Screening or is unwilling to use
contraception from the time of Screening through the 1-month Follow-up visit.
Acceptable methods of birth control include abstinence, barrier methods, hormones, or
intra-uterine device.

- If male, patient is unwilling to use a condom plus spermicide during sexual
intercourse from the time of Screening through the 1 month Follow-up visit.