Study to Assess the Efficacy and Long-term Safety of Dupilumab (REGN668/SAR231893) in Adult Participants With Moderate-to-Severe Atopic Dermatitis

Key Inclusion Criteria:

1. Chronic AD that had been present for at least 3 years before the screening visit;

2. Documented recent history (within 6 months before the screening visit) of inadequate
response to a sufficient course of out-patient treatment with topical AD
medication(s).

Key Exclusion Criteria:

1. Participation in a prior Dupilumab clinical trial;

2. Important side effects of topical medication (e.g. intolerance to treatment,
hypersensitivity reactions, significant skin atrophy, systemic effects), as assessed
by the investigator or treating physician;

3. Having used any of the following treatments within 4 weeks before the baseline visit,
or any condition that, in the opinion of the investigator, was likely to require such
treatment(s) during the first 2 weeks of study treatment:

1. Immunosuppressive/immunomodulating drugs (e.g, systemic steroids, cyclosporine,
mycophenolate-mofetil, Janus kinase inhibitors, interferon-gamma [IFN-γ],
azathioprine, methotrexate, etc.);

2. Phototherapy for AD;

4. Treatment with a live (attenuated) vaccine within 12 weeks before the baseline visit;

5. History of human immunodeficiency virus (HIV) infection or positive HIV serology at
screening;

6. Positive hepatitis B surface antigen (HBsAg), hepatitis B core antibody (HBcAb), or
hepatitis C antibody at the screening visit;

7. Active or acute infection requiring systemic treatment within 2 weeks before baseline
visit;

8. Known or suspected history of immunosuppression;

9. Pregnant or breastfeeding women, or planning to become pregnant or breastfeed during
the participant's participation in this study.

Note: The eligibility criteria listed above is not intended to contain all considerations
relevant to a participant's potential participation in a clinical trial therefore not all
inclusion/ exclusion criteria are listed.