['atopic dermatitis']
['dupilumab', 'matching placebo']

        Inclusion Criteria:

          1. Male or female, 18 years or older

          2. Severe, Chronic AD, (according to American Academy of Dermatology Consensus Criteria
             [Eichenfield 2014]) for whom treatment with potent TCS is indicated

          3. EASI score ≥20 at the screening and baseline visits

          4. IGA score ≥3 (on the 0 to 4 IGA scale) at the screening and baseline visits

          5. ≥10% body surface area (BSA) of AD involvement at the screening and baseline visits

          6. Documented recent history (within 6 months before the screening visit) of inadequate
             response to treatment with TCS

          7. Have applied a stable dose of topical emollient (moisturizer) twice daily for at least
             the 7 consecutive days immediately before the baseline visit

          8. Documented history by a physician of either:

               1. No prior CSA exposure and not currently a candidate for CSA treatment due to:

                    -  medical contraindications (eg, uncontrolled hypertension on medication), or

                    -  use of prohibited concomitant medications (eg, statins, digoxin, macrolide,
                       antibiotics, barbiturates, anti-seizure, nonsteroidal anti-inflammatory
                       drugs, diuretics, angiotensin-converting-enzyme inhibitors, St John's Wort,
                       etc), or

                    -  increased susceptibility to CSA-induced renal damage (elevated creatinine)
                       and liver damage (elevated function tests), or

                    -  increased risk of serious infections, or

                    -  hypersensitivity to CSA active substance or excipients OR

               2. Previously exposed to CSA, and CSA treatment should not be continued or restarted
                  due to:

                    -  intolerance and/or unacceptable toxicity (eg, elevated creatinine, elevated
                       liver function tests, uncontrolled hypertension, paraesthesia, headache,
                       nausea, hypertrichosis, etc), or

                    -  inadequate response to CSA (defined as flare of AD on CSA tapering after a
                       maximum of 6 weeks of high dose [5 mg/kg/day] to maintenance dose [2 to 3
                       mg/kg/day] or a flare after a minimum of 3 months on maintenance dose).
                       Flare is defined as increase in signs and/or symptoms leading to escalation
                       of therapy, which can be an increase in dose, a switch to a higher-potency
                       class of TCS, or the start of another systemic non-steroidal
                       immunosuppressive drug or

                    -  requirement for CSA at doses >5 mg/kg/day, or duration beyond those
                       specified in the prescribing information (>1 year)

        Exclusion Criteria:

          1. Participation in a prior dupilumab clinical study

          2. Treatment with an investigational drug within 8 weeks or within 5 half-lives (if
             known), whichever is longer, before the screening visit

          3. Hypersensitivity and/or intolerance to corticosteroids or to any other ingredients
             contained in the TCS product used in the study

          4. Systemic CSA, systemic corticosteroids, or phototherapy within 4 weeks prior to
             screening, and azathioprine (AZA), methotrexate (MTX), mycophenolate mofetil (MMF), or
             Janus kinase (JAK) inhibitors within 8 weeks prior to screening

          5. Treatment with TCI within 1 week before the screening visit

          6. Treatment with biologics as follows:

               -  Any cell-depleting agents including but not limited to rituximab: within 6 months
                  before the screening visit, or until lymphocyte count returns to normal,
                  whichever is longer

               -  Other biologics: within 5 half-lives (if known) or 16 weeks prior to the
                  screening visit, whichever is longer

          7. Regular use (more than 2 visits per week) of a tanning booth/parlor within 4 weeks of
             the screening visit

          8. Treatment with a live (attenuated) vaccine within 12 weeks before the screening

          9. Active chronic or acute infection requiring treatment with systemic antibiotics,
             antivirals, antiparasitics, antiprotozoals, or antifungals within 2 weeks before the
             screening or superficial skin infections within 1 week before the screening visit.
             NOTE: patients may be rescreened no sooner than 2 weeks after infection resolves

         10. Known or suspected history of immunosuppression, including history of invasive
             opportunistic infections (eg, tuberculosis [TB], histoplasmosis, Listeriosis,
             coccidioidomycosis, pneumocystosis, aspergillosis) despite infection resolution; or
             unusually frequent, recurrent, or prolonged infections, per investigator judgment

         11. Presence of any 1 of the following TB criteria:

               1. A positive tuberculin skin test at the screening visit

               2. A positive blood QuantiFERON®-TB or T-Spot test at the screening visit

               3. Chest x-ray (posterior-anterior and lateral views) at screening or within 3
                  months before the screening visit (radiology report must be available) with
                  results consistent with prior TB infection (including but not limited to apical
                  scarring, apical fibrosis, or multiple calcified granuloma). This does not
                  include non-caseating granulomata.

             NOTE: Any of these 3 TB tests will be performed on a country-by-country basis
             according to local guidelines only if required by regulatory authorities or ethics
             boards.

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

         13. Positive hepatitis B surface antigen (HBsAg), hepatitis B core antibody (HBc Ab), or
             hepatitis C antibody (HCV Ab) at the screening visit
      