The purpose of this study is to determine whether OC000459 is in reducing disease severity and preventing flares in people with moderate to severe atopic dermatitis (AD).

The study will include patients with a Th2 high eosinophilic phenotype who typically have more severe disease and are prone to flare.

Inclusion Criteria:

1. Atopic dermatitis as defined by a score of at least 9 on the Nottingham Eczema Severity Score, stratified into moderate (score 9 to 11 inclusive) and severe (score 12 to 15 inclusive) disease.
2. Fully documented history of the use of topical corticosteroids (TCS) and/or topical calcineurin inhibitors (TCI). Subjects without a fully documented history will be excluded from the study.
3. Male and female subjects with moderate to severe atopic dermatitis treated with by TCS and/or TCI (with or without emollients) at the time of screening and over the previous month.
4. Subjects must have had at least 1 AD flare in the previous 6 months.

Exclusion Criteria:

1. Receipt of any forbidden medication including over the counter preparations and herbal medicines within 14 days of the first dosing day with the exception of paracetamol up to a maximum of 2g daily.

2. Use of systemic steroids within 4 weeks of the screening visit, light therapy or immunosuppressants within 2 months of the screening visit.

3. Use of NSAIDs.

4. Subjects initially diagnosed with AD aged 2 years or over will be excluded unless they have either coexisting or a history of asthma and/or allergic rhinoconjunctivitis.

5. Subjects with contact dermatitis will be excluded.

6. Subjects with acute skin infection or acute disease flares. Subjects with active flares during the screening to randomisation period (visits 1 to 2) may be managed according to normal clinical practice and be rescreened once their flares are no longer active.

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Up to 6 months

Standardised coding using MedDRA