DFD01 Spray HPA Axis Suppression Study in Adolescent Patients With Moderate to Severe Plaque Psoriasis

Inclusion Criteria: 1. Subjects must weigh at least 55 pounds 2. Subjects must present with a clinical diagnosis of stable (at least 3 months) plaque psoriasis. 3. Subjects with psoriasis involving ≥ 10% BSA, not including the face, scalp, groin, axillae and other intertriginous areas.. 4. Subjects must have moderate to severe plaque psoriasis at the Baseline Visit. 5. Subjects whose results from the screening ACTH stimulation test are considered normal (cortisol level \>18 ug/dL at 30 minutes post stimulation) and show no other signs of abnormal HPA axis function or adrenal response. Exclusion Criteria: 1. Current diagnosis of unstable forms of psoriasis including guttate, erythrodermic, exfoliative or pustular psoriasis. 2. History of organ transplant requiring immunosuppression, HIV, or other immunocompromised state. 3. Have received treatment for any type of cancer within 5 years of the Baseline Visit. 4. Use within 60 days prior to the Baseline Visit of: 1) immunosuppressive drugs (e.g., tacrolimus, pimecrolimus), 2) systemic antipsoriatic treatment (e.g., methotrexate, cyclosporine, hydroxyurea), or 3) biologic treatment for psoriasis (e.g., infliximab, adalimumab, etanercept, ustekinumab, secukinumab, or alefacept). 5. Use within 30 days prior to the Baseline Visit of: 1) topical antipsoriatic drugs (salicylic acid, anthralin, coal tar, calcipotriene), 2) PUVA therapy, 3) systemic anti-inflammatory agents (e.g., mycophenolate mofetil, sulfasalazine, 6-thioguanine), or 4) UVB therapy. 6. Use within 30 days prior to the Screening Visit of any product containing corticosteroids. Inhaled, intraocular, intranasal, etc. steroids are not allowed. 7. Subjects who have an abnormal sleep schedule or work overnight. 8. Subjects with a known history of acute adrenal crisis, Addison's disease or decreased adrenal output, low pituitary function or pituitary tumors. 9. Subjects who have a history of an adverse reaction to cosyntropin injection or similar test reagents.