A Study of Ustekinumab (STELARA®) in Adult Japanese Participants With Severe Atopic Dermatitis

The purpose of this study is to assess the safety and effectiveness of 2 doses of ustekinumab compared with placebo (inactive medication) in adult Japanese participants with severe atopic dermatitis.

This is a randomized (the study medication is assigned by chance), double-blind (neither physician nor participant knows the identity of the assigned treatment), placebo-controlled (one of the study medications is inactive), multicenter, parallel group study (each participant group receives different treatments simultaneously). Participants will be randomly assigned in a 1:1:1 ratio to receive either ustekinumab 45 mg, ustekinumab 90 mg, or placebo. The study will consist of a screening period, a 12-week double-blind treatment period, and a 12-week follow-up period. During the double-blind treatment period, participants will receive one subcutaneous injection of study medication at Week 0 and Week 4. Participants will return to the study center for 7 evaluation visits on Weeks 2, 4, 8, 12, 16, 20, and 24. Clinical response will be evaluated by Eczema Area and Severity Index (EASI), Investigator's Global Assessment (IGA), photography, and Dermatology Life Quality Index (DLQI). Participants will record their itch condition twice daily using the participant daily diary from 2 weeks prior to randomization until Week 12. Blood samples will be drawn at time periods during the screening, double-blind treatment, and follow-up periods. Participant safety will be monitored throughout the study. Participants are permitted to use concomitant topical medications, as defined in the protocol and without any increase in dose, from 4 weeks prior to randomization through to the end of the treatment period. After Week 12, additional treatment can be started or the dose of concomitant medications can be increased, if no improvement in clinical response is observed; in these cases EASI, IGA, and photography evaluations will be stopped. The study duration for each participant is expected to be approximately 30 weeks. Ustekinumab (also known as STELARA) is an antibody medication that inhibits the inflammatory proteins IL-12 and IL-23 and is approved as a treatment for moderate to severe plaque-type psoriasis; this study will examine whether ustekinumab can provide benefit in atopic dermatitis and assess for any risks or side effects.

Eligibility Criteria:
Inclusion Criteria:

* Must be Japanese
* Must have a diagnosis of atopic dermatitis, with childhood onset (under age of 13), in accordance with the definition and diagnostic criteria of the Japanese Dermatological Association and must have pruritus and eczematous changes; the condition must be chronic or chronically relapsing in nature
* Inadequate response to, or not willing to use strong treatment with a topical corticosteroid and/or a topical calcineurin inhibitor and/or phototherapy
* Must meet all the following criteria regarding severity of atopic dermatitis: Rajka-Langeland score of 8 to 9; severe or very severe disease as defined in standard treatment guidelines; an Eczema Area and Severity Index (EASI) score of \>= 12; and an Investigator's Global Assessment (IGA) score of severe disease or very severe disease
* Must conform to the following tuberculosis (TB) screening criteria: no history of latent or active TB prior to screening; no signs or symptoms suggestive of active TB; no recent close contact with a person with active TB; and a negative Interferon Gamma Release Assay (IGRA) result within 2 months prior to the first administration of study drug

Exclusion Criteria:

* History of or current clinically significant medical illness that the investigator considers should exclude the participant or that could interfere with the interpretation of the study results
* Has an indeterminate initial and repeat IGRA result or a newly positive IGRA result and is unwilling or unable to undergo TB prophylaxis treatment
* Has received any of the following medications or therapies within 4 weeks prior to randomization: systemic non-steroid immunosuppressive or immunomodulatory drugs; systemic corticosteroids; high daily dose of inhaled corticosteroids; topical corticosteroids of strongest potency for atopic dermatitis; topical antihistamines (including topical doxepin); topical anesthetics; topical nonsteroidal anti-inflammatory drugs; topical counter-irritants (eg, capsaicin, menthol, wintergreen oil); antidepressants or antipsychotics; soporifics; phototherapy including ultraviolet A , ultraviolet B, and psoralen with ultraviolet A (PUVA); hyposensitization (desensitization) therapy
* Has changed the dose and dosing regimen within 4 weeks prior to randomization of any of the following drugs: topical corticosteroid (excluding the strongest potency) for atopic dermatitis; topical calcineurin inhibitor; emollients; anti-leukotriene therapies (including therapies for other allergic indications); systemic histamine H1 blocker (including sleep medications with antihistamine properties); sodium cromoglicate; suplatast tosilate; tranilast; thromboxane A2 inhibitors; and topical or oral herbal preparations for the treatment of atopic dermatitis
* Has received any of the following biologic agents within the following time periods: any marketed immunomodulatory biologic within a period of 3 months or 5 half-lives, whichever is longer, prior to randomization; a biologic agent targeting IL-12 or IL-23, including but not limited to ustekinumab (CNTO 1275), briakinumab (ABT-874), guselkumab (CNTO 1959) or MK-3222 at any point in time; or an experimental biologic therapy within the previous 6 months