A Study of Lebrikizumab in Adults and Adolescents With Face and Neck Atopic Dermatitis

The main aim of the study is to evaluate the efficacy and safety of lebrikizumab treatment for up to 32 weeks in participants with moderate-to-severe face and neck atopic dermatitis (FNAD) who also have moderate-to-severe AD outside of the face and neck region, and who are in need of systemic therapy.

Inclusion Criteria: Participants eligible for inclusion in this trial must fulfil all of the following criteria: * Adults and adolescents (aged \[greater than or equal to (\>=)\] 12 years to \[less than (\=40 kilograms \[kg\]) who are candidates for AD systemic therapy. * Chronic AD (according to Hanifin and Rajka Criteria (Hanifin 1980)) that has been present for \>=1 year before the Screening visit. * At least moderate FNAD with F-IGA \>=3 (scale of 0 \[clear\] to 4 \[severe\]) at Screening and Day 1/Baseline. * Overall EASI score \>=12 at Day 1/Baseline with distinct atopic dermatitis lesions in at least one area outside the face and neck. Exclusion Criteria: Participants fulfilling any of the following criteria are not eligible for inclusion in this trial: * Prior treatment with lebrikizumab. * Prior treatment at any time with more than one of the following advanced systemic treatments: Dupilumab, tralokinumab, nemolizumab, or oral JAK inhibitors. * Presence of dermatological conditions and/or skin signs or symptoms on the face and/or neck that may interfere with study assessments including but not limited to rosacea, flushing, demodicosis, and seborrheic dermatitis * Participants with suspected clinically relevant contact dermatitis of the face and neck region, and participants with a confirmed contact allergen known to exacerbate their atopic dermatitis who cannot commit to allergen avoidance or when allergen avoidance is not possible. * History of human immunodeficiency virus (HIV) infection (including known positive HIV serology in medical history). * Intention to use any concomitant medication or therapy that is not permitted by this protocol or failure to undergo the required washout period for a particular prohibited medication. * Uncontrolled chronic disease that might require use of systemic corticosteroids, eg, uncontrolled asthma. * Known liver cirrhosis and/or chronic hepatitis of any aetiology and/or current infection (at Screening) with hepatitis B or hepatitis C. * History of malignancy, including mycosis fungoides, within 5 years before the Screening visit, except completely treated in situ carcinoma of the cervix, completely treated and resolved nonmetastatic squamous or basal cell carcinoma of the skin with no evidence of recurrence in the past 12 weeks. * Pregnant or breastfeeding women, or women planning to become pregnant or breastfeed during the study.