Previous treatment with lebrikizumab or participation in a lebrikizumab study.

History of anaphylaxis as defined by the Sampson criteria.

Treatment with topical corticosteroids, calcineurin inhibitors, Jak inhibitors, or crisaborole within 1 week prior to the baseline visit.

Prior treatment with dupilumab or tralokinumab.

Treatment with any of the following agents within 4 weeks prior to the baseline visit:

1. Immunosuppressive/immunomodulating drugs (e.g., systemic corticosteroids, cyclosporine, mycophenolate-mofetil, IFN-., Janus kinase inhibitors (JAKi), azathioprine, methotrexate).
2. Phototherapy and photochemotherapy (PUVA) for AD.

Treatment with the following prior to the baseline visit:

1. An investigational drug within 8 weeks or 5 half-lives (if known), whichever is longer.
2. Cell-depleting biologics, including to rituximab, within 6 months.
3. Other biologics within 5 half-lives (if known) or 16 weeks, whichever is longer.

Use of prescription moisturizers within 7 days of the baseline visit.

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

Treatment with a live (attenuated) vaccine within 12 weeks of the baseline visit or planned during the study.

Uncontrolled chronic disease that might require bursts of oral corticosteroids, e.g., co-morbid severe uncontrolled asthma requiring systemic [oral and/or parenteral] corticosteroid treatment or hospitalization for > 24 hours).

Active chronic or acute infection requiring treatment with systemic antibiotics, antivirals, anti-parasitics, antiprotozoals, or antifungals within 2 weeks before the baseline visit, or superficial skin infections within 1 week before the baseline visit. NOTE: patients may be rescreened after infection resolves.

Evidence of active acute or chronic hepatitis (as defined by the Department of Health & Human Services Centers for Disease Control and Prevention) or known liver cirrhosis.

Diagnosed active endoparasitic infections or at high risk of these infections.

Known or suspected history of immunosuppression, including history of invasive opportunistic infections (e.g., tuberculosis [TB], histoplasmosis, listeriosis, coccidioidomycosis, pneumocystosis, and aspergillosis) despite infection resolution: or unusually frequent, recurrent, or prolonged infections, per the Investigator's judgment.

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

In the Investigator's opinion, any clinically significant laboratory results from the chemistry, hematology or urinalysis tests available in the medical history.

Presence of skin comorbidities that may interfere with study assessments.

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 non-metastatic squamous or basal cell carcinoma of the skin.

Severe concomitant illness(es) that in the Investigator's judgment would adversely affect the patient's participation in the study. Any other medical or psychological condition that in the opinion of the Investigator may suggest a new and/or insufficiently understood disease, may present an unreasonable risk to the study patient because of his/her participation in this clinical trial, may make patient's participation unreliable, or may interfere with study assessments.

20. Pregnant or breastfeeding women, or women planning to become pregnant or breastfeed during the study.