Long-term Safety and Efficacy Study of Lebrikizumab (LY3650150) in Participants With Moderate-to-Severe Atopic Dermatitis (ADjoin)

Inclusion Criteria for participants coming from a parent study:

Participants must meet all the following criteria to be eligible for this study:

• Received treatment in a lebrikizumab study, NCT04146363, NCT04178967, NCT04250337,NCT04250350 and have adequately completed the study treatments and last patientvisit of the parent trial.

• For women of childbearing potential: agree to remain abstinent (refrain fromheterosexual intercourse) or use a highly effective contraceptive method during thetreatment period and for at least 18 weeks after the last dose of lebrikizumab orplacebo.

Exclusion Criteria for participants coming from a parent study:

Participants meeting any of the criteria below will not be included in this study:

• Participants who, during their participation in the parent trial, developed aserious adverse event (SAE) deemed related to lebrikizumab, which in the opinion ofthe investigator or of the medical monitor could indicate that continued treatmentwith lebrikizumab may present an unreasonable risk for the participant. *

• Participants who, during their participation in the parent trial, developed an AEthat was deemed related to lebrikizumab and led to study treatment discontinuation,which in the opinion of the investigator or of the medical monitor could indicatethat continued treatment with lebrikizumab may present an unreasonable risk for theparticipant. *

• Conditions in the previous parent study consistent with protocol-defined criteriafor permanent study drug discontinuation, if deemed related to lebrikizumab or ledto investigator - or sponsor-initiated withdrawal of participant from the study (e.g., non-compliance, inability to complete study assessments, etc.). *

• Pregnant or breastfeeding women, or women planning to become pregnant or breastfeedduring the study.

Open-Label Addendum Inclusion Criteria:

Participants must meet all the following criteria to be eligible for this study addendum:

• Male or female adults and adolescents (≥12 to <18 years of age and weighing ≥40kilogram (kg).

• Chronic AD (according to American Academy of Dermatology Consensus Criteria) thathas been present for ≥1 year before screening.

• Eczema Area and Severity Index (EASI) score ≥16 at baseline.

• Investigator Global Assessment (IGA) score ≥3 (scale of 0 to 4) at baseline.

• ≥10% body surface area (BSA) of AD involvement at baseline.

• History of inadequate response to treatment with topical medications; ordetermination that topical treatments are otherwise medically inadvisable.

Open-Label Addendum Exclusion Criteria:

Participants meeting any of the criteria below will be excluded from this study addendum:

• Have received a dose of lebrikizumab in any prior lebrikizumab clinical study.

• History of anaphylaxis

• Treatment with topical prescription moisturizers, corticosteroids, calcineurininhibitors, or phosphodiesterase-4 inhibitors such as crisaborole within 1 weekprior to baseline.

• Treatment with any of the following agents within 4 weeks prior to the baseline.

• Immunosuppressive/immunomodulating drugs (e.g., systemic corticosteroids,cyclosporine, mycophenolate-mofetil, Interferon gamma (IFN-γ), Janus kinaseinhibitors, azathioprine, methotrexate, etc.)

• Phototherapy and photochemotherapy (PUVA) for AD.

• Treatment with the following prior to baseline:

• Immunosuppressive/immunomodulating drugs (e.g., systemic corticosteroids,cyclosporine, mycophenolate-mofetil, IFN-γ, Janus kinase inhibitors,azathioprine, methotrexate, etc.)

• Phototherapy and photochemotherapy (PUVA) for AD.

• Treatment with the following prior to baseline:

• An investigational drug within 8 weeks or within 5 half-lives (if known),whichever is longer.

• B Cell-depleting biologics, including rituximab, within 6 months.

• Other Biologics within 5 half-lives (if known) or 8 weeks, whichever is longer.

• Regular use (more than 2 uses per week) of a tanning booth/parlor within 4 weeks ofbaseline.

• Treatment with a live (attenuated) vaccine within 12 weeks of the baseline orplanned during the study.

• Uncontrolled chronic disease that might require multiple intermittent uses of oralcorticosteroids, e.g., co-morbid severe uncontrolled asthma, (as defined by theinvestigator).

• Pregnant or breastfeeding women, or women planning to become pregnant or breastfeedduring the study.

• Evidence of active acute or chronic hepatitis

• History of human immunodeficiency virus (HIV) infection or positive HIV serology atscreening.

• History of malignancy, including mycosis fungoides, within 5 years before screening,except completely treated in situ carcinoma of the cervix, completely treated andresolved non-metastatic squamous or basal cell carcinoma of the skin with noevidence of recurrence in the past 12 weeks.

Open-Label Extension Addendum Inclusion Criteria:

Have completed Week 100 of Study KGAA and have not yet completed the safety follow-up visit for the main study.

Open-Label Extension Addendum Exclusion Criteria:

Have initiated treatment with a medication prohibited by Study KGAA before addendum baseline. This includes use of biologics for AD (for example, dupilumab and tralokinumab) during the safety follow-up period of Study KGAA.