A Study of Lebrikizumab (LY3650150) in Participants 6 Months to

The main purpose of this study is to measure the effect, safety and how well the body absorbs lebrikizumab in pediatric participants 6 months to \<18 years of age with moderate-to-severe atopic dermatitis (AD).

Inclusion Criteria: * Have a diagnosis of AD prior to screening as stated in the criteria by the American Academy of Dermatology for at least, * 12 months if participants are ≥6 years of age * 6 months if participants are 2 to \<6 years of age * 3 months if participants are 6 months to \<2 years of age. * Have an EASI score ≥16 at the screening and baseline * Have an IGA score ≥3 (scale of 0 to 4) at the screening and baseline * Have ≥10% BSA of AD involvement at the screening and baseline. Exclusion Criteria: * Are currently enrolled or have participated within the last 8 weeks in a clinical study involving an investigational intervention or any other type of medical research judged not to be scientifically or medically compatible with this study. * Treatment with the following prior to the baseline: * An investigational drug within 8 weeks or less than 5 half-lives, whichever is longer. * Dupilumab within 8 weeks. Note: The enrollment of participants with prior use of Dupilumab will be limited to \<20%. * Treatment with a topical investigational drug within 2 weeks prior to the baseline. * Have received a Bacillus Calmette-Guerin vaccination or treatment within less than 4 weeks before randomization.