A Study to Learn About the Study Medicine Called Tilrekimig in People With Moderate-to Severe Eczema

The purpose of this study is to find out how well tilrekimig works, how safe it is, and how it affects the body in adults and adolescents with moderate to severe atopic dermatitis (eczema). Eczema is a condition which can cause dryness, itching, and redness of your skin.

The study is seeking participants who

• Are aged 12 years or older.
• Were confirmed to have atopic dermatitis (AD) at least 12 months ago.
• Are not having an effective treatment result from medicines that are applied on skin for AD.
• Are considered by their doctors to have moderate to severe AD.

The study treatment period will be 52 weeks. During the 24-week initial treatment period, participants will be randomized to one of three study treatments - tilrekimig, dupilumab, or placebo. Placebo does not have any medicine in it but looks just like the medicine being studied. These treatments will be randomized based on a 2:2:1 ratio. This means out of 1375 participants, about 550 participants will receive tilrekimig, 550 will receive dupilumab, and 275 will receive placebo. This will be followed by a 28-week maintenance period. The last dose of study treatment will be administered at week 48.

Some participants will join the long-term extension (LTE) study C4531008 at week 52. A long-term extension study is an additional study that some participants may be able to join after completing the study if they are interested and meet eligibility requirements. It allows researchers to continue collecting information about how well the study medicine works. It also helps them assess how safe it is when used for a longer period of time. Participants who do not join this study will enter a 12-week safety follow-up period. This period ends 16 weeks after their last dose of study treatment.