Upon joining the study, you will be confirmed to have a diagnosis of moderate to severe atopic dermatitis by a dermatologist. This confirmation is based on specific criteria known as the Hanifin/Rajka criteria, which should have been established at least one year prior to the start of the study.

You will need to have an Eczema Area and Severity Index (EASI) score of 16 or higher and an Investigator Global Assessment (IGA) score of 3 or higher. Additionally, at least 10% of your body surface area should be affected by atopic dermatitis.

During the baseline visit, you will continue using an additive-free, bland emollient at least once daily. This should have been used for at least 7 days prior to this visit and will continue throughout the study.

Your initial health status and the severity of your atopic dermatitis will be assessed to establish a starting point for the study.

You will receive either the study medication RO7790121 or a placebo. The medication is administered as a subcutaneous injection, which means it is injected under the skin.

The frequency and dosage of the medication will be determined by the study protocol, and you will be informed of the schedule during the trial.

Throughout the study, your progress will be monitored regularly. This includes checking for any changes in your EASI score and IGA score at specified intervals, such as Week 16 and Week 32.

You will also be assessed for any side effects or adverse events related to the treatment. This is to ensure your safety and the effectiveness of the medication.

At the end of the study, your overall response to the treatment will be evaluated. This includes determining if there has been a significant improvement in your condition, such as achieving an EASI-75 response, which means a 75% improvement from the baseline.

Final assessments will be conducted to gather data on the long-term effects and safety of the treatment.