This clinical trial is focused on studying Atopic Dermatitis, a condition that causes the skin to become red, itchy, and inflamed. The study is testing a medication called Upadacitinib, which is a type of drug known as a small molecule JAK inhibitor. This medication is taken orally in the form of a modified-release tablet, which means it is designed to release the drug slowly over time.

The purpose of the study is to evaluate how flexible the dosing of Upadacitinib can be for adults with moderate to severe Atopic Dermatitis. Participants will start with a specific dose of the medication, and depending on their response, the dose may be adjusted. The study will explore two main approaches: increasing the dose for those who do not see enough improvement and reducing the dose for those who achieve significant improvement. The study will last for a period of 24 weeks, during which participants will be monitored for changes in their condition.

Throughout the study, the effectiveness and safety of the medication will be assessed by looking at improvements in the severity of the skin condition and the level of itching experienced by participants. The goal is to find the most effective and safe dosing strategy for managing Atopic Dermatitis with Upadacitinib.