This clinical trial is focused on studying a condition known as Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease (MOGAD). This is a rare neurological disorder where the immune system mistakenly attacks a protein in the central nervous system, leading to inflammation and damage. The study is testing a treatment called Rozanolixizumab, also known by its code name UCB7665. This medication is given as a solution for injection under the skin, a method known as subcutaneous use.

The purpose of the study is to evaluate how effective and safe Rozanolixizumab is for treating adults with MOGAD. Participants in the study will be randomly assigned to receive either Rozanolixizumab or a placebo, which is a substance with no active medication. The study is designed to be double-blind, meaning neither the participants nor the researchers will know who is receiving the actual medication or the placebo. This helps ensure the results are unbiased. The study will also include an open-label extension period, where all participants will have the opportunity to receive Rozanolixizumab.

Throughout the study, participants will be monitored for any changes in their condition and any side effects they may experience. The study will track the time it takes for participants to experience a relapse of their symptoms and will also record any adverse events that occur. The study aims to provide valuable information on the long-term safety and effectiveness of Rozanolixizumab for people living with MOGAD.