This clinical trial is focused on studying the treatment of Immunoglobulin A Nephropathy (IgAN), a kidney disease that occurs when an antibody called IgA builds up in the kidneys, leading to inflammation and damage. The treatment being tested is called Sibeprenlimab, which is a type of protein known as a monoclonal antibody. This protein is designed to target specific parts of the immune system to help reduce the effects of the disease. The purpose of the study is to evaluate the long-term safety and tolerability of Sibeprenlimab in individuals with IgAN.

Participants in the study will receive Sibeprenlimab through an injection under the skin, known as a subcutaneous injection. The study will monitor participants over a period of time to observe any side effects and to assess how well the treatment is tolerated. The study will also look at how the treatment affects kidney function over time, using measures such as the estimated glomerular filtration rate (eGFR), which is a test to check how well the kidneys are working, and the amount of protein in the urine, which can indicate kidney damage.

The trial will last for several years, allowing researchers to gather comprehensive data on the effects of Sibeprenlimab. This information will help determine if the treatment is safe and effective for long-term use in managing IgAN. Participants will be closely monitored by healthcare professionals throughout the study to ensure their safety and to collect necessary data for the research.