This study is about testing a new medicine called ravulizumab for people with a kidney problem known as Immunoglobulin A Nephropathy (IgAN). IgAN happens when a protein, called immunoglobulin A, gets stuck in the kidneys and causes damage. The study aims to see if ravulizumab can help reduce protein in the urine and improve kidney function, measured by something called eGFR, which shows how well your kidneys are working.

The study will have about 510 adults who are at high risk of their kidney disease getting worse. Participants will be split into two groups by chance; one group will get ravulizumab, and the other will get a placebo, which means no active treatment. The study will last up to 106 weeks, with a check-up at 34 weeks and a final review at the end to see how the medicine worked.

• You can join if your kidney function is over a certain level and you're on stable treatment.
• The study lasts a long time, over two years.
• After the main study, you might be able to try ravulizumab openly.