This study is exploring the effects and safety of a drug called iptacopan on patients with C3 Glomerulopathy (C3G), a kidney disease. The study is organized as a multicenter trial, meaning it takes place in various locations. Participants will either receive the drug or a placebo (a harmless pill that looks like real medicine), without knowing which one they are taking. This is called a double-blind study to ensure fairness.

Participants need to be aged between 12 and 60 and must have a confirmed diagnosis of C3G. The study requires vaccinations against certain infections before starting. The trial will last for a period determined by the research team, but all medications should be stable for at least 90 days before joining.

• Duration: Medications must be stable for 90 days before joining.
• Visits: Regular health checks and kidney biopsies (in adults) will be part of the trial.
• Risks: Possible side effects, and unmet vaccination requirements can lead to disqualification.

Before deciding to join, it's important to understand the requirements and potential risks involved. Make sure to consult your doctor for any questions or concerns.