This clinical trial is focused on studying a condition known as diffuse cutaneous systemic sclerosis, a type of autoimmune disease that causes hardening and tightening of the skin. The study will evaluate the effectiveness and safety of a treatment called ianalumab, also known by its code name VAY736. This treatment is administered as a solution for infusion, which means it is given through a needle into a vein. The trial will compare the effects of ianalumab to a placebo to determine if it is more effective in treating this condition.

The purpose of the study is to see if ianalumab can improve symptoms of diffuse cutaneous systemic sclerosis over a period of 52 weeks. Participants will be randomly assigned to receive either ianalumab or a placebo, and neither the participants nor the researchers will know who is receiving which treatment. This is known as a double-blind study. The study will involve regular visits to the clinic for assessments and monitoring of health, including blood tests and other evaluations to check the response to the treatment and any side effects.

In addition to ianalumab, the study will also involve other medications such as tenofovir alafenamide, emtricitabine, tenofovir disoproxil, and entecavir, which are antiviral drugs. These medications are taken orally, meaning they are swallowed in pill form. The study aims to gather information on how these treatments affect the disease and to ensure they are safe and well-tolerated by participants. The trial is expected to continue until 2030, with the recruitment of participants starting in 2024.