SIZOMUS Safety of Ixazomib Targeting Plasma Cells in Multiple Sclerosis

The production of antibodies in the form of oligoclonal bands (OCBs) from plasma cells (cells involved in the body's immune response), is the hallmark of MS. Recent evidence suggests that plasma cells are resident in the meninges (protective membranes of the brain and spinal cord) of people with Multiple Sclerosis (pwMS). Ixazomib is a drug which has been effective in treating multiple myeloma, a disease caused by aberrant plasma cells. The purpose of this study is to investigate whether ixazomib can reduce or clear OCBs from the cerebrospinal fluid (CSF) of pwMS. Participants will be randomly assigned to receive either ixazomib capsules (active drug arm) or placebo capsules (placebo arm) for up to 24 months. Participants with relapsing remitting MS (who are stable on disease modifying therapy) and those with progressive MS (who are not on disease modifying therapy) will be invited to take part in the study.