This study is looking at a treatment for a type of blood cancer called multiple myeloma (MM). Multiple myeloma is when cancerous plasma cells build up in the bone marrow. The study tests a drug called belantamab mafodotin, which is a special medicine that combines an antibody, a protein that targets cancer cells, with a drug that helps kill them. This is a phase I/II study, meaning it's checking if the drug is safe and how well it works. The study will test belantamab mafodotin alone and with other treatments.

• The study might require several visits; details depend on the specific sub-study.
• Participants may have a history of at least 3 different treatments for MM.
• Compensation for participation varies, check with study coordinators for specifics.

Participants need to be adults with a confirmed diagnosis of relapsed or refractory multiple myeloma. Some people might not qualify, such as those with certain infections, recent surgeries, or other health conditions. Always discuss with your doctor to understand the risks and benefits of being part of the study. Participants cannot receive certain vaccines or treatments during the study.