Study Summary: This study aims to test the safety and effectiveness of a new treatment called BMS-986393 for people with multiple myeloma, a type of cancer affecting blood cells. The treatment is a special kind of therapy called CAR T Cell Therapy. This means scientists take some of your immune cells, change them to better fight cancer, and put them back in your body.

Key Points:

• The study is for adults whose multiple myeloma has come back or has not responded to past treatments.
• You need to have had at least four types of treatments before and must have a performance status of 0 or 1, which means you are fully active or have some activity restrictions.
• If you join, you cannot have certain infections or past treatments targeting a specific protein, GPRC5D, without a rest period.

Before joining, ensure you are ready for multiple visits and tests. Talk with your doctor to see if this is a suitable option for you. Remember, this study is focused on people who have tried several treatments already without success. Always consider the potential benefits and risks with your healthcare provider.