This study is exploring a treatment called anitocabtagene-autoleucel for patients with a type of blood cancer called relapsed or refractory multiple myeloma (MM). The treatment is a special type of therapy known as CAR-T cell therapy, which means it uses a patient's own immune cells that have been changed in a lab to help fight cancer. The study involves several steps, including screening, chemotherapy to prepare the body, the main treatment with the CAR-T cells, and follow-up checks. Patients will receive one dose of the treatment, and doctors will monitor them for safety and effectiveness for up to two years, or longer if needed. The study also plans to collect long-term safety data for up to 15 years.

• Participants must be 18 or older and have had at least three prior treatments for MM.
• The study requires several visits over a period of up to two years, plus long-term follow-up.
• Participants must agree to use birth control and be willing to follow study procedures.