The purpose of this study is to evaluate the study drug, elranatamab for people with multiple myeloma that has relapsed or not responded after previous treatment.

Elranatamab is considered investigational because it is not approved by the U.S. Food and Drug Administration (FDA).

Elranatamab is a B-cell maturation antigen (BCMA) CD3-targeted bispecific antibody (BsAb) designed to bind to BCMA, which is highly expressed on the surface of multiple myeloma cells, and CD3 receptors found on the surface of T-cells. This process brings the two together, activating the T-cells to kill the myeloma cells.

Treatment with elranatamab is broken up into 28-day cycles and will always be administered in the clinic by the study team. Elranatamab is given by an injection under the skin (subcutaneous injection) in your abdomen or thigh. Participants will receive elranatamab 2 times during the first week only and if they tolerate the first dose well, the doses will increase in subsequent weeks. For the first and second doses, a hospitalization period (minimum of 2 days for the first dose, and 1 day for the second dose) is required for safety monitoring. Throughout the entire treatment period, the study team will monitor participants closely for any side effects.

Participation will last until participants no longer benefit from the drug, side effects become too severe, or participants choose to stop taking part in the study. Participants may also be asked to provide blood and urine samples, as well as undergo imaging, electrocardiograms (ECG), and physical examinations during study visits.