Study on the Clinical Efficacy of Teclistamab

This study collects real-world data on how well teclistamab — a recently approved immunotherapy for multiple myeloma — works in everyday clinical practice outside of a controlled trial setting. **You may be eligible if...** - You are 18 or older with relapsed and refractory multiple myeloma (cancer of plasma cells in the bone marrow that has come back or stopped responding to treatment) - You have already received at least three prior treatments - Your cancer has stopped responding to at least one proteasome inhibitor, one immunomodulatory drug, and an anti-CD38 antibody - Your doctor has decided to start you on teclistamab as part of routine care **You may NOT be eligible if...** - You have previously participated in a teclistamab clinical trial - You started teclistamab more than 14 days before the screening visit Talk to your doctor to see if this trial is right for you.