This study looks at how safe and effective a drug called talquetamab is for people with a specific type of blood cancer called relapsed or refractory multiple myeloma. This type of cancer means the myeloma has either come back or does not respond to treatment. The study will test the drug at a phase known as Phase 2, where the best dose is being used to see how well it works.

• The study requires people with multiple myeloma who meet certain health conditions.
• Participants must have a good health status according to a simple health score.
• Women who can have children need to test negative for pregnancy before starting the study.

If you have tried certain types of cancer treatments before, you might not be able to join. Also, you shouldn’t have had certain health issues like a stroke recently. It's important to be able to follow study rules. Remember, always talk with your doctor to see if joining the study is right for you.