This study is for adults with a blood cancer called **multiple myeloma (MM)**, which affects the plasma cells in the blood. MM can cause bone and kidney problems. The study will test a new drug called **Etentamig**, combined with other medicines. The study has two parts: Phase 2 and Phase 3. In Phase 2, participants will try different doses of Etentamig with another drug called **daratumumab**. In Phase 3, participants will receive either Etentamig with daratumumab or a combination of daratumumab, lenalidomide (a capsule), and dexamethasone (a tablet or injection).

Participants will need to visit the hospital or clinic regularly for check-ups, blood tests, and to answer questions. The study will last about 16 years, and there might be more work for participants compared to normal treatment. This study is only for those who haven't had certain other treatments for MM and who aren't suitable for intense treatments like stem cell transplants.

• Study lasts approximately 16 years with regular hospital visits.
• Phase 2 tests different doses of Etentamig; Phase 3 compares two treatment options.
• Participants will undergo medical assessments and blood tests to monitor effects.