A Study Of TAK-981 Given With Monoclonal Antibodies (mAbs) In Adults With Relapsed or Refractory Multiple Myeloma (RRMM)

The drug being tested in this study is called TAK-981. TAK-981 in combination with an anti-CD38 monoclonal antibody (mAbs) is being tested to treat people who have RRMM. The study will include a dose escalation phase and a dose expansion phase.

The study will enroll approximately 81 participants; approximately 30 participants in the dose escalation phase (Part 1) approximately 15 participants in (Part 2) and up to 36 participants in dose expansion phase (Part 2). Participants will receive escalating doses of TAK-981 in combination with fixed doses as follows:

* Phase 1b, Part 1 - Dose Escalation: Arm A - TAK-981 Twice Weekly (BIW) + Mezagitamab * Phase 1b, Part 1 - Dose Escalation: Arm B - TAK-981 Weekly (QW) + Mezagitamab * Phase 1b, Part 2 - Dose Escalation: TAK-981 + Daratumumab and Hyaluronidase-fihj

Once RP2D is determined in Phase 1, participants with RRMM will be enrolled in Phase 2.

• Phase 2 - Dose Expansion: TAK-981 + Daratumumab and Hyaluronidase-fihj or Mezagitamab

This multi-center trial will be conducted in North America. The overall time to participate in this study is 2 years. Participants will make multiple visits to the clinic, and progression-free survival follow-up for maximum up to 12 months after last dose of study drug.