The purpose of this study is to characterize the safety of Talquetamab and to determine the recommended Phase 2 dose(s) (RP2Ds) and dosing schedule assessed to be safe for Talquetamab (Part 1 \[Dose Escalation\]) and to further characterize the safety of Talquetamab at the recommended Phase 2 dose(s) (RP2Ds) (Part 2 \[Dose Expansion\]).