∙ \- 18 years of age to 70 years of age, inclusive

• Have an ECOG performance status score of 0 to 2 at screening

• Have an ECOG performance status score of 0 to 2 at screening and immediately prior to the start of administration of study treatment

∙ Participants in Arms A, A1, B, D, E, E1, F, F1 and G must also satisfy all of the following criteria to be enrolled in the study:

∙ 1\. Documented multiple myeloma requiring treatment as defined by the criteria below:

⁃ Multiple myeloma diagnosis according to the IMWG diagnostic criteria

⁃ Measurable disease at screening as defined by any of the following:

⁃ 1\. Serum M-protein level ≥1.0 g/dL or 2. Urine M-protein level ≥200 mg/24 hours or 3. Serum immunoglobulin free light chain level ≥10 mg/dL and abnormal serum free light chain ratio 2. Newly diagnosed participants for whom HDT and ASCT is part of the intended treatment plan (except Arm D and G participants).

⁃ Participants Arm C and C2 must also satisfy all of the following criteria:

‣ Newly diagnosed multiple myeloma according to IMWG criteria.

‣ Must have received 4 to 6 28-day cycles of 3 or 4 drug-induction therapy that includes a proteasome inhibitor and/or an IMiD with or without anti-CD38 monoclonal antibody and a single or tandem ASCT. Post-ASCT consolidation is permitted for up to 2 cycles as long as the total number of induction plus consolidation cycles does not exceed 6.

⁃ 3 Must have received only one line of therapy and achieved at least a PR as per IMWG 2016 response criteria based on the investigator's assessment. Participants with plasmacytomas at the time of diagnosis must meet IMWG 2016 response criteria for ≥PR based on repeat imaging utilizing the same modality 4. Must have received HDT and ASCT within 12 months of the start of induction therapy and be within 6 months of the last ASCT (7 months for participants who received consolidation) at the time of enrollment.