GMMG-HD10 / DSMM-XX / 64007957MMY2003, MajesTEC-5

Inclusion Criteria:

• 18 years of age to 70 years of age, inclusive

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

• Have clinical laboratory values meeting prespecified criteria during the ScreeningPhase.

Participants in Arms A, A1, B, D, E, E1, F and F1 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:

2. Multiple myeloma diagnosis according to the IMWG diagnostic criteria

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

4. Serum M-protein level ≥1.0 g/dL or

5. Urine M-protein level ≥200 mg/24 hours or

6. Serum immunoglobulin free light chain level ≥10 mg/dL and abnormal serum freelight chain ratio

7. Newly diagnosed participants for whom HDT and ASCT is part of the intendedtreatment plan (except Arm D participants). Participants Arm C and C2 must also satisfy all of the following criteria:

8. Newly diagnosed multiple myeloma according to IMWG criteria.

9. Must have received 4 to 6 cycles of 3 or 4 drug-induction therapy that includesa proteasome inhibitor and/or an IMiD with or without anti-CD38 monoclonalantibody and a single or tandem ASCT. Post-ASCT consolidation is permitted forup to 2 cycles as long as the total number of induction plus consolidationcycles does not exceed 6.

3 Must have received only one line of therapy and achieved at least a PR as per IMWG 2016 without evidence of progression at the time of enrollment.

4. Must have received HDT and ASCT within 12 months of the start of inductiontherapy and be within 6 months of the last ASCT (7 months for participants whoreceived consolidation) at the time of enrollment.

Exclusion Criteria:

• CNS involvement or clinical signs of meningeal involvement of multiple myeloma.

• Stroke or seizure within 6 months prior study start Cycle1 Day1.

• History of transplantations requiring immunosuppressive therapy.

• Seropositive for HIV, HEP B, Active Hep C infection (details see protocol).

• COPD with a FEV1 <50% of predicted normal.

• Moderate /severe persistent asthma within the past 2 years or any uncontrolledasthma. Exclude if FEV1 <50% of predicted normal.

• Concurrent medical or psychiatric condition or disease that is likely tointerfere with study procedures, or that in the investigators opinion wouldconstitute a hazard for participants.

• Contraindications or life-threatening allergies, hypersensitivity, orintolerance to any study drug/excipients.

• Pregnant, breastfeeding, or planning to become pregnant while enrolled in thisstudy or within 6 months after the last dose of any study treatment regimen.

• Plans to father a child while enrolled in this study or within 100 days afterthe last dose of any component of the study treatment regimen. Arm A, A1, B, D, E, E1, F, F1

• Prior or current systemic therapy or stem cell transplant for any plasma celldyscrasia, with the exception of emergency use of a short course (equivalent ofdexamethasone 40 mg/day for a maximum 4 days) of corticosteroids beforetreatment.

• Arm B only: Peripheral neuropathy or neuropathic pain Grade 2 or higher asdefined by the NCI-CTCAE Version 5. Due to a potential interaction with bortezomib, received a strong CYP3A4 inducerwithin 5 half-lives prior to enrollment Arm C and C2

• Discontinued treatment due to any AE related to lenalidomide as determined bythe investigator.

• Progressed on multiple myeloma therapy at any time prior to screening.

• Received a cumulative dose of corticosteroids equivalent to ≥40 mg ofdexamethasone within the 14 day period before the start of study treatmentadministration.

• Intolerant to the starting dose of lenalidomide (10 mg). For further details on inclusion/exclusion criteria please refer to the studyprotocol.