The Relapse from MRD Negativity As Indication for Treatment (REMNANT) Study

Inclusion Criteria part one: * Each patient must meet all of the following inclusion criteria to be enrolled in the study: 1. Patient with newly diagnosed multiple myeloma (IMWG criteria) eligible for high-dose therapy and ASCT. 2. Patient must be \>18 and \< 75 years of age at the time of signing the informed consent 3. Must have measurable disease as defined by the International Myeloma Working Group; serum monoclonal paraprotein (M-protein) level \> 10 g/L or light chain multiple myeloma without measurable disease in the serum; serum immunoglobulin FLC \> 100 mg/L and abnormal serum immunoglobulin kappa lambda FLC ratio. 4. Voluntary written informed consent 5. Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1, or 2. ECOG 3 can be enrolled if caused by myeloma. 6. Patient must be willing and able to adhere to the study protocol visit schedule and other protocol requirements. 7. Female of childbearing potential (FCBP) must have a confirmed negative serum pregnancy test within 7 days prior to inclusion. 8. FCBP and male subject who are sexually active with FCBP must agree to use highly effective concomitant methods of contraceptive during the study and for at least 28 days following the last study drug dose. Male subjects must use contraception and refrain from donating sperm for at least 28 days after the last dose of lenalidomide according to Pregnancy Prevention Plan (Appendix 4: Contraceptive Guidance and Collection of Pregnancy Information). Inclusion Criteria part two: * Each patient must meet all of the following inclusion criteria to be enrolled in the study 1. Patient must be MRD negative measured by Euroflow NGF after 1.L therapy. The cutoff for inclusion into part 2 will be 100 PC per 10 mill. nucleated cells monitored in BM. 2. Has received 1.L treatment in part 1 of the study. 3. ECOG performance status score 0, 1 or 2 Exclusion Criteria part one: 1. Received more than one cycle of induction treatment for multiple myeloma. 2. Patient with ongoing or active systemic infection, active hepatitis B or C virus infection or known human immunodeficiency virus (HIV) positive 3. Concurrent medical or psychiatric condition or disease that is incompatible to HDM and ASCT or that will likely result in reduced study compliance and reduce ability to follow study procedures, or that in the opinion of the investigator, would constitute a hazard for participating in this study. 4. No active malignancy with a lower life expectancy than myeloma 5. Female patient who have a positive serum pregnancy test during the screening period. 6. Female patient who is lactating during the screening period but are not willing to stop lactating prior to the first treatment cycle starts. 7. Known allergy to any of the study medications, their analogues, or excipients in the various formulations of any agent. Exclusion Criteria part two: 1. No active malignancy with a lower life expectancy than myeloma 2. Known allergy to any of the study medications, their analogues, or excipients in the various formulations of any agent