Up to 70 patients over 18 years of age who have a diagnosis of Multiple Myeloma and have completed at least 2 years of lenalidomide maintenance therapy. Participants would be divided in two groups: Group 1. Patients with detectable disease, failed to achieve Complete Remission (CR) or Very Good Partial Remission (VGPR) continuing on maintenance therapy. Group 2. Patients who meet International Myeloma working Group (IMWG) criteria for very good partial response (VGPR) or complete response (CR). Patients who have achieved sustained MRD negative remission by next generation flow cytometry (NGF),defined by IMWG as MRD-negative at two time points that are at least 1 year apart, To the participants in this group will be offered to discontinue maintenance therapy, and it will be further divided in the following subgroups: Subgroup A) Patients who are willing to continue maintenance therapy. Subgroup B) Patients who are willing to discontinue maintenance therapy and continue monitoring. This subgroup will also include patients who have discontinued maintenance therapy earlier than 2 years due to side effects but also achieved sustained MRD negative CR might be also included.~The number of the study participants will be limited by the number of patients treated in CUH who are meeting inclusion criteria.
An interventional, non-randomised study to assess the risk of progression after discontinuation of maintenance therapy in sustained MRD negative complete remission by flow cytometry MM patients without high-risk features who have completed at least two years of maintenance therapy with lenalidomide or who have discontinued lenalidomide maintenance due to side effects. The primary endpoint is to assess the rates of sustained MRD negativity by NGF in the bone marrow at 12 months after discontinuation of maintenance therapy.