Functional cure and long-term survival in multiple myeloma: how to challenge the previously impossible

Abstract

Multiple myeloma (MM) is a heterogeneous disease with survival ranging from months to decades. The goal of ‘cure’ remains elusive for most patients, but has been shown to be possible, with durable remission and a transition to a plateau phase (analogous to monoclonal gammopathy of uncertain significance/smoldering Myeloma (MGUS/SMM)). Two representative cases set the stage to illustrate how this might be possible and what still needs to be determined to achieve functional disease control over a prolonged period. Several developments have emerged, such as improved diagnostics including the definitions and use of SLiM-CRAB criteria and MRD with whole genome- /single-cell-sequencing as well as other correlates to better understand disease biology. These advances enable earlier detection, more accurate risk stratification and improved personalized treatment strategies by facilitating analysis of genetic alterations and clonal heterogeneity. Whole genome sequencing may also identify driver mutations and modes of resistance to targets like immunotherapies (IOs) as well as other targeted therapies. Today, induction with a CD38 antibody (CD38mAb), proteasome inhibitor, immunomodulatory drug, and dexamethasone, potentially followed by ASCT and lenalidomide maintenance, can be considered standard of care for transplant-eligible (TE) newly diagnosed (NDMM) patients. Whether prolonged disease control and functional cure can be achieved in non-transplant eligible (NTE) patients is currently emerging as a distinct possibility: data from phase III trials that incorporate a CD38mAb into the treatment of NTE NDMM patients demonstrate impressive MRD negativity rates that appear sustained over several years. While the long-term durability of CAR-Ts, bi-specific antibodies and other IOs are evaluated, several clinical trials are now investigating their role in frontline treatment for TE and NTE patients. These will address whether CAR-Ts will replace ASCT and whether such IOs will represent a truly curative option. We conclude that whilst cure remains elusive, the concept of operational or functional cure provides a new benchmark to strive for and is an emerging area of active and potentially achievable clinical research for MM.