Smoldering Myeloma Treatment: Who, What, and When.

Smoldering multiple myeloma (MM) is a clonal plasma cell disorder characterized by excess marrow involvement and immunoglobulin production. It is the precursor of MM, differing by the lack of end-organ damage. Smoldering MM encompasses a heterogeneous group of patients, with a median risk of progression to active disease of 50% in the first 5 years. Until recently, the standard of care would dictate observation off therapy until the development of end-organ damage. The recognition of high-risk and ultrahigh-risk subgroups of smoldering MM, with more likely evolution to MM, has led to earlier initiation of therapy in the disease course. Ongoing studies to define the ideal timing and patient population are underway, as well as identification of which agents would be of greatest benefit, as the armamentarium for MM continues to grow.