Symptomatic patients and those with organ dysfunction should be treated with drug therapy, which may include corticosteroids, chemotherapy drugs, proteasome inhibitors, immunomodulatory agents, monoclonal antibodies, selective inhibitors of nuclear export, histone deacetylase inhibitors, and cellular and antibody-based immune therapies targeting B-cell maturation antigen. Stem cell transplantation is an option for some patients, but newer, highly effective treatment options may make it unnecessary in others.