Understanding MGUS and Smoldering Myeloma

Monoclonal gammopathy of undetermined significance (MGUS) is a non-cancerous condition associated with the possible subsequent development of myeloma. Smoldering multiple myeloma (SMM) is an asymptomatic precursor to active disease; the FDA granted its first-ever approval of a treatment for SMM in November 2025. If you are a person with MGUS or SMM, it is important to learn about your diagnosis in order to have an active role in your own medical care in partnership with your doctor.