Additional Study Information: The purpose of this study is to determine whether patients with high-risk smoldering multiple myeloma when treated with daratumumab in addition to lenalidomide and dexamethasone live longer when compared to patients with high-risk smoldering multiple myeloma patients treated with lenalidomide and dexamethasone. We would also like to know whether the period of time in which patients are free of multiple myeloma symptoms differs between the two treatment groups. Daratumumab is already approved by the FDA for use in combination with lenalidomide and dexamethasone in people who have received at least one prior medicine to treat multiple myeloma. It is not, however, approved for treatment of smoldering multiple myeloma, either alone or when combined with the treatment regimen of lenalidomide and dexamethasone, and therefore is considered experimental. Lenalidomide and dexamethasone are approved for treatment of multiple myeloma (symptomatic) but not for the treatment of smoldering multiple myeloma and therefore is also considered an experimental treatment.