Adult Outpatient Linvoseltamab With Tocilizumab Prophylaxis to Mitigate the Risk of Cytokine Release Syndrome (CRS)

This study is researching whether the use of tocilizumab before the first dose of linvoseltamab will decrease the risk of Cytokine Release Syndrome (CRS) in participants who have Relapsed or Refractory Multiple Myeloma (RRMM) who have already been treated with at least four lines of treatment for their multiple myeloma, including medicines called a proteasome inhibitor, an immunomodulatory drug, and an anti-Cluster of Differentiation (CD) 38 antibody. The aim of the study is to see how safe, tolerable and effective linvoseltamab is when given after tocilizumab. The study is looking at several other research questions, including: * What side effects may happen from taking tocilizumab before the first dose of linvoseltamab * Whether tocilizumab has an impact on CRS, including whether participants require hospital care and, if so, how many hospital visits occur and how long they last * How frequently other medications (for example, corticosteroids or additional doses of tocilizumab) are used to support participants' care if needed