Inclusion Criteria:

          -  Diagnosis of multiple myeloma (IMWG criteria)

          -  Measurable disease, as defined by at least 1 of the following

               1. Serum myeloma (M) protein ≥0.5 g/dL (5 g/L)

               2. Urine M protein ≥200 mg/24 h

               3. Serum free light chain (FLC) >100 mg/L (10 mg/dL) with abnormal kappa:lambda
                  ratio

          -  Participants must have progressed on or been intolerant of at least 3 prior therapies
             including proteasome inhibitor, IMID drug and anti-CD38 antibody, either in
             combination or as a single agent

          -  ECOG PS 0, 1 or 2. PS 3 is permitted if PS is due solely to bone pain

          -  Adequate bone marrow, hematological, kidney and liver function

          -  Resolved acute effects of any prior therapy to baseline severity or CTCAE Grade 1

          -  Not pregnant and willing to use contraception

        Exclusion Criteria:

          -  POEMS syndrome

          -  Any other active malignancy within 3 years prior to enrollment, except for adequately
             treated basal cell or squamous cell skin cancer, or carcinoma in situ

          -  History of active autoimmune disorders

          -  Any form of primary immunodeficiency

          -  History of severe immune-mediated adverse event with prior immunomodulatory treatment

          -  Stem cell transplant within 12 weeks prior to enrollment

          -  Active graft versus host disease other than Grade 1 skin involvement, or that
             requiring immunosuppressive treatment

          -  Requirement for systemic immune suppressive medication

          -  Active, uncontrolled bacterial, fungal, or viral infection, including HBV, HCV, known
             HIV or AIDS related illness and SARS-CoV2

          -  Previous administration with an investigational drug within 4 weeks or 5 half-lives
             preceding the first dose of study intervention used in this study (whichever is
             longer)

          -  Known or suspected hypersensitivity to component of elranatamab (PF-06863135), murine
             and bovine products

          -  Live attenuated vaccine within 4 weeks